1915.] 



THOMOMYS DOUGLASI GROUP. 



119 



Measurements. — Type ( c? acL): Total length, 222: tail vertebrae, 

 68: Hind foot, 32. ShuU (of type): Basal length, 35.5; nasals, 15; 

 zygomatic breadth, 22.7; interorbital breadth, 6.6; mastoid breadth, 

 18; alveolar length of upper molar series, 7.7. 



Remarlcs. — This is a well-marked form of the douglasi group 

 probably not occurring beyond the margins of the Puget Sound 

 prairies. The heavily timbered areas of western Washington and 

 Oregon seem to exclude pocket gophers, but the scattered colonies 

 of related forms strongly suggest a time when the valley prairies 

 were more extensive in area, and the range of the gophers more or 

 less continuous from Puget Sound to the Umpqua Valley. Isolated 

 colonies have become more or less differentiated in characters. Even 

 those from Roy, Spanway, and Steilacoom, Wash., differ to some 

 extent from the type series from Tenino, but not sufficiently for sep- 

 aration. 



Specimens examined. — Total number, 44, as foUows: 

 Washington: Roy, 19; Spanway, 6; Steilacoom, 16; Tenino, 3. 



THOMOMYS DOUGLASI MELANOPS Merriam. 

 Black-Headed Pocket Gopher. 

 (PI. vm, fig. 6.) 



Thomomys melanops 'SLeniixm, Proc. Biol. Soc. Washington. XIII, 21, Jan. 31, 1899. 



Type. — Collected at timberline at head of Soleduck River, Olympic 

 Mountains, ClaUam County^ Washington, by C. Hart Merriam and 

 Vernon Bailey, August 28, 1897. T}^e specimen in U. S. Nat. Mus., 

 Biological Survey collection. 



Distribution. — Olympic Mountains, Wash. (fig. 5) . 



CJiaracters. — About the size and color of yelmensis, but with more 

 black on nose and head; ears small and pointed; skull long, with 

 upper outline more arched than in yelmensis or douglasi; pterygoids 

 small and wide apart. 



Color. — August pelage: Upperparts dark russet, with dusky *nose 

 and face, and large black ear patches; underparts paler, more ochra- 

 ceous, usually T\'ith white cliin, wrists, and hning of cheek pouches; 

 fore feet pure white; hind feet and tip of tail whitish. 



Shall. — Long and well arched; lower outline of rostrum con- 

 stricted; nasals long and deeply emarginate; premaxillfe wide; inter- 

 parietal very smaU and oval or circular : buU^e narrow, and basioc- 

 cipital wide between them; pterygoids high and wide apart. 



Measureraents. — Type ( 9 ad.) : Total length, 206; tail vertebrae, 63; 

 huid foot, 27. Topotype ( 9 ad.): 202, 58, 27. There are no adult 

 males from the type locality and those from Happy Lake, Wash., are 

 not correctly measured. Sl-cull (of type) : Basal length, 33 ; nasals, 13 ; 

 zygomatic breadth, 20; mastoid breadth, 16; interorbital breadth, 



