106 MAMMALIA. 



zle of the Ornithorhynchi presents the closest external resemblance to the 

 bill of a Duck, and the more so as its edges are similarly furnished with small 

 transverse laminae. There is a membrane to the fore feet, which not only 

 unites the toes, but extends far beyond the nails; in the hind feet the mem- 

 brane terminates at the root of the nails; two characters, which, with the 

 flattened tail, make them aquatic animals. The Ornithorhynchi inhabit the 

 rivers and marshes of New Holland in the neighbourhood of Port Jackson. 



Two species only are known, one with smooth, thin, reddish fur, the 

 Ornithorhynchus paradoxus, Blumenb., and the other with blackish-brown, 

 flat and frizzled hair. Probably these are only varieties of age. 



ORDER VII. 



PACHYDERM AT A.(l) 



The Edentata terminate the series of unguiculated animals, and 

 we have just seen that there are some of them whose nails are so 

 large, and so envelope the extremities of the toes, as to approximate 

 them in a certain degree to the hoofed animals. They still, however, 

 possess the faculty of bending these toes round various objects, and 

 of seizing with more or less force. The total deficiency of this 

 faculty characterizes the hoofed animals. Their forms and habits 

 present much less variety than those of the Unguiculata, and they 

 can hardly be divided into more than two orders, those which rumi- 

 nate, and those which do not; but these latter, which we designate 

 collectively by the term Pachydermata, admit of subdivision into 

 families. 



The first is that of the Pachydermata which have a proboscis and 

 tusks. 



FAMILY I. 



PROBOSCIDIANA. 



The Proboscidians have five toes to each foot, very complete 

 in the skeleton, but so encrusted by the callous skin which surrounds 



(1) Thick-skinned wiimalf. 



