42 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY. 
namon rufous in A. feguina) ; skull lighter and more delicate; rostrum lighter; 
nasals narrower; palatal slits rather wider; audital bullae slightly larger; 
molar-form teeth heavier — wider. 
Color. — Upper parts uniform dark yellowish brown (a color that might, 
perhaps be called tawny burnt-umber) under parts, broccoli-brown; hands, 
feet, tail, and ears, blackish (slightly grayer, less intense black than these 
parts in A. teguina apricus ; due to greater hairiness). 
Measurements — 
No. Sex. Total length. Tail vert. Hind foot. Ear. 
10,240 type & old ad. 145 65 17 14 
10,239 & ad. 140 65 17 13 
10,241 & yg. ad. 127 56 18 13 
_ Skull. ¢ old ad. type, basal length, 19.2; occipitonasal length, 22.6; 
zygomatic width, 11.6; mastoid width, 10.8; interorbital width, 4.2; length 
of nasals, 8.6; width of nasals, 2.6; length of palate, to palatal notch, 9.6; 
upper molar series, 4; length of single half of mandible, 13. 
Remarks. — The little Akodon of the summit of Volcan de Chiriqui is very 
different from the one found at lower altitudes and is entitled to full specific 
rank. The three examples were taken on the desolate top of the Volcano, a 
little below actual timber line, but still where the forest had become stunted 
and sparse. Like A. teguina apricus they were found in open rocky country. 
Macrogeomys cavator,!sp. nov. + 
Type. — Mus. Comp. Zool., No. 10,881, old ad. @, Boquete, Mar. 9, 1901. 
4,800 feet. 
Twenty-six specimens, both sexes, Boquete, 4,000 to 7,000 feet. February, 
March, and April. 
Characters. — Differs from the four known Costa Rican species, though 
nearest M. dolichocephalus Merriam. Compared with the type of that species, 
the skull is shorter and wider across zygoma; nasals, longer; distance from 
postorbital process to back of zygomatic arch, shorter; audital bulle, flatter; 
sagittal and lambdoidal crests, heavier; zygomatic arch heavier and more 
angulated, standing widely and squarely out from skull. Color, very dark and 
nearly uniform —not pied as in the other species. Pelage, short, close, and 
rather harsh. 
Color. — Upper parts dark seal-brown — almost black ; under parts similar 
but slightly grizzled, the pelage sparse, so that the skin shows through; a 
small white anal patch, and sometimes small white patches under chin and on 
under side of wrists ; whiskers colorless; feet, hands, and tail, naked —in 
dried skin yellowish brown to dusky, the end of the tail black. In many 
1 Cavator, one who hollows out or excavates. 
