220 PROCEEDINGS OF THE ACADEMY OF [June, 



III. THE MELANELLID^ {Eulimidoe). 



The absence of sculpture and the rarity of color, together with 

 the simplicity of form, reduce the number of available specific charac- 

 ters in this family, rendering determination of species difficult. 

 The arrangement of varices, whether in one or two longitudinal 

 straight or spiral series, or sparsely scattered, is a valuable feature, 

 also the width of the gray border below the suture, and the curvature 

 of the outer lip; but these have often been overlooked in published 

 descriptions. The size of the apex is often useful, also the degree 

 of curvature, which, however, is individually rather variable. 



All of the known Hawaiian species are mentioned below, but there 

 are certainly many more. At least half a dozen species, beach 

 material, are represented in our collection hy specimens somewhat 

 worn, or by single shells which may not be adult, though obviously 

 distinct. 

 Melanella thaanumi n. sp. PI. XIV, figs. 5 to 6 a. 



The shell is white, slightly transparent, rather solid, with strongly 

 developed curvature in two directions. Whorls very slightly convex, 

 each with one varix. The varices are opaque white, the series 

 ascending the spire spirally on the right side and back, making 

 between a fourth and a half turn. The aperture is ovate. Outer 

 lip arches very strongly forward. Length 25, diam. 7 mm. ; length 

 of aperture 6 mm.; 13 wdiorls, the apical ones lost (type, figs. 5, 5a). 

 An immature specimen 19 mm. long has 16 whorls, the apex perfect. 



Hilo, Hawaii, D. Thaanum. Type and paratypes No. 108471 

 A. N. S. P. Also No. 19764, from Dr. Newcomb, from ''Sandwich 

 Islands. " 



This species is probably Eulima arcuata Sowerby, Conch. Icon., 

 PI. 2, fig. 14, 1865, not E. arcuata C. B. Ad., 1849. 



None of the series before me is so much curved as Sowerby's figure, 

 yet the individuals vary considerably in curvature. 



There is an allied species from Mauritius (PI. XIV, figs. 2, 2a) 

 which differs from thaanumi by the somewhat larger size and wider 

 form. It differs from Eulima major by the much more strongly arched 

 outer lip. Length 28.5, diam. 9, length of aperture 8 mm.; 15 whorls, 

 some at the apex lost. This form may be called Melanella robillar- 

 diana. Type No. 19763 A. N. S. P., figs. 2, 2a; two other specimens; 

 collected by V. Robillard. 



Melanella major (Sowb.),* from Tahiti, is a larger, less curved 



^ Eulima major Sowerby, Proc. Zool. Soc, 1834, p. 7; Conchological Illustrations, 

 Eulima fig. 1 (not fig. 1*, and probably not fig. 1**). Locality, Tahiti. 



