244 Mr. R.J.L.Guppy on new Species of Fluviatile and 
spiral ridges; epidermis pale olive or horn-colour, closely 
covered with minute striz ; 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 
m ponds are usually dwarfed and distorted. 
The present shell differs from Ad. Chemnitzi, 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 Ampullaria to be found in some parts of Trinidad 
which seems to be a variety of A. effusa, Chemn. (A. glauca, 
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. 
Ampullaria 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 23 whorls, nearly similar to that 
of the adult, but quite imperforate. 
Bithinia spirals, 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 
