. Fresh-water biology. Freshwater biology. Fig. 1485. lis (117) Outer gills only serving as marsupia. Shell alike in both sexes; triangular to rhomboid, usually with a prominent umbonal region; beaks at or near the anterior end; beak cavities shal- low; hinge complete; surface smooth, brown to yellow, usually not very dark, frequently rayed. Pleurobema Rafinesque . 116 This is a large group, of which more than seventy species are known. With the exception of a few species found in the Ohio and Mississippi drainage, it is confined to the streams of the Southeastern States from Tennessee and Geo
. Fresh-water biology. Freshwater biology. Fig. 1485. lis (117) Outer gills only serving as marsupia. Shell alike in both sexes; triangular to rhomboid, usually with a prominent umbonal region; beaks at or near the anterior end; beak cavities shal- low; hinge complete; surface smooth, brown to yellow, usually not very dark, frequently rayed. Pleurobema Rafinesque . 116 This is a large group, of which more than seventy species are known. With the exception of a few species found in the Ohio and Mississippi drainage, it is confined to the streams of the Southeastern States from Tennessee and Georgia to the Mississippi. The shells of this genus are easily distinguished from the Quadrulae, which they often resemble by the uniformly shallow beak cavities. Type, P. dava Lam. (Fig. 1487).. Fig. 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
