24 
1856. Lewis, James: List of Living Mollusca in Little Lakes, Otsego County, N.Y.; 
Proc. Bost. Sac. N.H., VIII, p. 260. Trivolvis. 
1856. Carpenter, P. P.: Rept. Moll. West Coast N.A., pp. 210, 316. Binneyi. 
1857. Dawson. J. W. (?) : Description of Some of the Fresh Water Gastropods 
Inhabiting the Lakes and Rivers of Canada; Can. Nat., II, p. 202. 
“Seetns little more than exuberant growth of this shell. ” Large form of 
trivolvis. 
1858. Complete Writings of Thomas Say, etc., Binney’g Ed., p. 128, PI. 74, fig. 9. 
Corpulentum. 
1859. Chenu, L. C. : Man. de Conch., I, p. 482, f. 3560. Binneyi. 
1859. Cooper, J. G.: Pacific R.R. Report, Mollusca, p. 378. Binneyi. 
1860. Lapham, I. A.: A List of the Shells of the State of Wisconsin; Proc. Acad. 
Nat. Sci. Phil., p. 155. “N.W. Territory, Say.*' Corpulentum. 
1861. Tristram, H. B.: Cat. Coll. Terr, and Fluv. Moll, in Guatemala; Proc. Zool. 
Soc., p. 231. This reference might have been based on specimens of 
tenuis or caribaeum. None of the large Pierosoma is found in Central 
America. 
1863. Whiteaves, J. F.: On the Land and Freshwater Mollusca of Lower Canada; 
Can. Nat. and Gcol., VIII. p. 104. Under trivolvis , corpulentus is said 
to be but a variety of the former species. 
1864. Carpenter. P. P.: Supplement to Rept. on Moll. West Coast of N.A., pp. 532, 
558, 599, 607, 675. Binneyi. 
1865. Binney, W. G.: Land and 1 Fresh-water Shells of North America, pp. 114, 115; 
Smith. Misc. Coll., 143. The true corpulentus is figured and described 
on p. 114, after Say. Figs. 191 and 192 of p. 115 are binneyi. Fig. 193 
is occidentale Cooper. 
1867. Tryon, Geo. W.: Am. Jour. Conch., Ill, p. 197. The corpulentus of Gould, 
Haldeman, and Binney is here described as binneyi. Tryon considers 
corpulentus Say a synonym of trivolvis. 
1870. Tyron, Geo. W.: Con. Hald. Mon. Freshwater Shells U.S., pp. 199, 204, Refers 
the figures of Haldeman and Binney to binneyi. Considers corpulentus 
a synonym of trivolvis. 
1872. Carpenter, P. P.: Mollusca of Western North America, pp. 18, 44, 85. 93, 161. 
Binneyi. 
1873. Strebel, IJ.: Beitr. Mex. Land-und Sussw.-Conch., I, p. 39, PI. 5, fig. 19. 
Planorbis trivolvis or corpulentus. Later described as Planorbis tenuis 
var. strebelianus by von Martens, in Biol. Cent.-Amer., p. 385 (1899). 
1875. Dawson, George M.: Land and Fresh-water Mollusca collected during Sum- 
mers of 1873-74, etc.; British N.A. Boundary Com., Report on Geology 
and Resources, etc., Appendix E, p. 349. Flag island, Lake of the Woods. 
Dawson remarks that if corpulentus is a variety of trivolvis it is a well- 
marked one. Although no specimens have been examined from this 
expedition there is every reason to believe that these specimens were the 
true corjmlentus. 
1876 (?). Sowerby, G. B.: Reeves’ Conch. Icon., XX, fig. 4. Binneyi. 
1876. Ingersoll, Ernest: Report on the Natural History of the United States Geological 
and Geographical Survey of the Territories, 1S74; Ann. Rept. U.S. G. and 
G. Surv. Terr., 1874, p. 404. Oregon and Washington references are 
binneyi ; lake Osoyoos and Okanagan river are binneyi. 
1881. Stearns, R. E. C. : Observations on Planorbis; Proc. Acad. Nat. Sci. Phil., 
pp. 94, figs. 4, 4a; p. 103, figs. 18, 19 are binneyi. In the list of species 
on p. 101 the forms represented are: Indian river, Texas (error for Indian 
