of the Ornithorhynchus .Hystrix. 351 
three inches long; the palms of the feet are covered with a 
strong cuticle. 
The hind legs are longer than the fore legs, and have five 
toes ; four of these have long strong claws, the innermost is the 
longest. The fifth toe is short, and, being opposed to the others, 
resembles a thumb. The length of the leg, to the point of the 
longest claw, is six inches. Just at the setting on of the heel 
there is a spur, similar to that of the paradoxus, only weaker 
and smaller ; it is of an inch long. 
The tail is covered with hair, and is about half an inch in 
diameter; it terminates in a blunt end. 
Description of the internal Parts. 
The internal structure so nearly resembles that of the Orni- 
thorhynchus paradoxus, that a particular description of many of 
the parts will be unnecessary. 
The panniculus carnosus is similar to that of the paradoxus. 
The tongue is cylindrical, very small towards the point, and 
eight inches long. Near the root there is an oval portion, more 
massy than the rest, on which are placed the horny teeth al- 
ready described. 
The velum pendulum palati, and glottis, resemble those of the 
paradoxus ; but, at the termination of the fauces in the oeso- 
phagus, there is a projecting fold or valve, peculiar to this 
species ; and the epiglottis is bifid in a small degree. 
In the structure of the bones of the chest, there are the same 
general peculiarities as in the paradoxus ; but, in the Hystrix, 
there is a xiphoid cartilage, having its origin from the under 
surface of the sternum, and being about one inch in length. 
Z Z 3 
