20 BULLETIN OF THE 



not anchylosed, and in the female considerably separated. Acetabula 

 opposite the posterior end of the second sacral vertebra. Ears provided 

 with a sub-cylindrical external conch. The skull has a well-developed 

 orbital process and an alisphcnoid canal ; the mastoid process is strong 

 and salient, distinct from the auditory bulla, -which is much smaller than 

 in the Phocidce. Molars either | ~ § or f ~ f ; canines, ^ ^; incisors, 

 f = | 5 whole number of teeth, fzzf = i|=:34, or J^ — J^=fg==36. 

 Testes scrotal, situated as in the Suidce. 



Rank and Affinities. ■*- The seals were all referred by the earlier 

 writers to the Linnasan genus Phoca. Buffon was the first naturalist 

 who recognized the division of the seals made by seamen into eared 

 seals and earless seals, accordingly as they possessed or were devoid of 

 external ears. Later Peron,* in 1816, regarded these two groups as 

 genera, and gave to the eared seals the name of Otaria, leaving the 

 earless seals in Phoca. Finally these two groups were regarded by 

 Brookes,f in 1828, as constituting two families, the walrus, in his 

 system, forming a third. 



These groups have been generally recognized as natural, but their 

 rank has been variously estimated by different authors. Turner { 

 regarded the eared seals, the earless seals, and the walrus as to- 

 gether constituting a single family, which he divided into three sub- 

 families, — Arctocephalina, embracing Otaria and Arctocephalus ; 

 Trichecina, embracing only the walrus; and Phocina, embracing all 

 the earless seals. Pie observes, however, in referring to the classifica- 

 tion of the Pinnipedia made by Gray in 1837, § that if the sub-families 

 of the Phocina, proposed by that author, be entitled to that rank, 

 " the walrus and the Arctocephaline group, which differ so decidedly 

 from the other seals, would almost seem entitled to the rank of families." 



All writers, except Brookes and Gervais, previous to 18GG, seem to 

 have regarded these three groups as constituting a single family. Gill, 

 however, in his Prodrome, || considered them as distinct families, which 

 view has since been adopted by Gray.H 



* Voy. Terr, aust., Vol. II, p. 37, 1816 

 t Cat. of his Anatom. and Zoiil. Mas., p 36, 1828. 

 J Proc. London Zool. Soc, p. 88, 1848. 

 § Charlesworth's Mag. Nat. Hist., Vol. I, p. 583. 



|| " Prodrome of a Monograph of the Pinnipedes," Proc. Essex Institute, Vol. V, 

 p. 7, .Inly, 1866. 



T Ann. and Mag. Nat. Hist., 3d Ser., Vol. XVIII, p. 229, 1866. 



