GUPPY — M0LLU3CA OF TRINIDAD. 
33 
Ampullaria rugosa, Brag. Enc. Meth , Vers , pi. 457, f. 2. 
,, urceus, Wood , Ind. Test., Helix. 72. 
A large black globular Ampullaria found in our larger 
rivers and swamps. It is most abundant in the Garoni 
and its tributaries, but it is not rare in the streams of Na- 
parima. It is eaten in great numbers by the Africans and 
the savage squatters of the inland districts, and it is some- 
times brought into town. It inhabits South America and 
is also found in Tobago (Bland). 
Height 84 mill., diameter 86 mill. 
Var. purpurascens. Smaller, thinner, and with a some- 
what more elevated spire. 
Ampullaria effusa Miiller. 
Nerita effusa, Muller. 
Helix effusa, Chemn. Cone. Cal . vol. ix, f. 1144. 
Helix glauca, Linne (in part). 
Ampullaria effusa, Lamarck. 
,, glauca, Wood , Ind. Test. Helix 73. 
A smaller species than the last, very common in all 
our streams and ponds. There are several varieties, two 
of which I have distinguished as conica and tristis. The 
usual form is decorated with several dark bands. 
This species is also found in South America. 
Height 28 mill., diameter 38 mill. 
Var. conica . — - Spire more elevated and umbilicus nar- 
rower than in the type. Shell generally smaller and usu- 
ally adorned with dark bands. Allied to A. crocostoma 
Phil., of Venezuela. 
Var. tristis. Spire more elevated, peristome prominent, 
color-bands obsolete. 
Marisa Gray 1824. 
Pluviatile Operculata with depressed or discoid widely 
umbilicated shells having a simple aperture furnished with 
