308 Mr. O. Thomas on new Mammals 



Skull : basal length 20*5 ; basilar length 18'8 ; greatest 

 breadth 12*4; nasals 10x2"9; interorbital breadth 4, inter- 

 parietal 3*2 X 9*7 ; palate length from henselion 11 ; diastema 

 6'5 ; anterior palatal foramina 5'4 x 1"6 ; length of upper 

 molar series 3"6. Lower jaw : condyle to incisor-tip 15'1. 



Hab. Chilecito, Prov. K,ioja, Argentina, alt. 1200 metres. 



Collected and presented by Dr. F. P. Moreno, the distin- 

 guished head of the La Plata Museum, in whose honour I 

 have named this very pretty little mouse. 



Eligmodon Moreni is most nearly allied to E. elegans^ 

 Waterh. {E. typus, F. Cuv.), but is distinguished by its 

 greater size, longer feet, and heavier muzzle. The type of 

 Waterhouse's species being a bleached and deteriorated skin, 

 and all the examples of the new form being in spirit, it is 

 impossible to compare them very satisfactorily ; but when 

 further specimens are available there is little doubt that, 

 judging by the great distance between the localities, other 

 differences will become appreciable. 



Oxymycterus Iheringiy sp. n. 



Much smaller, more slenderly built, and less Oxymycterine 

 than 0. nasutus, rufus, and the other more typical species. 

 Fur soft and thick. General colour uniform grizzled brown, 

 scarcely paler below. Eyes not unusually small. Ears 

 fairly large, thinly haired, brown. Claws much less length- 

 ened than in 0. nasutus, but still with the essential fossorial 

 structure characteristic of the group ; pollical claw short. 

 Fifth hind toe decidedly longer than the hallux, reaching to 

 the level of the base of the fourth toe. Tail almost as long 

 as tlie head and body, slender, thinly haired, brown above, 

 rather paler below. Mammse 1 — 2 = 6. 



Skull not specially elongated anteriorly, although the 

 muzzle shows something of the characteristic Oxymycterus 

 structure. Supraorbital edges smoothly rounded. Inter- 

 parietal and anterior zygoma-root and other details very much 

 as in 0. nasutus, in spite of the great difference between the 

 two in the general proportions of the skull. 



Dimensions of the type (an adult female in spirit) : — 



Head and body 100 millim. ; tail 94 ; hind toot 23'5 ; 

 ear 167. 



Skull : basal length 23 ; basilar length from henselion 

 21'4 ; greatest breadth 13; nasals llx3'8; interorbital 

 breadth 6 ; breadth of brain-case above meatus 12*5, inter- 

 parietal 2*2 x 7*3; palate length from henselion 10*7; 

 diastema 6"8 ; anterior palatine foramina 52 X 2*2 ; length of 



