10 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 6o 



traction of the squamosal platform, and the greater anterior de- 

 velopment of the basioccipital below the plane of the audital bullae. 

 Specimens examined. — Total number, 15, from localities in eastern 

 Panama as follows: Cana (type locality), 11; Boca de Cupe, 4. 



HETEROMYS CRASSIROSTRIS, sp. nov. 



Type from near head of Rio Limon (altitude 5,000 feet), Mount 

 Pirri, eastern Panama. No. 179016, male adult, U. S. National 

 Museum (Biological Survey Collection), collected by E. A. Gold- 

 man. April 26, 191 2. Original number 21649. 



General characters. — A small species of the desmarcstianus group 

 allied to panamensis, but decidedly smaller, color paler; skull with 

 much broader, more massive rostrum. 



Color. — Ground color of upper parts dark mouse gray, shaded 

 with black on median dorsal area and in a line down rump to base 

 of tail ; slender hairs ochraceous huffy, somewhat altering the gen- 

 eral color and producing a grizzled effect ; under parts, including 

 inner sides of limbs, lips and borders of pouches, white; outer sides 

 of forearms and hind legs dark mouse gray ; fore feet usually 

 white, but sometimes clouded with dusky to near toes, the toes white ; 

 hind feet dull white, changing to dusky on proximal third of meta- 

 tarsus : ankles dusky all round ; tail brownish above, whitish below, 

 in some specimens becoming white all round on a subterminal band 

 or at tip. Young (in first pelage) : Upper parts varying from 

 nearly uniform blackish slate to slate black ; under parts pure white. 



Skull.- — Similar in general to that of panamensis, but smaller with 

 rostrum much broader and heavier ; brain-case rather smoothly 

 r< tunded, the temporal and supraorbital ridges only moderately de- 

 veloped. 



Measurements. — Type: Total length, 267 mm.; tail vertebra?, 

 132; hind foot, 32.5. Average of eight adult topotypes : 266 (255- 

 277); 140 (132-149); 32.9 (31.5-34). Skull (average of five 

 adults) : Greatest length, 34.5 (33.7-35.5) ; zygomatic breadth, 16.3 

 I 15.8-17) ; interorbital breadth, 9.3 (9-9.5) ; nasals, 14 (13.8-14.3) ; 

 width of brain-case in front of projection of auditory meatus, 14.6 

 1 14.5-14.8) : interparietal, 9.4 x 5 (8.2 x 4.8-10 x 5.3) ; maxillary 

 tooth row, -^.2 (5-5.5). 



Remarks. — //. erassirostris is one of the smallest of the known 

 species of the genus. It requires close comparison only with pana- 

 mensis. from which it is quite distinct. The supraorbital shelves are 

 rather weakly developed for a member of the desmarcstianus group 



