CLASS PELECYPODA 
115 
Venericardia incisa Dali, 1902. 
Proc. Acad. Nat. Sci. Phila., p. 714; Proc. U. S. N. M., 26; pi. 63, fig. 4. 
Shell small, polished, with a smooth, lovely olive-green periostracum; 
over eighteen to twenty flat radial ribs separated by linear incised sulci and 
crossed by similar concentric sulci, about as distant as the ribs are wide, 
lunule almost obsolete, no escutcheon visible; beaks moderately high, 
somewhat anterior; hinge delicate, internal margins strongly crenate; 
siphonal end of the valves usually overgrown by a commensal minute 
hydroid. Height, 10; length, 9.5; diameter, 5.3 mm. (Dali.) 
Type in U. S. N. M., No. 109267. Type locality, Unalaska. 
Range. Unalaska to Semidi Islands, Alaska. 
Subgenus Miodontiscus Dali, 1903. 
Venericardia prolongata Carpenter, 1864. 
Plate 2, figs. 5, 6. 
Suppl. Rep. Brit. Assoc., pp. 236 and 642. 
M. testa parva, solida, tumida, compacta, albida; ventraliter antice 
valde prolongata, excurvata; lunula longa, rectiore, haud impressa; 
umbonibus antice inflectis, obtusis, valde prominentibus; margine dorsali 
postico parum excurvato; costis radiantibus; x.-xii. latis, obtusis, marginem 
attingentibus, parum expressis, dorsaliter obsoletis, a liris incrementi con- 
centricis, plus minusve distantibus, expressis, hie et illic interruptis; intus, 
margine a costis plus minusve obsoletim crenulato; cardine dentibus v. 
dextr., uno postico, inter duas fossas, elongato, et lat. ant. lunulari; v. 
sinistr., dent. ant. triangulari, post, valde elongato, lat. ant. minimo, 
obsoleto; cicatr. add. subrotundatis, ventraliter sitis. (Carpenter.) 
Shell small, high, the anterior end longer, with narrow umbos and 
radial ribbing, a well-marked lunule and escutcheon present, the hinge 
with the right cardinal absent and a posterior right and anterior left 
lateral feebly developed. Length, 5; height, 5; diameter, 3 mm. 
Type in U. S. N. M. Type locality, near Neah Bay, Washington. 
Range. Middleton Island, Alaska, to San Diego, California. 
Venericardia meridionalis Dali, 1916. 
Proc. U. S. N. M., 52:408. 
Shell small, solid, white, with nine or ten strong rounded adjacent 
radial ribs cut by about as many concentric incised lines, the segments of the 
ribs more or less swollen; beaks small, erect, no visible lunule, or es¬ 
cutcheon; teeth strong; inner basal margin coarsely crenulate. Length, 
4; height, 4; diameter, 2 mm. (Dali.) 
