MUSEUM OF COMPARATIVE ZOOLOGY. 31 



brae, which in Phoca are the smallest. These features, with others of a 

 similar character, especially the high crests of the skull in all the eared 

 seals, show these animals to be possessed of relatively much greater 

 muscular power than the common Phoca, and that they are not only 

 fitted for greater activity on land, but that they must also possess su- 

 perior powers of motion in the water. The most strongly developed 

 features in the skeleton of the Phoca type are those that best serve its 

 strictly aquatic mode of life, and the character of its whole structure, 

 as previously mentioned, gives it a rank far below the Otariadce. 



Comparison with Macroriiinus, Cystophora, and MONACHUS. — 

 In respect to size the Phoca vitulina and the Macrorhinus elephantinus 

 represent the two extremes, not only of the Phocidce, but of the Pinni- 

 pedes, the sea elephant in size far exceeding the walrus. Yet in general 

 osteological features Macrorhinus is strikingly like Phoca. In the form 

 of the pelvis and scapulae, however, it slightly approaches the Otariadce, 

 and what is known of its habits indicates that it has greater powers of 

 locomotion on land than the common Phoca. 



Cystophora differs in no important particular in the general skeleton 

 from Phoca and Macrorhinus. Monachus, from Cuvier's* figure of its 

 skeleton, much more nearly approaches the Otariadce, and is hence a 

 higher form than either Macrorhinus, Phoca, or Cystophora. The greater 

 development of the neural spines and the other apophyses, the strongly 

 developed crests of the skull, the very broad strongly keeled scapula;, 

 together with numerous other osteological features, indicate it to be an 

 animal of great muscular power, whilst at the same time its compar- 

 atively slender form, and especially the elongated form of the thorax, 

 indicate that it has a much nearer affinity to the Otariadce than either 

 Macrorhinus, Cystophora, or Phoca have. 



These four, forms — Monachus, Macrorhinus, Cystophora, and Phoca 

 — represent four of the leading types of the Phocidce. Their relative 

 rank is doubtless in the order given, Monachus being unmistakably 

 the highest and most like the Otariadce. Stenorhynchus, it seems to me, 

 is still lower than either of the above-mentioned genera. I should hence 

 arrange the sub-families of the Phocidce in the following order, with Mona- 

 chus as the highest genus of Phocince, which is the highest sub-family: — 

 Phocinje. 

 Cystophorix.k. 

 Stenoriiyni.'iii.we. 

 * Oss. foss.. Tome V, Plate XVII. 



