NERVOUS SYSTEM. VERTEBRATA. 117 



The optic lobes, which apparently occupied this space (for 

 no signs of them are visible in the Avian position upon the 

 lateral or ventral surface) were probably of some size, to 

 judge by the magnitude of the optic nerves. The cerebellum 

 was of considerable extent in transverse and dorso-ventral 

 directions, but whether it was also antero-posteriorly ex- 

 panded as in Crocodiles, Chelonians, and Birds, or a mere 

 transverse plate as in other Reptiles, it is difficult to say. 

 The form of the projecting lateral parts favours the latter 

 supposition. 



Andrews, Ann. Mag. Nat. Hist. ser. 6, vol. xix. 1897, 

 p. 585. 



EMYDOSAUKIA. 



D. 135. The head of a young Sharp-nosed Crocodile (Crocodilus 

 americanus) with the brain exposed from above. The 

 hemispheres form by far the largest part of the brain. 

 They are short and broad with a strongly arched dorsal 

 surface, and in general features much resemble those of a 

 Bird. Anteriorly they abruptly taper to form a pair of 

 long olfactory peduncles, by which they are connected with 

 two strong fusiform olfactory bulbs that lie side by side 

 close behind the nasal chamber on a level with the anterior 

 margin of the eyes. The optic lobes are moderately 

 developed, and lie upon the dorsal surface of the brain 

 between the hemispheres and the cerebellum. The cere- 

 bellum is very large for that of a Reptile and superficially 

 bears some resemblance to that of a low Shark, being 

 a smooth rounded protuberance above the anterior end of 

 the fourth ventricle and showing upon its surface a feeble 

 transverse furrow. 0. C. 1317 A. 



Rabl-Ruckhard, Zeits. wiss. Zool., Bd. xxx. 1878, p. 336. 



D. 136. " The brain of a Crocodile six feet long " *. This brain 

 measures only 40 mm. in length, and does v not equal 25 mm. 



* This, in all probability, is the Crocodile alluded to in the following 

 passage from a Hunterian MS. obtained from the executors of Sir Everard 

 Home, and entitled ' Modern History of the Absorbing System ' : 



" In the beginning of the winter 1764-5 I got a Crocodile which had been 

 in a show for several years in London before it died." 



