OCR Text |
Show 558 MR. E. A. SMITH ON CYPR.EA DECIPIENS AND [May 3, 4. Note on Cypraa decipiens. By E D G A R A. SMITH. [Received March 23, 1881.] My description of Cyprcea decipiens appeared in the Society's 'Proceedings' for 1880, p. 482. At that time only a single specimen was known, and that, unfortunately, in a worn and somewhat bleached state. The British Museum has lately purchased two other examples in most brilliant condition, brought home by the master of a trading vessel from Port Walcot, North-west Australia. At the time of describing this species I pointed out several distinctions between it and the South-Australian C. thersites, which differences are maintained in the two fine shells before me. These are similar in size to the type figured (P. Z. S. 1880, pi. xlviii. figs. 8, 8 a), and present the same excessive dorsal humpiness; but their base is scarcely so flattened, the outer lip especially being decidedly rounded. The colour, too, appears to be variable. One specimen has the base perfectly black; and this colour extends up the sides almost halfway to the vertex ; and the spotting on the back is much darker than originally described. The second example is greyish brown or mouse-colour at the base, becoming rather darker towards the teeth. The former tint extends only a little way up tbe sides, and is varied with a few remote irregularly placed roundish dark spots. The upper or dorsal region, however, is like that of its fellow example. The teeth were stated to be about twenty in number; but in these two shells there are two more. The colour of the aperture far within is lilac; and the body-whorl within, beyond the teeth, is brownish white. It is most satisfactory to obtain two further specimens of a species which, at first sight, so much resembles a dwarfed G. thersites; for they not only prove the stability of the species, but at the same time confirm the judgment originally expressed as to its specific distinctness. 5. Descriptions of two new Species of Shells from Lake Tanganyika. By E D G A R A. SMITH. [Received April 16, 1881.] Mr. Damon, of Weymouth, knowing the interest I have taken in the shells of this lake, has kindly submitted to me for examination a small collection which he recently obtained from this locality. The two species about to be described are the only novelties. These, however, possess much interest because of their relationship to the genus Tiphobia. The opercula of the two forms are identical; but the character of the shells is so different that I am inclined to propose a new section, or subgenus, for the reception of the two new ones. These in texture are solid, longitudinally costate and trans- |