OSCANIUB. Dilkey 
Enum. Moll. Sicil., ii, p. 87 (1844). Not P. tuberculatus of delle 
Chiaje, Cantraine, Vayssiére, and some other writers, which is O. 
testudinarius. 
Lamellaria membranacea Mont., Trans. Linn. Soc., xi, 1811, p. 
184, pl. 12, f. 4.—Pleurobranchus membranaceus FLEMING, Brit. 
Anim., 1828, p. 291. Forges & Han.ey, Hist. Brit. Moll., iii, p. 
558, pl. 114 F, f. 5; pl. xx, f.3.—Sowersy, Genera of Shells, figs. ; 
Ilustr. Index Brit. Sh., pl. 20, f. 29.—Jerrreys, Brit. Conch., v, 
p- 10, pl. 97, f. 3—GranceEr, Moll. de France, 1885, p. 239, pl. 17, 
f. 34—Bueg., Daurz. & Doutr., Moll. du Rouss., i, p. 551, pl. 65, 
f. 3.—Sows., Conch. Icon., xvii, f. 4—VayssteRr, Journal de 
Conch., 1880, p. 211, pl. 7, f. 4, 4a (shell).—Monrerosaro, Journ. 
de Conch., 1878, p. 320.— Oscanius membranaceus Mont., ADAMs, 
Gen. Rec. Moll., ii, p. 39, pl. 60, f. 56.—CueEnu, Manuel de Conch., 
i, p. 397, f. 3012.—VayssterE, Rech. Moll. Opistobr., Tecti- 
branches, p. 122, pl. 4, figs. 96-101 (anatomy). 
Pleurobranchus Lesueur [sic] BLAINVILLE, Manuel de Malacol- 
ogie, p. 470, pl. 43, f. 2, 2a (1825-1827) ; cited as P. Lesueurit by 
-Philippi—P. Lesuerti BLAINVILLE, Dict. Sci. Nat., xxxxi, p. 371 
(1826). 
Pleurobranchus de Haanii CANTRAINE, Malac. Méd. et Litt., 
Mém. de |’Acad. Roy. Bruxelles, xiii, p. 89, pl. 4, figs. 6, 6a (1840). 
Conf. Monts., Journ. de Conchyl., 1878, p. 320, p. 160 (“deshaanii”’). 
—P. haanii Locard, Prodr. Mal. France, in Ann. Soe. Agric. Lyon, 
1885, p. 70. 
Oscanius argentatus Lracu, Synops. Moll. Gt. Brit. p. 29.— 
Pleurobranchus denotarisii VERANY, Catalogo degli Anim. Invert. 
Marini del Golfo di Genova e Nizza (estratta dalla Guida di Ge- 
nova), pp. 16, 19 (1846).—P. contarinti VERANY, /. ¢. 
The mantle bears much smaller tubercles than in O. testudinarius, 
and is of less extent than the foot; and the membranous shell, 
which 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. dehaaniti Cantraine. See pl. 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 
