1350 THE RODENTS 



The only other member of the genus to which we shall allude is the 

 aguchi (D. cristata}, which inhabits Northern Brazil and Guiana as 

 well as parts of the West Indies. This species is distinguished from the others by 

 its smaller size, and its longer and more slender tail, which is clothed with silver- 

 white hairs. Its general color is rich chestnut brown, with a characteristic bright 

 golden yellow, or rust-colored patch behind each ear. 



It may be added that fossilized remains of agutis are met with abundantly in 

 the caverns of Lagoa Santa, in Brazil. 



The Rodent known in South America by the title of paca (Coelo- 

 genys paca), is readily distinguished externally from all its allies by 

 the longitudinal rows of light spots ornamenting its 

 fur; while internally it is remarkable for the ex- 

 traordinary structure of its skull. Its hind-feet are 

 distinguished from those of the agutis by having five 

 distinct toes; and the limbs are much shorter and 

 the whole build far more massive than in the latter. 

 In the skull, as shown in the accompanying figure, 

 SKUI.IV OF PACA. t* 16 zygomatic or cheek arches are greatly expanded 



from above downward, so as to form huge bony 



capsules on the sides of the face, each of which incloses a large cavity communicat- 

 ing by a narrow aperture with the mouth. Externally the paca is stout bodied, 

 measuring about two feet in length, with rather short limbs, and a broad head, ter- 

 minating in a blunted muzzle covered with fine hair. The ears are rather small, 

 and but scantily clothed with hair; the feet are naked below; and the tail is re- 

 duced to a fleshy tubercle. The fur is coarse, and closely applied to the body. Its 

 general color varies from fawn to blackish, and the number of longitudinal rows of 

 spots is likewise variable, being in some instances only three, while in others there 

 may be five such rows. The female has two pairs of teats, placed at a considerable 

 distance apart. 



The common paca has a very extensive range, being found throughout the 

 greater part of South America as far as Paraguay. In Brazil it is fairly common, 

 but it is much scarcer in Paraguay, while in Peru it is rare. It occurs in Tobago 

 and Trinidad, but is unknown to the westward of the Andes. In the highlands of 

 Ecuador, at elevations of from six thousand to ten thousand feet, it is represented 

 by Taczanowski's paca (C. taczanowskii), distinguished by its inferior size, and the 

 difference in the form of the skull, as well as in coloration. 



The habits of the common paca appear to be very similar to those 

 of agutis; these animals going about either singly or in pairs, and 

 being strictly nocturnal. Their resting place during the day is either some cavity 

 among the roots of a forest tree, or a burrow excavated by their own exertions, 

 and reaching to a depth of from four to five feet. Their food is precisely similar to 

 that eaten by the agutis. In disposition they are shy and timid, and when pursued 

 they invariably make for the water, in which they swim well and with considerable 

 rapidity. During the summer the female produces a single (occasionally two) off- 

 spring, which is believed by the natives to remain in the burrow during the period 



