NOTES ON A SMALL COLLECTION OF AMPHIPODS FROM 

 THE PRIBILOF ISLANDS, WITH DESCRIPTIONS OF NEW 

 SPECIES. 



By A. S. Pearse, 



Of the University of Wisconsin, Madison, Wi8C(msin. 



The following notes pertain to a small collection made at St. Paul 

 Island, Pribilof Islands, by Mr. M. C. Marsh and Mr. W. L. Hahn of 

 the United States Bureau of Fisheries. 



ALLORCHESTES MALLEOLUS Stebbing. 



This species was apparently abundant in the skeletonizing box at 

 the village landing, and collections were made on November 30 and 

 December 12, 1911. The color in life was brown or reddish-brown. 

 These specimens are larger (22 mm.) than the total length given by 

 Stebbing for the species (7 mm.). The flagellum of the first antenna 

 is 22-segmented ; that of the second 18-segmented. The last three 

 perseon and the first four pleon segments are carinate dorsally. 



GAMMARUS LOCUSTA (Linnseus). 



About 25 specimens were taken from the skeletonizing box at the 

 village landing, December 12, 1911. Color in Ufe, blue or bluish- 

 black. Length, 17 mm. 



GAMMARUS PRIBILOFENSIS, new species. 



Head with lateral lobes rounded. Side plates 1-3 rather deep; 

 nearly as broad as deep. Pleon segments 2 and 3, posterior angles 

 produced and armed with a seta. Pleon segment 4 with a row of 

 about 12 spinules along posterior dorsal margin; pleon segment 



5 with one strong acute posterior median dorsal spine ; pleon segment 



6 with one submedian and three lateral spines (total '8) on each side 

 of the posterior margin. 



Eyes plump, small, somewhat reniform, black. Antenna 1 not 

 half as long as body ; first segment about as long as second and thii'd 

 combined; flagellum one and one-half times as long as peduncle, 



Proceedings U. S. National Museum, Vol. 45— No. 1 998. 



571 



