INDEX. 233 
Classes of molluscous animals, 3. 
Clausilia genus, 165 ; geological distribution and synoptical 
list of species of, 166. 
bidens, 167. 
biplicata, 166. 
— dubia, 169. 
laminata, 167. 
— Mortilleti, 170. 
nigricans, 168. 
—— perversa, 168. 
— Rolphii, 169. 
rugosa, 168. 
Clausiwm, nature of, 165. 
Ccelenteratous animals, 2. 
Coil snails (Planorbis), characters of, 210; red fluid of, 2b. ; 
geological distribution of, 211; synoptical table of 
species of, ab. ; collecting small species of, 218. 
Cold, effects of, on Paludina vivipara and Anodon cygneus, 
56; on land snails, 97. 
Collecting bivalves, 19 ; small water snails, 218 ; small land 
snails, 223. 
Colour, secretion of, in shells, 46. 
Colourless blood of molluscous animals, 15. 
Columella of shells, 44. 
Composition of shell in bivalves, 11 ; in univalves, 46. 
Concentric operculum, 46. 
Conchiferous animals, 3. 
Conovulus bidentatus, 179. 
denticulatus, 178. 
—— myosotis, 179. 
—— pyramidalis, 179. 
Corbicula consobrina, geographical distribution of, 43. 
Crystalline style in stomach of bivalves, 14. 
CycLapDIp& (family), 32; genera of, 33. 
Cyclas (genus), 33. 
calyculata, 36. 
