FAUNA OF THE ALEUTIAN ISLANDS AND ALASKA PENINSULA 379 



whale (Scheffer 1939). Known at the Akutan whaling station 

 as a "whale louse," this amphipod clings tenaciously to the skin 

 of the whale around the genital opening and, to a certain extent, 

 over the entire body. When pried loose, it immediately seizes the 

 collector's fingers with sickle-shaped claws. 



ISOPODS 



The isopods or sea slaters commonly are found clinging to clamp 

 rocks in the tidal zone. A few species are parasitic on fish. 



Exosphaeroma oregonensis is common throughout the islands, 

 not only in the tidal zone but also in brackish pools some distance 

 from the sea. In Nikolski Lake, on Umnak Island, this isopod 

 was living in water that had, to the taste, no perceptible salt 

 content. The animal curls up into a round ball when disturbed. 



Idothea ochotensis, a large, dark species, was taken only once, 

 in Chichagof Harbor, Attu Island. 



Lygia pattasi is 1 of the 2 most common isopods ; it is flat, lead- 

 gray or blackish brown, with a broadly oval outline. It is found 

 on, or under, damp stones, and it was found from the mainland 

 to Attu Island. It has been taken from fox droppings. 



Idothea ivosnessenskii also is abundant. It is somewhat more 

 slender than Lygia and occupies a similar habitat. 



Mesidotea, Munna, and Synidotea were each collected once. 



Rocinela belliceps is a flesh-colored isopod about 25 millimeters 

 long, with a suffusion of reddish and brown, paler on the ventral 

 side; eyes are black. It attaches to the body, fins, or operculum 

 of the cod throughout the Aleutian Islands. 



SHRIMPS 



Shrimps of many species are found in dredge hauls or are re- 

 covered from the stomachs of cod, sculpins, and halibut. In the 

 1936-38 collections, Argis, Crago, Pandalus, Spirontocaris, Leb- 

 beus, Eualus, and Heptacarpus are represented. Crago alasken- 

 sis and Spirontocaris dalli are represented from more collecting 

 stations than any other species. 



HERMIT CRABS 



Six species of Pagurus are represented in the collections, of 

 which P. hi rsutius cuius is by far the most common. Hermit crabs 

 are found everywhere along the beaches, in shells of periwinkles 

 or larger molluscs. 



