NO. 8 INTERRELATIONSHIPS OF THE CETACEA WINGE 37 



p. Intermaxillary strongly broad- 

 ened anteriorly, 

 (i) Nostril not pushed espe- 

 cially far back. Teeth 

 not atrophied. Flip- 

 pers quite short. 

 Pscudorca. 

 (2) Nostril pushed unusually 

 far back. Teeth some- 

 what atrophied. Flip- 

 pers very long. 

 Globiceps [ Glohicephala] . 

 b. Crowns of teeth in part compressed, widened out 

 leaf-wise. 

 Phoc^n^. 



a. Face relatively long and narrow. Brain- 

 case relatively small. 

 Phocccna. 

 j3. Face relatively short and broad. Brain- 

 case large. 

 Neomcris [^Neophocccna]. 



Physeteridas. — The Physetcridcc probably originated from the 

 most primitive Delphinids, from Delphinids in which the margin of 

 the facial depression must have been so widened that it covered the 

 temporal fossa, but which at the same time retained these primitive 

 features : zygomatic process of the squamosal relatively large and 

 somewhat arcuate ; teeth small and conical, but still with traces of 

 notching on the margin of the crown ; teeth in the intermaxillary well 

 developed ; anterior part of mesethmoid free, not covered over by the 

 intermaxillaries ; free though stunted lacrimal ; separate cervical 

 vertebrae ; rather short transverse processes on the thoracic vertebrae ; 

 a well-developed capitulum on all the ribs, etc. The character that 

 already places even the most primitive Physeterids on a higher plane 

 than the Delphinids is a result of stronger action of the facial cushion. 

 It appears as if the Physeteridce had from the very first trained them- 

 selves to swifter, more violent swimming than other whales, and that 

 the fat-pad in front of the nose had therefore been pressed in with 

 greater force against the facial part of the skull. The pad, together 

 with the nasal muscles, etc., has modified the face to an unusual 

 degree. Especially the posterior margin of the facial depression is 

 transformed, more or less conspicuously elevated. The crookedness 



