MUSEUM OF COMPARATIVE ZOOLOGY. 23 



taneously, as the names of different sub-divisions of the group, but Arc- 

 tocephalina still embraced both hair and fur seals. Later still, the 

 same author restricted Otariina, so that it embraced but a single species, 

 while the other, also greatly restricted in its scope, embraced still both 

 hair and fur seals. In view of this confusion, the name Trichophocince* 

 is proposed for the hair seals, and Oulophocince | for the fur seals, in 

 allusion to the different character of the pelage in the two groups. 



Hitherto, owing to the fact that our beat classifications of them have 

 been based mainly on the number and position of the molar teeth, the 

 hair and fur seals have been associated pell-mell and in almost every 

 possible mode of combination. Formerly Arctocephulus was a hetero- 

 geneous association of members of two widely different natural groups. 

 Although of late the hair and fur seals have been usually placed in 

 different genera, the genera of the one set have variously alternated 

 in the systems of different authors, and in the different systems of the 

 same author, with those of the other set. 



Comparison of the Skeleton of the Otariad^e with those 

 of the Principal Types of the Phocid.e. 



The chief osteological differences which serve to distinguish the 

 eared seals from the other types of the Pinnipedes, as the common 

 Phoca, \ Cystophora, Monachus, Mucrorkinus, and Posmarus, § may be 

 indicated as follows : — 



Comparison of the Otariad.e (Eumetopias) with Rosmarus. — 

 The eared seals (of which Eumetopias is here taken as the type) differ 



* 0p<f = hair, and 4>u>xv = Phoca. 



•f ouAos = soft, <t>"\v = rhoca. 



t The materials mainly used in the following comparisons consist as follows: (1.) Of 

 the eared seals, two complete ligamentary adult male skeletons cf Eumelopias Stelleri, 

 and two adult male and two adult female complete ligamentary skeletons of Grflorkinus 

 ursinta. (2.) Of the earless seals, a complete adult male ligamentary skeleton of Phoca 

 vitvlina, and other partial skeletons of the same species; three complete ligamentary 

 skeletons of Cystophora cristata, and two nearly complete disarticulated male skeletons 

 of Macrorhinus elephantinus, besides partial skeletons of other species. (3.) Of the 

 walrus, two complete ligamentary skeletons. Cuvier's figures of the skeleton of the 

 "Phoque a ventre Wane " (Moimchus albiventer), Pander and D' Alton's of that of the 

 Otaria jubata, and Schelgel's of that of Zahphus Gilleepii, have also been examined. 



§ Trichechtts, as has been pointed out by Petersl4md Gill, was originally based by 

 Linne" (Syst. Nat., 10th Ed., 1758, I, 34) solely on the Manati ( T. Manatus), and must 

 hence be retained for that animal. 



