NKBVOUa SYSTEM. VERTEBRATA. 



147 



have been restrained by the resistance of the cranium, and 

 they have extended chiefly in the lateral direction. This 

 lateral extension has been carried to an extreme degree in 

 the postero-ventral region of the neopallium, which has 

 grown downward and then mesially so as to produce a 

 peculiar bending of the pyriform lobe (fig. 39). 



Fig. 39. (Nat. size.) 



PONS 



In all ant-eating mammals the snout is prolonged to 

 form a long tubular structure which lodges the vermiform 

 tongue. This elongation of the skull may involve the 

 cranial cavity, and in that case the brain assumes an elon- 

 gated form in adaptation to the shape of its bony case. 

 The Great Anteater (Myrmecophaga, D. 282) and the Aard- 

 vark (Orycteropus, D. 288) afford instances of this. On the 

 other hand, the elongation may be restricted to the beak, 

 and the brain then becomes packed away, so to speak, in 

 a short cranial cavity lying entirely behind the maxillary 

 region. The brain of the Pangolin (Mam's, D. 287) and that 

 under consideration exemplify this type, in which the brain 

 develops in a cavity which restricts its antero-posterior 

 growth. The hemispheres thus expand chiefly in the lateral 

 direction, and the restriction to elongation expresses itself 

 in a series of transverse sulci, the disposition of which is 

 re-described in the account of the next specimen. 



The olfactory bulb is a large, flattened, foot-like mass 

 partly overlapped by the anterior pole of the hemispnere. 



L2 



