"STROPHIA GRAYI Novo.
Gray's Strophia.
Fig. 42, A, front, B, side view, of type.
DESCRIPTION.
SP. CH. Size, rather large. Shell, thick and heavy. Striations, present. Whirls, eleven. Examined 700 specimens.
Form of shell, cylindrical, the first three whirls being about equal in diameter, the fourth is a little smaller; then the shell slopes to a blunt point, forming an angle of sixty-nine degrees.
The striations are not numerous, sixteen to the first whirl, are rather prominent, not very regular, and not arranged in lines; they are not furrowed, are smoothly rounded, and slightly polished; the interspaces between them are wider than they are, and furrowed with longitudinal
lines of growth. .
Aperture small, with the corners decidedly angular, especially below, slightly contracted at the entrance. Lower tooth quite prominent, .04 high, as wide as high, and twice as long as high; it is set very far back, .12 from the frontal bar, is not at all elevated; and is about central in position. Upper tooth absent.
Margin produced forward beyond the diameter of the shell, is inclined to the right beyond the diameter of the shell; is thinner than the shell behind it, and the edge is sharpened without being rolled over, but is much roughened on the sides by lines of growth. The frontal bar is developed to a remarkable degree, protruding far beyond the shell (.08), as far, in fact, as the rest of the margin, and has three or four lines of growth between its edge (which is thin, sharpened as in the other portions of the margin) and the striations.
Color of shell, throughout, externally, dull white; internally, deep brown, fading into white on the tooth and margin beyond it.
DIMENSIONS.
Size of type, 1.25 by .55. Largest specimen, 1.40 by .67; smallest, 1.05 by .47. Longest specimen, 1.40; shortest, 1.05. Greatest diameter, .67; smallest, .47.
OBSERVATIONS.
Individual variation is mainly in the direction of a form with fewer striations, sometimes as few as thirteen only are found. Some individuals have the upper tooth developed, then there are more striations, and the margin is thicker, with the edge smoothed and not sharpened as in the type. I regard these specimens as decided reversions toward S. ritchiei which is undoubtedly the parent stock of this species. In concluding that S. ritchiei is the older species' I have been guided not only by the fact that S. grayi shows considerable reversion towards that species, but also because S. grayi appears quite unsettled, for it has not only produced three well marked forms, but two other forms which I must regard as sub-species. The three forms are as follows:
No.1, shorter and proportionately thicker than in the type (1.10 by .57.); whirls, ten, the first three of which are about equal in diameter. Margin not produced forward as far as the diameter of the shell, and with the edges slightly rounded. Striations, twenty to the first whirl. Tooth and color, as in the type, but the upper tooth is present, but small. Variations are toward producing a sub-form with a thickened margin, bnt in some cases the margin is produced forward with the edge upward. These are about one per cent. of this form.
No.2. Also short, but more slender, 1.06 by .50. Whirls, ten. Margin not produced forward any farther than the diameter of the shell. Striations, eighteen to the first whirl. The variation in one direction is toward a sub-form, with a less number of less distinct striations and a more cylindrical shell, and on the other hand, toward a greater number of more prominent striations, but with the form typical. There are rather more than two per cent. of this form.
No.3. A remarkable form, with a short, thick cylindrical shell, which, from the fourth whirl, slopes to a very blunt point, forming an angle of eighty-five degrees. Margin, teeth and color about as in form No.1, excepting that the upper tooth is well developed. Striations, nineteen to the first whirl. See fig. 43, A. I have seen ten or twelve only of this remarkable form.
Strophia grayi may be at once distinguished in the type form from S. ritchiei by the coarser, fewer striations and above all by the projecting margin with its sharpened edge, which character will separate it also from all other Strophias which I have examined. In fact, in Strophia grayi this margin appears to have reached the maximum development and seems to be its strongest character. A specimen of form No 1 which has had the margin broken, has replaced it with one that measures .30 in length and which has the frontal bar projecting about .20 beyond the shell. See 43, B. It is a significant fact, that the central tooth, being no longer necessary with such a length of margin, has become nearly absorbed.
There appears to be a great tendency among injured shells of this species to replace the broken parts with deformites, but as I intend to figure those peculiarities later, among others of other species, I will not enlarge upon them here.
I have named this species from Mr. Arthur F. Gray, of Boston, the well-known and accomplished conchologist.
HABITS AND DISTRIBUrION.
In my account of S. ritchiei, I have said that there is a range of hills along the eastern side of Highburn Key. At the Northern end of the key these hills terminate in a conical peak which is about a hundred feet high. The sides of this hill are not only very steep but but are composed of crumbling lime rock, and were it not for the fact that itisc overed everywhere with a dense growth of trees it would be almost impossible to climb it.
This hill is the home of typical S, grayi and here they are very abundant, living by preference on the stems of a kind of wild fig tree which has white bark.
Form No.1 occurs at the base of thc hill on the western side, while No.2 oocurs on the flats near the northern bay, and the singular No. 3 in the vicinity of the ruins of the house on the top of the hill, midway of the eastern arm of the key. The range of S. grayi may be thus given, as from the ruin, of which I speak, northward along the esatren border of the range of hills about a mile to the northern hill, when it extends all over this hill, thence westward across the plain, passing through the forms No.1 and 2, to the bluffs on the western borders of
the key, thence northward about one half the length of the key, to a deep gorge that makes in from the sea, just north of a point of cliffs. Then, excepting along the very edge of the cliffs, the species is replaced by the small sub-species described."
