GASTEROPODA. 



199 



a dry tin box ; five weeks afterwards the box was opened, 

 and upon placing them in a glass of sea-water the Trun- 

 catella crawled forth alive, but the other Molluscs were 

 dead." 



They are called " looping snails " from their peculiar 

 method of walking ; Mr. Reeve says, " the foot is divided 

 into two parts, and the animal acquires motion by con- 

 tracting the space between them into the form of a loop." 



T. Montagui has been found on the British south shore, 

 also at Scarborough, and in Scotland. 



Menestho. Moeller. (Pyramis Couth.) — Shell turret- 

 shaped, not decollated. A?iimal, according to a manuscript 

 delineation of Moeller, is similar to that of Truncatella, 

 except that the foot is lengthened, and the mouth simple, 

 without a tongue membrane. — 1 species. 



M. (Turbo) albulus is the speeies, 



Family 8. — AMPULLARIA CEA. 



The body of the animals of this family can be wholly 

 drawn into a spiral-formed shell, which has an entire aper- 

 ture, angular above. The head is lengthened ; each side 

 is drawn out into a feeler-like appendage; there are two 

 long tentacula, the eyes on short stalks on the outer base 

 of them; in the lung cavity are also 

 gills ; an operculum. — Found in fresh 

 waters only. 



Ampullaria. Lam. — Shell gene- 

 rally large, thin, and globular; spire 

 very short; mouth semicircular, with 

 the lips united, the outer being acute ; 

 operculum thin and horny, rarely cal- 

 careous ; the shell has an epidermis, 



o 4 



Ampullaria fasciata. 



