GASTEROPODS 375 
Genus Cerithidea  . 
C. scalariformis. This species has the suggestive outlines of the 
family, but the aperture is simpler. The outer lip is considerably thick- 
ened, sinuous, and yellow; there is a very slight notch at the angle 
of the columella, and the lip’serves for an anterior canal. The apex is 
wanting by reason of the usual truncation of two or three whorls of the 
spire. There are revolving ribs on the base ; longitudinal ribs elsewhere. 
The color is a dingy drab; within, brownish-yellow. It is found in 
brackish water in Georgia and Florida. This species is said to suspend 
itself from overhanging vegetation by means of glutinous filaments. It 
may remain out of water for an almost indefinite time. (Plate LXIX.) 
_C. sacrata. A species very common on the mud-flats of San Fran- 
cisco Bay. It is a high-spired shell of ten heavily ribbed whorls, with a 
series of revolving ribs on the body-whorl. The outer lip is sinuous, 
and the columella is slightly twisted. It is nacreous and brown within, 
dingy blue-black without. Length one inch to an inch and a quarter. 
(Plate LXIX.) 
FAMILY VERMETIDE 
Genus Vermicularia 
V. spirata. This is a very curious creature 
when considered from the point of view of the 
gasteropod mollusk. It seems at first as though 
it would be better to regard it as a worm which 
had.created for itself a calcareous covering. But 
it is a true prosobranch notwithstanding the fact 
that it has departed widely from the conven- 
tional design in the fashioning of its shell. At 
first the shell starts out in a regular form, and 
then the whorls become separated, finally wander- 
ing about in a seemingly aimless manner. The 
irregular prolongation sometimes measures ten 
inches in length. The animal is in no way re- 
markable except in having the viscera greatly 
elongated and the foot very shortand broad. The 
color of the animal is light brown with black 
spots; the shell-color is rufous or ashy-white. 
Shells of this genus are often found grouped 
together in an inextricable mass. It is found 
in shallow water from New England to Florida. 
Vermicularia spirata. 
FAMILY STROMBIDE 
This is a particularly interesting family, but it is tropical, and 
is represented on the shores of the United States by only one 
