314 Bulletin American Museum of Natural History. [Vol. XXVII, 



But whether Patriofelis was partly aquatic or not may after all throw 

 but little light on the origin of the Seals, because Patriofelis and O.rijoena 

 possess several characters which seem to debar them from near relationship 

 with that group. 



The Pinnipedia possess a large, wholly consolidated scapho-lunar-cen- 

 trale like that in the Fissipedia, whereas in the Oxysenidse these bones are 

 entirely separate. If the amphibious ancestors of the Pinnipeds had had 

 these elements separate it seems that atiuatic adaptation would have in- 

 creased the separation and flexibility of the carpals as it has in the Cetacea. 

 It must be confessed, however, that the consolidation of the scaphoid, 

 lunar and centrale in the Sirenia weakens the force of this argument. The 

 Oxyaenida? and the Pinnipedia differ radically in the dentition; in the former 

 the molars are larger than the i)remolars, whereas in the Pinnipedia the 

 premolars are relatively large and the molars are reduced or absent. In the 

 Oxysenida? the molars were of a peculiarly specialized sectorial character and 

 if the Piiinipedia had been derived from that family it is likely that some- 

 where in the group some traces of these characters would be found. In no 

 Pinniped do the cheek teeth retain the slightest resemblance to those of the 

 Oxyeenidse but the pattern of the postcanine lower teeth of Phoca gichigensis 

 Allen (1902) might readily be derived from those of the curious Amphicyonine 

 Canid Ci/)uircfus saxatilis INIatthew (1902, p. 281, fig. 1). The degenerate 

 and varied molars of the Pinnipedia range from a secondarily triconodont 

 to a secondarily haplodont condition (cf. Osborn, 1907, p. 144, fig. 103). 

 That a haplodont crown can be very quickly evolved out of a tritubercular 

 crown is indicated by the peg-like teeth of Proteles, whose nearest relatives 

 are the tritubercular Viverridfe. 



Genetic ReJafions tvith the Fissipedia. 



The derivation of the Pinnipedia from arctoid Fissiped Carnivora has 

 been supported by Weber, (1907, p. 551), who has shown that in spite of 

 markedly divergent habits, the Seals retain a number of very significant 

 characters in common with the Bears. The maxilloturbinals are greatly 

 enlarged and scroll-like and exclude the ethmoturbinals from the anterior 

 nares as in the " Hypomycteri " (Bears, Dogs, Mustelines) ; the long intestine 

 lacks a duodeno-jejunal flexure and lies in a simple mesentery, the kidneys 

 and liver are divided into a number of separate lobules; in the male Cowper's 

 glands are wanting and there is a large os penis. As in other Fissipedes, 

 the placenta is deciduous and zonary, the uterus bicornuate, the brain has * 

 four crescentic gyri which bend around the Sylvian fissure. The bvdla in 

 general appearance resembles the Arctoid rather than the ^F^luroid type. 



