OCR Text |
Show 110 MR. G. NEVILL ON THE [Feb. 17, allied to H. nemoralis, H. williamsiana, and other undoubted species of Tachea, but shows great affinities to II. paretiana, of which it might almost be described as a miniature form, while U. cedesima is a depressed form with peculiar aperture, more vivid coloration, and umbilicus scarcely covered with the columellar callosity, and H. ben-neti is a dwarf convex form with small aperture. Type, Indian Museum, Calcutta; also in collection of M M . Bourguignat and Coombe Williams. HELIX (TACHEA?) CEDESIMA, n. sp. Testa ad prmcedentem peraffinis, sicut H. lucasi, Deshayes, ad H. lacteam, Miiller: imperforata, aut plus minusve subrimata, de-presso- globosa, sat fragilis ; obsolete malleata et subregulariter striata, striis delicatis obliquis; albida, zonulis variis circum-cincta ; spira depressa, parum elevata, ultimo anfractu paululum compressa, lente descendente, subtus ad regionem columellarem paululum excavato ; apertura obliqua, transverse oblonga, superne contracta, marginibus callo brunneo junctis; peristoma vivide coloratum, superne subrecte productum, pergradatim rotundatum, ad basim abrupte angulalum, ac tuberculo subobsoleto munilum; margine columellari perobliquo, contortulo, subrugosa, locum um-bilicalem callo tenui vix tegente. Diam. 27|, alt. 9 ; apert. lat. 15^, alt. 13| millim. Type, from deposit F, Indian Museum, Calcutta; also in collection J. R. Bourguignat. Var. COLORATA, nov. Varietas major, sat tenuis, scepe subrimata, vix malleata, zonulis latis ac continuis ornata. Diam. 31^; apert. lat. 18^, alt. 16 millim. Type var., from deposit D, Indian Museum ; also in collection of Coombe Williams. Var. CRASSIOR, nov. Varietas major, solidior, imperforata, valde malleata, ordinarie zonula unica circumcincta, apertura minus contracta, margine externo magis rotundato. Diam. 32, alt. 21 ; apert. lat. 19, alt. 16| millim. Type var. from deposit E, Indian Museum, Calcutta ; also in collection Bourguignat and Coombe Williams. This is a very remarkable form, bearing much the same relationship to H. mentonica as II. lucasi to H. lactea. It is much more depressed, with a remarkable aperture, the columella (much twisted and with a small tubercle at base) being bent inwards, so as to contract the body portion of the aperture; the external margin is straightly produced, very gradually rounded, in this differing from every other species of Tachea I know (H. mentonica, H. williamsiana, II. nemoralis, & c ) , in all of which it is more or less rapidly rounded. Unfortunately, though I found a great number of spe- |