42 



ODOB^NUS ROSMAEUS ATLANTIC WALEUS. 



females.* They agree witli tlie one already described as to 

 small size, the absence of well-developed crests and ridges for 

 muscular attachment, small, slender tusks, and general weak- 

 ness of structure, as comj)ared with male skulls of correspond- 

 ing age.t The closed sutures show that they belonged to aged 

 individuals, but in other respects might be iiresumed to be skulls 

 of young animals, for which such skulls are doubtless usually 

 mistaken. 



Fig. 2. Odoicenus rosmarus, $ . 



From these data it seems fair to conclude that there are well- 

 marked sexual differences among Wah-uses, manifested espe- 

 cially in the inferiority of size of the female, in the comi)aratively 

 weak development of the bones of the skull, the smaller size of 

 the bones of the general skeleton, and in the size and form of 

 the tiTsks. These differences are, in short, just such as, from 

 analogy, one would naturally expect to exist, and confirm the 



* This I inferred from their small size aud light strncture, and was pleased 

 to have my determination confirmed by so comi^etent an authority as Dr. 

 Emil Bessels, who pronounced them to be unquestionably those of females. 

 Dr. Bessels's judgment, it is perhaps needless to say, is based on j)ersonal 

 experience while on the Polaris Expedition, during which ho secured and 

 prepared numerous specimens of both sexes, Avhich were lost with the ill- 

 fated vessel. 



t In the National Musemn there is also a female skull of the Pacific Wakus 

 that presents corresiionding differences as compared with male skulls of the 

 same species. 



