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Show 1873.] MR. R. B.WATSON ON MADEIRAN MOLLUSKS. 391 RISSOA PARVA, da Costa. Two specimens. An Upper-Tertiary fossil. Living, its distribution is like that of the last. M y two specimens are old and broken. HYDROBIA ULVJE, Pennant. Distribution, fossil and living, like the last. I have found a dozen and a half of young bleached and broken shells, such as ballast-boats would probably pick up on a flat shore. Besides these, two other species require mention :- RISSOA CORONATA, Scacc. MS., quoted by Philippi, vol. ii. p. 127. This species is not uncommon here, but is undoubtedly not a Rissoa, but, as Philippi hints, a Scalaria, whether 8. scacchi, Homes, as Weinkauff (vol. ii. p. 238) asserts on the authority of Hanley, or S. macandrewi, Forbes, MS., = S. crassilabrum, Sowerby (Thesaurus Conchyliorum), as Mr. Gywn Jeffreys (in litt.) assures me. RISSOA CINGILLUS. Mr. Gwyn Jeffreys (Brit. Conch, vol. v. p. 208) has given Madeira on m y authority as a locality for this species. I had never meant to say so, but merely to inquire whether R. picta, Jeff., might not possible be an aberrant variety-a question which we were ultimately agreed must be answered in the negative. EXPLANATION OF THE PLATES. PLATE. Fig. 1. Rissoa leacocki, p. 365. 2. cancellata, p. 367. 3. aurantiaca, p. 367. 4. striata, var. lirata, p. 368. 5. costata, p. 369. 6. crispa, p. 369. PLATE Fig. 11. Rissoa watsoni, p. 375. 12. canariensis, p. 376. 13. novarensis, p. 377. 14. violacea, p. 378. 15. costulata, p. 378. 16. similis, p. 379. Fig. 21. Rissoa pulcherrima, p. 383. 22. perminima, p. 383, 23. abjecta, p. 385. 24. glabrata, p. 386. 25. sabulum, p. 387. XXXIV. Fig. 7. Rissoa gibber a, p. 371. 8. macandrewi, p. 372. 9. macandrewi, var. spreta, p. 373. 10. moniziana, p. 373. XXXV. Fig. 16 a. Rissoa similis,r&v. levis, p. 379. 17. albugo, p. 379. 18. picta, 381. 19. concinna, p. 381. 20. depicta, p. 382. Fig, 26. Rissoa lincta, p. 387. 27- coriacea, p. 389. 28. tenuisculpta, p. 389. 29. Eulima paivensis, p. 364. 30. Chascax maderensis, p. 362. PLATE XXXVI. |