DIFFERENTIAL CHARACTERS. 



169 



sible seeing evident from the fact of the existence, during por- 

 tions of the year at least, of areas of open water along those 

 portions of the' Arctic coast supposed to separate the habitats 

 of the two species. Further than this, I have seen a skull (now 

 in the Museum of the Boston Society of Natural History) which 

 Capt. Charles Bryant (certainly a trustworthy authority) 

 assures me was taken by his assistant, on Walrus Island, in 

 the summer of 1871 or 1872, that agrees in every particular 

 with the skulls of the Atlan- 

 tic species. This skull hav- 

 ing been somewhat fantas- 

 tically painted (the lower 

 surface deep red and the 

 upper yellowish-white), led 

 me at first to doubt the cor- 

 rectness of the alleged local- FIG. 34. Odolanm rosmarus. Young, 

 ity, supposing that if really obtained at the Prybilov Islands 

 it might have been brought there from some distant point. 

 This quaint ornamentation proves, however, an aid in fixing 

 the locality of its capture as Walrus Island. It differing so 

 widely from the form usually occurring in those waters, it at 

 once attracted attention, and was mounted on a bracket and 

 preserved as a curiosity, the paint being applied, as Captain 

 Bryant informs me, to facilitate its being kept' free of dust ! 

 Captain Bryant states (in a letter to the writer) that he has 

 himself "seen two specimens like it," but adds that he "did not 

 succeed in killing them." Hence, of course, their resemblance 

 to the one now in question is 

 only presumed, the animals 

 being only seen alive. He 

 writes, further, that this 

 "head" was recognized as 

 "different from any before 

 seen there." I will merely add 



.that this Skull is indistin- FIG. 35. Odolxenus olesus. Young. 



guishable in any essential detail from skulls of corresponding 

 age from the Atlantic waters, and points to the occasional oc- 

 currence of Odobcenus rosmarus within the habitat of Odobcmus 

 obesus. As von Middendorff has shown (see antea, p. 78), the 

 Walrus (presumably the Atlantic species) has occurred much 

 further to the eastward than the limits assigned it by von Baer, 

 he having traced it, satisfactorily to himself, apparently, to 



