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Show 1873.] MR. R. B. WATSON ON MADEIRAN MOLLUSKS. 381 fathoms ; Porto Santo, 50 fathoms ; Funchal Bay, 50 fathoms ; Cruz Point, 50 fathoms. Semifossil in the Canical beds. Teneriffe. Baron Schwartz von Mohrenstern, in a letter (April 1868) to Mr. Gwyn Jeffreys, says of this, " probably a variety of your R. picta." With this view Mr. Gwyn Jeffreys does not agree, considering it unquestionably "a new and good species." From R. picta it may be distinguished easily, being longer and narrower in proportion, apex blunter, whorls rounder, suture deeper, base contracted, mouth quadrangular, pillar straight and long, texture of shell and whole system of coloration utterly different. The shell it is most liable to be confounded with is a smooth and attenuated variety of R. similis; but that shell has a blunter (*. e. broader) and flatter apex, spire rather more contracted, mouth larger and less quadrangular, and both shouldered and sinuated above, is not flattened on base, nor angulated at junction of lip and pillar ; shell less glassy ; tip of embryo stained with blackish brown, its colour never crimson but always brown, not in minute dots but in continuous zigzag lines, often dying out but never breaking into minute regular dots on base. The white spots, too, are more elongated, more indefinite, being shaded off at edges ; connected, too, with a system of longitudinal ribs, of which there is in that species always some, though often faint, trace. From Mr. M'Andrew I have received two specimens of a Rissoa marked by him "n. s.?" but so much bleached as barely to present any trace either of the crimson dots or of the white spots, but which I am satisfied belong to this species, whence I have added Tenerife to the localities where it has been found. RISSOA PICTA, Jeffreys. (Plate XXXV. fig. 18.) Not in M'Andrew's list. Hab. Gorgulho, shore; Santa Cruz, shore ; Seixal, shore; Selvagens, shore; mouth of Ribeiro Secco, 10 fathoms; Piedade (Canigal), 15-20 fathoms ; Ponta S. Lourengo, shore and 45 fathoms ; Funchal Bay, 50 fathoms; Porto Santo, up to 50 fathoms. R. picta is longer and narrower than R. depicta, has no labial varix, the spiral striae are much more indistinct and more like one another, the whorls are more flattened, the spire is longer, and the tip of the shell has no stain. Than R. concinna it is longer, narrower, more compressed in the whorls, different in sculpture and it? colouring. From R. cingillus, which the banded form much resembles, it differs in being greatly smaller even than the young of that species, having the same number of whorls ; it is not at all pointed on the extreme point of the base, which that species when young always is; and the lowest band lies much higher up on the base and never discolours the pillar. RISSOA CONCINNA, Monterosato. (Plate XXXV. fig. 19.) Not in M'Andrew's list. Hab. Gorgulho shore ; Santa Cruz, shore to 15 fathoms ; Machico, |