80 MALACOZOA. GASTEROPODA. PULMOBRANCHIATA. 



a fleshy collar, closing the shell ; the head distinct ; the 

 mouth opening longitudinally, with a fleshy lohe on 

 each side, and internally a lingual mass and an upper 

 denticulate hard piece ; tentacula four, retractile, sub- 

 ulate, all terminating in a knob, the upper long and 

 each bearing an eye at the tip, the lower short ; the 

 foot large, elongated, depressed, flat beneath, tapering 

 behind ; orifice of the pulmonary cavity on the right 

 side, on the collar; anal aperture beside it; genital organs 

 united, and opening near the upper right tentaculum. 



Shell orbicular, subglobose, subconical, or depressed, 

 umbilicate, thin, spirally twisted ; the aperture roundish 

 or sumilunar with the margin thickened, and more or 

 less reflexed, but incomplete behind. 



The number of species being very great, and present- 

 ing great differences in the form of the shell and its 

 aperture, various subdivisions have been instituted by 

 authors, which however it would be of no utility to in- 

 dicate in the present case, our species not being numerous 

 enough to render it difficult to distinguish them. 



The Snails are equally destructive to vegetables as 

 the Slugs, which they resemble in their habits. When 

 the animal is in motion, the shell is balanced obliquely on 

 its back, and the tentacula are^continually advancing and 

 retiring. 



1. H&lix aspSrsa. Spotted Snail. 



Shell subglobose, imperforate, moderately thick, rugose 

 and subreticulate ; the whorls four, the last very convex ; the 

 aperture roundish, lunate ; the margin thickened, reflexed ; 

 the colour reddish or brownish-yellow, with four longitudinal 

 bands of blackish-brown, interrupted by yellowish curved spots ; 

 the margin internally white. Diameter an inch and a-half. 



It varies greatly in colour : sometimes the bands are very 

 distinct, sometimes apparent only on the spire ; in some the 

 last whorl is nearly all yellow, in others nearly all dark- 

 brown, but more frequently variegated with brown and yellow 

 in transverse undulating bands. 



The animal, when in motion, presents an oblongo-lance- 

 olate foot, tapering behind to a somewhat acute tip, of a pale 

 yellowish-grey colour beneath, margined with a corrugated 



