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JOHNS HOPKINS UNIVERSITY MORPHOLOGICAL MONOGRAPHS. 



the visual cells of Schewiakoff, then again we find nonconformity to a 

 spindle-shaped type, and nuclei not always at a lower level. The matter 

 of alternation of nuclei at different levels seems to me any way too slight 

 a distinction upon which to base a difference in function. It is a neces- 

 sary mechanical consequence of the crowding together of many cells on 

 one surface. And in many cases in perfectly radial sections through the 

 retina I find the nuclei fewer in number and arranged in very nearly a 

 single level. The retina of the smaller eye represented in Fig. 69 shows 

 this. In sections further along in the same series the nuclei are found 

 at different levels, due without doubt to the slanting cut. 



t'O 



[Dr. Conant did not complete Fig. 72, and the accompanying outline of Fig. 7 of 

 Schewiakoff' s memoir (Beitrage zur Kenntnis des Acalephenauges, Morph. Jahrb., 

 Bd. XV, H. 1) has been substituted. EDITOR.] 



EXPLANATION OF LETTERS IN TEXT FIGURE. C concretion cavity ; CO cornea ; 

 CP capsule of lens ; CSC cavity of sensory club ; EC ectoderm ; EN endoderm ; 

 ENC endoderm of sensory club ; L lens ; NC network cells ; NF nerve fibres ; 

 RT retina ; SLA supporting lamella ; VF vitreous body. 



Fig. 72 is a horizontal section through the large eye, and shows that 

 here, too, when the sections pass through the eye just radially, the 



