ARKIV FÖR ZOOLOGI. 



BAND 7. X:o 2. 



Remarks oii tlie deiitition of Delpliiiiapteriis 



leucas. 



By 

 EINAR LÖNNBERG. 



With 7 Figures in the Text. 

 Read Mai ll:th 1910. 



In a recently published paper ^ True has drawn attention 

 to the fact that the teeth of the White Whale {Delphinaptervs 

 leucas) are not all of them such simple concial fångs as they 

 usually are described to be. Examining young skulls of this 

 species he found »that the crowns of at least four of the 

 posterior teeth on either side of the lower jaw and perhaps 

 some in the iipper jaw, are really trituberculate when perfect. 

 The crowns of the teeth mentioned are somewhat flattened 

 internally and curved inward at the apex. Situated on either 

 side of the main cusp (anteriorly and posteriorly) and a little 

 internally is a small, linear accessory cnsp, which is attached 

 to the crown, of the tooth throughout its length. These acces- 

 sory cusps do not reach the level of the apex of the main cusp». 



FavourabJe material in this museum enables the present 

 writer to add further information to this interesting fact and 

 throw some more light on the development of the dentition 

 of this whale and at the same time, as I hope, to a certain 

 extent on its phylogeny. 



^ Observations on living White whales {Delphinapterus leucas) ; with a 

 note on the dentition of Delphinapterus and Stenodelphis- Smithsonian 

 Miscell. coll. Vol. 52. Part. 3. N:o 1864. Washington 1909. 



Ärl-iv för zoologi. Band 7. N:o 2. 1 



