74 BULLETIN 138, UNITED STATES NATIONAL MUSEUM 



Measurements. — Holotype, length of carapace 18.4 mm., width in 

 front of lateral spine 27.9 mm. ; f ronto-orbital width 20 mm., width 

 of front 6 mm., length of chela, top view 17.5 mm., length of palm, 

 same view, 9 mm. Approximate length of impression of carapace 

 (Washington, 80) 30.6 mm., width in front of lateral spine 42.6 mm 



Occurrence. — 



ALASKA 



East branch of Redwood Creek; Oligocene series; 12 specimens 

 including 2 males and 3 females ; one specimen embedded in a nodule 

 is selected as holotype; in University of California. 



Nichowak District, just below the lower seepage on Pearl Creek, 

 on Pearl Creek oil claim No. 11; Oligocene series; two specimens 

 (one male). 



WASHINGTON 



I 



Sandstone and shale sea cliffs along west shore of Oak Bay, 1 to ' 

 2 miles south of Portage Spit between Port Townsend and Port ^ 

 Ludlow ; lower ( 'I ) Oligocene series ; one specimen. | 



Sea cliffs between Classens Wharf and the ship canal estuary, 

 Townsend Bay ; lower Oligocene series ; small fragment of linger. 



Vance's Creek, two and one-half miles above junction with Skoko- 

 mish River, 13 miles above Union; lower Oligocene; one specimen 

 and impression, also one palm. 



Tuffaceous sandstone bluffs along the Willapa River north of 

 Holcomb; middle Oligocene; two specimens, a chela and a portion 

 of a large hnger. 



One thousand six hundred feet above first railroad bridge on 

 Willapa River below Holcomb; section 25, township 13 north, range 

 8 west; Oligocene series; impression of a large specimen. 



Near Eugene; upper Oligocene series; one specimen and impres- 

 sion. 



Relations. — This species is easily distinguished from the two preced- 

 ing by its shape ; the carapace is squarer, the orbits wider, the antero- 

 lateral margin shorter. The shape is much like that of certain of 

 the Goneplacidae, as, for example, Tetraplax ^^ and Euryplajx.^^ The 

 areolation, on the other hand, is similar to that of the two preceding 

 species. The upper as well as the under surface of the manus is 

 smoothly rounded, as in Euryplax^ not provided with ridges as in 

 P. tTiangulum described above and as in most Portunids. The outer 



■'■' Ratlibun, Bull. U. S. Fish Coniin., vol. 20, for 1900, pt. 2, 1901, p. 9. 

 " Stimpson, Ann. Lye. Nat. Hist. New York, vol. 7, 1859, p. 60. 



