Lamarck's Genera of Shells. 239 



Type. Anostoma depressum*, (Helix ringens. Linn.) 

 Shell suborbicular, convex on both sides, somewhat de- 

 pressed, obtusely carinate, imperforate, smooth, whitish ; a cir- 

 cular red line on the upper part; aperture with five teeth; lip 

 very much reflected. India. PI. VII. Fig. 132.— 2 Species. 



4. Helicina. 



Shell subglobular, no umbilicus. Aperture entire, semi-oval. 

 Columella callous, transverse, rather flattened, with a sharp 

 edge forming an angle at the lower base of the right lip. Oper- 

 culum horny. 



The HelicintB resemble small neritse, but the latter are sea 

 shells. They are distinguished from the helices by their trans- 

 verse columella, which is callous, depressed, and thin at the 

 lower part. They are land shells, and inhabit warm climates. 



Type. Helicina neritella. 



Shell ventricose, globular-conoidal ; smooth, white ; margin 

 reflected. Antilles. PI. VII. Fig. 133. — 4 Species. 



5. PuPAt. 



Shell cylindrical, generally thick. Aperture irregular, semi- 

 oval, rounded, and subangular at the lower part; margins 

 nearly equal, reflected outwards, and disunited above by an 

 interposed columellar lamina. 



Type. Pupa mumia J. 



Shell cylindrical, attenuated, obtuse, thick, white ; furrows of 

 the whorls longitudinal, oblique; aperture red-brown, biplicate; 



margin reflected. Antilles. PL VII. Fig. 134 27 Species. 



6. Clausilia §. 



Shell generally fusiform, slender, summit rather obtuse. 

 Aperture irregular, rounded-oval ; margins united throughout, 

 free, reflected outwards. 



The essential character of the clausilia, is that the two bor- 

 ders of the aperture are completely united, free in their con- 

 tour, and reflected outwards. 



• Depressed. t A puppet. t A mummy. 



i From claudo, to shut, because the aperture of the shell is closed by a 

 little apparatus, consisting of two small valves, situated in the penultimate 

 whorl, and not visible exlerimlly. 



Vol. XV, R 



