1915. ] 



THOMOMYS BOTT^ GROUP. 



47 



Color. — Upperparts uniform clear rusty ochraceous or almost 

 snuft brown, brighter than in hottse and wdth less black; underparts 

 hght buffy ochraceous^ m strong contrast with upperparts; feet and 

 distal haK of tail and usually hps and chin whitish. Summer and 

 winter pelage identical in all specimens examined. 



ShuU. — Similar to that of hottse, but shghtly wider in proportion 

 to length; middle of malar arch more indented; auditory meatus less 

 inflated; lateral ridges not meeting in old males; nasals wide and not 

 sharply emarginate posteriorly. Dentition about the same as in hottse 

 or shghtly heavier. 



Measuremnents . — Average of 5 topotypes ( ad.); Total length, 

 264; tail vertebrae, 88; hind foot, 33. Average of 5 topotypes 

 ( $ ad.) : 226, 77, 30. Slcull (of topotype, ad.) ; ^ Basal length!^ 43; 

 nasals, 16; zygomatic breadth, 30; mastoid breadth, 23; alveolar 

 length of upper molar series, 9. 



Remarks. — The subspecies laticeps is closely related to hottde, but 

 seems not to intergrade directly with it, as a smaller form of hottse 

 comes between. It can stand, however, as a weU-marked subspecies. 

 Specimens from the region of Humboldt Bay only are typical, while 

 those from Crescent City are slightly paler. Two from Rio Dell 

 may be grading toward leucodon and a small female from Alton 

 Junction is doubtfully referred to laticeps. Specimens from Cuddeback 

 and Hoopa are clearly intermediate between laticeps and leucodon, 

 but are referred to the latter. 



Specimens examined. — Total number, 90, as follows: 



California (coast region of Humboldt and. Del Norte Counties): Alton Junction, 

 1; Areata (on Humboldt Bay), 49; Crescent City, 10; Eureka, 1; Requa, 6; 

 Rio Dell, 2 ; Smith River, 2 : Table Bluff (on Humboldt Bay), 16; Trinidad, 3. 



THOMOMYS BOTT^ LEUCODON Merriam. 

 White-Toothed Pocket Gopher. 

 (PI. n, fig. 11; PL ni, fig. 5.) 

 Thomomys leucodon Merriam, Proc. Biol. Soc. Washington, XI, 215, July 15, 1897. 



Type. — Collected at Grants Pass, Rogue River YaUey, Oregon, by 

 Clark P. Streator, December 17, 1891. Type specimen in U. S. Nat. 

 Mus., Biological Survey collection. 



Distrihution. — Portions of northern California and southwestern 

 Oregon, from Grants Pass, Oreg., south to Fairfield and Placerville, 

 Cal. (fig. 6). 



Characters. — Smaller, fighter, and brighter colored than hottse; in 

 winter pelage, very similar in color and markings to laticeps, much 

 brighter in summer pelage; skull short and mde, with slender, pro- 

 jecting incisors, which are generally white or white tipped and with 

 obscure inner grooves; mammae in 4 pairs. 



iNo, 58452, U. S. Nat. Mus. 



