PROCEEDINGS

Vol. 32, pp.169-172 September30, 1919

PROCEEDINGS

OFTHE

BIOLOGICAL SOCIETY OF WASHINGTON

A NEW POCKET GOPHER FROM WESTERN WASHINGTON.

BY WALTER

^P.

TAYLOR.

Specimens

^of

pocket gophers

^collectedfor

the

_Biological

Sur- ve

₃^r

by George ^G. Cantwell during the winter

of 1918, ^six miles

south

of

Tacoma,

^Pierce

County, Washington, prove

to repre- sent

a new

_subspeciesof

the

_douglasii

group.

Thomomys

douglasii tacomensis,

new

subspecies.

TACOMA POCKET

GOPHER.

Type.

— From

six miles south of Tacoma, ^Pierce County, Washington;

No. _231,096, U. S. National

Museum

(Biological Survey collection); 9

young

adult; collected

by

George G.Cantwell,

December

24, 1918;original no. 857.

Generalcharacters.

—

Darker than any^othersofthepocketgophers occu- pying^{thelowlandsof}western Washington. ^Similarto

Thomomys

douglasii yelmensis, towhich itappears ^tobe most closely related, but_upperparts andfacedarker; postauricular black area

more

extensive; nasalsnarrower anteriorly. Similarto T.d.melanops,but withinterparietal larger.

Geographicdistribution.

— The

typicalformoccurs ona _prairiesix miles southof

Tacoma,

^PierceCounty, Washington. Specimens from Olympia, Thurston County, andSteilacoom, PierceCounty, ^aretentativelyreferred to this subspecies.

Color.

—

_Upperparts (winter pelage) in general, cinnamon-buff or clay color, grizzled with blackish; face blackish; black postauricular area one centimeter square nearly continuous with blackish of sides of face; nose usuallywithwhite_spots; whiskers, white^orgray;underparts ratherpale, ochraceous-buff_{or light buff,}atrifledarkerin

some

examples, lacking the irregularwhite areas observableincertainspecimensof yelmensis.

Skull.

— As

in

Thomomys

douglasii yelmensis, but nasals averaging nar- roweranteriorly; anterior nasal openings apparentlysmaller; rostrum_ap- parently

more

_slender;craniumalittle

more

_rounded;interparietalaverag- ing shorterandnarrower.

34—

Proc.Biol. Soc.Wash., Vol.32,1919. (169)

170 Proceedings

of^theBiological Society of

Washington.

Remarks.

— The

pocketgophers^oftheisolated prairies ofwestern

Wash-

ington

show

theeffectsof segregation. Broadlyspeaking,one

may

say that those inhabitingeach_prairie represent a^{localvariant.} Whilethecharac- terization ofeachofthesewould be_confusing, the recognition^ofthe

more

obviousformsisdesirable.

Thomomys

douglasii douglasii^isone of these, T. d. yelmensis another, and T. d. tacomensis a third. Specimens from

localities between ^thetype locality ofthe present subspecies

and

that of yelmensis are^of

somewhat

intermediate_character, and might^bereferred to either subspecies, according ^to specimens

now

in hand. Their _precise allocation

must

await theacquisition ofadditionalmaterial.

Specimensexamined.

—

Total

number

_16,as follows:

Tacoma

(6miles_south), PierceCounty,8; Steilacoom, Pierce County, 2;

Olympia

⁽⁴miles south),Thurston County,^6.

Taylor — _New Pocket Gopher from Western Washington.

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