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Show 40 DR. GWYN JEFFREYS ON THE MOLLUSCA OF THE [J Distribution. Mediterranean from Gibraltar to Palermo, Madeira (McAndrew), G.Mexico (Pourtales), Jamaica (Barrett); 18-117 fms. Fossil. Miocene : Calabria (Seguenza). Pliocene : (?) Biot, Central Italy, and Sicilv. Solarium aldrovandi of Foresti is a variety. Deshayes proposed this genus in 1830 under the name of Omalaxis or Omalalaxis, and in 1832 as Bifrontia. The former name, slightly but necessarily altered in the spelling, must therefore be retained, although Bifrontia is equally appropriate. But I am not satisfied that the genus is distinct from Solarium. The shape of the shell, and especially of the peculiar operculum, closely resemble those of S. archita. The sculpture of the present species varies greatly in respect of the short longitudinal striae, which in some specimens are strong and close-set, and in others are entirely wanting. The whorls are often wholly or partly disjoined or are occasionally united. 1. ADEORBIS SUPRANITIDUS, S. Wood. A. supranitidus, S. Wood, Mon. Crag Moll, in Pal. Soc. Publ. 1848, p. 137, t. xv. f. 5, a, b. Omalaxis supranitida, G. O. Sars, Moll. reg. arct. Norv. p. 214, t. 22. f. 20, a-c. ' Porcupine ' Exp. 1870 : Atl. 36, Tangier B. Distribution. Lofoten I. 200 fms. (6?. O. Sars), New England (Verrill). Fossil. Pliocene : Coralline Crag. Both the ' Porcupine' specimens are imperfect; but they agree with Crag specimens in every respect (especially in being tricarinated) except in being spirally and rather strongly striated. A. tricarinatus of Searles Wood is certainly another variety, as he suspected. The spiral striae are wanting in Norwegian specimens, but are conspicuous in the umbilicus of Crag specimens. The operculum is not known ; and it is therefore questionable whether the present species belongs to Adeorbis or to Homalaxis. It shares some of the characters of both genera. 2. ADEORBIS SUBCARINATUS, Montagu. Helix subcarinata, Mont. Test, Brit. p. 438, t. 7. f. 9. A. subcarinatus, B. C. iv. p. 231, pi. iii. f. 5 ; v. p. 216, pi. lxxix. f. 1. ' Porcupine' Exp. 1869 : St. 18, Lough Swilly. Distribution. British and Irish coasts, from Aberdeenshire to Guernsey, Atlantic coasts of France, Spain, and Portugal, throughout the Mediterranean and Adriatic, and Mogador ; low water to 35 fms. The habitat is sublittoral. Fossil. Miocene : Bordeaux Basin and Transylvania. Pliocene : Coralline and Red Crag, Belgian Crag, Central and Southern Italy. Post-tertiary : Portrush and Selsea. Several obsolete synonyms. The animal and its habits were described by Mr. Duprey in |
