Truncatella valida, Pfeiffer.

Pfeiffer, Zeits. Malak., 1846, p. 182; Conch. Cab., i., "Truncatella," 1855, p. 11, pl. ii., figs. 7, 8, 19, 20, 21, 23. Truncatella vitiana, Gould, Moll., U.S. Explor. Exped., 1852, p. 109, pl. viii., figs. 126, 126a, 126b.

Abundant at Funafuti where it has already been found by Graeffe.^* This belongs to a semimarine, semiterrestrial assemblage of which I have already written that—"The smallest islands which possess any life at all are usually stocked by these forms, which appear to range from Ceylon in the west, to the Sandwich Islands in the east, and to be limited north and south by the tropics."^†

Gould remarked that T. vitiana, admitted to be variable in size, "is not very different from T. valida." The differences in sculpture, small perforation, basal keel and posterior fusion of the ribs, on which he relied to separate the two, are shown by a series before me to be quite inconstant features. Smith says,^‡ " When the genus is remonographed, it is probable that some older name will be discovered to replace that of valida." A sentence which admirably expresses the assistance tendered by London writers to students of the Pacific Mollusca.