24 
DESCRIPTION OF SPECIES. 
opposite the few houses at the west end; here they absolutely swarmed 
in certain spots. Not only was the low herbage covered with them, but 
they fairly whitened the bases of the stems of the cocoa-nut trees, and 
often accumulated in such numbers on the small stumps, that they 
clung one top of another, often three or four deep, and could be gathered 
by the double handfuls. As the weather was mostly dry, they did not 
move much, so I could not decide upon what plant they fed, but judging 
from their numbers, this food plant must have been abundant, and by 
cultivation of the soil, the Strophias were placed under favorable cir- 
cumstances for the increase of the species. Through the agency of man, 
three or four other species had been introduced into this large colony 
which occupied in all, about half a square mile of country. 
9. STROPHIA PARVA Novo. 
Little Strophia. 
Plate II, 9 & 9b, shell. 
DESCRIPTION. 
Sp. Ch. Size, very small. Striations, present. Teeth, two, and 
rather long. Whirls, 9. Tentacles, quite short. Examined about 
1,000 specimens. 
Form of shell, nearly oval, with the second whirl the largest; the 
first and third are a trifle smaller and about the same size, from the 
third the shell tapers to quite a blunt point, forming an angle of about 
60 degrees. The striations are 1 8 on the first whirl, are quite promi- 
nent, slightly furrowed, but with the edges rounded; the interspaces are 
narrower than the prominences. Sutures, rather deep. 
Aperture, not very small, but open, and the diameter of the cavity 
just within is a trifle more than at the entrance. Lower tooth, placed 
a little to the right of the center, and is .16 long by .05 high; the upper 
is situated just above it, is only .02 high, but makes a complete turn 
around the column. 
The margin is not produced forward quite as far as the diameter of 
the shell, it is not thick, measuring only .06, and is provided on the outer 
posterior portion with a rather blunt edge which is slightly rolled back- 
ward. The frontal bar is quite well developed, and the striations do 
not appear within it. ^ 
Color of shell externally, dull white, with an occasional patch of pur- 
plish yellow which is due to a wearing away of the outer surface through 
abrasion. The margin, externally and internally, and the teeth are yel- 
