Strophia pannosa Maynard, 1889

Original Description

"I. STROPHIA PANNOSA Novo.

Ragged Strophia.

Plate I, 13, animal; ib., 2, jaw.

Plate II, 1 & IB, shell; Ie, section; 1D, young.

DESCRIPTION.

            SP. CH. Size, large. Shell, robust and heavy. Strations, pres­ent but coarse. Tentacles, short, about one fifth as long as eye pedun­cles; teeth, two, both very long. Whirls, 12. Examined 400 specimens.

            Form of shell, long oval, that is, the greatest diameter is through the second whirl; the first and third being a little smaller. Each whirl below is successively .05 smaller than the one above it, thus tapering to a blunt point, and forming an angle of about .60 degrees. There are 18 coarse, widely separated, irregularly formed striations, some of which are omitted, making the interspaces even wider. The striations are not arranged in continuous rows, and are inclined from right to left. The sutures between the whirls are not deep.

            Aperture, small, contracting rapidly within, where there are two, very prominent, long teeth, the lower of which extends backward into the shell .26, and is about .05 high, while the upper makes a complete turn around the column. The position of the lower tooth is about cen­tral and the upper is elevated just above it.

            The margin is not produced forward beyond the diameter of the shell but is greatly thickened, with the outer posterior portion provided with a thin, though not very prominent edge. The frontal bar is well developed, completely interrupting the striations; thus the lower wall of the aperture is smooth. Animal, large; eye peduncles, .25 long; jaw, with lower portion covered with tubercles.

            Color of shell externally, white, with the apex pale purplish brown; internally, pale purplish brown, but this color does not extend beyond the teeth, fading gradually as it approaches them, so that both they and the walls beyond them are flesh color. Color of animal, pale brown, with a V-shaped mark of dark brown on the back; see Plate I, 13, upper and lower figures.

DIMENSIONS.

            Size of types, 1.27 by. 57 and 1.23 by .50. Largest specimen, 1.27 by .58; smallest, 1.00 by .48. Greatest diameter, .58; smallest, 47. Longest specimen, 1.47; shortest, 1.00.

OBSERVATIONS.

            There is some variation in form as well as in size, some individuals exhibiting a tendency to become shorter and proportionately wider than the type, but this character in uninjured and perfectly adult specimens is not very marked; on the other hand, at one point within the range of the species, I found a colony having nearly parallel sides; that is the three first whirls are nearly equal in diameter, and the margin is not as thick as that of the type, measuring only .08, the type being .12; an approach to this form is figured on Plate II, lB. In color, the species is quite uniform; some are slightly flecked with brown, but this is rare, and they are oftener white to the apex. The striations are most numerous and most regular in the cylindrical form. They vary in number from 17 to 24 on the first whirl. The whirls vary from 10 to 12 .

            Known from all others by the large size, elongated teeth, irregular, widely separated, coarse striations, thickened margin, and white color.

DISTRIBUTION AND HABITS.

            The Ragged Strophia occurs on the west end of the island of Little Cayman, living on the coarse vegetation which grows among the rocks that lie just above the beach. I have never found them east of the little cove, on the north side, called Bloody Bay, where the rocks of what is known as the Iron Shore terminate, nor east of the few houses which constitute the only settlement on the key, on the south side; thus they occupy a line, somewhat broken, of a few yards in width and about three miles long. This narrow strip was occupied by them almost exclusively, insomuch so that out of three hundred Strophias that I gathered in a two mile walk, twelve only were of another species, (S. levigata).

            In habit they differ from many of the species occurring on the Cay­mans, in being rather solitary, at best only a dozen or so being found together, consequently they were not abundant. At the time of my visit the last week in April, the weather was mainly dry, and they were cling­ing to the low, stunted plants, or to rocks, and not feeding. Upon ex­amining the basket, in which I had placed some during the day, late in the evening, I found them crawling actively, and upon being brought north, they were occasionally active until cold weather, when they all died, but for at least six months they lived entirely without food of any description." (Maynard, 1889:10-11)

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