. The edible clams, mussels and scallops of California. Mollusks; Shellfish. Fig. 6. Modiolus rectus. One-half natural size. bb. Adductor muscles equal or nearly so; umbo not at end of valve in forms here treated (except Solen) ; mantle edges fused in at least two places forming two siphonal apertures, which are usually prolonged into siphonal tubes; adults without byssal attachment; usually capable of moving about by means of the foot; all capable of burrowing to some extent and habitually doing so ; color of shells various ; never black. True clams c. Valves closing completely, or at least w
. The edible clams, mussels and scallops of California. Mollusks; Shellfish. Fig. 6. Modiolus rectus. One-half natural size. bb. Adductor muscles equal or nearly so; umbo not at end of valve in forms here treated (except Solen) ; mantle edges fused in at least two places forming two siphonal apertures, which are usually prolonged into siphonal tubes; adults without byssal attachment; usually capable of moving about by means of the foot; all capable of burrowing to some extent and habitually doing so ; color of shells various ; never black. True clams c. Valves closing completely, or at least wilh no marked gapuig, siphons com- pletely retractile and not visible in the closed shell. d. Shells thick and strong, animal symmetrical with similar valves, siphons usually united and short; if burrowing not lying on one side, e. Siphons extremely short, not projecting beyond shell when extended ; no pallial sinus; not burrowing deeply. (See Fig. 7; compare with Fig. 8). Cockles Curdinm. Fig. 7. Cardiiiiii cor- Fig. 8. Donax laevigata, bis. One - half natural One and one-half times size. natural size. f. Radiating ribs conspicuous and ."sharply raised above surface, g. Ribs roughened. C. co7-his p. 28; pi. 5 , fig. 2 gg. Ribs with rows of spines. C. quadrlfjenayium p. 28; pi. .5 , flg. 1 ff. Ribs faint and gently rounded. C. datum p. 29. 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
