60 THE CAEASISSI. 



brown externally, and have yellowish-white hairs within. The belly 

 and inner side of the thighs are generally of a dirty pale yellow. 

 Habitat. Guiana and Demerara to the La Plata. 



Dimensions of a large and of a small specimen. 



Centimeters. 

 Length from end of snout to root of tail. . . 7O5 86'5 



of tail 29-5 30-5 



from heel to end of longest digit . . 13'0 ] 3'0 

 of ear 6'0 6'4 



Cranial and Denial Characters. 



We have been unable to detect any remarkable cranial characters 

 as distinctive of this species, but it seems to be subject to remark- 

 able abnormalities of dentition. An additional L? is occasionally 

 present, and we have found in one instance * an additional lower 

 molar (MTI) on both sides. The most singular anomaly we have found, 

 however, is, as mentioned in our Introduction, the existence on one 

 side of a group of five small denticles, placed close together, in lieu 

 of the third lower molar f. 



As we have said, the outline of the skull of the variety brasiliensis, 

 as represented by Lund, is somewhat aberrant. 



The average dimensions of ?ii to that of M - l+M. 2 we j^g f oun( j 

 to be 1-27 and 1-57 respectively, or as 100 to 123. That of the 

 same teeth in the figure of Lund's brasiliensis is as 100 to 122. 



Centimeters. 



Basion to ovalion . 2'6 



sphenoideum 3'8 



Sphenoideum to gnathion 8'8 



Length of palate 6'5 



Breadth 3*7 



Length of nasals 4'7 



Breadth of I'l 



brain-case 4'2 



zygomata 7'1 



* No. 1033 6 in the British Museum. f See ante, p. xxiv. 



