NERVOUS SYSTEM. VERTEBRATA. 



139 



within the scope of this account, but others may be appre- 

 ciated by the naked eye even in specimens so imperfect as 

 these. 



The elliptical olfactory bulb (figs. 34, 35, 36, and 37) 

 projects well beyond the anterior end of each cerebral hemi- 

 sphere, and appears to have a pointed anterior pole. This 

 is due to the fact that the true olfactory nerves are collected 

 into a compact bundle (compare specimen 1380 I [0. 0.]), 

 which is inserted into the anterior pole of the olfactory bulb 

 (fig. 35). Such an arrangement is commonly found among 



Fig. 34. (Nat. size.) 



2- CER.HEM. 



CEREBEL. 



OLF.BULB 



OLF TUBER 



PONS 



FLOC. 



Fig. 35. (Nat. size.) 



V.M. 



the Sauropsida and Ichthyopsida, and occurs nowhere else 

 in the Mammalia, not even in the Spiny Anteater. The 

 lateral wall of the olfactory bulb is peculiar in being deeply 

 invaginated so as to practically obliterate the olfactory 

 ventricle. On the left bulb, an oblique v furrow indicates 

 the situation of this invagination (fig. 34) . 



The pyriform lobe is seen upon the ventral surface of the 

 hemisphere (fig. 35) as a very narrow, sinuous band pro- 

 longed backward from the peduncle of the olfactory bulb. 

 In the separated hemisphere (fig. 36) its posterior extremity 



