MARINE MOLLUSKS — MACGINITIE 181 



Macoma calcarea (Gnielin, 1792) 



Plate 24, figures 5-7; Plate 26, figures 6-9 



Tellina calcarea Gmelin, 1792, vol. 7, p. 3236. 



Macoma calcarea Oldroyd, 1924, p. 173, pi. 42, fig. 5.— Abbott, 1954, p. 430, fig. 

 88f (outline drawing). 



This was one of the three most abundant species of bivalves col- 

 lected in the area investigated at Point Barrow, and over 200 speci- 

 mens were taken. It was found at all stations having a muddy 

 bottom, including the stations at 477 feet (2 small, 8.5 mm. and 10.5 

 mm. long) and 741 feet (2 small, about 8 mm. and 11 mm.; 1 large, 

 the next to the largest specimen taken, 41.3 by 27.5 by 12.3 mm.). 

 A few small specimens were taken from bottoms characterized by 

 rocks and stones: 1 (7.5 mm. long) from 295 feet; 1 (5 mm.) from 341 

 feet; and 1 (9 mm.) from 453 feet. The others came from stations 

 with originally muddy bottoms or stations where mud had been 

 deposited in the autumn of 1949. The majority of specimens range 

 between 13.5 and 37 mm. in length; the largest (47.5 mm. long by 26 

 mm. high) came from 141 feet. 



In addition to those mentioned above, small specimens were col- 

 lected as follows: 3 (between 8.5 and 11 mm.) from 72 feet on July 

 21, 1950; 1 (about 6 mm.) from 120 feet; 1 (about 8 mm.) from 130 

 feet; 25 (between 8.5 and 17.5 mm.) from 132 feet; 2 (about 7 mm.) 

 and 8 (between 13.5 and 17 mm.) from 148 feet; 1 (about 2.5 mm.) 

 from 151 feet; 1 (about 5 mm.) from 162 feet; 1 (about 7 mm.) from 

 185 feet; 9 (between 8.5 and 20 mm.) from 204 feet; and 8 (between 

 9 and 21 mm.) from 213 feet. The haul from 132 feet also yielded 

 13 specimens from 19.5 to 39.5 mm. long and the one from 148 feet 

 yielded 14 specimens from 14.5 to 37 mm. long. 



At Point Barrow, M. calcarea lives in extremely sticky mud, maldng 

 it necessary to wash each specimen separately. Dragging the loaded 

 dredge in the wake of the boat was entu-ely ineffectual — the mud had 

 to be worked over by hand. 



Other material examined: About 40 specimens from localities 

 ranging from Point Barrow to Plover Bay, Kamchatka, Nunivak 

 Island, the Aleutians, and off the coast of Washington (12 specimens), 

 off the coast of Oregon (1 specimen), and Monterey Bay (1 specimen); 

 about 75 specimens from Labrador, Nova Scotia, Newfoundland, and 

 Massachusetts; and over 100 specimens from Spitzbergen, Norway, 

 Scotland, Iceland, and Greenland. 



Discussion: These shells vary from light to relatively heavy; some 

 are considerably higher in proportion to the length than others (pi. 

 24, figs. 5, 6); some are more pointed posteriorly and in some the 

 posterodorsal margin slopes more abruptly than in others; some are 

 more inflated below the hinge than others; and in some the laminate 



