242 
INDEX. 
Shell of bivalves, 10; of slugs, 67. 
- structure of, in bivalves, 11 ; in snails, 46. 
-parts of, in univalves, 44. 
Sinistral shells, 45. 
S liggaun, 31. 
Slugs (family Limacidse), 66 ; differences between slugs and 
snails, ib. ; shell of slugs, 67 ; medicinal properties of, 
ib. ; lingual ribbon of, 68 ; slime of, ib. ; genera of, ib .; 
glutinous suspending thread of, 78 ; preservation of, 90. 
Snails. See Land Snails. 
Species, definition of, 5. 
Spiral lines on shells, 45. 
- operculum , 46. 
Stomach of bivalves, 14. 
Structure of shell in bivalves, 11; in univalves, 46. 
Sub-kingdoms of animals, 2. 
Succinea, genus, 174 ; characters and definition of, ib. 
- elegans, 175. 
-oblonga, 176. 
- putris, 174; teeth of, ib. 
Suture , 44. 
Swan mussel, 30. 
Synoptical table of the families of the Pulmonifera, 66; of the 
genera of the Helicidee, 99 ; of the species of Helicella, 
104; of Helix, 111 ; of Pupa, 153 ; of Vertigo, 158 ; 
of Clausilia, 166 ; of the genera of the Limnseidse, 
184; of the species of Planorbis, 211. 
T. 
Teeth of bivalves, 12. 
Tentacles of snails, 47 ; structure of, in Helix, 92. 
Testacella haliotidea, 84 ; tongue of, 87 ; reproduction of, 
88 ; hybernation of, ib. 
- Maugei, 89. 
Thickness of bivalve shells, 11. 
Transverse lines on shells, 46. 
