104 CONCHOLOGY. 



FAMILY VI. 



LiMAciNEA. Five genera. 



1. Onchidium. Has no shell. Two species. 



Onchidium Typhae. Onchidium Peronii. 



2. Parmacella. One species. 

 Lamarck has given a description of the animal of this ge- 

 nus, but only mentions that the scutcheon contains a shell or 

 solid crustaceous body. 



Parmacella Olivieri. 



3. Limax. Four species. 



The animal belonging to this genus is furnished with a 

 coriaceous shield, wrinkled. 



Limax rufus. Limax cinerus. 



L. albus. L. agrestis. 



4. Testacella. One species. 



Shell external, very small, ear-shaped; very depressed, 

 summit inclined posteriorly, not spiral ; aperture oval, very 

 large ; the left edge sharp, a little rolled inward, especially 

 behind. 



T.Haliotidea. The Haliotis-shaped Testacella. PI. 17, 

 fig. 6. 



Answering to the above description ; very thin, transpa- 

 rent, and yellowish. 



5. Vitrina. One species. 



Shell proportionally very small, extremely thin, pellucid, 

 almost membranous, oval or sub-globular ; spire very short, 

 of which the last whorl is very large; aperture large, semi- 

 lunar ; the edges sharp ; the left edge arched, and extending 

 itself interiorly to the summit. 



V. pellucida. The pellucid Vitrina. PI. 17, fig. 3. 

 Extremely thin, pellucid, and glossy ; depressed, spire 



