NO. 1864 LIVING WHITIS WHALES TRUL 329 



tip of snout to anterior base of pectoral fin, 32 in. ; to eye, 14^ ; 

 to ear, 213/2; length of pectoral, 18; greatest breadth of pectoral, 

 13; transverse breadth of flukes, 37>4 ; greatest antero-posterior 

 breadth of flukes, 17 in.; depth of notch of flukes, 4; distance from 

 notch of flukes to anus, 41 ; to prepuce, 54>^. 



Note; on the Dentition of Delphinapterus and Stenodrlphis. 



In the literature relating to the white whale, the teeth are de- 

 scribed as having simple conical crowns, like the typical dolphins. 

 Dr. John Struthers, for example, remarked in 1895 that "the teeth 

 of Beluga have all originally a simple conical fang and a simple 

 conical crown. "^ An examination of young skulls in the National 

 Museum, however,' having the teeth, or a part of them, entirely un- 

 worn, shows that the crowns of at least four of the posterior teeth 

 on either side of the lower jaw, and perhaps some in the upper jaw, 

 are really trituberculate when perfect. The crowns of the teeth men- 

 tioned are somewhat flattened internally and curved inward at the 

 apex. Situated on either side of the main cusp (anteriorly and pos- 

 teriorly) and a little internally is a small, linear accessory cusp, 

 which is attached to the crown of the tooth throughout its length. 

 These accessory cusps do not reach the level of the apex of the main 

 cusp. 



The presence of these accessory cusps would at first appear to 

 lend support to Professor Abel's opinion^ that the genus Delphinap- 

 terus belongs in the family Iniidse (Acrodelphidse of Abel) rather 

 than in the Delphinidse. It seems to me probable, however, that the 

 character of the teeth adds one more item to the evidence, chiefly 

 paleontological, which is accumulating, that the two families cannot 

 be kept separate, if the fossil forms are taken into consideration. 

 Leaving out of account the genus Stenodelphis, the affinities of which 

 are still in dispute, there are two other genera, at least, beside Del- 

 phinapterus in the family Delphinidas in which the crowns of the 

 teeth are not entirely simple cones. These genera are Phoccena, in 

 which the teeth are appressed, and many of them multituberculate ; 

 and Steno, in which the enamel of the teeth is rugose. It is reason- 

 able to suppose that the teeth in the earlier representatives of the 

 Delphinidag were furnished with a number of cusps, and I believe 

 it will be found eventually that neither simple teeth nor conjoined 

 cervical vertebne can be regarded as an essential character of the 



' Journ. Anat. and Phys., vol. 30, 1895, p. 137. 



" Mem. Mus. Roy. Hist. Nat. Belgique, vol. 3, 1905, p. 129. 



