1915.] 



THOMOMYS TALPOIDES GROUP. 



105 



underparts dark buff with no trace of white in topotype series; feet 

 and tail soiled whitish or buffy. Winter pelage (as shown in long 

 fur retained on rump of type and one topotype): More grayish 

 brown. 



S'kull. — Low and wide, with very short and posteriorly pointed 

 nasals; temporal ridges parallel; interparietal triangular; audital 

 bullae rather small; basioccipital wide between bullae; interpterygoid 

 fossa narrow and sharp. Dentition light; upper incisors strongly 

 projecting; inner grooves not so distinct as in 'talpoides. 



Measurements. — Type ad.): Total length, 210; tail vertebrae, 

 60; hind foot, 29. Average of 2 female topotypes: 201, 53, 28.5. 

 Slcull (of type): Basal length, 34; nasals, 12.5; zygomatic breadth, 

 22; mastoid breadth, 18.5; interorbital breadth, 5.7; alveolar length 

 of upper molar series, 7. 



Remarlcs. — This seems to be a very local form of the higher slopes 

 of the Pryor Mountains, and undoubtedly grades into some of the 

 other forms below. It seems to be distinct from caryi, the gopher 

 on the Bighorn Range, from which it is separated by the deep canyon 

 of the Bighorn River, and also from huUatus, from which it is sepa- 

 rated at Fort Custer by the river. The shallow, slender rostrum and 

 arrangement of mammae place it in the talpoides group, but the pecu- 

 liar nasals and projecting incisors are not found in any of the other 

 forms. 



Specimens examined. — Total number, 7, as foUows: 



Montana: Bighorn River (west side, near Fort Custer), 2; Pryor Mountains 

 (cold slopes, edge of Canadian Zone), 5. 



THOMOMYS TALPOIDES AGRSSTIS Merriam. 

 San Luis Pocket Gopher. 



(PI. Vn, fig. 4.) 



Thomomys talpoides agrestis Merriam, Proc. Biol. Soc. Washington, XXI, 144, June 

 9, 1908. 



Type. — Collected atMedano Ranch (15 miles northeast of Mosca), 

 San Luis Valley, Colorado, by Merritt Cary, October 29, 1907. Type 

 specimen in U. S. Nat. Mus., Biological Survey collection. 



Distribution. — San Luis Valley, Colo. (fig. 8). 



Characters. — Decidedly larger and paler than typical clusius; 

 skull heavier and more conspicuously ridged; more nearly resembling 

 hullatus, but with relatively narrower skull, and larger, more pointed 

 nasals. 



Color. — -Summer pelage: Upperparts buffy or brownish gray, 

 richest along median line of back; ear patch blackish; nose gray; 

 underparts buffy; chin white in two specimens; a white spot on 

 breast in one; feet and tail whitish or buffy gray. Winter pelage: 

 Upperparts lighter, more grayish; underparts whitish or creamy. 



