Cerion acuta Maynard, 1889

Original Description

"4. STROPHIA ACUTA Novo.

Pointed Strophia.

Plate II, 4 & 4B, shell.

DESCRIPTION.

            SP. CH. Size, rather small. Shell, moderately heavy. Striations, absent. Tentacles, not very short, about one third as long as the eye peduncles. Examined 500 specimens.

            Form of shell, pointed oval, the greatest diameter being at the su­ture between the first and second whirls, and each whirl below the sec­ond is successively .05 smaller than the one above it, and thus the shell tapers quite rapidly to the apex, forming an angle of about 46 degrees. There are only faintly defined lines of growth, that assume but little prominence even on the upper whirl; hence the shell is very smooth, and even the sutures between the whirls are very shallow.

            The aperture is small but rather open, the internal diameter, just ,inside the margin, being a trifle more than at the entrance. The lower tooth measures .18 in length by .05 high, is placed a little to the right of the center, and the upper placed slightly above it, is long, making a complete turn around the column, but is not very prominent.

            The margin is not produced forward quite as far as the diameter of the shell and is slightly inclined backward at the top; it is not greatly thickened, measuring .05, and the posterior portion is produced back into a rather blunt and not prominent edge. The frontal bar is well developed. An interesting series of immature specimens of this species not only show that the shell is greatly thickened after it becomes nearly, or quite, fully grown, but also show that the frontal bar is not formed until the margin is completed. The animal is not very large; eye pe­duncles, .15 long; tentacles, .05.

            Color, white, slightly tinged with purplish or bluish; internally, purplish brown which becomes paler on the lower wall of the aperture, and fades on the upper walls and teeth, into flesh color. Color of animal, very pale brown, with the back wholly brown of a darker shade.

DIMENSIONS.

            Size of types, .94 by .40 and .94 by .38. Largest specimen, 1.07 by .45; smallest, .80 by .33. Greatest diameter, .45; smallest, .33. Longest specimen, 1.07; shortest, .80.

OBSERVATIONS.

            The type described is constant in a very large percentage of speci­mens, the chief variation being in size, and this, excepting in the smallest specimen given which is an isolated example, and may even prove a distinct species, is not great. Two different forms appear; one, cylin­drical and proportionately slender, having the first three whirls of the same diameter, and with the aperture inclined considerably to the right, and one wherein the form is proportionately thicker than the type, with the sutures very deep. The color is uniform, some pinkish tipping ap­pearing which is, however, due to abrasion.

            Known from all others, by the pointed apex, small size, absence of striations, long teeth, and white color.

DISTRIBUTION AND HABITS.

            Under Habits and Distribution in the preceding species, I have spoken of two paths that crossed the island of Little Cayman, and these two ways formed a junction a few hundred yards from the south shore. Near this junction, the western most crossed a small open patch of ground, the borders of which were surrounded with quite low bushes. The bushes that grew on the south side of this little natural clearing, were the stronghold of the Pointed Strophias, and I did not find them elsewhere.  The border line to the north, was sharply defined at the clearing, but south, they straggled out along the higher bushes for some few hundred feet, but the entire space occupied by them, did not exceed a quarter of an acre in extent.

            In habit, the Pointed Strophia is highly gregarious, hundreds oc­curring together in a few square yards. They appear to feed upon the foliage of the bushes, on which they were clinging, a small leaved shrub. which I did not, however, find in bloom, so cannot tell to what family it belongs."  (Maynard, 1889:15-17)

 

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