156 Prof. M'Intosh's Notes from the 



constriction about the middle, is in contrast with the broad 

 plates of Globiocephalus, which leave only a narrow margin 

 of the maxilla externally. 



In Orca a large part of the maxilla is free (one of Rein- 

 hardt's specific characters), the contour is more uniform and 

 symmetrical, the maxilla comes nearly as far forwards as the 

 median process of the premaxilla, and its tip is bifid. The 

 prominences of the maxillae (with zygomatic process and 

 frontals) above the eyes are roughened, but less than in the 

 very old female. A marked feature of the skull in contrast 

 with its allies is the great size of the temporal fossa, which, 

 as Keinhardt truly says, makes the skull of this species, in 

 contrast with that of Beluga or even of GlobiocepliaJus, akin 

 to the contrast afforded by the skulls of the lion and the 

 horse or ox. The powerful muscles which pass through this 

 huge space are attached to the mandible, the mass in front 

 of the condyles being very large. 



The ventral aspect of the cranium is equally diaguostic 

 when contrasted with Globiocephalus. Thus the vomer 

 comes to the surface for 3-\ inches, and the premaxillaries 

 in front of it form part of the roof of the mouth for fully a 

 foot (a character lleinhardt considers unusual in true Killers) . 

 In Globiocephalus the long vomer blocks the upper part 

 of the median fissure of the palate in front, and the pre- 

 maxillse only occupy a small area of the palate at the tip of 

 the snout. The arch of the palate in Orca slopes upward 

 and inward to the median line, giving it a characteristic 

 spout-shape when the skull is laid on its dorsum ; whereas 

 in Globiocephalus the palate, while it has the deep median 

 fissure at the tip, is flattened, or shows a slight outward 

 curve to the dentary edge, which is little more than half the 

 length of that in Orca, though the hard palate is proportion- 

 ally broader. The palatines in the two forms equally 

 diverge, those in Orca forming a narrow lozenge fully 9 

 inches in length, whereas in Globiocephalus they have but a 

 brief mesial course (about 2^ inches) posteriorly, and then 

 curve outward like a V behind the maxilla. In the same 

 way the pterygoids diverge, those in Globiocephalus are aided 

 by the palatines in the formation of the large postpalatine 

 air-sinuses, whereas in Orca these are proportionally smaller 

 and are formed by the pterygoids. The jugal is com- 

 paratively slender, but considerably longer and stouter than 

 in the old female. 



The armature of the jaws in this specimen is formidable, 

 for the teeth are massive, long, and slightly curved at the 

 crown. The number of teeth in each jaw is 13, and their 



