1 54 Ruminanxia. MAIMMALIA. Ruminantia. 
to assign to them. “These animals inhabit ti-ees,” 
says Cuvier, “ and never remove from that on which 
they are located until they liave stripped it of every 
leaf, so painful to them is the requisite exertion to reach 
another ! ” Our readers are well aware how frequently 
these errors have been exposed by Bell, Blyth, Buck- 
land, Broderip, Owen, and a host of other distinguished 
English writers; nevertheless we have pleasure in quot- 
ing some apt remarks of the last-named authority, 
recently given in his manual of the “ Skeleton and 
Teeth.” Alluding to tlie Ai, Professor Owen observes 
that “ it is less able to raise its trunk above its limbs 
than the seal, and can only progress by avahmg itself 
of some inequality of the soil offering a holdfast to its 
claws, and enabhng it to drag itself along. But to 
judge of the creative dispensations towards such an 
animal by observation of it or report of its procedure 
under these unnatural circumstances, would be as 
reasonable as a speculation on the natural powers of 
a tailor suddenly transferred from his shopboard to the 
rigging of a ship under weigh, or of a thorough-bred 
seaman mounted for the first time on a full blood-horse 
at Ascot. Rouse the prostrate Sloth, and let it hook 
on to the lower bough of a tree, and the comparative 
agility with which it mounts to the topmost branches 
will surprise the spectator. In its native South Ame- 
rican woods, its agility is still more remarkable, when 
the trees are agitated by a storm. At that time the 
instinct of the Sloth teaches it that the migration from 
tree to tree will be most facilitated. Swinging to and 
fro, back downwards, as is its habitual position, at tire 
end of a branch just strong enough to support the 
animal, it takes advantage of the first branch of the 
adjoining tree that may be swayed by the blast within 
its reach; and stretching out its fore-limb, it liooks itself 
on, and at once transfers itself to what is equivalent to 
a fresh pasture. The story of the Sloth voluntarily 
dropping to the ground, and crawling under pressure 
of starvation to another tree, is one of the fabulous 
excrescences of a credulous and gossipmg zoologyu” 
Such, in brief, is a fair estimate of tlie capabilities of 
the Ai in a state of nature ; and the testimony of such 
trustworthy travellers as Stedman and Waterton as to 
its power of rapid motion under certain circumstances, 
has long placed the matter beyond dispute. “ He 
travels at a good round pace,” says the latter, “ and 
were you to see him, as I have done, passing from tree 
to tree, you would never think of calling him a sloth.” 
In conclusion, we may remark, that the female is fur- 
nished with two mammae, and produces one young at 
a single birth, which adheres to the parent by its claws 
until able to shift for itself. The Ai is much sought 
after by the natives, who consider the flesh to be 
excellent eating. When on the move it utters a short 
plaintive cry resembling our pronunciation, in a shrill 
voice, of the two-lettered name by which it is appro- 
priately called. 
THE GIPAKEIOU {Bradijpus torquatm) is, like the 
above, a native of the north-easterly districts of Brazil, 
but it occurs more sparingly. The fur exhibits a friz- 
zled, ferruginous aspect along the under parts of throat 
and belly; but above it has an orange-yellow colour 
generally, whilst the face is black and destitute of hair. 
A more characteristic feature is seen in the presence of 
a deep black band, forming a sort of collar round the 
neck ; its specific distinctness being rendered still more 
certain by differences observable m the structure of the 
cranium, compared with that of other sloths. The habits 
of the Gipakeiou closely resemble those of tlie ai. 
THE UNATJ {Cholcepus didactylus), or Two-TOED 
Sloth, has been generically separated by Illiger from 
the above-described species, on account of certam pecu- 
liarities in the teeth, associated with a comparative 
elongation of the head on the one hand, and a short- 
ening of the anterior pair of limbs on the other. The 
fore-feet are, as above indicated, furnished with only ' 
two digits ; and the tail, which in the ai is reduced to 
a mere stumpy appendage, is altogether wanting in the 
Unau. The first molar teeth of this animal are long, 
and sufficiently acuminated at the summit to resemble 
ordinary canmes, whilst the superior pair, during the 
closure of the jaw, are placed in front of the lower ones. 
Besides these spurious canines, there are fourteen other 
molars, four on either side above, and three on either 
side below, the crowns of which are wedge-shaped, that 
is to say, in their worn condition. In regard to the 
skeleton, its claidcles are fully developed, and the bones 
of the carpus and tarsus become very early consolidated 
together. The Unau is about half as large again as 
the common ai, whilst the fur exhibits a dark-greyish 
broAvn colour generally, being here and there tinged 
with red. A living specimen of this singular species 
may be seen in the London Zoological Society’s Gar- 
dens, Regent’s Park. 
Order IX.— EUxMINANTIA. 
Throughout the entire mammalian series, there is not 
a better defined group than that formed by the rumi- 
nating quadrupeds here associated together mider the 
above distinctive title. This waS the opinion of the 
greatest of French naturalists, and it is in no degree 
contra-indicated by Professor Owen, in whose more 
exacting system of classification — an outline of which is 
given at page 8 — these cud-chewing species collectively 
maintain their zoological continuity, as a subordinate 
division of the even-toed migulates — more precisely 
called Artiodact^da. 
The essential features by which the ruminants may 
he distinguished are not confined merely to one or two 
trifling characters, but involve the structure and mor- 
phology of several important organs and appendages. 
In a few words they may be stated as follows : — All 
the feet terminate in two digits, the ultimate phalange 
of each being armed with a tightly investing hoof ; and 
the opposed surfaces of these hoofs are flattened in such 
a way as to impart to the foot an appearance of splitting 
in the mesial line. With an exception in the case of 
the camels, all the species are destitute of incisive 
