COMPARISON WITH ALLIED SPECIE S. 607 



DIFFERENTIAL, CHARACTERS. In color the Einged Seal is 

 not easily distinguishable from certain phases of the Harbor 

 Seal, but it differs from it in its general form, which is much 

 slenderer, with longer limbs and tail, narrower head, and more 

 pointed nose, The Einged Seal may, however, be distin- 

 guished externally from both the Harbor aud the Greenland 

 Seals by the form of the manus, in which the first digit is the 

 longest, the others successively slightly decreasing. The cra- 

 nial characters, and especially the dentition, differ too widely 

 from those of the Harbor Seal to even require a comparison in 

 the present connection, as do also most of the principal bones 

 of the skeleton (see antea, pp. 565-571). 



The Eiuged Seal differs externally from the Greenland Seal 

 in its smaller size and in the very different coloration of the 

 adults of the two species. When in the " white coat," and in 

 the earlier spotted stages, coloration often fails to be diagnostic, 

 but they may be distinguished by the character of the maims 

 already given. The dentition of these two species, allowing for 

 the difference in size, is quite similar, although the teeth are 

 relatively (as well as absolutely) larger in PJioca grcenlandica. 

 In the general form of the skull there is also a close resem- 

 blance, although the facial portion is rather more attenuated in 

 P. grcenlandica. The form of the palatal region, however, is 

 widely different in the two, the broad shallow posterior nares, 

 completely divided into two separate passages by a bony sep- 

 tum, and the squarely truncate, instead of deeply emarginate, 

 posterior border of the palatine bones serving at a glance to 

 distinguish P. grcenlandica. 



The relationship of Phoca fcetida to the Baikal and Caspian 

 Seals (Phoca siMrica and P. caspica) is apparently much closer 

 than to any other. The earlier writers, however, as Erxleben, 

 Gmeliu, and Pallas, associated them with Phoca vitulina, they 

 forming respectively Erxleben's varieties ft and ? of this spe- 

 cies, and Gmeliu's varieties siMrica and caspica. The Caspian 

 Seal was first recognized as a distinct species by Kilssou in 

 1837, and called by him Phoca caspica. Later its specific dis- 

 tinctness was admitted by Gray (1844), Wagner (1840), and 

 Eadde (1862). Mlsson was also the first to make known the 

 fact of its much closer resemblance to Phoca fcetida (=- P. an- 

 nellata, Xilss.) than to Phoca vitulina* Wagner arrived at the 



* After detailing its characters, lie remarks, "Jeder sieht ein, dass diese 

 Form der PA. annellata viel uiiher stelit, alsder PA. vitulina. Doch bildet sic 

 otiue alien Zweifel cine von ersterer bestimmt verschiedeue Art : sie ist viel 



