NOMENCLATURE AND HISTORY. 171 



however, does not again occur, so far as I can find, either in 

 this paper or in any of the writings of this author. The name 

 obesus has several pages priority over diver gens, and must hence 

 be adopted for the Pacific Walrus. 



The next names applied to the Walruses are those used by 

 Fremery, who, in 1831, recognized three species, namely, Triche- 

 cJius rosmarus, T. longidens, and T. cooki. The first is the com- 

 mon Walrus of the North Atlantic. The second was founded 

 on a skull with long, slender, and somewhat converging tusks, 

 the locality of which is not stated, but the species is usually 

 considered as based on the skull of a female Atlantic Walrus, 

 The third is obviously the Walrus described and figured by Cap- 

 tain Cook. The latter is hence synonymous with obesus (and 

 divergens) of Illiger. The second (longidens) has generally been, 

 as just stated, considered as based on a female skull of the 

 common Atlantic Walrus. 



In 1842, Stannius, while referring all the previously given 

 names to one species, characterized what he believed to be a 

 second species, under the name dubius, based on a large skull 

 presenting unusual features of individual variation. I do not 

 find that the locality of this specimen is distinctly given, but 

 von Middendorff appears to consider Stannius's T. dubius to 

 have reference to the Pacific Walrus.* 



In 1866, Gill, in adopting Rosmarus as the generic name of 

 the \Valruses, took Illiger's name obesus for the specific name of 

 the single species he (Gill) at that time recognized. Later (as 

 already noticed, see antea, p. 22), in naming the two presumed 

 species of Walruses, Gill chose obesus as the name of the Atlantic 

 species, and took cooJcii of Fremery for the Pacific species, over- 

 looking the fact that obesus was originally applied to the Pacific 

 species, in obvious allusion to its supposed more robust or 

 thicker form as compared with the Atlantic Walrus. 



HISTORY. The Pacific Walrus appears to have received its first 

 introduction into literature through the early exploration of the 



* Von Middendorff says: "Ersterer verglich [he refers at this point in a 

 footnote to Stannius's paper] Schiidel und Gebisse der Walrosse unter einan- 

 der und fand die Hauer bei den Walrossen der Beringsstrasse etwas langer, 

 diinner und gelinde spiralig gegen einander gekriiinmt, iin Vergleiche mit 

 denen des atlantischen Eismeeres. Seine eigenen schliesslichen Zweifel 

 spricht aber der vorgeschlagene Name, Tricliechus dubius, deutlich genug 

 a.usSibiri8che Reise, Bd. iv, p. 792. I do not understand, however, that 

 Stannius's T. dubius had any reference to either these characters or to the 

 pacific Walruses. (Compare Stannius's paper in Miiller's Arch, fur Anat. r 

 1842, pp. 392, 405-407). 



