Eycleshymer-Davis, Epiphysis and Paraphysis in Amia. 6i 



ally ringing in the ears of the more ardent phylogenists will be 

 hailed with delight. 



Since the observations of Professor Locy are of such great 

 theoretical import it may not be out of place to review them 

 somewhat in detail. If we interpret correctly th " text and fig- 

 ures given by the author in his various articles, we might sum- 

 marize the evidence gathered from surface study as follows : 

 The accessory optic vesicles do not appear \\i all embryos. 

 Their number is far from constant (see Figs. 9 and 16, PI. 

 XXVI, Jour. Morph., Vol. XI, which represent embryos of the 

 same age). Their time of appearance is extremely variable, as 

 shown by Figs. 5, 6, 8, 9, 10. They may appear as unpaired 

 structures as well as paired, as shown in Figs. 5, 9, 10. 



The above facts taken collectively form an argument which 

 cannot be overlooked. They certainly indicate that one must 

 be extremely cautious in the interpretation of the so called 

 "accessory optic vesicles." 



It may be opportune to mention that while studying the 

 paired depressions in the above named Amphibia the senior au- 

 thor frequently noticed other depressions in both the neural 

 plate and folds ; since they appeared at different stages, and were 

 neither uniform in size or depth, nor constant in number or po- 

 sition, they were regarded as artifacts. 



In view of the uncertainty of the meaning of these de- 

 pressions, when based upon surface study alone, one naturally 

 seeks for further evidence in their histological structure. This 

 Professor Locy sums up in his final paper as follows: "My 

 sections are not favorable for a critical study of the histological 

 conditions, but it is clear, from them, that a differentiation 

 starts in the anterior patches similar to that mentioned above, 

 for the true eye vesicles. There is a greater frequency of 

 dividing cells and many of the cells become elongated and pear- 

 shaped. " 



If we turn to the description of the true eye vesicles, we 

 read: "Sections of the earHest-formed circular areas, show 

 something in the direction of histological differentiation. Mi- 

 toses are more frequent and more of the cells are elongated and 



