240 VERTEBRATA. 



Huxley, also considering that the placenta affords the "best cha- 

 racters " for classification, divides them as follows : A discoidal 

 deciduate placenta : Primates, Insectivora, Chiroptera, Eodentia. 

 A zonary deciduate placenta : Carnivora, Proboscidea, Hyracoidea. 

 A non-deciduate placenta : Ungulata, Cetacea. [Placenta of Si- 

 renia unknown.] A variable placenta : Edentata. 



The classification adopted here is substantially the one now in 

 use, only that the Pinnipedia are sometimes combined with the 

 Carnivora, and the Hyracoidea are not always disunited from 

 the Proboscidea, or Sirenia from Cetacea. The Lemurs also, 

 under the name of " Prosimii," or " Prosimise," are by some sepa- 

 rated from the Quadrumana. 



Without a placenta [Implacentalia] . 



No abdominal pouch ...."....'..... MONOTREMATA. 



An abdominal pouch in the female MARSUPIALIA. 



With a placenta [Placentalia]. 

 With hind legs. ~ 

 Hind legs free. 



No thumb opposable to the fingers. 



Unguiculate [claws on the upper part 



of the toes only]. 

 Claws small or moderate. 



No canines EODENTIA. 



With canines. 



Fore limbs formed for flight ... CHIROPTERA. 

 Fore limbs normal. 



Canines small INSECTIVORA. 



Canines large CARNIVORA. 



Claws very large BRUTA, 



Ungulate [claws enclosing the toes, i. e. 



hoofs]. 

 Placenta deciduajgu. 



InCiSors tusbxformed PROBOSCIDEA. 



Incisors normal HYRACOIDEA. 



Placenta non-deciduate UNGULATA. 



A &umlFOpptTsable to the fingers. 



Teeth uneven, interrupted QUADRUMANA. 



Teeth even, uninterrupted BIMANA. 



Hind legs fin-like PINNIPEDIA. 



No hind legs, a horizontal tail-fin. 



Nostrils on the muzzle SIRENIA. 



Nostrils on top of the head CETACEA. 



