130 ALLEN’S NATURALIST’S LIBRARY. 
difference, that in the latter the pre-molars are two, and the 
molars three, above and below on each side. Their flattened 
nose, with its wide partition between the nostrils, and their 
non-prehensile bushy tails, are also distinguishing, characters. 
The face is nude, the ears large and sometimes fringed. Their 
hind-limbs are proportionately larger and longer than their fore- 
limbs, while the nails of their fingers and toes are not flattened 
as in the Old World Apes, but all form sharp curved claws, 
except on the much shortened great toe. ‘The thumb is elon- 
gated and lies parallel, but quite unopposable to, nor indeed is 
it separable at will from, the rest of the digits. The fore-foot, 
consequently, “is a mere paw, and the term ‘hand’ is not applic- 
able toit.” . . . Theplantar surface of the hind-foot “is very 
long, and the digits are very short. It follows from these facts 
that the term ‘quadrumanous’ is not applicable in any sense 
to the Marmosets.” (//w«/ev.) hese animals have no callosi- 
ties over the ischial (or buttock) bones, and no cheek-pouches. 
In their smooth and rounded skull superciliary ridges are con- 
spicuously absent ; and the ear-capsules have, as has been 
already observed, no external bony canal for conducting sound 
vibrations to the inner ear. The hyoid bone resembles that of 
the Lemurs. 
This family has been divided into two genera, distinguished 
from each other only by a variation in the relative length of 
their incisor and canine teeth, which is so slight as to render it 
doubtful whether these differences really warrant the generic 
separation of the two groups. As, however, the distinction has 
been maintained by nearly all writers upon these animals, the 
arrangement has been followed here, and the various species of 
the family will be described as true Marmosets (/afa/e) and 
