56 



I have compared the excellent figure of Feitsch^) with the spe- 

 cimen from which my Fig. 2U was made, and note some difierences 

 as regards proportion of parts and other details. In my specimen, 

 the thalamencephalon is considerably shorter than in that drawn by 



? 



,oc 



oii- 



/ ' 



71. nov. 



trt. olf. 



n. opt. 



Fig. 20. Brain of adult Galeus canis, from above, nat. size. B, slightly enlarged 

 view of the roots of the new nerve in Mustelus canis. 



Fritsch, and the tractus is shorter than in his specimen. The olfac- 

 tory cups are not represented in his figure, and little attention has 

 been given to the shape, size and divisions of the bulbus. Details of 



1) I am aware of the confusion in the nomenclature of these two 

 forms. The Galeus canis, as identified at Naples, is not identical with 

 Mustelus canis of the E. coast of the U. S. 



