172 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I28 



son ( 1944) . He lists four varieties of one species, in addition to the 

 typical form, and refers to intergradations between two of the varieties. 

 The bivalves include one new genus and species and several species 

 that have as yet eluded identification. The prosobranchs include about 

 15 species that are either new or of questionable identity. I am in- 

 debted to my wife, Nettie MacGinitie, for identifying these groups 

 and also the amphineurans. The results of her study will be pub- 

 lished shortly. The opisthobranchs were sent to Dr. F. M. MacFar- 

 land, who died before the identifications could be made. They are 

 now going to Dr. H. Lemche of Copenhagen. Dr. Grace E. Pickford 

 identified the octopuses, and Gilbert L. Voss the single species of 

 squid. Dr. Gunnar Thorson of Copenhagen is working on the egg 

 capsules and larvae. 



Class PELECYPODA 



None of the bivalves was taken in sufficient numbers to be of eco- 

 nomic importance, but bivalves do serve as food for other animals. 

 Serripes groenlandicus and Pecten islandiciis are large enough for 

 food but they never appeared in sufficient quantity to make their col- 

 lection feasible. Macoma calcarea is abundant, but it lives in such 

 tenaciously sticky mud that dredging it is not practicable. 



Nucula tenuis Montagu lives in muddy bottom and was common 

 at depths of 72 to 122 feet, occurring occasionally in hauls down to 

 741 feet. A single specimen of Nuculana arctica (Gray) was taken 

 at 28 feet, and one or two Nuculana minuta occurred in practically 

 every haul from 70 to 741 feet. 



Of the three species of Yoldia found at Point Barrow, Yoldia 

 myalis Couthouy was the most abundant, occurring especially in hauls 

 from 70 to 213 feet, but one specimen was taken at 246 feet, one at 

 295 feet, and one at 453 feet. About 18 specimens of Yoldia hyper- 

 borea Loven were dredged from y2 to 477 feet. Shells of this species 

 from 28 to 32 mm. long are from 2.5 to 3 years old. One shell of 

 Yoldia scissurata Dall was dredged at 141 feet. 



Pecten islandicus Muller usually came up singly in dredge hauls. 

 Six adult specimens were taken from 175, 341, 420, 438, and 522 feet. 

 Juveniles were also rare. The smallest living specimen, which was 

 13 mm. high, was found among foliaceous bryozoans. 



Although Mytilis edulis Linnaeus is the commonest Icelandic bi- 

 valve (Madsen, 1949), only a single valve of this species was dredged 

 at Point Barrow ( Eluitkak Pass), undoubtedly because there is no 

 place in the immediate vicinity where conditions are suitable for such 

 tidal-zone animals as Mytilus. 



