. Fresh-water biology. Freshwater biology. IOI2 FRESH-WATER BIOLOGY 151 (152) Male and female shells alike. Whole outer gill serving as marsu- pium, its edge thrown into a number of folds. Shell elon- gate-triangular, solid and thick; hinge complete; hinge plate wide and fiat. Ptychobranchns Simpson. The typical species, P. phascolus Hild. (Fig. 1515; X 1), is common, ranging from Michigan south to Alabama and Louisiana. Five other species are known, four in Alabama and one in Fig. 1S15. IS-' (153) Male and female shells alike. Marsupium occupying nearly the whole of the outer gill
. Fresh-water biology. Freshwater biology. IOI2 FRESH-WATER BIOLOGY 151 (152) Male and female shells alike. Whole outer gill serving as marsu- pium, its edge thrown into a number of folds. Shell elon- gate-triangular, solid and thick; hinge complete; hinge plate wide and fiat. Ptychobranchns Simpson. The typical species, P. phascolus Hild. (Fig. 1515; X 1), is common, ranging from Michigan south to Alabama and Louisiana. Five other species are known, four in Alabama and one in Fig. 1S15. IS-' (153) Male and female shells alike. Marsupium occupying nearly the whole of the outer gill and, when fully developed, folded. Shell solid, round-triangular; hinge complete; hinge plate wide and flat; surface sculptured by irregular ridges and humps, painted \\ith undulating, radiating, broken hair- lines or maculations. . Dromiis Simpson. Only two species are known, both from the Tennessee and Cumberland river systems. Type, D. dramas Lea (Fig. 1516; X a).. 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 Ward, Henry Baldwin, 1865-1945; Whipple, George Chandler, 1866-1924. joint author. New York, John Wiley & sons, inc. ; [etc. ,etc. ]
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectfreshwa, bookyear1918
