CONTRIBUTIONS FROM THE ZOOLOGICAL LABORATORY OF THE MUSEUM OF COMPARATIVE ZOOLOGY AT 
HARVARD COLLEGE, NO. 234 © 
THE NUMERICAL RELATIONS OF THE HISTOLOGICAL 
ELEMENTS IN THE RETINA OF NECTURUS 
MACULOSUS (RAF.) 
SAMUEL C: PALMER 
TWELVE FIGURES 
CONTENTS 
I WiehewlWOMONNG suas odsncgeom our DA ay bitte df oecice tae Arle SRR oes Pao oe 405 
MR EMIS DO nie al TEMICW. 5 onc cre ete ehae lc tigs Ae oh oaetnly De be Oe LE ee ee 407 
ACPBEVG GIN as creas a fils ok yn Red Pesca dare Aik, ceaps fan eke nee 407 
BS BO) ag CHET Ve ree oop 5 ee hele dans Stee a ta Oa pane Oe a 411 
IRS VWiaterializancdietechmrgueiscs.cccs ast) o> cic bococento sclera e cesta opts ae 412 
JN, IIE NAOT gee Sen, Dei on Rg ek eso ee ORME gh rey ear A LU Nd A VK 412 
ES Peaie CLM Sere Aria ske tis ene bin al cae ae AUS oe eee 413 
IW 2  OLOSVeS AGEN KON IRS co na Goat Oe eae een Sr A RE SE se ee A ds FON ae 417 
JANES IMIR DIRS COSI CUS ame ie ERE re eR ETO oie PEON Sk Oe Ca ab ee anes 417 
Dee Retin ewlayens eid stew thepeats see Oee aee teee e e e ee 417 
In > Cross-sections' of the Optic nerve. 4.068 ete aon 2a ee eee 419 
a MUnIGEAtODSes ces oe. oie ae 8S RE aI SAS DES Le eee 420 
oe Visita Cell Sie. hos ate Mg, ashlee parle gee tt oie Orie Aiea SEN al oe 420 
be Outermuclear layer sco v5) teh ate «eyes Sees ew chorea: 423 
ce: Ganglionievlayers 20.55 jie oA nS anne ee te eng tek eee 424 
di Millers: fibers 3 2h 61s AT age i ats hee te ed 425 
é: Linmer- nuclear layer s)2 ty. cs eee rad oe tet Geese ok: 427 
£- OptiG NEF Ve TIDELS . jcaieniac0 kee mae eee ee bre eae eee eke me 429 
WEMIDTSCUSSIONG stu creeee ln sehen Ane ea OE oct ee the eee 431 
Wile eonretical: CONSID EEA TIONS! Os.4 <4.c1/0 4.15 cree a ee ee sete ee ba eee 436 
WN OSOTITEIOL) gy 2) ns | ce ned ere Be A lh 5 Mess ie at oe a 0 Se 438 
“CIPULS eho a ese | ce eR RIE Re DR er od Se ake Ne | Mme is 2 439 
I. INTRODUCTION 
Although the vertebrate eye has long attracted the attention 
of investigators and has been the subject of numerous researches, 
few attempts to enumerate the histological elements of the retina 
and of the optic nerve have been made. The exceedingly deli- 
cate nature of the retina has always been a serious difficulty 
in the way of its histological study, but with the introduction 
405 
THE JOURNAL OF COMPARATIVE NEUROLOGY, VOL. 22, NO. 5 
OCTOBER, 1912 
