83 
Length two-fifths of an inch. Width more than three-tenths. 
Inhabits Maine. Cabinets of Messrs. Stone, Hyde and Say. 
We are indebted for this shell to Mr. Aaron Stone. It is com- 
monly invested with a dirty greenish-white pigment, beneath which 
it is sometimes reticulated with abbreviated yellowish lines, on a 
brown or dusky ground. 
ScALARiA LiNEATA. — Shell brownish, elongated, with about 
seven volutions ; costa robust, obtuse, little elevated, and from 
seventeen to nineteen on the body whirl; body whirl with gener- 
ally a blackish, more or less dilated line, which is nearly concealed 
on the volutions of the spire by the suture ; margin of the mouth 
robust, white, more dilated at the columella base. 
Length about half an inch. Inhabits the southern coast. Cabinet 
of the Academy and the Philadelphia Museum. 
Very much resembles Turbo clathratulus of Montague, which is 
figured by Maton and Rackett as a variety of T. clathrus, (Trans. 
Lin. Soc. Lond. vol. 8, pi. 5, fig. 1,) but the lip is more robust, 
and the basal portion of that part is more dilated than the quoted 
figure of that species. It is possible, however, that it is only a 
variety of that species. 
Turritella alternata. — Shell dusky; acute at the apex; 
volutions eight, with about eight unequal, revolving, slightly ele- 
vated lines, which are maculated with rufous, and decussated by 
transverse, elevated, obtuse lines, which are obsolete below the 
middle of the body whorl and prominent on the spine ; labrum not 
thickened, a slight indentation at its base. 
Length one-fifth of an inch. Inhabits the coast of the United 
States. Cabinet of the Academy and Philadelphia Museum. 
Animal. — Foot longer than the aperture of the shell, rather 
acute behind, and truncated a little convexly before ; tentacula 
filiform, cylindrical, obtuse at tip, nearly as long as the foot, white, 
annulate with brownish lines ; eye at the external base of the ten- 
tacula, not prominent ; rostrum about one-third the length of the 
tentacula ; operculum blackish. 
The shell, when taken from the water, becomes whitish-cinereous. 
They abound amongst Fucus, and sometimes on the shell of 
Limulus Polyphemus. The animal considerably resembles that of 
Melania Virginica as respects form, and in common with many 
