OSCANIU8. 215 



Enum. Moll. Sicil., ii, p. 87 (1844). Not P. tuberculatus of delle 

 Chiaje, Cantraine, Vayssiere, and some other writers, which is 0. 

 testudinarius. 



Lamellaria membranacea MONT., Trans. Linn. Soc., xi, 1811, p. 

 184, pi. -12, f. 4. Pleurobranchus membranaceus FLEMING, Brit. 

 Anim., 1828, p. 291. FORBES & HANLEY, Hist. Brit. Moll., iii, p. 

 558, pi. 114 F, f. 5 ; pi. xx, f. 3. SOWERBY, Genera of Shells, figs. ; 

 Illustr. Index Brit. Sh., pi. 20, f. 29. JEFFREYS, Brit. Conch., v, 

 p. 10, pi. 97, f. 3. GRANGER, Moll, de France, 1885, p. 239, pi. 17, 

 f. 34. BUQ., DAUTZ. & DOLLF., Moll, du Rouss., i, p. 551, pi. 65, 

 f. 3. SOWB., Conch. Icon., xvii, f. 4. VAYSSIERE, Journal de 

 Conch., 1880, p. 211, pi. 7, f. 4, 4a (shell). MONTEROSATO, Journ. 

 de Conch., 1878, p. 320. Oscanius membranaceus Mont., ADAMS, 

 Gen. Rec. Moll., ii, p. 39, pi. 60, f. 56. CHENU, Manuel de Conch., 

 i, p. 397, f. 3012. VAYSSIERE, Rech. Moll. Opistobr., Tecti- 

 branches, p. 122, pi. 4, figs. 96-101 (anatomy). 



Pleurobranchus Lesueur [sic] BLAINVILLE, Manuel de Malacol- 

 ogie, p. 470, pi. 43, f. 2, 2a (1825-1827) ; cited as P. Lesueurii by 

 Philippi. P. Lesuerii BLAINVILLE, Diet. Sci. Nat., xxxxi, p. 371 

 (1826). 



Pleurobranchus de Haanii CANTRAINE, Malac. Med. et Litt., 

 Mem. de PAcad. Roy. Bruxelles, xiii, p. 89, pi. 4, figs. 6, 6a (1840). 

 Conf. MONTS., Journ. de Conchyl., 1878, p. 320, p. 160 ("deskaanii "). 

 P. haanii LOCARD, Prodr. Mai. France, in Ann. Soe. Agric. Lyon, 

 1885, p. 70. 



Oscanius argentatus LEACH, Synops. Moll. Gt. Brit., p. 29. 

 Pleurobranchus denotarisii VERANY, Catalogo degli Anim. Invert. 

 Marini del Golfo di Geneva e Nizza (estratta dalla Guida di Ge- 

 nova), pp. 16, 19 (1846). P. contarinii VERANY, /. c. 



The mantle bears much smaller tubercles than in 0. testudinarius, 

 and is of less extent than the foot ; and the membranous shell, 

 wKich is well known in collections, is much larger in proportion to 

 the size of the mantle than in the other species. 



The specific name proposed by Meckel must stand for this species, 

 although it has been dropped for over half a century. His descrip- 

 tion and figures are unmistakable. 



Var. dehaanii Cantraine. See pi. 51, figs. 54, 55. 



According to Monterosato, the P. dehaani of Cantraine is distinct 

 in the shell, which is more solid, more convex, and of a more 



