330 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 53. 



MELANELLA (BALCIS) YOD Carpenter. 



Plate 40, fig. 9. 



Leiostraca yod Carpenter, Cat. Maz. Shells, 1857, p. 441. 



Mclania distorta Philippi, Moll. Sci., vol. 1, p. 158, pi. 9, fig. 10. 



Eulima distorta Deshayes ia Lamarck An. s. Vert., vol. 8, p. 454. — Philippi, 



Moll. Sci., vol. 2, p. 135.— Forbes and Hanley, Brit. Moll., vol. 3, p. 232,— 



Clark, Moll. Test. Mar. Brit., p. 451. 

 Leiostraca distorta, H. and A. Adams, Gen. Rec. Moll., vol. 1, 1854, 236. 



"L. t. ' L. distortae' simillima, sed niinima; parte suturali paululum 

 latiore. 



"The type of Leiostraca iota C. B. Ad. erroneously labeled 'Jamaica' 

 in Mus. Cuming, and very incorrectly figured by Sow. is somewhat 

 broader and less bent than the Mazatlan shells: in other respects it 

 exactly accords. After repeated comparison of very fresh specimens 

 with the British dwarf variety of L. distorta, the characters appear 

 exactly alike, except that the sutural portion, wliich (the shell being 

 transparent) gives an appearance of a spiral line, is slightly narrower 

 in the Scarborough specimens received from Mr. Bean. The same 

 glossy deposit over the base, with the rather separate parietal lip, 

 giving in some directions of light the appearance of an umbilicus, 

 appears in each, and of the same shape. No difference can be traced 

 in the minute vertex, nor in the varices. The colour in fresh speci- 

 mens exactly accords. The specimens in Mr. Andrew's collection, 

 grouped under Eu, distorta, vary extremely in size and arcuation. 

 The Mazatlan shells are on a much smaller scale, generally more bent, 

 and most beautifidly glossy and transparent. The same form occurs 

 in the West Indies (B. M.). According to Deshayes (Lam. An. s. 

 Vert., vol. 3, p. 455, No. 8) it is found fossil in Grignon and other 

 places. If it extends so far back in time, it is natural that the living 

 sheU should occupy a widely distributed space. As, however, the 

 animals ma}" be distinct, both in this and in L. iota, a name is added 

 expressive of its (for the genus) extreme minuteness. The smallest 

 sp. (of 3 normal whorls) measures '035 by '016. A remarkably 

 large sp. measures long. '082, long. spir. '055, lat. '033, div. 18°. 



"Hah. — Norway to Mediterranean, Forbes; W. Indies, B. M. 



" (Var. Tod.) Mazatlan; 34 sp. living on Spondylus, dead on 

 CTiama; L'pool Col. 



"Tablet 2027 contains 4 sp. of different ages. The largest possesses 

 its operculum, which appears hke that of CJirysallida, but with the 

 rugae much coarser. Another is broken so as to show the axis of the 

 upper whorls." 



We have not seen specimens of this minute, curved species and have 

 copied Carpenter's description and figure; tlic latter is a camera 

 lucida sketch. 



