1922] Kellogg: Pinnipeds from Miocene and Pleistocene Deposits 87 



discussed a humerus of Apterodon macrognathus from the Upper 

 Eocene of Egypt which exhibits certain structural peculiarities that 

 are practically identical with some in Potamotherium. The fact that 

 certain limb bones of some of the hyaenodonts indicate that one or 

 two forms lived an aquatic or semi-aquatic life may throw additional 

 light upon the origin of this group. As pointed out before, the 

 solution of the ancestry of the Phocidae will necessarily remain an 

 uncertainty until we know the skull and dentition of the Miocene 

 Phocidae. 



MONACHINAE 



Considerable uncertainty exists as to whether or not the Monachinae 

 should be placed nearest the Phocinae or the Lobodoninae. On the 

 whole their relationships with the other members of the Phocidae are 

 rather confusing. The Upper Miocene members of the Monachinae, 

 referable to five species and probably all belonging to the same genus 

 Monotherium, had at that stage a range extending from the Antwerp 

 basin to the Mediterranean and Black seas. The most interesting- 

 member of the Monachinae is the Monotherium, gaudini, represented 

 by a well preserved skull and part of the mandibular ramus. Ugolini 

 examined the skull and pointed out that three upper incisor teeth 

 were present. This places its affinities more closely with the Phocinae 

 and breaks down one of the subfamily distinctions which was assumed 

 to be diagnostic. Allen, many years previously, had stated that Mono- 

 therium gaudini was the prototype of the Mediterranean Monachus. 



During the Pliocene, but one species, Paleophoca nystii, is known 

 from the Antwerp basin of Belgium. At this stage, the Scaldisian 

 seas covered the greater part of Holland, the Antwerp basin of 

 Belgium, and part of Germany, and extended over the counties of 

 Norfolk and Suffolk in England. Paleophoca was a larger and bulkier 

 form than Pristiphoca of the Mediterranean region, and may have 

 descended from Monotherium. The femur and humerus of Paleophoca 

 are considerably larger and of a rather different type than those of 

 Pristiphoca occitana. It is probable that Paleophoca died out at the 

 close of the Pliocene. The phocid from the Wadi Natrun in Egypt 

 is of a type allied to Pristiphoca rather than to Paleophoca. The 

 mandibular ramus is evidently of the long, slender type characteristic 

 of Pristiphoca, and not the larger, heavier type exhibited by Paleo- 

 phoca. The skull and mandibular ramus of Pristiphoca, so far as 

 known, agree very closely in many respects with those of the existing 

 genus Monachus. 



