68 



BULLKTIN 73, UNITED STATES NATIONAL MUSEUM. 



SKaLL. 



The skull of Berardius bairdii presents many characters by which it may be 

 distinguished from that of arnuxii, whether adult or young. As compared with 

 the latter, the rostrum is less massive at the base. The pterygoid has a rounded 

 extension posteriorly and superiorly, so that the posterior portion of the upper 

 border of the pterygoid sinus is convex, rather than nearly straight, as in arnuxii. 

 The exoccipital is. larger and broader distally below, and its external surface is 

 plane or concave, rather tiiau convex, as in arnuxii. The distal end of the zygo- 

 matic process is much more incurved. The nasal bones instead of presenting 

 lateral extensions have nearly straight sides. The vomer is deeply emarginate at 

 the base of the skull posteriorly where it rests against the presphenoid. The pala- 

 tines extend scarcely or not at all in front of the pterygoids. The foregoing differ- 

 ences will readily be seen by comparing the figures on Pis. 26-29 with those of the 

 type of B. arnuxii given in Van Beneden and Gervais's Osteography, plate 23. 



The following are dimensions of skulls of both species: 



Dimensions of Jive skulls of Berardius bairdii {including the type) and of three skulls of B. ar)iu.rii. 



Measurements. 



New New 



Brighton, 'Zealand 

 New I (V. B. 

 Zealand I and 



18(18 1 r.erv.). 

 (Flower). (Tvpe). 

 No. 3. '(") 



Total length o! staill 



Height from vertex to inferior 

 border of pterygoids 



Breadth across middle of orbits. 



Breadth across postorbital proc- 

 esses 



Breadth across zygomatic proc- 

 esses 



Length of rostrum 



Breadth of rostrum at base 



Breadth of rostrum at middle d . . 



Length of premaxillcc 



Breadth of premaxilla^ at middle d 



Greatest breadth of premaxillfe 

 in front of nares 



Greatest breadth of premaxilUv 

 behind nares 



Distance from anterior end of pre- 

 maxillee to posterior end of 

 pterygoids (median) 



Distance from anterior end of pre- 

 maxillee to anterior end of vo- 

 mer 



mm. 

 1.372 



533 

 c 025 



fi71 

 919 

 399 

 152 



21511, 

 U.S. 



N. M., 



New 



Zealand 



young. 



mm. 

 1,392 



494(? 

 684 



748 

 894 

 414 

 150 



1,097 



90 

 210 

 246 



1,080 



mm. 

 '■1,174 



493 



577 



584 

 SCO 

 378 

 149 



101 

 189 

 193 



935 



49726, 



St. 

 George 

 Island, 

 female, 



adult. 



49725, 

 Center- 

 ville, 

 Cali- 

 fornia. 

 male(?) 

 adult. 



mm. 

 1,524 



563 

 766 



750 

 900 

 475 

 207 



120 

 235 

 215 



1,185 



20992, 

 Bering 

 Island, 

 (Type). 



mm. 

 1,423 



544 

 682 



675 

 925 

 420 

 197 



119 

 217 

 195 



270 



mm. 

 1,378 



428 



188 



49727, 



St. 

 George 

 Island, 



male, 

 young. 



mm. 

 1,062(?) 



530 

 500 



520 



578-1- 

 310 



115 

 238 

 181 



187 

 165 



720-1- 



260 ■ 115-1- 



Mounted 

 skull, 

 Bering 



Island(?) 

 (Greb- 



nitzki?). 



mm. 

 1,474 



575 

 [716] 



[700] 



[740] 



1,025 



429 



223 



125 

 239 

 197 



a From Van Beneden and Gervais figure. 

 6 A little broken at tip. 



c" Suprafrontal processes of maxilKT;." 

 d Same point. 



