Strophia obliterata Maynard, 1896

Original Description

"STROPHIA SCRIPTA OBLITERATA Novo.

Pale Strophia.

Plate I, fig. 5, front. fig. 6, side view of type.

DESCRIPTION.

           SUB SP. CH. Size, small, shell, rather thick and heavy, striations

present, whirls, 10, examined 102 specimens.

Form of shell, a pointed cylinder with the first whirl the largest, the second, third and fourth are successively a little smaller, then the shell tapers to a rather obtuse point, forming an angle of about sixty­three degrees. The striations are few, fifteen to the first whirl. They are quite prominent, rather irregular, quite straight, but not arranged in lines. They are not furrowed, but are smoothly rounded and polished.

           Aperture, rather small, slightly contracted within. Both teeth

are represented by a mere tubercle.

Margin produced forward about as far as the diameter of the shell and is scarcely inclined to the right. The margin is only slightly

flanging and is not rolled over, while the edge is slightly rounded. The frontal bar is quite well developed, but the striations appear within it

as quite prominent ridges which extend into the shell quite to the apex, as shown in a sectionized specimen.

Color of shell, ashy white externally, rather sparingly marked with longitudinal patches of inconspicuous pale reddish brown. These patches are frequently broken into transverse lines by the encroachment of the white. Within, yellowish brown which becomes paler on the margin.

DIMENSIONS.

Size of type 1.08 by .40. Longest specimen, 1.13 by .43. Small­est 1.00 by .30. Greatest diameter .43, smallest, .30. Longest specimen, 1.13, shortest, 1.00.

OBSERV ATIONS.

         There appear to be a number of quite distinct forms.

No.1 is without markings, being pure white, and as is usual in

similar cases, where a white form has become evolved from a colored one, the shell is thinner, with a consequent less development of frontal bar. The average size is a little smaller, but the form is similar. There are about ten per cent of this form.

No 2. Smaller than the type, proportionately stouter, with nine whirls, otherwise similar. There are about seventy per cent of this

form in the collection, but as the form described as typical, approaches nearest to the true S. scripta. I have considered it as the type of the

sub-species.

No.3. More cylindrical than the type, with the first three whirls about equal in diameter and the shell is more slender, measuring about .30 in diameter. Whirls, 10. There are about seven per cent of this form.

No.4. A beautiful color form of a rich reddish or purplish brown throughout with delicate horizontal lines of white. This may prove to be a well marked sub-species, but as I have two specimens only give it as a form.

No. 5. White in color, with few or no fleckings and with the upper whirl somewhat larger than the second. There are eight per cent of this form.

This sub-species, which after all may prove not to intergrade with S. scripta, may be readily distinguished from it by the smaller size and from the often nearly obliterated markings. These were also labeled "P. chrysalis" followed by the more valuable application of" Matanzas Cuba, rocks close to the sea." Judging from the maps, Matanzas

is distant some twenty miles from Cardenas, the home of the true S. scripta. Although both forms may spread over a large area, and thus intergrade at some point on the coast, this is quite improbable and as intimated above, the two may prove quite distinct."

Close Window