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Show 1873.] MR. R. B.WATSON ON MADEIRAN MOLLUSKS. 361 Fig. 1. Sithon aurea, p. 352. 2. scopula, p. 352. 3. pallida, p. 352. 4. valida, p. 352. 5. Amblypodia olinda, p. PLATE XXXIII. 354. Fig. 6. Papilio lowii, p. 358. 7. Astictopterus armatus, p. 359. 8. Plesioneura signata, p. 360. 9. Satarupa affinis, p. 360. 6. On some Marine Mollusca from Madeira, including a new Genus of the Muricidce, a new Eulima, and the whole of the Rissoce of the Group of Islands. By the Rev. ROBERT BOOG WATSON, F.R.S.E., F.G.S.* [Eeceived February 3, 1873.] (Plates XXXIV.-XXXVI.) To the 127 species named by Mr. M'Andrew in his necessarily imperfect list of Madeiran shells published in 1854 I have added some 200 or 250 more, making about 400 in all. Of these, 80 or 90 are probably new. I propose to publish the rest as may be convenient. In the mean time I begin with a somewhat remarkable new genus, a new Eulima, and the whole of the Rissoce which I have noticed here. Of species already described, some present peculiarities in their Madeiran forms worthy of notice. The measurements I offer are somewhat elaborate, but m a y easily be passed over by those who will. I think some may find them very useful. They are the average resulting from very many tiresome observations. I reject Latin in the descriptions. That language refuses to lend itself pliantly to such purposes ; and no man's ease in its use, though of ready acquisition, enables him to throw individuality into his word-pictures. C H A S C A X , gen. nov., Watson. (ydoKat,, a gaper, so called from the immense open umbilicus in its snout-like base.) Shell spindle-shaped, strongly umbilicated, longitudinally ribbed and spirally ridged, but without varices. Epidermis horny. Mouth-edge angulated. Outer and inner lip quite smooth. Canal long, narrow, and deep, bent a little to the left, but not at all reversed in front. Operculum strong, horny; nucleus terminal, internally strengthened by a broad ridge all along the right margin. I regret to propose a new genus, believing as I do that great wrong has thus been often done to true science, the reckless multiplication of genera causing a stumbling-block even more pernicious than that of species-mongering. But in this case there is no help for it. It is obvious that to no genus, as at present defined, can this mollusk be reduced; and both Mr. G w y n Jeffreys and Dr. Fischer, * Communicated by J. Gwyn Jeffreys, F.R.S., F.Z.S. |