33 Bulletin American Museum of Natural History. [Vol. XX, 



distinctly not the same, and there are very obvious cranial 

 differences, A. frustrator having a much narrower and more 

 pointed rostrum, and at the same time a much broader 

 palatal fossa. 



Lives in irrigating ditches, vicinity of Merida. 



20. Holochilus venezuelae, sp. nov. 



Type, No. 16973, a half grown female, El Llagual, Venezuela, March 

 20, 1901 ; cotype, No. 16964, a very old male, same locality and date; 

 coll. Samuel M. Klages. 



Adult male: General color above reddish brown, strongly varied 

 with black along the mid-dorsal region, from nose to lower back; 

 lighter and more fulvous on the sides, and reddish fulvous on lower 

 back and rump ; below buffy gray, the hairs gray basally with yellow- 

 ish white tips, which are deep buff on the longer hairs; ears, in size, 

 shape, and hairiness, about as in Nectomys palmipes; feet thinly haired, 

 grayish flesh-colored ; claws whitish with a subapical dusky ring, and 

 fringed with whitish hairs at the base; tail dark brown, not appreci- 

 ably lighter below, with short black bristles, increasing in length and 

 abundance apically, the terminal fifth of the tail being well clothed 

 with blackish bristly hairs, quite concealing the annulations. 



The young specimen is still partly in first pelage, the middle of 

 the back being clothed with the soft woolly first coat, of a dull rusty 

 brown color; .flanks, from cheeks to thighs, clothed with the coarser, 

 longer, firm pelage of the mature animal, bright rusty fulvous varied 

 slightly with black- tipped hairs; ventral surface grayish white with a 

 slight buffy tinge superficially and gray basally. Ears rather more 

 hairy than in the adult, the tail much less so. 



Measurements. Adult male: Total length, 409 mm.; head and 

 body, 203; tail vertebrae, 206; hind foot (from dry skin), 50; with- 

 out claws, 47; ear from crown (in dry skin), 16. 



This species differs from H. guiance Thomas, from the 

 Kanucha Mountains, British Guiana, its nearest geographical 

 representative, in being very much larger and more rufous as 

 well as somewhat in cranial details. Represented by two 

 specimens, one a very old male with the enamel pattern of the 

 teeth obliterated, the other a young female with wholly un- 

 worn teeth. For this reason the younger specimen is desig- 

 nated as the type, the unworn teeth showing it to be a 

 Holochilus and not a Nectomys; but there is no doubt that the 

 two specimens are young and adult of the same species. 



