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. My two specimens are old and broken. 



Hydrobia vlyje, 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 Scrtluria, whether S. scacchi, 

 Homes, as Weinkauff (vol. ii. p. 238) asserts on the authority 

 of Hanky, or S. macandrewi, Forbes, MS.,=S. crassilabrum, Sowerhy 

 (Thesaurus Conchyliorum), as Mr. Gvwn Jeffreys (in litt.) assures 

 me. 



Rissoa cingillus. 



Mr. Gwyn Jeffreys (Brit. Conch, vol. v. p. 208) has given 

 Madeira on my authority as a locality for this species. I had never 

 meant to say so, but merely to inquire whether li. picta, Jeff., 

 might not possible be an aberrant variety — a question which we were 

 ultimately agreed must be answered in the negative. 



Fis 



EXPLANATION OF THE PLATES. 



Plate XXXIV. 

 Rissoa /'< acocki, p. 365. 



cancellata, p. 307. 



auruntiava, p. 307. 



striata, var. lirata, p. 3GS. 



eostqta, p. 300. 



crispa, p. 369. 



Fig. 7. Rissoa gibbera, p. 371. 



8. macandrewi, p. 372. 



- macandrewi, var. spreta, 



10. 



p. 373. 



- moniziana, p. 373. 



Plate XXXV. 



Fig. 11. Rissoa watsm 



12. 

 13. 

 14. 

 15. 

 1(5. 



p. Slo. 



■ cananensts; p. 370. 

 - novarensis, p. 377. 



molacea, p. 378. 

 : costulata, p. 378. 



si mil is, p. 37'J. 



Fig. 10 a. Rissoa similis,vsr. /ct<is, p. 379. 

 1 7. albugo, p. 379. 



18. picta, 361. 



19. coneinna, p. 381. 



20. depicta, p. 3S2. 



Plate XXXVI. 

 Fig. 21. Rissoa pvdcherrima, p. 383 



22. perminvma, p. .383. 



23. abjecta, p 385. 



24. glabrata, p. 386. 



25. sabulum, p. 387. 



Fig. 26. Rissoa lineta, p. 387. 



27. coridcea, p. 38'.'. 



28. tenuisculpta, p. 389. 



20. Eulima paivensis, p. 304. 

 30. Chascax maderenms, p. 362. 



