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University of California Publications in Geology [Vol.13 



been reduced in size, and gradually tilted forward and upended, until 

 now it no longer projects backward in any of the living Otariidae. 

 In coordination with the reduction of the occipital crest, the median 

 supraoccipital ridge has also become reduced. It persists as a feebly 

 developed ridge, but is, nevertheless, distinct in all cases. We find 

 that the same thing has taken place in the Odobenidae only carried 

 much further and accompanied by a crowding backward of the rostral 

 region as well. 



In this connection it is interesting to note that the view of the 

 skull given by True 79 indicates that the occipital crest of Pontolis 

 magnus agrees more closely with that of Eumetopias than that of 

 Alloelesmus. The same appears to be true of Desmatophoca oregon- 

 ensis, although Condon so stated: 1 



The development of the occipital crest cannot be determined with absolute 

 certainty as that part of the brain case has been damaged, but it would seem to 

 have been poorly developed, as that portion of the occipital bone directly above 

 the foramen magnum sloped forward at an angle of forty-five degrees, and there 

 is reason to believe the general shape of the occipital or lambdoidal crest pre- 

 sented that characteristic U-shaped form of Plwca rather than that of Otaria. 



From the measurements given by Condon, and also from his plates, 

 one is led to the conclusion that Desmatophoca resembled very closely 

 in size and appearance the existing Eumetopias jubata, although it 

 may have lacked an occipital crest, as stated by Condon. 



Desmatophoca oregonensis was a true otarid and not a connecting 

 link between the Otariidae and the Phocidae. This form possessed 

 postorbital processes, large canines, and a salient mastoid, but the 

 contour of the nasals resembles more closely that of the Phocidae. The 



dentition was : I ^ ; C i ; Pm % ; M ^ . This is the same as that of 

 2 1 ' 4 ' 1 



the genus Eumetopias. According to Condon, the outer upper incisors 

 (I-) are much larger than the two inner pairs (I 1 , I-) ; Pm 1 is single 

 rooted ; Pm= is two rooted ; Pm- has two roots, while Pm- has three 

 roots, with a main crown as well as an inner and a posterior cusp ; 

 yet M- has two roots. This description is rather doubtful for the 

 matrix as shown by Condon's photograph, has not been sufficiently 

 cleared away to allow one to determine whether they are three-rooted 

 or not. 



-•■> True, F. W., op. cit., pi. 22. 



so Condon, T., A new fossil pinniped from the Miocene of the Oregon coast. 

 Univ. Oregon Bull., vol. 3, suppl., p. 7. 1906. 



