SYSTEMATIC INDEX. 



CLASS I. 



MOLLUSCA GASTEROPODA. 



ORDER TRACHELIPODA. 



Family I Neritacea. 



Genus 1. 



Neritina Lamarck. 



1. fluviatilis... p. 1, pi. I, f. 1, 2, 3 



Family II Peristomida. 



Genus 2. 

 Paludina — Lamarck. 



1. vivipara p. 3, pi. I, f. 4, 5 



2. Achatina p. 4, f. 6, 7 



3. impura 8, 9 



4. ventricosa p. 5, f. 10, 11 



Genus 3. 



AssiMiNiA Leach. 



1. Grayana ... p. 6, pi. I, f. 12, 13 



Genus 4. 

 Valvata. — Milller. 



1. piscinalis... p. 6, pi. I, f. 14, 15, 

 variety 16, 17 



2. cristata p. 7, f. 18, 19, 20 



Family III Lymn^cea. 



Genus 5. 



LymnjEA Lamarck. 



Section 1 . — Elongate ; volutions gra- 

 dually enlarging ; spire longer than 

 the aperture. 

 1. stagnalis... p. 28, pi. 1, f. 21, 22, 

 23, 24, 25 



Lymnjka. 



2. palustris p. 9, pi. 11, f. 1, 2 



varieties... 3, 4, 5, 6,. 7, 8, 9, 10 

 .3. minuta pL I, f. 26. 27 



4. elongata p. 10, pi. Ill, f. 1, 



2, 3, 4 



Section 2 Subovate; body ventri- 



cose ; aperture longer than the spire ■ 



5. auricularia... p. 11, pi. II, f. 11, 



12, 13, 14 



6. pere^a... 15, 16, 17, 18, 19, 20, 



21, 22, 23, 24, 25 



7. involuta p. 13, f. 27 



Genus 6. 

 Amphipeplea. — Nilsson. 



1. glutinosa... p. 13, pi. Ill, f. 7, 8 



2. lacustris p. 14, f. 5, 6 



Genus 7. 

 Physa. — Drapernaud. 



1. fontinalis... p. 15, pi. Ill, f. 13, 14 



variety H, 12 



variety 15, 16 



2. acuta p. 16, f. 9, 10 



3. hypnorum 17, 1*^ 



Genus 8. 



Planorms Miiller. 



Section 1. — Volutions devoid of a 



carina, rounded on both sides ; 



spire slightly concave. 



1. corneus ... p. 17, pi. HI, f. 21, 



22, 23 



