OBNITHORHYNCHUS PARADOXUS. 309 



They are also inhabitants of a part of the globe in 

 which the Mammalia are almost exclusively Marsu- 

 piata. They certainly do not possess the pouch, but 

 this has been observed to exist only in a rudimen- 

 tary state in some of the Opossums. 



THE ORNITHORHYNCHUS. 



Ornithorhynchus paradoxus, Blumenbach. 

 Platypus anatinus, Shaw. 



PLATE XXXIV. 



This animal is about 18 or 20 inches in length; 

 the body tapers at both extremities, and is moreover 

 of a somewhat depressed form ; the head is small, 

 but the facial portion is greatly developed, and from 

 its peculiar form has often been compared to the beak 

 of a duck ; this beak is about one third longer than 

 broad, flat and broader in front than behind ; it is 

 covered by a thick skin, which in dried specimens 

 resembles leather; this leather-like membrane is sup- 

 ported by the bones of the face, which, together, form 

 a framework of the figure just described, but the 

 membrane, both at the sides and in front, extends 

 beyond the bone, and such parts are therefore free 

 and flexible; in front the free membrane (in an adult 

 animal) measures about half an inch or more, and at 

 the sides rather less ; besides the free membrane at 

 the sides and in front there is a fold of skin surround- 

 ing the base of the beak, which in fresh specimens 

 probably averages about half an inch in width ; it is 



