82 PATAGONIAN EXPEDITIONS: ZOOLOGY. 



Similar in size and general appearance to Eligmodontia lepida (Thomas), 

 but easily distinguished by the much larger claws on the fore feet. Above 

 grayish fawn color, below white ; tail short, covered with short close hairs, 

 concealing the annulations, pale fawn above and white below. Front feet 

 armed with long, fossorial claws, similar to those of Akodon [Chelemys) 

 macronyx ; claws of hind feet rather long; soles naked, flesh-color; ears 

 small. 



Measurements. — Total length, 115 mm.; head and body, 80; tail ver- 

 tebrae, 35. Skull, total length, 20; greatest breadth, 13; length of nasals, 

 9.7; palatal length, 11 ; diastema, 6.1 ; upper molar series, 3.2. Descrip- 

 tion abridged from Thomas (/. c). 



This small species appears to be still known only from the unique type, 

 collected by Mr. Lebrun, a little southward of Santa Cruz (lat. 50° S.), 

 Patagonia. It is not included in the very large series of Muridae collected 

 near the type locality by the Princeton Expeditions, and it is therefore 

 probably not numerously represented. 



Genus OXYMYCTERUS Waterhouse. 



Oxymycterus^2Xtx\io\Xi>&, P. Z. S., 1837,21. Subgenus oi Mus. Type, 

 Mus [Oxymycterus) nastttits Waterhouse. — Tomes, P. Z. S., 1861, 

 285 (full genus). — Thomas, P. Z. S., 1884, 450 (subgenus of Hes- 

 peromys)\ P. Z. S., 1896, 308 (full genus). 



The chief characters of Oxymycterus are the long narrow rostrum, rela- 

 tively narrow interorbital region with evenly rounded supraorbital edges, 

 the maxillary branch of the zygoma narrow with its antero-superior border 

 rounded, fossorial claws, and small ears. There is nothing very char- 

 acteristic in the structure of the molars to distinguish it from Akodon and 

 allied genera. 



The group contains at present some 15 to 20 species, ranging from the 

 Andean region eastward and southward over southern Brazil to Patagonia. 

 They vary greatly in size, and somewhat in other features. Thus O. 

 lanostts is but little larger than a house mouse, while O. inco, O. juliacce 

 and 0. apicalis are as large as a half-grown house rat, with other species 

 intermediate in size. The whole dentition, incisors as well as molars, is 

 weak in all, but in the smaller species is apparently even more reduced 

 than in the larger forms, but the maxillary branch of the zygoma is rela- 

 tively broader and less rounded on the upper anterior border than in the 



