278 DAVIDSON BLACK 



of Orycteropiis (v. Elliot Smith, 13, fig. 1) may well correspond 

 to grooves for the lodgement of a highly developed tractus bulbo- 

 tuberculare, and as such they have been labeled in figure 4. 



The small area corresponding to the locus perforatus anticus, 

 situated lateral to the chiasma ridge and between the protuber- 

 ance of the olfactory tubercle and that of the caudal end of the 

 pyriform lobe, is obscured on both sides by indistinct and irreg- 

 ular markings which are evidently of vascular origin. The pyri- 

 form lobes are large and prominent, and in shape and proportions 

 again recall the conditions obtaining among modern Edentates 

 in the highly macrosmatic brain of Orycteropus (vide 11 et infra) . 



In proportion to the size of the olfactory roots, the optic tracts 

 are small. The chiasma ridge is depressed and the optic nerves 

 at the point of their emergence from the endocranium do not 

 appear to be separated from one another by a bony lamina. 



As is usual among artiodactyls the foramen lacerum anterius 

 affords passage for both ophthalmic and maxillary divisions of 

 the trigeminus and the mandibular division of this nerve makes 

 its exit from the skull by way of the foramen ovale. In propor- 

 tion to the size of the cast these roots are very large. 



The pituitary fossa is represented by an elongated, oval, azygos 

 protuberance whose indistinct rostral boundary is indicated by 

 a shallow depression a short distance caudal of the chiasma ridge. 

 A sharply marked but shallow depression corresponding to the 

 posterior clinoid processes forms the caudal limit of this area. 



On each side between the pituitary protuberance and the ele- 

 vation corresponding to the ophthalmic-maxillary division of 

 nerve V, are narrow but well marked longitudinal ridges which 

 represent skull grooves for the lodgement of the small internal 

 carotid arteries. These arteries appear to enter the skull at the 

 rostral angle of the posterior lacerated foramen. 



Cerebral hemispheres. (Right, figs. 2 and 28.) On the right 

 lateral aspect of the cast the full extent of the exposed course of 

 the rhinal fissure is clearly indicated and the relatively large size 

 of the pyriform lobe at once becomes evident. Above the pro- 

 tuberance of the olfactory tubercle and on the lateral surface of 

 the pyriform lobe two irregular ridges are present corresponding 



