. The edible clams, mussels and scallops of California. Mollusks; Shellfish. ii. Valves niai-ked with concentric ridges and sometinics ribs. j. No ladiating ribs, concentric ridges low, rounded, occasionally dividing into two, covered with a heavy, glossy, persistent periostracvnn ; pallial sinus reaching about half way to anterior miiscle sear; valve margin smooth; shell white. Sea cockle Ainiantes callosa p. 34 ; pi. 5 , fig. 3 jj. Radiating ribs picsent, concentric ridges not smoothly rounded n(jr dividing, with thin, grey, easily detached periostracum; pallial sinus small, not deeper than
. The edible clams, mussels and scallops of California. Mollusks; Shellfish. ii. Valves niai-ked with concentric ridges and sometinics ribs. j. No ladiating ribs, concentric ridges low, rounded, occasionally dividing into two, covered with a heavy, glossy, persistent periostracvnn ; pallial sinus reaching about half way to anterior miiscle sear; valve margin smooth; shell white. Sea cockle Ainiantes callosa p. 34 ; pi. 5 , fig. 3 jj. Radiating ribs picsent, concentric ridges not smoothly rounded n(jr dividing, with thin, grey, easily detached periostracum; pallial sinus small, not deeper than diameter of posterior muscle scar; valve margin roughened; shell greyish. Hard-shell cockles Chione k. No distinct lunule or escutcheon, ribs more prominent than concentric ridges in posterior 5 of valve; pallial sinus acute. C. fluctifraoa p. 37 ; pi. 9 , fig. ] kk. Distinct lunule and escutcheon present, concentric ridges usually more prominent tlian ribs in all parts of valve; pallial sinus rounded. 1. Numerous thin, concentric ridges, ribs eveiywhere small and inconspicuous. C undatclla p. 37; pi. 9, fig. 2 1. Fig. 11. Chione succhictd. One and one-third times natural size. (A) Exterior anterior end. (B) Interior right valve. 11. Concentric ridges heavier and less numerous, ribs at pos- terior end more distinct than elsewhere but not more conspicuous than ridges. C. succincta p. 37 ; pi. 9 , figs. 3, 4 lih. Ligament internal, valves lighter, tliin and sharp at edges. Size modei-ato or large, pallial sinus reaching 5 to i distance to anterior muscle scar. Dish shell Spisiila p. 54 dd. .\ninial asymmetrical with valves unlike especially at sipbonate end; shell usually thin and weak particularly at margins (least marked in Semele and TeUiva) ; siphons separate, slender and very long: forms deeply bur- rowing in sand or mud where they are found lying on the side, e. Ligament wholly external ; pallial sinus united with pallial line ; shells generally thin, f. Shell elongated (ab
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectmollusks, bookyear192
