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Show 272 MR. E. A. SMITH ON THE [Apr. 1, IANTHINA EXIGUA, Lamarck. Hab. South Atlantic ; " New Zealand, New South Wales, aud S. Australia" (Hutton). I have compared New-Zealand specimens in the Museum with the one from St. Helena, and can discover no distinction. IANTHINA UMBILICATA, d'Orbigny. Ianthina umbilicata, d'Orb. Sagra's Hist. Cuba, Mollusq. vol. ii. p. 85, Atlas, pi. xx. figs. 22, 23 (bad!); id. Voy. Amer. Merid. vol. v. p. 414; Reeve, Con. Icon. figs. 22 a, 6; Sowerby, Thesaurus, pi. 444. fig. 22. Testa parva, violacea, infra suturam albo anguste zonata, anguste perforata; anfractus 5, primi duo (nucleus) obliqui, parvi, papilliformes, pellucidi, cceteri convexi, nitidi, ultimus in obtuse angulatus et sulcatus, incrementi lineis, in medio angu-latis, sculptus; apertura mediocris, inferne anguste effusa; columella rectiuscula, paulo reflexa; labrum profunde et acute incisum. Alt. 9^millim., diam. 8. The British Museum received many specimens of this species from Mr. Nuttall iu the year 1855, under the name of I. bifida1. They were obtained at the Sandwich Islands. The shell figured by Reeve under that name is altogether different, and seems to me but a form of I. exigua, as suggested by Sowerby. Besides the lines of growth, which are perhaps a trifle coarser on the under surface than upon the spire, there are indications of feeble spiral stria?, chiefly upon the base. The figure given by d'Orbigny is not good, and does not accord with his description. The labrum is described as acutely sinuated, and the surface as smooth, or scarcely marked with faint lines of growth, yet the figure depicts no sinuation, but represents rather well-marked incremental striae. In d'Orbigny's South-American shells are preserved three or four specimens of this species, marked I. umbilicata in his own handwriting. These certainly agree with the single specimen from St. Helena and the large series from the Sandwich Islands. The figure in Reeve's ' Conchologia' represents the form correctly, but does not show the deep labral notch. D'Orbigny describes the colour as uniform deep blue, but his specimens have the pale infrasutural line as described above. All the specimens of this species which I have examined are of small size, none exceeding the dimensions above given. IANTHINA PALLIDA, Harvey. Hab. Ireland (Thompson) ; Straits of Magellan (Jeffreys). The single St. Helena specimen, half an inch in length, agrees very closely with Forbes and Hanley's figure (Brit. Moll. pi. 69. figs. 10, 11). 1 Blanford, ' Geology and Zoology of Abyssinia,' p. 463, gives off coast of Arabia as a locality for this species. |