500 THE YAPOCK OPOSSUM. 
The general hue of the body is a pale fawn-grey, with a very watery look about it, 
and set closely upon the skin. Four dark bands of sooty-black are drawn across the body 
in a peculiar, but extremely variable manner. The first band extends over the shoulders 
as far as the first joint of the fore limbs; the second passes saddlewise across the back, 
extending only half-way down the sides of the body; the third passes over the hinder 
quarters and traverses the greater portion of the thigh; while the fourth is reduced to a 
broad patch upon and above the insertion of the tail. Along the spine runs a broad black 
band, which consists of three dark patches, and spreads into a wide black patch upon the 
top of the head. The tail is dark for two-thirds of its length, and white for the remaining 
third. 
In the young animal these peculiar markings are very strongly defined, for the pale 
greyish-fawn becomes almost white, and contrasts powerfully with the dead, sooty-black 
of the dark portions of the fur. 
On a closer examination of the structure of the Yapock, we come upon certain pecu- 
liarities which distinguish the animal from any other of its relations, and give ample cause 
for placing it in a separate genus, if not in a separate family. Intended for an aquatic 
existence, and to gain its food in and about the waters, the Yapock is well fitted for its 
course of life by the structure of its feet. The hind-feet aref urnished with a membranous 
web that connects the toes together as far as the base of the claws, and serves as a paddle 
by which the creature may drive itself rapidly through the water, or as a rudder by which 
it may direct its course. 
The fore-paws are endowed with great powers of grasping, and have a very hand-like 
aspect. They are webbed only as far as the first joint. One peculiarity in their form 
deserves notice. To a casual observer, the fore-feet of the Yapock appear to be furnished 
with six toes, the superabundant member being devoid of a nail. So close a resemblance 
does this structure bear to a real toe that it has been described as such by a very eminent 
naturalist. It is, however, nothing more than an unusual development of the pisiform 
bone, which supports a fold of the skin, 
The under side of the feet is furnished with a large, rough, fleshy pad, and there are 
also large, rough pads upon the toes. The claws are small and weak, and the thumb-joint 
is not opposable to the others. The ears are moderate in size, sharp, and pointed, and 
the head tapers rapidly towards the nose. The entire aspect of the creature is aquatic, its 
elongated body and peculiarly shaped limbs being sufficient to proclaim it a skilled 
swimmer even if its webbed feet were not taken into consideration. 
It is not a very large animal, its total length being only two feet, the head and body 
measuring rather more than ten inches. In some specimens the tail is more developed 
than in others, and measures as much as fifteen inches in length. 
Another peculiarity of structure in the Yapock is the presence of large cheek-pouches, 
apparently similar in their use to those of certain monkeys. It is supposed that the object 
of these receptacles is to enable the animal to engage in a lengthened chase of the various 
aquatic animals on which it feeds, and to lay them up in store until it returns to shore 
laded with the produce of its watery toils. These cheek-pouches extend far backwards 
along the sides of the mouth, and seem to be capable of containing a large supply of food. 
As may be supposed from its structure, the Yapock feeds principally on fish, aquatic 
insects, crustaceans, and other water-loving creatures. Powers of climbing would be useless 
for such an animal, and it is accordingly found that the Yapock is unable to ascend trees, 
but, as if in compensation for this deficiency, isa most admirable swimmer and diver, One 
of these animals was once taken in a fish “crawl,” or conical basket, which affords ingress 
to the fish but does not permit them to get out again. The Yapock had evidently dived 
after a fish, followed it into the basket, and not being able to make good its retreat, had 
been ignominiously captured. 
The residence of this animal is always near water, and is generally made in a hole that 
is tunneled close to the water side. It is a very rare animal, and comparatively few 
specimens have as yet been taken. On account of its aquatic propensities and the nature 
of its prey, it has been taken for an otter, and has been described under the title of the 
Demerara Otter. Buffon notices it under the name of Petite Loutre de la Guyenne. It isa 
native of Brazil, and is generally found by the banks of the smaller streams and rivers. 
