THE

AMERICAN NATURALIST

AN ILLUSTRATED MAGAZINE

OF

NATURAL HISTORY

EDITED BY ROBERT PAYNE BIGELOW

With the assistance of an Editorial Board and the following Associate Editors.

J. A. ALLEN E. A. ANDREWS W. S. BAYLEY

C. E. BEECHER D. H. CAMPBELL J. H. COMSTOCK

W. M. Davis D, S. JORDA A. KOFOID

C. PALACHE D. P. PENHALLOW M RICHARDS

W. E. RITTER F. RUSSELL . C. RUSSELL

E. F. SMITH L. STEJNEGER W. TRELEASE S. WATASE

VOLUME XOX AI

BOSTON GINN & COMPANY The Atheneum Press 1898

INDES.

PAGE

ABORIGINES of Queensland . ee Advance of oe in T: . 867 African lake fau - 526 gas - 147

Aga: Lou

A ar ati bot any

Alaska, zoological knowledge of Eskim

Algæ, de Toni s sylloge algarum caer Algæ, preservation of . . $32 Allen, J. A. Pocket mouse in con-

me - 58 Amphioxus, eyes o - 447 Angiosperms, primitive . i12 Annelids of Pacific Coast 35 Ants, psychical t iers of . 439 Apogamy in ferns 532 Aquarium plan 962 Arbacia, case o Gon H. 5 P EN and nucleus of £ Big:

nonia .

a ` 369 Arape, “have all a basidi-

omycetous stage a Astasia, development oF 287 Atkinson, oe _Mycelia and

fungi fro - 98 Azores, bia pian S in. 128 BACILLUS, COR tie otoi . 287 Bacteria, sulp 456 Bangs, O Mammals of Labrador 489

Beal, W. J. Some unique

ples os dispersion of nation san mee frui : Bees, pais of a hive of Bees, ay Sree qualities of . Bessey, C. A e ag As CN ckets

pe 439

as thermom Bessey, C: E "Foot: hill vegeta tion of Nebraska w E Lifehistories of kes

ical stations in Ameri rica

Panes Islands : 86 Blepharoplasts and c aei . 100 Boston basin, rocks - 534 Botanical ea 212, 294, 371, 884, 962 Botany at Gene 61 Brassempoi, finds at in 1896 .

. 586

PAGE Brown rot of cabbage. . . . 99 Brown rot of Crucifera + 290

ryozoa, development o + « 205 Bud Bee ap wee 26 Bum

yak Si Identification of fish prea hatche Bunting, as Cork tissue in i roots of Rosaceze Bureau of ‘erhinblégy report

- 407

52 Seg A erie. prehistoric, in Maine 877 Have all Asc viet gic a aa ei ertog 98 CABBAGE, brown rot of 99 r E E ee TOF California, eruptive rocks «6330 California, rocks of - 614, 967 Campbell, D. H. Botanical as- pects of Jamaic ae Campbell, D. T'S mor- phology of the Marattiaceæ . . 597 Campbell, D. H. Go "a —— ographie der Pfi - 606 Canadian botany É x 461 ase, E. gnificance of changes in the < ever of primitive Reptil Caulerpa, mia of the genus 959 Cell, and ble a. plast Cell lineage a ea i P Cell or corpusélées: o. ccu 4 Gas B48 Cell, plant, new organs 102 entrosomes and blepharoplasts . 100 Centrosomes, origin of 280 Cetacea, stom OF + 449 pipaeag development . 794 Cheese, ing o: 457 Cheirostr 3

robes . 46 Chelonian carapace and plastron, orphology of

Sra analysis of the plankton, 952

irre cal changes in ?

. 334 Chilopods, development : . B8r Chriacide and primates . 261

Claspers of elasmobranchs ; - Sor Cleavage omaha origin of . 280 Clinohedri Sag ie T. D. A. _ Development

of Man - 513

iv INDEX.

PAGE Color vision we Comstock, J. A and Needhash. J a SoM wings insects 231, 335) 413, 561, = 903 Sgt. bibliographicum . 876, 92 5

Conopholis

Cork tissue in Ro set Crickets as thermometers . - 263 Cr on dissimilar oo aa 355 Crucifera, brown rot of . <5 200 Cruciferæ; floral plan or. es 363

Cryptogams of the River Elbe . . 962 Crystal an ‘er e538

Cuba, flora of gee | Suits Manasseh, etch o. 75 Cyclostome, : > | soe Pietera Pupi a a a G

DaIsy, variationin ... . S9 Date, albamen of 2 Davenport, C. B. The advance of 189

G.C. Aga k n the embryology of the turtle 187 Dermochelys, systematic position . 929 Determination of sex in plants. . 124 De Toni’s sylloge

- 961

Seong min of chilopods ~ 881 tiond, geresis of = . - - - 6fo TEE skull of . ooa y y

Dig estion in pitcher plan ts n

Dinichthyds, osteolo oe 47 dei of seeds and fruits . . 859 Drosera, buds o a so II4 Dine. ar, R Archesporium and nucleus of Bignonia 7 EARLE, Ea The Chriacidze™ | prima ooo Nour on n fossil mammals ae ope Earth worm, regeneration of head 460 Eastman, C. R. Agassiz’s work o fossil fishes . 177 Dentition i _Ptyctodonts, Ary 545 N points in dinichth osteology Editor-in-chief - 949 Editorials : “The aim of the American Naturalist 49 Artificial ss asm - 949 Card bibliographies . - 518 ographicum . 876

pega biblio Diagnostic characters of birds 430 : 949

-chiel. 3: An editor found . . . : . 949 Fiftiet

of American Association . . 515

Editorials : The fur-seal problem . . . 199 Georg Bau

<7 Marine biological ‘station for - 783 120 519 2

Need of 3 an Anei tke

85 new iological 3 journ nal. ; . i18 et = rk State College of -8

Can Saveliens techn nique Methods in systematic work . scientific sser oint-

try Plea for r systematic zoology As an

: madd Scientific 11g Society for "Plant Morphology 121 Uniform system of cranio;

266

A ae of ‘extermination 429 Zoology in Japan. . < 3 450 Madnaenel daie sien SO Epiphyllous flowers. : =- 370 Eskimo, graphic art of 3 ; 3

Etiolated leav

Europe, fresh-water fauna of, 789, 793

Europe, r 203

Deane a a halfcentury of. . 623

Eyes of Amphiox + 447

FARLow, W. G. aap of species sf affected by in Saas

tion ungi . - 075 Fauni, fresh-water, of Ceylon 5 OOO

Fauna of France 594, 957 Faunas = Europe and America ted .

oS » 525 erns E Nicata agua = 210 Field. G W. Methods in plank- tonology . 735 Field, e H. Work of the Con- cilium Bibliographi - 925 Filose pears in eatin eggs . 878 Fins of fishe 524 ae identification of artificially tched . es F om port ach . se QO Fishes, mating of viviparous 305 Fishes to New England - 958 Fishes ot New Yo i oe < 209 Fishes of the Canary Islands . . 881 shes, paired finsof . . . : . 524 Flies of New Men es ee Flora of Pleistocene . 296 Florida, mammals o; 433 rai vegetation : - 602 Fluid for preservin

ga 532 Forestry, New York Scie College of . Fouilles à Brassempouy .

INDEX. Vv

PAGE Frog biography . . - : 436 Fruits, ripening of . E ae 207 Funafutti, Eoy of 586 Fungi, edible ig re N OOS Fungi from a coal m a ress Fungi of Netherlands. Sadia Fusion of pup uer 879 as APAGOS, birds A 3986 anoids, dain of Eor Ganon igi ga e of Cuab i N OY Gar 13 anam m, » phi m in IIO Generic. characters 218 Gentian, erine of 265 Geological changes ane roS. 623 Gemman under geer sical con-

diti ie Gerould, J HA viviparous Ho- lothur Gneiss o ara Anglesey, England ; Gneisses, Adirondack . : 7 Granite: nodular ss - 614 tolites

< 892 © 534

Grasses, Lodicu les of Gratacap, L. P. Delon ‘of James Hall to American geology . 891 Grave, C Psychical qualities of ants and bees . » 439 Grout, A. J. Adventitious buds i in x . $14 Growth, réle of water i in . £22 HATIR, distribution of . - 447 Hall, James, his relation to Ameri-

can geology Hardness of minerals 377 Harper, R. A. Spore imation i in rangia 10 Harshberger, J. W. ater stor: age and conduction in Senecio . 108

Hawaiian Islands, eid and sir 537 Hawks, alternation of sex in a brood of . te Hay, O. P. Classification of amioid ie lepidosteoid fishes . 341 On ostega, the systematic nae ye Dermochelys and

rapace an oooO Head, segmen ` 58; Helix nemoralis, variation of . . 913

i piy and hybridization + ~ 10%

Heredity, variation versus . . 821

rian, viviparous . . > «» 272

cree WR ko eaaa BS Hovey, E. O. Notes on some

_ European museums . 69 owe, J. L. tion in the shell of Helix nemoralis in the

GE Humphrey, J. E. Manasseh Cutler pe ppt oan gee acid, animals and

plants . 104 Fma budding i in 526 IGNEOUS oe classification of . 465 Indian cere ials 432 Indians, Kwakiutl es A In nfusoria, classification of eee Insect wings, 42, 81, 231, 335 413,

561, 768, 903 Iron woods, East India Nees T Irritability in climbing plants 530 Italy, basic rocks of . . eT eee JAMAICA, botanical aspects of . . 34 Johns Hopkins, zoology at . 128 Jordan, D. S. Agassiz on recent fishes sees pepsin E F. C. Activity of hive © Kofoid, Cc. A. ` Fresh- water bio- PEN eats" of Am - 391 -e nt faunistic R. in e 789, 793 Kramer s disease of ‘sugar beets 4.299 Kwakiutl Indian 35

Labrador, mammals of . 489 Lakes classified by temperature WA Lefevre, oa Origin. of. cleavage

centroso 280 Leguminoseæ, root tubercles of 365 Lemnacea = aN th America . 59 Lepidophlo 2 ae Lepidos Ss pte ges Eeucting ten “Montana - 466 Life zones -= thay zones 884 Fose A in ae Low raoi botany OF =: 60t FO F. C. Variations in the dais à 509

Maa M. A Mycorhiza in the of Philesia . E o) Mact te aks ae Ser iw. G6 Mammals of Florida . . . 433 mals of Labrador 489 Mammalia, es aa . 309 Mantis, development of ne! M: i , morphology of . 597

| Maya territory, human remains E a ee Mendota, plankton of . 3 a n a, filose activity . 878 Meteo <n icc. opin joke of 534 Millepora . as S27 Mineralogy, Dana’s text-book 965

Minerals, catalogue of . oo 379

vi INDEX.

pb ena hace and symmetry of bri

Minerals, hardness o 7 ker development BE oe es Mounds in Lo Murdock, Kiima known to

the aeg” s Alaska - 719 Muse rope, notes on. . 697

f Mushrooms, Sira upon . Mycorhiza in the roots of Philesia 97 Mydaidz of New Mexico - 448

NATURAL Scienc - 949 Nebraska, vegetation of foothills. III Nerve cells, fine - 361

6 erve termin si - 590 Netherlands, fungi of 462 ea Mexico, 4

of - 4 w York State College of For- . 8

estry ret doen ferns ‘ob. 2 Nickerson, W. S. Morphology of of Does ales : Nomenclature in horticulture Noxious animals, w T 7I Nutting, C. C. seca of Plu-

ergi ridæ pen eae Uani, new “hardy oe

ODONTOID process i ; go seta life- histories aE Os Origin of the i + 309 Osborn, H. L. "Variatio | in ‘Are MEMES ce ee as 3 reer a half-century of evolu- with reference to the effects of cobtcigionl changes : 623 —— Philos sss mae views of Agas- ? I Se ours Sa. Sees oes Paleozoic of Poland 2 Pammel, L. Brown rot of nae era Morpho logy ‘and dev Di g ment of Astasia and Bacillus . 287 a ology, a new journal of. . 800 Patten, W. A is for a theory

of alee vision ~ 8 Peirce, G. J. Living plants and their propert i Pfeffer’s Pilanzen h siolo e 450 Phloém in Gelsemium af ie Ho Phytoplankton, | studies i Alternating dry-

ess and moistur re and e mma- Suge se 106

.

mber ? Picker acne digestion in : = 2t Plankton, chemical a analysis of. Plankton methods .

PAGE Plankton methods in pe 789, 793 Plankton of Lake me

Plankton of Puget Sok on Plankton studies . 125 KAREE flora . ; 296 Plu > sarcostyles er. eee Pocket mo onfinement . . 583

land, leoia A Sa o Pollination of Ge 265 zoa, development o 205 Porphyries of Lake Champlain 534 Potamogeton, emaren of 109 Pronephros of cyclosto 526 Proprietary rights in por ae 133 Protoplasm, artificial < O40 Protoplasm, studieson . . . x 271 Protoste + 929 Psychical qualities of of ants ‘and bees 439 Ptyctodon . 473» 545 amas variation ii: 779 Pupe, . 878 Paos, systematic position . 958

QUEENSLAND, Aborigines of . . 269

Races of Euro Pe peo 205 Ranunculus, life- history of Regeneration in tubulari 123 Regeneration ae arthworm's head 369 Re egressive evo

Regulation in ea of organisms 12 3 oe skull of primitive . 69 Reviews :

Rasa! s Faune de a 594,95 7 Allgemeine Erdkun Andrews’s The liring Sub-

s 2

n Annuaire du Jardin Botanique

de : Archiv ads Pirani itol logie ; 3 900 ithe; s Vegetable Physiology 292

Bailey’s Garden Makin 54 Bailey’s Lessons wit nts . 284 Birge’s Plankton of Mendota 282 Britt d Brown’s Flora 02 Bureau of Ethnology, 16th Re-

e Sa Butler’ ’s Birds of Indiana 880

Carrière’s Development of the all-Be ee. - 794 Clark’s Laboratory Manual of

Clasen’s Rabbit Anatomy . Combs’s Cuban Plants. . . 369 Cope’s Lectures on Verte-

ra i BET ae ara Credner’s Elemente der Geo- ogie Crick’s Fossil Cephalopods in in eum . SII

the British s Dana’s Text-Book of Geology 375

INDEX. vil Review PAGE | Reviews: PAGE Dais Text-Book of Miner- Walker’s ang ta of the - 965 higan . . 956 ee. sand “Moor’s Plant Weber-Van eae Monogra- Physiology . 804 phie des Caulerpes 5 De Toni’s Sylloge Algarum . 961 d’s ks on Insects 58, 59 Miss Eastwood’s Stu 130 Wisconsin Geological d Fairhurst’s Cigale Evoladon atural History Survey 883 Considered a DIO Wocke’s Alpen-Pflanzen 2 Fernald’s Pterophori ridæ „5906. | Rhoads, S. N: OF Frank’s Agricultural Botany . 883 “beneficial” ? false poa in Fuch’s Determinative Miner- zoolog e Ryg alog EY Rhodolite, a ; new gamet 7 - 613 ore Organographie der Ripening of chee ere hs . 606 | Ripening z Sechy fruits... 209

Handlivech’ s Phymatidæ ; Hann’s Klimatologie Harris’s Australasian Tertiary

Mollu 34 n Cheeks List of Plants 459 enry’s Feeds and Feeding History of the Smithsonian nstitution . 200 Hookers F lora of British nes à 130

Indian any - aul he Ai s eA of the Cat . 520 Lange’s Handbook of Nature

Lapparent „Leçons ‘de Geo- graphie Physique

wre ee s debetis Rocks of Calif 13

Low’s tana: als of Labrador 489

Monkeme ae Sumpf- und

Wasserpflanzen . 962 T mah Botanical ‘Studies . 805 prsia Botanical Garden

ort 28 Oxford Herbari 61

Packard’s Takk Book of Ento- molo;

Parker and Haswell’s Zoology 787 Pfeffer’s E OPE 450 a s Archiv

Pittonia peti Porter’ s Translation of the

Bonn” Bot

Proceatiabs of “the Indiana Academy of Scien 2 poy seedy Darwin sae after

[e] N

- 273 Scherer’ s ; Vegetation der Elbe 962 Scudder’s Melanopli . - 59 Shimek’s Ferns of Nicaragua 210

_Shufeldt’s oo on Natu- ral Hi to 278

uess’s La Face de la Terre . 63 gel Pot compe Geo inte « 363

nf Th mpson’s Le 59 Urbina’s Catalogue or Mexi- can Plan - 605

Sex Shufeldt, R. W.

Rockery plants . 962 n associated with | iron ores in

Switzerland . 812 Ro ks, ‘basic, in Italy . Ro

: . SII I , 465, 613 Racks. eruptive of C alifornia

230 Ro a omenclature of contact . 814

a S Ay n °

asin

Roc ks of California . . 614, 967

Rocks of Castle mountain, Montana 1 37

ie ee of Ee, Re . 365 = W. Lodicules of

pe I

Ruedemann, R. Studies of grapto- ites

promes E Fouilles à Brassem-

. 586

= Ethnology of Funafutt 1. oe ds of Sata Pe Tani of 203

—— The import er the totem é i 54

SALPA, anatomy of . - 524 Sargent, F. pa Lange’ s handbook

of eak tud : c Fes Scale city goe plants of Schists of Switzerland Schiveley, A. Tek production in in

Amphicar ary oe news, 64, 140, 214, 299,

. ari 81

, 80, 469, 540, 617, my 886, E Sea o Seedlings, vari y Segm £ vertebrate head « 587 Sentate pana of dioctyledons . . 132

, determination of in plants i t24 Alternation of

=~ ina dg of 567

s 9

Sim Skull os sept tiles ece 09 Skulls of Hawaiian Isl: ander me Smith, E. F. Bacterial Eroe ro ot

of cabba

ages À —— Bailey’s lessons with plants . 284 First meeting of the wt oa & of Plant Morphology an and Phys

ology .

Vill INDEX. PAGE PA Smith, E. F. Kramer’s disease of VARIATION in ambulacral smem sugar beet of Arbacia 259 -—- Pinsent of c - 457 | Variation in Puccinia . 779 Root event of Legumi- Variation in seedlings . 952 nose . - 365 Variation in the : 509 hu ur bacteria . . 45060 | Variation of Helix ; 713 Snakes, life-histori 17 | Variation versus heredity 821 Society for plant morphology > 96 | Vertebrate head, segmentation of 587 Sonoran flora 5 om 88 Volcanics of Michigan 952 Special cre 878 sn conception of 675 | Warp, H. B. Archives de Para- Spenc 463 pico ; . 80 Snowe formation i in some Sporangia IOI arren, J. A. V ariations i in the Squawro 108 teleutospores of Puccin - 779 Sterki, v: "Classification of Ciliate Water in bead 122 nfus Skoi fs « $35 Stimulation of- plants and ‘chemical Webb, R. J. Pollination of genti an 265 chan a 354 | Webber ,H.J. Are blepha eae Sto ech movements 524 | distinct from centrosomes 100 Stomach o 590 | Whales, nomer nE 449 Sugar pea pTi of 99 | Wheeler velopment of ugar ae ues eles oa the ts one (Chalicode ma) . 94 Salor Dab 456 | Whipple, G. C. Classification of Sunstroke aint: haton «$33 lakes according to temperature. 25 Swing’ Here redity, o rigin Wiegan . M. Embryology of of and Sriep a 16 Po otamogeto eton _ 109 Two new o: ko of the pen Wilder, B. G. Agassiz at Penikese 189 - . 102 | Williams, H. S. Variation versus Swiss schis . 81 heredit 21 Switzerland rocks associated with Wilson, L. L. American squaw- iron o root (Cono holis o8 Wings of insects, 42, ŝi, 231, 335, AATDOIDS, fossil of France II5 43 sér, zo 903 mporal region of rE skull. 69 | Wisconsin, Forest o . 603 Fodmales of brain Wisconsin - 883 hompson, C. Phloëm in gel- olpi, rT at winter solstice 432 siiig 110 oods, A. T. Variable reactio mport of To S of plants and Meie to hydr = ; Trematodes, morphology of - 954 | -~ cyanic acid . 104 Trotting horse 55 | Wright, A. A. Agassiz: and the Tubereeaon roots of Leguminoseæ Di ice age - 164 Tumors and germ layers zy Tunai flora of . 461 UNIONIDÆ of Michigan . . 956 | ZooLocy at Johns Hopkins 128

# VOL. XXXII, NO. 373 4) JANUARY, 1898

THE AMERICAN NATURALIST

A MONTHLY JOURNAL DEVOTED TO THE NATURAL SCIENCES IN THEIR WIDEST SENSE

CONTENTS

I. Synopsis of Recent Progress in the Study of Graptolites . Dr. R. RUEDEMANN II. Contributions on the Life Histories of Certain Snakes . GEORGE E. BEYER III. Classification of Lakes according to Temperature . . GEORGE C. WHIPPLE IV. Botanical Aspects of Jamaica . . . DOUGLAS HOUGHTON CAMPBELL V. The Wings of Insects. I. . . . J H. COMSTOCK and J. G. NEEDHAM VI. Editorial: The Aim of the American Naturalist ; VIL Reviews of Recent Literature: Anthropology, Report ofthe ie of Ethnology, The Import of the Totem: by Frank Russell General Biology, A Studyin Heredity Zoology, Weed’s Life Histories of American Insects, Weed’s Stories of Insect Life: by J. H. C. Botany, North American Lemnacez: by The Oxford Herbarium, Botany at Geneva: by T.— -a Geography, Recent Works VIII. Scientific News

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WITH THE ASSISTANCE OF AN EDITORIAL Sora AND THE FOLLOWING ASSOCIATE EDITORS : E. A. ANDREWS, PH.D., Johns Fraa = Baltimore. G. BAUR, PH.D., University of Chicag WILLIAM S. BAYLEY, Pu.D., Colty eid Waterville. CHARLES E. BEECHER, PH ie Yale University, New Haven. DOUGLAS H. CAMPBELL, PH.D., Leland Stanjord Junior University, Cal. J. H. COMSTOCK, S.B., Cornell University, It Lthac Agere M. DAVIS, M.E. Harvard Univ, Berii, Cam . S: JORDAN, LL.D., Leland Stanford Junior Cniversiy, Cali ifornia. c PALACHE, PH.D., Harvard University, Cambridge. D. P. PENHALLOW, S.B., F.R.M.S., McGill University, Montreal. H. M. RICHARDS, $. D., Columbia University, New York. W. E. RITTER, P#.D., Unioerely sides beste rkeley. FRANK RUSSELL, A A.B., rvard University, Cambridge. ERWIN F. SMITH, S.D., ws amen of REA Washington. W. TRELEASE, S.D, Miss souri ee —— St. Lou S. WATASE, PH.D., University of Chic

THE AMERICAN NATURALIST is an illustrated monthly magazine of Natural History, and will aim to present to its readers the leading facts and discoveries in Anthro pology, General Biology, Zoology, Botany, Paleontology, Geology and Physical Geography, and Mine- ralogy and Petrography. The contents each month will consist of leading original articles containing accounts ane discussions of new discoveries, reports of scientific expeditions, biographical notices of distinguished naturalists, or critical summaries of progress in some line; and in addition to these there will be briefer articles on various points of interest, editorial comments on scientific questions of the day, critical reviews of recent literature, and a final department for scientific news and personal notices.

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AMERICAN NATURA ISS

VoL. XXXII. January, 1898. NO. 373-

II NOPSIS OF RECENT PROGRESS IN. THE SIUDY OF GRAPTOLITES.

Dr. R. RUEDEMANN.

THE graptolites have been a puzzling group of fossils to palzontologists ever since they were discovered. Though on account of their excessive abundance in certain strata, the beauty and variety of their delicate forms, and the strange mode of their vertical and horizontal distribution they have always received a full share of attention, the knowledge of their mor- phology has made only little progress, owing to their preserva- tion as completely flattened carbonaceous films. As a result of this incomplete knowledge of their structure, the systematic conscience of palzeontologists acquiesced in their being assigned to the Hydrozoa, in spite of the difficulty arising from the formerly commonly accepted presence of the virgula or solid rod in the rhabdosome and the supposed floating habit of the graptolites. The fact that they were found to furnish excellent data for the detailed division into zones of the Cambrian, Ordovician, and Silurian strata prevented their neglect, although so refractory to all attempts at close morphologic investigation, and the search for them in the field never relaxed. The grati-

2 THE AMERICAN NATURALIST. [VOL. XXXII.

fying result of this persistency is that at last material has been found which is accessible to modern refined preparative methods and to microscopic analysis.

Giimbel (78) was the first to isolate stipes imbedded in lime- stone. Later Tornquist (90, '92) obtained much valuable infor- mation by grinding pyritized material. The best results, however, have been obtained by the methods employed lately by Holm (90,'95) and Wiman (93,’95). For the details of these preparative methods, the reader is referred to Wiman’s interesting account in his paper, Ueber die Graptoliten ('95), the review (96) of his work in the American Geologist, and to Wiman’s Structure of the Graptolites’’ (96).

Both Holm and Wiman isolated stipes by dissolving the matrix. Various acids have been used for dissolving, according to the nature of the rock. Limestone material was found the simplest to handle, and muriatic acid in different states of solution or milder solvents, such as acetic acid, gave good results. Espe- cially interesting to American readers is the description which Wiman gives of his treatment of highly aluminous clay slates, as these are almost the only graptolite-bearing rocks found here. Wiman subjected them to the successive action of acetic and hydrofluoric acids. J. M. Clarke handled similar material successfully with acids and caustic potash. These methods, however, fail with a matrix that does not contain a sufficient lime-content.to lose its consistence by the dissolution of the latter, and this appears to be the case with most of the Ameri- can graptolite-bearing rocks. Wiman had also occasion to isolate graptolites from chert-masses by successively subjecting the rock to a treatment with concentrated hydrofluoric acid and muriatic acid.

The isolated graptolites have been decolored both by Holm and Wiman in different ways. Wiman used first Schultze’s maceration medium, which is a solution of calcium chlorate in nitric acid, but later substituted for it eau de Javelle or potas- sium hypochlorite, because Schultze’s medium is often too harsh. The specimens were then cleared with chloroform or other clearing fluids and mounted in Canada balsam, or, where this method could not be used on account of the thickness of

No. 373-] THE STUDY OF GRAPTOLITES. 3

the periderm, the specimens were prepared for the microtome according to the methods used by zoologists.

By the application of these preparative methods histological and morphological discoveries have been made.

The histology of the graptolites has been especially advanced by the researches of Holm (90), Sollas (94), and Perner (94). The last two investigators demonstrated the presence of three different layers in the periderm of Monograptus; vzz., a stronger middle layer between two thinner ones. Wiman (95) verified Perner’s observations as to Monograptus priodon and discerned the two outer layers in Diplograptus. The middle layer in Diplograptus contains the growth-lines observed repeatedly before. The histology of the Retioloidea has been studied by the above-named geologists and by Tullberg (82) and Térnquist (90, 93). Holm found three layers; vzz., smooth epidermic and endermic layers, which inclose the latticed network of chiti- nous threads, from which this group derives its name.

In the Dendroidea Wiman ('95) observed the two outer layers.

` However interesting the discovery of the differentiation of

the periderm of the graptolites is, especially on account of its bearing on the question as to the zoological affinities of this group, it is surpassed in importance by the knowledge which has been obtained as to the morphology and development of the graptolites. In reviewing the progress made in these directions we will separately regard the Graptoloidea, Retioloidea, and Dendroidea.

As an understanding of the conformation of the rhabdosome rests with the knowledge of its growth from the sicula, it will be opportune to review first the fundamental results obtained by Wiman as to the growth of the initial part of the rhabdo- somes of Monograptus (93), Diplograptus ('93), and some other Graptoloidea. The sicula of these consists of a thin-walled “initial part,” which is prolonged into a process, the “virgula,” and of the apertural part,” which shows distinct growth-lines and a three-spined symmetrical aperture (Fig. 1, s). From the sicula sprouts a new individual, the first theca (Holm considers the apertural part of the sicula already as “first theca”’), which

4 THE AMERICAN NATURALIST. [Vov. XXXII.

in Monograptus lies alongside the sicula and grows at once in an opposite direction (Fig. 1, z). From this theca grows another. The continuation of this process and the arranging of the thecze in one series along the virgula produces the monoprionidian thabdosome of Monograptus. Also from the sicula of Diplo- graptus, as Tornquist (93) and Wiman found almost simultane- ously, there sprouts but one bud, and Diplograptus is, therefore, also monoprionidian. The first theca, however, grows at first towards the aperture of the sicula and then bends in the same

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———

4

In Figs. 1-8, s = initial part of sicula ; $1 = apertural part of sicula ; v= virgula; Z= theca. Fic. 1. Monograptus dubius Suess : sicula end from sicula side (Wiman). Fic. 2. Diplograptus sp.: sicula end from sicula side (Wiman). Fic. 3. The same : a later stage from anti-sicula side (Wiman). Fic. 4. Climacograptus kuckersianus Holm : sicula side (Wiman),

direction as the thecze in Monograptus (Figs. 2, 3). The theca are arranged in two series, thus producing the diprionidian aspect. The supposition that the diprionidian graptolites con- sist of two coalescing monoprionidian branches, the double virgula and the double longitudinal septum of the older descrip- tions, has thus been refuted; the observations of Tullberg, Tornquist, and Wiman prove that not even a single longitudinal septum is always present, and that, if one is present, it does not necessarily extend throughout the entire length of the rhabdo- some. Fig. 4, representing a rhabdosome of Climacograptus,

No.373-] | THE STUDY OF GRAPTOLITES. 5

demonstrates that a septum is formed, where the theca, instead of sprouting on the opposite side of the adjacent older thecze (¢1 ¢2), spring from the same side as the latter did (¢4 Z5).

Holm (95) obtained most valuable information on the internal structure and development of some other important genera of the Graptoloidea; vzz., of Didymograptus, Tetragraptus, and Phyllograptus. The most interesting result of his researches is the demonstration of the conformity in the first stages of development of the rhabdosomes in these genera and the Diplo- graptide. It is probable, therefore, that the earlier develop-

Fie. 5. E eae aint anti- BI side (Wiman).

Fic. 6 s Toérnquist : anti-sicula side (Holm).

Fic. 7. Tet: a pares Hall: from the proximal end, with the sicula turned upwards, showing the aperture of the sicula, left and right thecæ, and the thecz of

the

Fic. 8. Phyllograpius angustifolius Hal: me perm. mo with the sicula side turned upwards, showing in th Pres. ed pst of the sicula, on each side of this th f the lef

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ment of all Graptoloidea was the same, and that it consisted in the formation of only one bud on one side of the sicula.

Fig. 5 (from Wiman, '95) shows the initial part of a Dichograp- tid, and Fig. 6 (from Holm) of Didymograptus minutus. Both figures serve to illustrate the diverging growth of the first two thecæ, which produces the characteristic bifurcation of these forms. The repetition of this process (Fig. 7) in Tetragraptus leads to the formation of four branches. The same takes place in the development of Phyllograptus (Fig. 8), “only that the four branches are disposed near each other and form a single, cru- ciform, four-winged, longitudinal septum.”

The conformity of the rhabdosomes of all Gtaptoloides has been made probable by these investigations (the Leptograp-

6 THE AMERICAN NATURALIST. [Vou. XXXII.

tidæ and Dicranograptide have not yet been isolated). The morphology of the entire colonial stock, however, is, owing to the frequent occurrence of only detached rhabdosomes, still little known. Hall (65) first described stellate groups of Dicho- graptidz from Canada; Hermann (‘g5) such from Scandinavian rocks; Moberg ('93) published a description of a Monograptus with disk; and Gurley (96) figured a Climacograptus with a disk- like expansion of the virgula. Ruedemann (95, '97) discovered colonies of two species of Diplograptus in Utica shale which. have been deposited under such conditions of quietude as to retain not only all the chitinous appendages of the mature col- onies, but also the successive growth-stages of the compound colonies.

It appéars from the material that the rhabdosomes of Diplo- graptus formed umbrella-shaped colonies, consisting of rhabdo- somes of various length, which radiate from a central organ,

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O SSS ATOI EN

SOK PPPE,

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Fic. _9. Diplograptus Soliaceus Murch (D. ristis Hall): complete colony (Ruedemann). Fic. 10.— The same: a, Gonangium filled with sicule; 4, sicula developing into a stipe (Ruedemann).

the central disk (Fig. 9). The latter, in its turn, is connected with a larger organ, the basal cyst, that probably served to secure the stability of the colony in the ooze of its habitat. The central disk is surrounded by a cycle of vesicles which

No. 373-] THE STUDY OF GRAPTOLITES. 7

contain numerous siculz attached by their apical ends (Fig. 10). The writer compared these vesicles with the gonangia of the sertularians, considering the sicule as the original chitinous

Fics. 11-20. The same: devel t of lony (Ruedemann)

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coverings of the embryos. (Holm sees in the initial part of the siculz the covering of the zooid germ.) The development of the colony is as follows :

1. The sicula is provided with a basal appendage to which it is attached by means of a little round node (Fig. 11).

2. The node becomes a central disk and funicle. The sicula produces at first one theca, then a second, a third, etc., as demonstrated also by Térnquist and Wiman (Figs. 12, 13).

3. The budding of the thecæ along the lengthening hydro- caulus produces the primary rhabdosomes (Figs. 14, 15).

4. While the latter is formed, gonangia, usually as four small capsules, arise from the central disk. At last the latter mature and open. Many, or perhaps all, of the sicula remain con- nected to the parent colony (Figs. 16, 17).

5. These siculz grow out to rhabdosomes (Fig. 18).

8 THE AMERICAN NATURALIST. [VoL. XXXII.

6. After this first generation of rhabdosomes has reached a certain age a second generation of gonangia begins to grow (Fig. 19).

7. The siculæ formed in these develop into a new verticil of rhabdosomes.

The result of this mode of development is a colony which consists of different generations of rhabdosomes, recognizable by the different lengths of the latter (Fig. 20). An espe- cially remarkable feature of the colonies is the position of the sicula at the distal end of the rhabdosome in regard to the central disk. The explanation of this peculiar position of the sicula is found in the observation that the first theca turns away from the aperture of the sicula and grows towards the apical part of the latter, or towards the central disk, thus forc- ing the whole rhabdosome to grow backward, so to say, towards the center of the colony. Wiman’s figure of the initial part of the rhabdosome of Climacograptus and Gurley’s figure of a colony indicate a mode of growth similar to the one described, only that in Climacograptus the colony apparently consisted of only one (the primary?) rhabdosome, as perhaps all siculæ became detached and developed colonies of their own. Also in Mono- graptus the same mode of growth prevailed. In Phyllograptus the rhabdosome grows also in an opposite direction to the sicula, but no virgula has been found by Holm, and the mode of fixa- tion of the rhabdosome is still doubtful.

In the other genera of the Graptoloidea, however, it has been found that the first theca grows more or less in the direction of the sicula. As a result, the sicula remains near the central disk, at the proximal end of the rhabdosome, and the latter grows distally. In the Dichograptide the whole colony is formed by dichotomous branching from one sicula, which remains at the center of the colony.

With the two different directions of growth of the rhabdo- somes from the siculz the presence of a virgula as rod in the thabdosome is closely connected ; for, by the observations of Tullberg, Tornquist, and Holm, the fact has been established that only the Graptoloidea with inward-growing rhabdosomes (Diplograptide, Monograptus) have virgulz, while the others

No. 373. ] THE STUDY OF GRAPTOLITES:. 9

have none. The explanation of this is found in the observa- tion that the initial part of the sicula of probably all Grapto- loidea is prolonged into a process (the virgula of Wiman, the hydrocaulus of Ruedemann, the nema of Lapworth), and that this process in the inward-growing rhabdosomes becomes incorporated as virgula, while in the outward-growing rhabdo- somes it remains outside (the nemacaulus of Lapworth). The virgula was originally hollow. This is indicated by Wiman’s observations in Monograptus and by the growth of gonangia from the central disk in Diplograptus, which gives the hydro- caulus the character of a stolon.

The demonstration that the virgula or “solid axis” of the older authors is present only in a very restricted number of Graptoloidea is of great interest, as the presence of this organ has been considered as one of the principal characters of the graptolites and has even procured them the name ‘“ Rhabdo- phora.” The virgula, as identical with the hydrocaulus or nema of the sicula, is, in reality, present in probably all grap- tolites, for long filiform processes of the sicula have been observed in numerous genera (e.g., Mzeandrograptus, Didymo- graptus, Tetragraptus). Lapworth concludes from the presence of this process that all rhabdosomes were either fastened to a central disk, as in the Dichograptidze and Diplograptide, or directly by the nema to foreign bodies.

We cannot leave the Graptoloidea without mentioning the important investigations of Tullberg (82), Jækel (90), Perner (94), and Giirich ('93,'96) on the shape and position of the