70 



BULLETIN 73, UNITED STATES NATIONAL MUSEUM. 



breadth, 4(5; least breadth of eustachian canal, 17; height at sigmoid process, 47. 

 Periofic: greatest length, 66; greatest breadth, 40; height at center of middle lobe, 

 35; length from tip of anterior lobe to anterior margin of internal meatus, 38. 



TEETH. 



Althougli all the specimens of Berardms bairdii are more or less incomplete, 

 two or three of the mandibular teeth have been preserved in nearly every instance; 

 namely, in the adult female from St. George Island, the left anterior and right and 

 left posterior; in the immature male from the same island, both anterior teeth; 

 in the Centerville beach specimen, the left anterior and right (?) posterior teeth; 

 in the skull from Bering Island formerly regarded as the type, all four teeth; in the 

 very young skull from Bering Island, the left anterior and posterior teeth. 



Taken as a whole, these teeth are not larger than those found in the specimens 

 of B. arnuxii thus far recorded, but in both species they vary so much on account 

 of age, or for other reasons, that a comparison of dimensions is unsatisfactory. 

 The dimensions are a.s follows : 



Dimensions of teeth of Berardius arnuxii and B. bairdii. 



A description of the teeth of the different specimens of B. bairdii is subjoined. 



No. 1421 18.— Bering Island; young (new born?). Anterior tooth conical, 

 hollow, with thin walls. The lower half of the tooth is filled with a mass of bony 

 pulp, wliich is separable. The tooth is widest at the base, and is without any con- 

 striction indicating the formation of a root. Outer and inner surfaces shghtly 

 convex, the latter ^vith several distinct longitudinal furrows, which extemi to the 

 apex. The whole tooth has a thin coating of cement, except the tip, for a length of 

 about 10 mm., which is more nearly white, and consists, presumably, of dentine. 



