182 Professor Owen, on the [Jan. 21, 



loe which touches the ground is incased in a hoof, which blunts its 

 sensibility and deprives the foot of prehensile power. With the limbs 

 restricted to support and locomotion, the Ungulata have no clavicles : 

 the fore leg remains constantly in the state of pronation, and they feed 

 on vegetables. 



A particular order, or suborder, of this group is indicated by fossil 

 remains of certain South American genera, e. g, Toxodon and Nesodon, 

 with long, curved, rootless teeth, have a partial investment of enamel, and 

 with certain peculiarities of cranial structure : the name Toxodontia 

 is proposed for this order, all the representatives of which are extinct. 



A second remarkable order, most of the members of which have 

 also passed away, is characterized by two incisors in the form of long 

 tusks ; in one genus (Dinotherium) projecting from the under jaw, in 

 another genus (Elephas) from the upper jaw, and in some of the 

 species of a third genus (Mastodon), from both jaws. There are no 

 canines : the molars are few, " large, and transversely ridged ; the 

 ridges sometimes few and mammillate, often numerous and with every 

 intermediate gradation. The nose is prolonged into a cylindrical 

 trunk, flexible in all directions, highly sensitive, and terminated by a 

 prehensile appendage like a finger : from this peculiar organ is de- 

 rived the name Proboscidia given to the order. The feet are penta- 

 dactyle, but the toes are indicated only by divisions of the hoof; the 

 placenta is annular ; the mammae are pectoral. 



Elephants are dependent chiefly upon trees for food. One species 

 now finds the conditions of its existence in the rich forests of tropical 

 Asia ; a second species in those of tropical Africa. These are all 

 that now remain of the order Proboscidia. 



Numerous species of Mastodon and Elephant roamed in pliocene 

 times in warm and temperate latitudes of America and Europe. At 

 a later or pleistocene period, a huge elephant, clothed with wool and 

 hair, obtained its food from hardy trees, such as now grow in the 65th 

 degree of north latitude ; and abundant remains of this Elephas pri- 

 migenius (as it has been prematurely called, since it was the last of our 

 British elephants) have been found in temperate and high northern 

 latitudes in Europe, Asia, and America. This, like other Arctic ani- 

 mals, was peculiar in its family for its longitudinal range. The Musk 

 Buffalo was its contemporary in England and Europe, and still lingers 

 in the northernmost parts of America. 



Both the proboscidian and toxodontal orders of Ungvlata may be 

 called aberrant : the dentition of the latter, and several particulars of 

 the organization of the Elephant, indicate an affinity to the Rodentia ; 

 the cranium of the Toxodon, like that of the Dinothere, resembles that 

 of the Sirenia in its remarkable modifications. 



The typical Ungulate quadrupeds were divided by the speaker, 

 according to the odd or even number of the toes, into Perissodac- 

 TVLA and Artiodactyla : the single hoof of the horse, the triple hoof 

 of the tapir, exemplify the first ; the double hoof of the camel, the 

 quadruple hoof of the hippopotamus, exemplify the second. 



The characters of these primary divisions were given, and illustrated 



