Four new Small Mammals from Venezuela. 413 



by its decidedly larger size, and especially its larger molars, 

 from S. savannarum of tiie mountains of liritisii Guiana. 

 Tlie ])rcsent species is as small us the Giiianan form, with 

 which its molars approximately agree, hut it lias much smaller 

 bullro. Geographically it should have nothing to do with 

 the latter. 



The fact that the type is itnmafurc does not affect the size 

 of the teetli, which have heen my chief guide in distinguishing 

 the sj)ecies, but it shouhl be noticetl by other workers, who 

 might be tleceived by the general measurements above given. 

 On the other hand the original type of S. alstoni \s old and its 

 molars are very much worn and crushed together, the series 

 being therefore below normal length ; the tooth-row measures 

 about 6 mm. when in prime. 



It may be here noted that Burmeister's Lasiomys hirsutus, 

 from Maracaibo, is clearly a Siijmodon, as is shown by the 

 figure of its skull given by Giebel. The incisors are 

 described without mention of a groove, so that it cannot be 

 a Sigmomys. 



Sylvilagus valencies, sp. n. 



Near *$'. cumanicus, but more rufescent. 



Size as in cumanicus, therefore decidedly larger than in 

 orinoci. General colour very much as in orinoci, not so grey 

 as in cu?nantcus, in which the flanks especially are very 

 markedly greyer than the dorsal colour. Under surface 

 strongly contrasted and sharply defined pure white, the hairs 

 white to their bases ; the incursion of huffy in the groin 

 reduced to a minimum. Head colour and markings as in 

 orinoci, more intense than in cumanicus, the white superciliary 

 line, blackish area between eye and ear, and deep rusty nape 

 the same in all three. Limbs as in orinoci, except that the 

 hind feet are more conspicuously white. Tail over an inch 

 in length, therefore longer than the mere stump of the allied 

 species, but these rudimentary tails are easily stretched out, 

 and there may be little real difference in this respect ; in 

 colour it is smoky greyish washed with rusty above, buffy 

 whitish below. 



ISkull very much as in cumanicus, conspicuously larger 

 than in orinoci. Bulla? somewhat larger than in the 

 former. 



Dimensions of the type (measured in the flesh) : — 



Head and body 412 mm.; tail 27; hind foot 90; 

 ear 62. 



{Skull : greatest length 80 ; condylo-incisive length 72*5 ; 



