Strophiops gigantea Maynard and Clapp in Maynard, 1921
"STROPHIA GRAYI GIGANTEA Novo.
FIG. 44, A, front view.
SP. CH. Size, very large. Shell, heavy. Striations, present. Whirls, eleven. Examined fifty specimens.
Form of shell, cylindrical, the first, second and third whirls are about equal in diameter, the fourth is but little smaller, then the shell slopes gradually to a rather acute point, forming an angle of sixty-five degrees. The striations are few, twenty-three to the first whirl. Are not prominent, quite regular, and arranged in lines; they are slightly inclined from right to left, are rather narrow, hence the interspaces between them are wider than they; they are not furrowed, but are smoothly rounded, but not polished.
Aperture, quite small, inclined to be rounded, and is slightly contracted at the entrance. The lower tooth is quite prominent, .04 high, and is about twice as long as high. It is set back about once its length, but is rather depressed below
the level of the frontal bar, and is about central in position. The upper tooth is slightly dl1veloped, and is about on a level with the middle of the central tooth.
Margin produced forward about as far as the diameter of the shell, but not beyond it; it is thin, being about as thick as the shell behind it, and the edge is smooth and rounded, but is not produced into a thin edge. The frontal bar is well developed, and completely interrupts the striations. Color of shell externally, dull white throughout; internally, pale brown, fading into white on the tooth and margin.
Size of type, 1.56 by .55. Largest specimen, 1.67 by .60; smallest, 1.40 by .55. Greatest diameter, .70; smallest, .55. Longest specimen, 1.67; shortest, 1.40.
Individual variation in this sub-species is considerable, the inclination being toward an even larger form, with coarser and fewer striations. This large form has twelve whirls and the largest specimen, of which the dimensions are given above, has thirteen whirls, thus exceeding the maximum number of any species hitherto examined by me. Aside from these variations there is a distinct form, as follows.
No. 1. Similar to the type in general form and size, but with narrower striations, which are less prominent, and the color is dull, ashy brown, with the striations creamy white, also darker brown internally.
HABITS AND DISTRIBUTION.
The Gigantic Strophia occurs in the thickens which grow along the hillside to the southward of the ruin of which I have spoken as being on the eastern hill, midway of the key. They are very solitary in habit, each usually living apart from its fellows.
The dark form I found in a little valley on the hillside near the landing-place, which is near the head of the southern bay, under the thick shade of some dense foliage."