63 
of the back of the animal;—Testacella, and Vi- 
trina. The shells of the two last genera are ex¬ 
ternal. 
Order 3. Trachelipoda. The family Coli- 
rnacea contains the genus Helix, a part of the 
numerous species of which are in this compart¬ 
ment. 
Table 18. Helix continued, together with 
the genera Caracolla, Anostoma, Helicina, 
Pupa, Clausilia, and Bulimus. 
Table 19. The four remaining genera of 
the Colimacea, viz. Achatina, Succinea, Au¬ 
ricula, and Cyclostoma. 
Table 20. The families Melaniana, Pe¬ 
ristomata, and part of the Neritacea, The 
genera of the first are Melania, Melanopsis and 
Pirena : of the second, Valvata, Paludina and 
Ampullaria : of the third, Navicella, Neritina, 
Nerita, and 
Table 21. Natica. The families Janthi- 
nea. Macrostomata, Piicacea, Scalariana, and 
part of the Turbinacea, are also in this compart¬ 
ment. The first has but one genus, Janthina : 
the second, the genera Sigaretus, Stomatella, 
Stomatia, Haliotis : the third, Tornatella, 
Pyramidella : the fourth, Vermetus, Scalaria, 
Delphinula : the fifth. Solarium, Rotella, and 
Trochus. 
Table 22. Monodonta, Turbo, Planaxis, 
Phasianella, and Turritella. Amongst the Sca¬ 
laria, is the costly and beautiful shell S. pre- 
tiosa 
ROOM VIII. 
Nat. Hist. 
