420 M. lleiiihardt 07i Carterodoa sulcldeus. 



legs. On the upper side of the tail the hairs are black, below 

 they are whitish yellow. 



The half-grown young animal w^as a male and resembled en- 

 tirely the old one, with exception of the spines still being con- 

 siderably narrower and less stiff; and those placed on the lower 

 parts of the body, which in the full-grown individual were yellow- 

 red, had here a grayish colour. I am unable to decide whether 

 this difference was accidental, or connected with the difference of 

 age or sex. 



Several points in its organization, particularly the broad fore- 

 legs, the proportionally weak hind-legs, and the long, slightly 

 curved claws, point at the Carterodon sulcidens having a consi- 

 derably developed power of burrowing, and its being destined 

 probably in a great measure to a subterraneous existence. This 

 in fact, as far as has been related to me, is really the case ; it 

 inhabits the open Campos, overgrow^n with shrubs and trees, 

 where it digs its residence, consisting of a rather long tube 3 to 

 4 inches in diameter, and leading in a slanting direction into a 

 chamber, scarcely beyond a foot from the surface of the ground, 

 which the animal lines with grass and leaves. The stomach of 

 the two specimens which I examined was entirely filled with a 

 yellow pasty substance, evidently of vegetable origin ; and to 

 conclude from the strong, broad incisors, it seems probable, that 

 the animal subsists wholly on vegetable food, rarely, if ever, con- 

 suming insects, as is the case in regard to the Echinomyds* with 

 narrower and sharper incisors. 



I subjoin the dimensions of the specimens. The male had 

 only two molars cut through, and can scarcely have been much 

 more than half-grown; the female wanted still the hindmost 

 fourth molar; but as it was pregnant with a foetus 1| inch long, 

 it may be considered as about full-grown. 



<? $ 



Entire length 196 270 millini. 



Length of tail 53 82 „ 



End of snout to anterior comer of the eye 14i 18 „ 



Length of the opening of the eye 7 » 



Distance of end of snout from anterior margin of the eye 29 35 „ 



Length of ear 19 „ 



Width of ear 18 „ 



Length of hind-foot 27 30^ „ 



Length of claw on the middle toe of the fore-leg 4 „ 



Ditto ditto ditto hind-leg 5 „ 



* What Dr. Lund says (View of the Animal World of Brazil before the 

 last Revolution of the Globe, Third memoir, p. 30) concerning the " habit 

 of the genus Nelomys " has reference to the other species. 



