16 NEW-YORK FAUNA — MOLLUSCA. 
near the suture, forms a channel. Aperture narrow above, enlarged beneath. Outer lip 
sharp, entire, joining the preceding whorl by a gradual approach, and then turning down the 
inner border in the form of a thick slightly attached plate of enamel: As it turns back from 
the front, it becomes thicker and rounded, and at the umbilical region it enters the shell, and 
forms a conspicuous fold. 
Color. Whitish or pale horn-color, with a thin ferruginous epidermis. 
Length, 0°1-—0°2; diameter 0°07 - 0-1. 
Found in the stomachs of fishes on the shores of Massachusetts, and by dredging in the 
harbor of New-York below the Quarantine ground. The presence of a prominent spire in 
this and a few other species, with a fold on the columella, would seem to indicate the neces- 
sity for a subgeneric division. The characters assigned by Lamarck, “‘n’ayant point de 
columelle ni de saillie 4 la spire,” certainly require revision. The B. canaliculata of Say, 
which belongs to this division, is referred by that author to Bullina of Ferussac, on account 
of the animal having two distinct tentacula; but this would necessarily remove it from the 
present family. I am not aware that Deshayes, who says that the animals of the two genera 
agree exactly, has had an opportunity of examining Mr. Say’s species. I scarcely know 
what to make of another species described by Mr. Say as a Bulla, under the name of B. 
fluviatilis (Journ. Acad. Vol. 2, p. 178), inhabiting fresh water. All the known species are 
marine. It may possibly prove to be what I have ventured to describe under the name of 
Physa planorbula. 
Buia LINEOLATA. 
PLATE 35 FIG. 334. 
Bulla lineolata. Coutnovy, Bost. Journ. Nat. Hist. Vol. 2, p. 179, pl. 3, fig. 15. 
B. id, GouLp, Invertebrata of Mass. p. 169, fig. 99. 
Description. Shell very small, oblong-ovate, broadest at the base, thin and fragile. Whorls 
three ; the last inflated, and enveloping all the others, with numerous impressed minute revolv- 
ing strie. Spire little, prominent, flattened, with the outer lip arising from near its summit. 
Aperture the whole length of the shell, narrow above, dilated beneath, somewhat effuse at the 
base ; a faint oblique fold near the middle of the columella. 
Color. Pale brown, with a thin ferruginous epidermis ; within, glossy yellowish white. 
Length, 0°15; diameter, 0°07. 
This very delicate and minute shell has as yet only been observed by its original describer, 
in the stomachs of haddocks and other fishes on the northern coast. 
