. Fresh-water biology. Freshwater biology. 38 (37) Shell sinistral; early whorls flattened and carinate above; base funic- ular Section Pierosoma Dall. This group includes nearly all the larger North American Planorbes and is represented by numerous species found in all parts of the country. Type, Planorbis trivolvis Say, (Fig. 1428). Fig. 1428. 39 (40) Shell sinistral; aperture campanulate; lip thickened. â ^ ~ Subgenus Planorbella Haldeman. The typical form, Planorbis campanulalus Say, (Fig. 1429; X iJ), is of common occurrence and wide distribution in eastern Canada and the United States no
. Fresh-water biology. Freshwater biology. 38 (37) Shell sinistral; early whorls flattened and carinate above; base funic- ular Section Pierosoma Dall. This group includes nearly all the larger North American Planorbes and is represented by numerous species found in all parts of the country. Type, Planorbis trivolvis Say, (Fig. 1428). Fig. 1428. 39 (40) Shell sinistral; aperture campanulate; lip thickened. â ^ ~ Subgenus Planorbella Haldeman. The typical form, Planorbis campanulalus Say, (Fig. 1429; X iJ), is of common occurrence and wide distribution in eastern Canada and the United States north of Tennessee. Fig. 1429. 40 (41) Shell dextral, much depressed; upper surface convex, base flattened; body-whorl carinate; lip simple. Subgenus Tropidiscus Stein. A single species. Planorbis cuUratus Orb., (Fig. 1430; X 2), of this (in America) tropical group has been collected in Texas and Florida. (.\'.~Mm']l_ 1 Fig. 1430. 41 (42) Shell small, dextral; periphery carinated; base convex; aperture oblique; lip simple Sutsgenus Hippuetis Agassiz. A group of small species of general distribution through the Northern States and Canada. All of our species belong to the section Menetus H. & A. Adams, of which the type is Planorbis opercularis Gld., (Fig. 1431; X 3), from CaUfornia. 42 (35) Shell small, depressed; body-whorl rounded or obtusely angulated; lip simple Subgenus Gyraulus Agassiz . 43. 43 (44, 4S) Surface spirally striate and hispid. Section Gyraulus 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
