116 PROCEEDINGS OF THE ACADEMY OF [Feb., 



opaque white; and between this tract and the periphery there is a 

 pale zone, sometimes marked with distant radial series of two red dots 

 each. The surface is smooth except at and above the periphery, 

 where there are several spiral striip. Wliorls 5J, slightly convex, 

 parted by an impressed suture. Umbilicus circular and deep, expand- 

 ing fuimel-like at the opening, where the sloping sides are excavated 

 in the middle and fineh^ sulcate radially. Aperture oblique, subcir- 

 cvilar, the peristome obtuse, the columellar margin broadly dilated, 

 covering a small part of the umbihcus. 



Alt. 5, diam. 9 mm. 



Alt. 4, diam. 7.7 mm. 



Yakushima, Osumi. Topotypes No. 88.314, A. N. S. P., from No. 

 1,428 of Mr. Hirase's collection. 



This species is evidently related to Ethalia rhodomphala E. A. Smith,' 

 and Isanda pulchella A. Ad.^ From the latter it differs by the much 

 wider last whorl as viewed from above, and by the less extensively 

 covered umbilicus and white callous. It differs from E. rhodomphala 

 Smith chiefly by the color of the columellar callous. This is not a 

 feature of much importance, and I w^ould rank the Yakushima form 

 under rhodomphala as a variety were it not that the name of that spe- 

 cies is preoccupied for a new Caledonian form apparently referable to 

 the same genus, E. rhodomphala Souv." 

 Dentalium rhabdotum n. sp. Pi. V, figs. 45, 46, 47. 



Shell curved posteriorly, the larger half nearly straight, slender, the 

 diameter contained about 11 times in the length, moderately solid, 

 lusterless; white, with more or less blackish incrustation. Sculpture 

 of 12 acute, even ribs at the small end, parted by wider concave 

 intervals; these ribs gradually become lower and wider, but usually 

 retain their predominance over subsequently acquired sculpture to 

 the end, though becoming low and obtuse. Secondary threads soon 

 appear in the intervals, and on the last third of the shell tertiary 

 threads, with some additional minor threads in some intervals, or rid- 

 ing on the slopes of the larger threads. In full-grown individuals all 

 longitudinal sculpture becomes subobsolete close to the aperture. 

 Growth-lines fine and obliquely circular throughout. The aperture is 

 circular with rather thin peristome. Apical orifice ovate, the inner 



* The Fauna and Geography of the Maldive and Laccadive Archipelagoes, II, 

 Pt. 2, Marine MoUusca, p. 618, PI. 36, figs. 1, 2 (1903). 



• E. von Martens, List of tlie Shells of Mergui and Its Archipelago, in Journal 

 of the Linnean Society, XXI, p. 107, PI. 16, fig. 3a-3e (1887). 



^^Trochus (Motiilea) rhodomphahis Souxerhie, Journal de Conchyliologie, 1S7 5, 

 p. 36, PI. 4, fig. 3. Tliis species seems, as Fischer has suggested, close to Trochus 

 rotellaformis Pliilippi, Cnnchijiien Cabinet, Trochus, p. 302, PI. 44, fig. 2. 



