NO. mo. SYNOPSIS OF NORTH AMERICAN TELLINIDJE— BALL. 323 



MACOMA SITKANA new species. 

 (PlatelV, fi«rH.(}, 7.) 



Shell thin, calcjircous, elongato, nearly ecjuilateral, white, with a 

 dull papvraceou.s, grayish-olive perio.stracuni; surface marked only by 

 lines of growth, which are stronger posteriorly; anterior end larger 

 and pretty evenly rounded, posterior end attenuated, rather squarely 

 truncate, flexuous, and moderately gaping; hinge delicate, normal; 

 pallial sinus di.screpant in the two valves, in the right valve shorter 

 and higher and about half confluent below, in the left longer, nearly 

 reaching the adductor scars and almost entirely confluent with the pal- 

 lial line below. Lon. 41, alt, 26, diam. 10 mm. 



%?6.— No. 108656, U.S.N.M., dredged at Sitka Harbor, Alaska, in 

 15 fathoms, ])y W. H. Dall. 



This species is nearest Macoriia calcarea Gmelin, which is less slender, 

 larger, heavier, and more inequilateral, the outline of the pallial sinus 

 in the left valve is more gibbous and less confluent below, and the 

 beaks much more conspicuous. 



MACOMA LEPTONOIDEA Dall. 



(Plate IV, tigs. 4,9.) 

 Macoma leptonoidea Dall, Nautilus, IX, July, 1895, |). o.'j. 



Type specimen. — No. 125532, U.S.N.M., from Matagorda Bay, 

 Texas; Lloyd. Figured specimen No. 108579, U.S.N.M., dredged 

 in 382 fathoms green mud, Santa Barbara Channel, California, by the 

 U. S. Fish Commission, at station 2903; and also found at station 

 2904, near by, in 314 fathoms, the bottom temperature being 44^ F. 



The occurrence of this species in two such different localities is diffi- 

 cult to explain; the facts, however, seem be3^ond question, and the 

 specimens show no differences whatever. Several years intervened 

 ))etween the receipt of the Texas specimen and that of the bottle of 

 dredgings from California, so that there seems no opportunity for a 

 confusion of labels. As the species has not hitherto been figured, illus- 

 trations of it are now furnished. 



MACOMA ALASKANA new species. 

 (Plate III, fig. 5.) 



Shell small, very inequilateral, moderately inflated, white, with a 

 polished pale-greenish periostracum; })eaks low ))ut acute, two-fifths 

 of the whole length of the shell from the posterior end; anterior end 

 produced, evenly rounded, posterior end descending rapidly to a rather 



