. The edible clams, mussels and scallops of California. Mollusks; Shellfish. — 16 — ff. Lower edge of pallial sinus not \mited with pallial line; cartilage pits unequal, tliat on tlie left \ alve on a conspicuous projecting tooth; retracted siphons usually not projecting beyond the shell, tip with- out plates; umbo not nearer the anterior end of the shell, g. Umbo central ; valves rounded and slightly gaping at the posterior (siphonate) end. Soft-shell Ml/a urenaria p. 56 ; pi. 17 , figs. 2, 3 gg. Umbo nearer the posterior end of sliell; valves truncated and widely gaping at posterior end. Pla
. The edible clams, mussels and scallops of California. Mollusks; Shellfish. — 16 — ff. Lower edge of pallial sinus not \mited with pallial line; cartilage pits unequal, tliat on tlie left \ alve on a conspicuous projecting tooth; retracted siphons usually not projecting beyond the shell, tip with- out plates; umbo not nearer the anterior end of the shell, g. Umbo central ; valves rounded and slightly gaping at the posterior (siphonate) end. Soft-shell Ml/a urenaria p. 56 ; pi. 17 , figs. 2, 3 gg. Umbo nearer the posterior end of sliell; valves truncated and widely gaping at posterior end. Platyodon Platijodon cancellatus p. 62 ; pi. 17 . fig-. 1. Fig. 17. Mya arenaria. One-half natural siz:^. (A) Interior right valve. (B) Exterior of portion of left valve. dd. Shell with anterior half sharply marked off from posterior, roughened and obviously adapted for boring in rock or clay; hinge region protected either by a membrane or by accessory plates. (See Fig. 14.) e. Shell gaping widely at both ends throughout life; a membrane but no accessory plates covering hinge region. PIddock gahbi p. 63 ; pi. IS , fig. 1 ee. Shell of adult closing completely or gaping only moderately, siphons com- pletely retractile, accessory plates present over hinge region, f. Siphonal end of valve formed in large part by soft epidermal scales; accessory plates long and slender. Borer Pavapliolas californica p. 64 ; pi. 19 , fig. 1 f f. Siphonal end of valve with epidermal scales which cover the firm shell; accessory plate short and triangular. Rock clam PhnUtdldea penita p. 64 ; pi. 19 , fig. 2. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Weymouth Frank Walter; California. State Fisheries Laboratory; California. Fish and Game Commission. Sacramento : California State Printing Office
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectmollusks, bookyear192
