262 Description of a new Species ofRostellaria. [No. 4, 



Explanation of Plate XIV. 



Fio-. 1. Papilio chjiia, v&r. Jlavolimbatus, Oberthiir. $. Upperside. 



2. $ • Underside. 



„ 3. Hebomoia roepstorffii, W.-M., $ . Upperside. 



n 4. $ . Underside. 



5, ij> . Upperside. 



XVII. — Description of a new Species q/ > Rostellaria,/W»;& the Bay of 

 Bengal. — By Geoffrey Nevill, C. M. Z. S. 



[Received November 3rd ; — Read December 7th, 1881.] 

 EOSTELLAEIA DELICATULA, 11. sp. 



Distinguished at once from all the other living species of the genus 

 by its thin, delicate, and translucent substance, in these respects showing 

 a highly important approach to some fossil forms. Colour a pale ochra- 

 ceous brown lineated on the last whorl with four narrow white bands, each 

 of which terminates in one of the four projecting digitate processes of the 

 outer lip, one only of these bands appearing in the middle of the preceding 

 four whorls ; spire not quite half the entire length, apex moderately acute ; 

 whorls 10^, moderately convex, the last conspicuously convexly tumid and 

 like the preceding one, marked with a slight sutural depression, produced 

 at the base into a short canaliculation, relatively less developed than in any 

 of the other known species, this " canal" is slightly tortuously deflected, 

 more conspicuously so than in B. niagnus (Chemnitz) ; the first three or 

 four whorls are sculptureless, the next three or four inconspicuously but 

 regularly spirally striated, striae about ten in number, filiform and slightly 

 punctured, becoming obsolete on the last two whorls, except at the base of 

 the last of all, where they reappear more coarsely developed than before ; 

 there are also five varices, somewhat inconspicuous, at intervals on the last 

 four whorls, which also show, under a lens, minute longitudinal striation, 

 the striae close set, fine, and flexuous ; aperture oval, rather large, with the 

 peristome thickened and denticulated with four equidistant, relatively 

 somewhat small, digitate processes. 



Long. 76, diam. 28 ; from the apex to suture of the last whorl 29^, 

 from base of the aperture to end of the " canal'' 6^ mill. 



This highly interesting and very characteristic form, quite unlike any 

 of the other seven known living species of the genus [as restricted] was 

 dredged in deep water off Cheduba, Arrakan Coast, by Surgeon J. Arm- 

 strong, late Naturalist to the Indian Marine Survey. 



