Strophia brownei Maynard, 1889

Original Description

"STROPHIA BROWNEI Novo.

Browne's Strophia.

Plate XVI, 4, 4A, & Fig. 53, shell.

DESCRIPTION.

            SP. CR. Size, medium. Shell, heavy and robust. Striations pres­ent, but not prominent. Examined 25 specimens.

            Form of shell, oval, the greatest diameter being on the second whirl, the first is very little smaller, and the third but slightly smaller than this, and from this last mentioned whirl the shell tapers to a rather blunt point, forming an angle of about 60 degrees. The striations are numer­ous, 20 on the first whirl, and occupy all but the two lowest whirls, are regular, but are not arranged in lines and are but slightly inclined from right to left. The striations are slightly furrowed on top but the edges are smooth and rounded, they are not widely separated, the depressions being about equal in width to the prominences.

            The aperture is quite small and contracts rapidly, measuring some­what less within than at the entrance, and the teeth are situated some distance inside the opening. The lower is short, about .05 and only .03 high, it is placed about midway between the two walls, while the upper, which is only represented by a protuberance is placed considerably above it.

            The margin is not produced forward beyond the diameter of the shell, is considerably thickened, measuring about .05, and the posterior portion is provided with a thin, though not very prominent edge. The frontal bar is very prominent and completely interrupts the striations.

            Color of shell, white externally, tinged with yellowish within the aperture.

DIMENSIONS.

            Size of type, 1.10 by .50. Largest specimen, 1.16 by .52 ; smallest, .90 by .49. Greatest diameter, .52; smallest,.49. Longest specimen, 1.15; shortest, .90.

OBSERVATIONS.

            Beyond question this species is related to S. alba, but whether as a remote pregenitor or as an offspring it is difficult to state, although I am inclined to think the former hypothesis the more correct one, for my studies of this genus lead me to believe that the lighter, thinner shelled species are the most recent. At an events S. brownei is distinct enough from alba at present. The shell is much smaller, thicker, with a considerably thickened margin with decided striations extending to the seventh whirl. There is a form of Browne's Strophia which has more widely separated striations than in the type, 19 or 20 to the first whirl, and these are wider on top. This form bears a strong external resem­blance to S. fusca, even to a brownish tinging between the striations, but a glance at the teeth will serve to separate the two species, brownei having a short, inconspicuous tooth, while fusca has the long tooth so characteristic of the Cayman species, in short, the two shells belong to different groups. (See remarks on page 130.) There is a shell on New Providence of which I have seen two or three specimens only, which may prove identical with this, but I shall have occasion to speak of this later.

            Strophia brownei may be distinguished then from all others by the thickened margin with contracted opening, with the short teeth placed well within it, and oval form.

            I have named this species for my friend Mr. Frank O. Browne of Framingham, who has evinced a great interest in my work on the genus Strophia, and to whom I am greatly indebted for the use of many speci­mens. It was in his cabinet that I saw a shell that called my attention to this speeies.

DISTRIBUTIONS AND HABITS.

            trophia brownei is found on Rum Key near the north side, and occurs among low shrubbery, where it appears to be not uncommon. While crossing the key on the day that I visited Hartford Cave, men­tioned in a preceding article, I saw numbers as I rode along the road and fully intended cellecting them as I returned, but when I passed the place in the evening, darkness prevented me from securing any, and I did not have an opportunity of visiting the locality again.

            I continue my article upon the genus Strophia with the additional advantage of another season's work among the Bahamas. In March and April, 1863, in company with Messrs. Curtiss and Thorndike I visited New Providence, and some of the adjacent keys, Highburn, U Key, and other keys about Allen's Harbor, Andros from Fresh Creek south to Middle Bight, taking in the out-lying keys off the coast. As will be seen by the following descriptions, my ideas regarding the limited distribution of species in this genus have not only not been changed, but my opinion in this respect has been greatly strengthened. Mr. Curtiss, who is an experienced naturalist, and who followed me in my investigations step by step, examining with me the Strophias in their native haunts, early became convinced of the justice of my conclusions regarding the species.

            A careful study of the keys on which the Strophia occur, with the idea of accounting for he distribution, has revealed two facts. One is, that these shells never appear on any key on which is not now inhabited by man, or which has not been inhabited by him in the past, or which is not now frequently visited by him, or which has not been in bygone times a resort of human beings. Palms not only indicate a more or less fertile soil, but as they are useful to mankind in several ways, prove attractive to him; hence their presence is an index of a present or past occupancy of any key. And the shells are probably transported from place to place by man."

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