XIII 



PHYLUM CHORDATA 



569 



The lower carnassial is thus the last of the series. In the Dogs 

 (Canidae) the formula is usually — 



• 3 1 4 2 ,„ 



and in the Bears (Ursidse) it is the same. 



3 

 In the Pinnipedia there are always fewer than ^ incisors, and 



o 



carnassials are not developed. The pre-molars and molars have a 



Fio. H97.— Left lower cai-nassial teeth o£ Carnivora. /, Felis ; //, Canis ; VI, Herpestes ; 

 IV, IiUtra ; V, Xlffeles J VI, TTrsus. 1, anterior lobe (paracoiild) of blade ; 2, posterior 

 lobe (protoconid) of blade ; 3, inner cusp (metaconid) ; 4, talon (hypoconid). (After Flower 

 and Lydekker.) 



compressed, conical, pointed form. The prevailing dental formula 

 of the Seals is — 



.314 1 „, 



In the Walrus the adult formula is — 



.1 1 3 .„ 



I. ^, c. -,p. ^, m.^ = ]8. 



The upper canines take the form of large, nearly straight tusks. 



In the large order of the Rodents the dentition is remarkably 

 uniform, and, in all its general characters, resembles what has 

 already been described in the Rabbit. But the second, smaller 



