64 
ROOM VIII. tached to the fore part of the back of the ani- 
nat. Hist, mal;—Testacella, and Vitrina. The shells of 
the two last genera arc external. 
The Mollusca Thachelipoda, or Spiral 
Shells, commence with the family Colimacea 
and contain the genus Helix, a part of the nu¬ 
merous species of which are in this compartment. 
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, Auri¬ 
cula, and Cyclostoma. 
Table 20. The families Melaniana^ Ten- 
stomata, and part of the Neriiacea» The genera 
of the first are Melania, Melanopsis and Pirena: 
of the second, Valvata, Paludina and Ampul- 
laria: of the third, Navicella, Neritina, Nerita, 
and 
Table 21. Natica. Janthlnea^ 
Macrostomata^ FUcacea, Scalariana^ and part of 
the Turhinacea^ are also in this compartment. 
The first has but one genus, Janthina: the 
second, the genera Sigaretus, Stomatella, Sto- 
matia, Haliotis: the third, Tornatella, Pyra- 
midella : the fourth, Vermetus, Scalaria, Delphi- 
nula : 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 
