8'; COMPARATIVE ANATOMY. 



tails, buccal pouches, and callosities on the buttocks. The 

 strepsyrrhine include the Galeopitheci and Lemurs, and in 

 their dental formula vary considerably from the other two 

 classes. We next come to the large class, the Carnivora, 

 which is divided into — 



1. Digitigrada, walking on their toes, 



2. Plantigfada^ Walking on the flat of their foot. 



3. Pinnigrada, walking on fins. 



Of the order of Carnivora generally, I would make the 

 following observations :- 



They are at once distinguished from all other quadrupeds 

 by having four large long well developed canine or dog-teeth, 

 which are well seen in this skull that I have in my hand, the 

 skull of a large dog. 



The first tooth after the false molars in the carnivora is 

 called a lacerator, being as you see of a larger size than any 

 of the others, and cutting with the opposing tooth in the 

 lower jaw like a pair of shears. 



You will see this characteristic in all the carnivora, very 

 plainly in this cat, the cats being amongst the most blood- 

 thirsty of the tribe ; as we shall realise when we remember 

 that the lions and tigers belong to this cat tribe. The other 

 molars vary very much in the different genera of the carni- 

 vora, according as they live more or less entirely upon flesh. 



They have also a large zygomatic arch leaving room for the 

 passage of the large muscle that moves the lower jaw 



You will observe the high occipital ridge on the skull for the 

 attachment of the muscle of the lower jaw, and in the lower 

 jaw the ascending ramus of the jaw above the condyle or hinge 

 is exceedingly long, giving great power or leverage. 



I have here on the table a skull of (i) dog and fox ; (2) an 

 otter; and (3) of a cat; giving examples of three different 

 families of the digitigrada. 



The dogs as you know have not retractile claws. 



In their dentition they more nearly approach the typical 

 formula of 44 teeth than any other animal except the three 

 already alluded to. 



Their dental formula is 



3—3 i_j 3_3 3__3 



I C PM M 42 



3—3 I — I 4—4 3—3 



