650 



1)U. 0. W. ANUnEWS ON Till'; 



But the concavity is I'egular and the middle poi'tion of the lamb- 

 doidal crest is not suddenly reflected backwiuds as in Zeuglodon 

 oslris. The occipital condyles and foramen magnum are relatively 

 smaller than in Prozeuglodon, the occipital crest more developed, 

 and the convexity of the lateral cranial surface less marked. The 

 snout was more slender and more prolonged in front of the narial 

 opening than in Prozeuglodon. 



This skull, both in the form of its occipital surface and in other 

 points, closely resembles that described by Stromer as Zeuglodon 

 osiris [in his paper of 1908) and distinguished by him as Mn.9. 

 It is very different from that described by the same writer as 

 Zeuglodon osiris in 1903 and called in his later paper Mn.l. 

 This latter seems to be the true Zeuglodon osiris, its lower jaw 



Text-figure 23. 



portion - — 

 of tempore/. 



Psroccipita/ 

 process. 



Occipital concfy/e. 



Fcramen 



magnum. 



Occipital surface of skull of Zeuglodon intermedins, sp. n. M. 10173. 



About 5 nat. size. 



agreeing very closely with that of the type-specimen of the 

 species as described and figured by Dames (1894). Mn.9 is either 

 the present species {Zeuglodon intermedins) or a form between it 

 and Prozeuglodon. 



The skulls of Zeuglodon osiris from which endocranial casts 

 have been made are two in number. One (M. 8150) is very 

 incomplete and reveals only the dorsal contour of the brain. 

 Tlie endocranial cast of this skull was figured and described by 

 Prof. Elliot Smith (1903). The other skull (M. 10228) is a 

 nearly perfect sjiecimen, and in order that the endocranial cast 

 might be made it was skilfully cut into sections and the matrix 

 removed by Mr. L. E. Parsons (text-fig. 24). 



The occipital region of this skull agrees exactly with.Stromer's 



