56 GASTEROPODA. HELICID. 
FAMILY II. HELICIDA. 
Corpus spirale, testa spirali tectum. Pes abdominalis. Caput 
tentaculis quatuor; superioribus elongatis, ad apicem oculi- 
geris ; inferioribus brevibus. Organorum Sexualium Apertura 
antica, sub tentaculo superiore dextro* posita. 
Synopsis Stirpium. 
I. Testa spiralis, anfractu ultimo maximo. 
Stirps 1. Umbilicus nullus. 
II. Testa subglobosa, orbicularis aut depressa. 
Stirps 2. Testa subglobosa, inzequilateralis. Umbilicus nullus. 
Stirps 3. Testa subglobosa, inzequilateralis. Umbilicus perfo- 
ratus. 
Stirps 4. Testa depressa aut conica, eequilateralis. Umbilicus 
centralis. 
Ill. Testa turrita. 
A. Apertura inermis. 
Stirps 5. Testa acutissimé turrita. 
Stirps 6. Testa obtusiusculo-turrita. 
B. Apertura denticulata. 
Stirps 7. Testa admodum turrita, smistrorsa. 
Stirps 8. Testa acuminato-turrita. Peritrema perfectum. Um- 
bilicus nullus. 
Stirps 9. Testa subacuminato-turrita, aut obtuse turrita. Peri- 
trema marginatum, interné inchoatum. Umbilicus 
perforatus. Tentacula quatuor; inferiora brevia. 
In common language the Helicide are named Snails; the 
whole of them are terrestrial, and breathe air. 
In all essential points they are very nearly allied to the Li- 
macide, from which they differ, principally, in the spiral form 
of their body, and in the existence of the spiral shell that 
covers it. 
* Sinistro in heterostrophis. 
