156 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL, I28 



means of obtaining amphipods in sufficient numbers to supply food 

 for survival. 



Since many of the amphipods cannot be identified in the field or 

 even in the laboratory without painstaking dissection of minute mouth 

 parts, it was impossible to keep as detailed collection data or natural- 

 history notes as the writer wished. However, complete records were 

 kept on the many species that are quite distinctive and easy to identify. 

 As a rule taxonomists studying amphipods see only the preserved 

 dead material, from which the color has completely faded or, at least, 

 has changed. In working with the amphipods at Point Barrow it 

 was noted that many of them have distinctive eye colors that fade out 

 so completely in preservative that it is sometimes difficult to locate 

 the eyes at all. The writer believes that by correlating adequate color 

 notes on the living animal with subsequent determinations of other 

 characteristics it would be possible in many instances to identify many 

 of the amphipods by eye color without dissecting them. 



The writer is indebted to Clarence R. Shoemaker of the U. S. 

 National Museum for identifying the amphipods, which comprised 

 about 100 species, including about 8 new ones (see Shoemaker, 1955). 



The commensal phronimid Hyperoche mcdiisariim (Kroyer) was 

 not found associated with certainty with any particular species of 

 jellyfish but was taken in plankton tows and from the beach. The 

 closely related Hyperia mcdusariim (Miiller) was much more abun- 

 dant, and large numbers could be found on the beach when storms 

 carried jellyfishes ashore. It appeared to be commensal with both 

 Chrysaora and Cyanea. Evidence indicates that there are two or 

 more generations of this species per year. The eggs, which are about 

 0.4 mm, in diameter, are white. Juveniles were taken on July 21, 

 1950. Dunbar (1942a) found this species, which is not often taken 

 in the Arctic and is rarely found at the surface, less abundant in the 

 Canadian eastern Arctic than Hyperoche. 



The free-living, widely distributed Arctic phronimid Themisto li- 

 bellula (Mandt) was extremely abundant, but during the summer of 



1948 only a few were taken in plankton tows or picked up on the 

 beach. By contrast, during almost the entire month of September 



1949 Themisto was washed ashore, sometimes in such enormous num- 

 bers as to form rows along the beach for miles. On September 12, 

 1949, there were three rows of Themisto at distances of about 4, 6, 

 and 15 feet above the waterline (see "Records of Surf Conditions and 

 Shore Collecting"). At no time were ovigerous females found, but 

 many newly molted specimens in which reddish-brown egg masses 

 were visible through the integument were collected on the above date. 



