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. Magellanicus : 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. 



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