174 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I28 



tion of age difficult. A shell 36 mm. long shows an age of 2 or 3 years 

 and three shells 47, 53, and 54 mm, each show an age of 6 years. 



About 16 living Liocyma flucfuosa (Dall) were taken at depths of 

 152 to 741 feet. This clam forms part of the food of Natica and 

 Polinices and drilled shells are not uncommon. 



With the exception of Hiatella, probably the most abundant species 

 of bivalve at Point Barrow is Macoma calcarea (Gmelin), which was 

 taken from depths of 60 to 741 feet. The greatest number came from 

 y2 feet, where the bottom is a stiff mud of great tenacity. The shells 

 of this species exhibit great variation in the proportion of length to 

 height, degree of inflation, and degree of roundness of the posterior 

 end. Small specimens are higher in proportion to the length than 

 older shells, and it is probable that young calcarea have been confused 

 with adult balthica. Lines of growth are less distinct than in some 

 species, but a shell 18 mm. long was obviously about 2.5 years old 

 and one 39 mm. long was 5 years old. 



A fe\v specimens of Alacoma oneilli Dall and M. moesta Deshayes 

 were taken, the former from 80 to 148 feet, the latter from 50 and 

 80 feet. 



A few living specimens of Mya japonica Jay and M. truncata Lin- 

 naeus were taken, the former mainly at Eluitkak Pass and at 10 feet 

 along the shore, the latter from Eluitkak Pass and from depths of 

 122 to 477 feet. None of these specimens was large. The largest col- 

 lected were those that washed ashore. Individuals of truncata with 

 shells from 37.5 to 41 mm. long appear to be between 4 and 5 years 

 old. 



Three left valves of Panoinya arctica Lamarck were dredged on 

 August 17, 1949, at 522 feet and one shell of Panomya ampla Dall 

 was taken at Eluitkak Pass. 



The most abundant bivalve at Point Barrow is Hiatella arctica 

 (Linnaeus) (=Saxicava arctica). It appeared in hauls from any 

 bottom on which there was some object to which it could attach or 

 some place in which it could nestle, therefore from no to 741 feet, 

 and it was especially abundant at Eluitkak Pass. Even hauls along 

 shore in the gravel zone yielded their quota, for in this region Hiatella 

 attached to several pieces of gravel by means of byssus threads. This 

 bivalve was found between barnacles, clinging to bryozoans, and 

 among old holdfasts. An old shell of Astarte horealis contained 21 

 living Hiatella from 7 to 13.5 mm. in length. A haul from Eluitkak 

 Pass on August 6, 1948, and one from 120 feet on September 15, 1948, 

 contained many hiatellas 2.5 mm. and more long. About half of the 

 mass brought up on August 23, 1948, from 150 feet consisted of old 

 dead shells of Hiatella. 



