MAMMALIA. 
81 
the Tucutuco. Of those I kept alive, several, even the first day, were quite tame, 
not attempting to bite or to run away ; others were a little wilder. The man who 
caught them asserted that very many are invariably found blind. A specimen 
which I preserved in spirits was in this state ; Mr. Reid considers it to be the 
effect of inflammation in the nictitating membrane. When the animal was alive, 
I placed my finger within half an inch of its head, but not the slightest notice was 
taken of it : it made its way, however, about the room nearly as well as the 
others. Considering the subterranean habits of the Tucutuco, the blindness, 
though so frequent, cannot be a very serious evil ; yet it appears strange that any 
animal should possess an organ constantly subject to injury. The mole, whose 
habits in nearly every respect, excepting in the kind of food, are so similar, has 
an extremely small and protected eye, which, although possessing a limited 
vision, at once seems adapted to its manner of life. 
“ Several species probably will be found to exist south of the Plata. At Bahia 
Blanca (Lat. 39°) an animal burrows under ground in the same manner as the 
C. Braziliensis, and its noise is of the same general character, but instead of 
being double and repeated twice at short intervals, it is single and is uttered 
either at equal intervals, or in an accelerating order. I was assured by the in- 
habitants that these animals are of various colours, and, therefore, I presume that 
the two kinds of noises proceeded from two species. However this may be, they 
are extraordinarily numerous : many square leagues of country between the Sierras 
Ventana and Guetru-heigue are so completely undermined by their burrows, 
that horses in passing over the plain, sink, almost every step, fetlock deep. At 
the Rio Negro (Lat. 41°) some closely allied (or same?) species utters a noise, 
which is repeated only twice, instead of three or four times as with the La Plata 
kind. The sound is, moreover, louder and more sonorous ; and so closely re- 
sembles that made in cutting down a small tree with an axe, that I have occa- 
sionally remained in doubt for some time to which cause to attribute it. Where 
the plains of Patagonia are very gravelly (as at Port Desire and St. Julian) the 
Ctenomys, I believe, does not occur; but at Cape Negro, in the Strait of Magellan, 
where the soil is damper and more sandy, the whole plain is studded with the 
little hillocks, thrown up by this destructive animal. It occurs likewise south of 
the Strait, on the eastern side of Tierra del Fuego, where the land is level. 
Captain King brought home a specimen from the northern side of the Strait, 
which Mr. Bennett* has called C. Mag ell aniens : it is of a different colour from 
the C. Braziliensis. I unfortunately did not make any note regarding the noise 
of this southern species : but the circumstance of its existence rather corrobo- 
rates my belief in there being several other kinds in the neighbourhood of the Rio 
* Transactions of the Zoological Society, vol. ii. p. 84. 
M 
