MR. E. T. BENNETT ON THE GENUS OCTODON. 81 
Artus subzquales, omnes pentadactyli, digitis liberis ; unguibus falcularibus, subcurvis, 
acutis ; wngue pollicart lamnari. 
Cauda mediocris, subannulata, pilosa, ad apicem floccosa. 
Americe Australis incole, terrestres vel arborei, subsalientes. 
Ocropon CumIneGlI. 
Tas. XVI. 
Oct. supra fusco-flavescenti-griseus nigrescente intermiztus, infra et ad pedes pallidior ; 
caudd supra et ad apicem floccosum nigrd. 
Octodon Cumingii, Benn., in Proc. Comm. Sci. Zool. Soc., part wi. p. 46. 
Dendrobius Degus, Meyen, in Nov. Act. Acad. Ces. Nat. Cur., tom. xvi. p. 600. 
tab. 144. 
Hab. in Chili, prope Valparaiso. 
In size and shape the present animal generally resembles the Water Rat, with which 
it is, systematically, nearly connected. The facial line is regularly and strongly arched, 
and the muzzle obtusely truncate ; the eyes are small, and seated nearly midway between 
the base of the ears and the nostrils ; and the ears are of moderate size, thinly covered 
both within and without with short adpressed hairs, and rounded at the tips. The 
whiskers are rigid, and the longest exceed the head in length. On the body, which is 
compactly proportioned, the fur consists almost entirely of straight hairs, lying flat, and 
varying in length from half an inch to nearly an inch: they become shorter on the 
limbs and beneath the body, and still more so on the tail and feet. Of the limbs the 
hinder are somewhat the longest, but the disproportion is by no means so great as 
might have been inferred from the saltatory habits of the animal. All the feet have five 
toes ; but the innermost, both before and behind, is very short, and is separated by a 
wide interval from the rest. Except the thumb of the fore-feet, which has a short, 
flattened, obtuse nail, all the toes are armed with rather long, slightly curved, sharply 
pointed claws, partially concealed by long bristly hairs. Of the four outer toes ante- 
riorly the two intermediate are nearly equal in length, and the two lateral somewhat 
shorter: posteriorly the three intermediate toes are of nearly equal length, and con- 
siderably exceed the outer. The tail, although covered rather thickly with short stiff 
hairs, is distinctly annulated. 
The general colour of the upper surface and sides is of a brownish gray, intermixed 
with frequent indistinct and undefined spots and patches of dusky black. It becomes 
slightly darker towards the rump; and the upper surface of the entire tail, together 
with its under surface for one third of its length from the tip, is so deep in colour as to 
approach closely to black. The under surface of the animal is dusky gray, mingled 
with a shade of brown, lighter and nearly white beneath the base of the tail, and deeper 
on the breast and neck, where it is almost of the same general hue with the upper sur- 
VOL. II. M 
