238 INDEX. 
Limnza (pond snails), characters of, 184; food of, 185 ; 
species of, 186 ; geological distribution of, «b. 
— auricularia, 190. 
—— Burnetti, 188. 
—— fossaria, 194. 
—— glaber, 195. 
—— glutinosa, 196. 
—— involuta, 198. 
—— lacustris, 187. 
—— minuta, 194. 
—— octona, 195. 
—— ovata, 187. 
— palustris, 193. 
—— peregra, 186 ; varieties of, 187 ; dispersion of, 188. 
—— stagnalis, 190; teeth of, 191; disappearance and re- 
appearance of, 192. 
truncatula, 194. 
LiunaIp family (water snails), characters of, 181 ; habits 
and reproduction of, 182; peculiar sensation produced 
by, 183; decollation of spire of shells of, 185 ; dispersion 
of, 188 ; disappearance of, 192 ; synoptical list of genera 
of, 184. 
Limpets, fresh-water, 205. 
Lines of growth, 11. 
Lingual ribbon or tongue, described, 48 ; methods of pre- 
paration of, 49 ; mounting of, 7b. ; different sets of teeth 
of, 50; numerical formula of, 51; value of in classifi- 
cation, 2. 
Lips of bivalves, 14. 
Lirrorinip# (family), 62. 
Longitudinal lines on shells, 45. 
Lunule of bivalve shells, 11. 
M. 
Mantle of bivalves, 13. 
Mantle-lobes, 13. 
