LYMN#ID2 OF NORTH AMERICA. iss 
specimens were killed when seventeen weeks old, the smallest speci- 
men being 4 mill. long and the largest 27 mill. No reason is apparent 
for the disparity in size. 
], LENGTH OF LIFE. 
The duration of life in the family Lymnzidz is from three to 
four years, full maturity being reached in about two years. Dr. Lyon 
has successfully raised Galba reflexa until fifty-two weeks old, the 
measurements at different stages of growth being as follows: 
6 weeks; length, 2.00; width, 1.50 mill. 
12, 7 . 500s Cy ae 
ee eee < S iteos: 500. 
Ge os cas Tisoom, & % 600 
iG wt ©" Mesp see 750 “ 
il © 21h: anon 
on. oe) 2500; | & 0G —* 
aS “og 5p: D507 i 
Be. # SNS 26007 °°.) Arsene 
5D ft fe 98505 1 < A050" ae 
Radix auricularia was raised by Mr. Woodruff until four weeks 
o!d, with the following result : 
When hatched, length 0.75; width .65 mill. 1% whorls’ 
12204 hours, old, ~“* oS — Sahat), a a 
2 weeks “ oh 6.50; fh 4.50 es 3 he 
4 “ “ce “ce 14-50% “ 8.00 “ 3% “ec 8 
m. BIBLIOGRAPHY. 
The following works have been consulted in the preparation of chapter II: 
Adams, C. C., 1906.—Andre, Emile, 1901.—Baker, F. C., 1902; 1906, b— 
Braun, M., 1888.—Brot, A., 1877.—Bunker, Robert, 1880.—Call, R. E., 1884.— 
Chaster, G. W., 1899.—Clessin, S., 1873, 1877, 1880.—Cockerell, T. D. A., 1885.— 
Colton, H. S., 1908—Cooke, A. H., 1895—Crowther, H., 1896.—Dall, W. H., 
1896—DeVarigny, H., 1894.—Fischer and Crosse, 1874.—Fischer, Paul, 1883.— 
Forel, S. F. A., 1869; 1874.—Friedel, Ernst, 1870.—Gleason, H. A., 1909.—Heyne- 
mann, D. F., 1868.—Hogg, Jabez, 1854; 1870.—Jeffery, W., 1882.—Jones, K. H., 
1899.—Jordan, H., 1883; Jordan and Copeland, 1877.—Lankester, E. R., 1874.— 
Leidy, J., 1887.—Lewis, J., 1868, a—Linden, Maria, Grafin von, 1891—Martens, 
E. von, 1899.—Ortmann, A. E., 1909—Pauly, A., 1877.—Pilsbry, H. A., 1896.— 
Ruthven, A. G., 1904.—Semper, Carl, 1874; 1881.—Siebold, C. Th. von, 1875.— 
Sterki, V., 1891, a—Stearns, R. E. C., 1900; 1901.—Stubbs, A. G., 1898.—Sykes, 
E. R., 1894.—Tryon, G. W., 1882.—Walter, H. E., 1906— Whitfield, R. P., 1882.— 
Wiedersheim, Prof., 1879—Willem, V., 1896—Woodword, S. P., 1856.—Young, 
12 alsieash 


1Shell white, vitreous, transparent. 
*Columellar plait very prominent, 
’Last whorl wide and shell globular. 
See the bibliography at the end of the volume. 
