Dwt'tjrfiniix of Xinc New Mammals. 165 



seven specimens'). Total length, 250; tail vertelmr, 80; bind 



foot, ;->o. 



CHI nidi McdxHmiu'iite. Total length of skull of t} r pe, 42 ; basi- 

 lar length (inferior lip of foramen magnum to posterior rim of 

 alveolus of incisor), 35; zygomatie breadth, 25; upper molar 

 series on alveola?, J). 



General Characters. Upper incisors bisected by a median snl- 

 cus ; size smallest of the known species; nose with a vertically 

 elongated naked pad or callosity, above which the hairs are 

 short, stiff, with the tips worn off; tail rather long and naked ; 

 claws moderate; color deep and bright chestnut above and be- 

 low, much deeper than in Geomys tnza from Florida and the 

 eastern Gulf region. An immature but full-grown specimen 

 (No. 33585) is dusky in color, and one in the molt has the an- 

 terior parts chestnut and the posterior dusky. 



Cranial Characters. Geomys nelsoni differs so widely frora any 

 of the species having the upper incisors bisected by a single 1 

 groove that detailed comparison is hardly necessary. Con- 

 trasted with G. clarldi from the Rio Grande region, it may be 

 distinguished at a glance by its much smaller size, more squarely 

 truncated zygomatic arches, absence of triangular plate at the 

 antero-inferior angle of the zygomatic arch, relatively longer and 

 more slender nasals, smaller and more smoothly rounded audital 

 bullse, and mastoids which occupy much less space on the 

 occipital plane, where they present a subquadrangular surface. 



Mr. Nelson states that the species " was found only in some 

 fields at the upper ranch at the foot of the main north slope 

 of the Sierra Nevada de Colima, Jalisco, in the upper border of 

 the lower pine belt, at about 6,500 feet altitude, where it was 

 common, and was found in company with the large species" 

 [here described as Geoiny* gymnurus}. Seven specimens were 

 secured. 



Geomys fumosus sp. nov. 



Typo Xo. 2?J? cT a<l. l y - N. National Museum (Department of Agricult- 

 ure collection). From Colima City, Mexico, March 27, 1H92. Collected 

 by E. W. Nelson. (Original number, 2338.) 



Measurements (in millimeters, taken in flesh by collector). 

 Total length, 2U2; tail vertebra?, 80; hind foot, 41*. 

 General ( 'hanivter*. Size medium, about equalling G. bit 



