386 PROCEEDINGS OF THE ACADEMY OF [Julj r 



been adequately defined; but the form I have considered to be that 

 species has a small, elevated nucleus of 2J whorls, followed by 

 about three costate whorls, the ribs crossed by two or three coarse 

 spiral cords; after which the sculpture becomes comparatively fine. 

 If I am correct in this identification, then articulata is a distinct 

 species; but as Hedley has lately hinted, many of the more critical 

 or difficult species of the ' ' London School ' ' of conchologists. of 

 which A. Adams and Reeve were shining lights, can be identified 

 with certainty only by visiting the British Museum. 2 Under the 

 circumstances I subordinate my form from Japan to D. fragilis as 

 a variety, content to have a name for this well-marked shell, evi- 

 dently of wide distribution in Japanese waters. 



D. supercostata of E. A. Smith seems, from a specimen before 

 me, to belong near fragilis, though clearly distinct in both form 

 and sculpture. D. ornata Hinds from New Guinea is evidently 

 allied, though with a different color-pattern. 



MITRIDJE. 

 Mitra (Costellaria) hizenensis n. sp. PL XXI, fig. 31. 



Shell slender, solid, dusky olive, with a brown or orange-brown 

 and rather prominent subsutural line and an ill-defined white zone 

 at the shoulder, in which the summits of the ribs are transversely 

 marked with short scattered brown lines; the narrow portion of 

 the base is pale yellow, with brown spots and dots. Surface rather 

 glossy, sculptured with rounded longitudinal ribs, nearly or quite 

 as wide as their intervals, 13 or 14 in number on the penultimate 

 whorl, becoming gradually weaker below the periphery of the last 

 whorl, and in adults obsolete toward the aperture; the concave in- 

 tervals crossed by very low, flat spirals, rather wider than the shal- 

 low, oblong pits between them, and about 6 in number on the 

 penultimate whorl. The last whorl is attenuated below, and has a 

 number of large spiral ribs and small cords and strise, the largest 

 rib continuous with the upper coluinellar plait. Whorls about 9 ; 

 apex dark. Aperture small/ dark purple-brown within, the lip 

 thin, white-bordered, multilirate inside. Columella with four sim- 

 ple plaits. Length 14.5, diam. 5, longest axis of aperture 7.5 

 mm.; length 17, diam. 6.5 mm. 



2 Or by imposing upon the present custodian of the collection of Mollusca, 

 whose g-ocl nature is admitted to be well-nigh inexhaustible. 



