DUCKBILL. 285 
is broad and somewhat flattened, with a coat of coarse hairs, which on the under 
surface become more or less worn off in old individuals. The short limbs have 
their feet—more especially the front pair—expanded and webbed for the purpose 
of swimming. Each foot has five complete toes furnished with strong nails; but 
while in the fore-feet the web extends considerably beyond the extremities of the 
nails, in the hind-pair it reaches only to their bases. The extension of the web of 
the fore-feet might appear to be a hindrance in burrowing; but this difficulty is 
avoided by the web being then folded back on the palm of the paw. The nails of 
the fore-foot are somewhat flattened and expanded, while those of the hind-foot are 
longer, narrower, and much curved. To the heel of the male is affixed a long, 





























































THE DUCKBILL (} nat. size). 
horny spur, curving upwards and backwards, and nearly an inch in length. A 
canal traversing this spur, and opening near its summit, is connected with a gland 
on the leg, which appears to secrete a poisonous fluid. 
The tongue is small and non-extensile; while the cheeks are provided with 
pouches of considerable size, doubtless used for storing food. If it be a fully adult 
specimen that we examine, it will be found that in lieu of teeth each jaw carries 
two pairs of horny plates, of which the more anterior are sharp and narrow, while 
those behind are broad and flattened. Between these plates the palate is thrown 
into a number of transverse wrinkles, like those ina duck. In young specimens, 
however, two or three pairs of cheek-teeth may be observed in the upper, and two 
pairs in the lower jaw; most of these teeth being broadly quadrangular in form, 
with two cusps on one side, separated by a hollow from a longitudinal crenulated 
ridge on the other. As these teeth are gradually worn away by the sand taken 
into the mouth with the food, the horny plates grow up beneath and around them, 
