244 Mr. R. J. L. Guppy on new Species of Fluviatile and 



spiral ridges; epidermis pale olive or horn-colour, closely 

 covered viiih minute striae ; whorls 6, convex above, the last 

 rather flat laterally; suture well impressed; spire convex- 

 conic ; aperture narrow, ovate ; peristome acute, its margins 

 joined by a thin callus spread over the penultimate whorl ; 

 right margin slightly reflected, columellar margin white, ex- 

 panded and reflected over the narrow umbilicus. Operculum 

 ovate, horn- coloured, concentrically striate; nucleus near the 

 sinuate inner margin. Height 2 inches, greatest breadth 

 1*4 inches. 



The animal is nearly black, with a very long siphon. It bears 

 a close resemblance to the animal of A. guianensis. The present 

 species is rarely found in a state of perfection : those occurring 

 in ponds are usually dwarfed and distorted. 



The present shell differs from A. Chemnitzii, which it some- 

 what resembles, in its greater height of spire and in the narrower 

 and more ovate form of the shell. The aperture also is nar- 

 rower, and the peristome less expanded. 



There is an AmpuUaria to be found in some parts of Trinidad 

 which seems to be a variety of A. effitsa, Chemn. {A. ylauca, 

 Linn.), with a tall spire. It presents the same variations of 

 colour as A. effusa, some examples being zoned with dark bands, 

 and others being simply of a brownish olive without colour- 

 bands. 



AmpuUaria effusa is found existing in many of the streams of 

 the island. Its eggs are deposited, in masses of fifteen or twenty, 

 on trees or rocks just out of the water. They are of a bright 

 green colour; but when the young mollusks come forth, the 

 calcareous covering of the eggs remains of a white colour. The 

 young mollusk has a shell of 2^ whorls, nearly similar to that 

 of the adult, but quite imperforate. 



Bithinia spiralis, n. sp. 



Shell small, oblong-conic, imperforate, dark reddish brown, 

 smooth, spirally striate, or ornamented on the upper part of 

 the whorls with a keel bearing a regular series of somewhat 

 aculeate rather moniliform projections, giving to the whorls 

 a sharply angulate appearance, and disappearing on the last 

 whorl; whorls six, little convex, gradually increasing, the last 

 forming nearly half the shell; apex conic, sharp; aperture 

 perpendicular, ovate ; peristome simple, acute, the margins 

 joined by a thin callus spread over the penultimate whorl ; 

 columellar margin narrow. Operculum thin, horny. Height 

 0*18 inch, greatest breadth 0*11 inch. 



The animal has a long, divided muzzle, at the base of which 



