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Show 378 MR. R. B.WATSON ON MADEIRAN MOLLUSKS. [Mar. 18, Sh. M. 5. 4. 3. 2. 1. L -087 *037 '042 *02 *011 *007 '006 B *055 *032 *042 *05 *033 *02 *013 Hab. Gorgulho, shore; Santa Cruz, shore to 15 fathoms; Machico, 10-15 fathoms; Piedade (Canigal), 15-35 fathoms; Ponta de S. Lourengo, 25-45 fathoms; Funchal Bay, up to 50 fathoms; Porto da Cruz, up to 50 fathoms. From R. canariensis this species differs in its squat and conical form, in not rising at all in steps, in having more numerous and flexuous ribs, more numerous and less-marked spiral threads, and the tendency of these to disappear instead of to become mucronate on the crests of the ribs. From R. punctura it differs in that it is much squatter, much more strongly sculptured, much more brilliant in colour, has fewer whorls, and terminates much more abruptly in a flattened and stained apex. The embryonic whorls are 11 (not 2^) to 3 ; and their spiral lines are formed of approximate stipplings, not, as in R. punctura, of remote tubercles. The name was suggested by Baron Schwartz v. Mohrenstern, to whom I had sent the species for description. He wished in this way to recall the frigate 'Novara,' employed by the Austrian government on a scientific voyage round the world. The name is unfortunately not very appropriate, but is better than a new name, whose substitu-tution might breed confusion, an already sadly prevalent misery in scientific nomenclature. The species is accepted as unquestionably new by Baron Schwartz and by Mr. Gwyn Jeffreys. RISSOA VIOLACEA, Desmarest. (Plate XXXV. fig. 14.) In M'Andrew's list. Hab. Porto Santo, up to 50 fathoms. A subarctic, European, Mediterranean, and Canary species. Mr. M'Andrew,in his 'List of Atlantic Mollusca,' has, through a slip of the pen, given this as R. purpurea. RISSOA COSTULATA, Alder. (Plate XXXV. fig. 15.) Not in M'Andrew's Madeiran list. Hab. Piedade (Canigal), 25-35 fathoms ; Ponta de Sao Lourengo, 25-45 fathoms; Funchal Bay, up to 50 fathoms; Porto da Cruz, up to 50 fathoms. A European and Mediterranean species. In accordance with the present received opinion I accept R. violacea and R. costulata as distinct species. Beyond question they can be distinguished: R. costulata is on the whole more drawn out altogether and in all its parts than the other ; but the best mark of distinction is that it has the spiral striae stippled with minute, equal, close-set, longitudinally elongated dots; while in R. violacea these pitted dots are much larger, are variable in size, are parted by broad flat bars, and are elongated across, i. e. in the breadth of the shell. The whole of these differences, however, really resolve themselves |