136 Mr. W, H. Benson on anew Genus of Auriculacea, 



XVII. — Characters of Coilostele, an undescribed Genus of Auri- 

 culacea (?), and of Species of Helix, Pupa, and Ancylus, from 

 India, West Africa, and Ceylon. By W. H, Benson, Esq. 



CoiLOSTELE, B., nov. gen. 



Testa imperforata, elongate- cylindrica; axis columellaris interna 

 spirse obsoleta. Apertura semiovata ; margine columellari superne 

 oblique subspiraliter uniplicata. 



Coilostele scalaris, B. 



C. testa imperforata, elongato-cylindricaj Isevi, hyalina, nitida ; spira 

 elongata, gradatim scalariter attenuata, apice obtuso, sutura pro- 

 funda ; anfractibus 6, convexiusculis, superne obtuse angulatis, 

 penultimo cylindraceo ; apertura subobliqua, semiovata, subpyri- 

 formi ; peristomate tenui, recto, marginibus remotis, margine 

 columellari crassiusculo, plica spirali obliqua elongata superne 

 intrante munito. 



Long. 3, diam. vix 1 mill. Apert. |, lata | mill. 



Habitat ad Humeerpore, Bundelkhund, prope ripas fluviorum Jumna 

 et Betwa. 



I discovered this shell, in October 1826, in the sand of the 

 Betwa river, while searching for Achatina Balanus, of which I 

 had taken a specimen in the aperture of a derelict Helix ; and 

 after a few days I took dead specimens, with the same minute 

 Achatina, among the clay-covered roots of a large tree which 

 had fallen in the peafowl jungle on the left bank of the Jumna 

 opposite to Humeerpore, and in a dried hollow near it, whither 

 those shells had been washed in the rains M'ith Bulimus gracilis, 

 Hutton. In January 1839 I took, I believe, a single specimen 

 among the porphyritic and greenstone rocks of the singular 

 crater-like hill of Khaneen, sixteen miles south of Hansi, in the 

 Delhi district, but broke it before I could examine it under a 

 lens. 



In a list published in the Calcutta ' Gleanings in Science ' of 

 1829 I set this shell down as a minute Pupa ; but on observing 

 that the spiral column was obsolete or absorbed, as in the genus 

 Pythia {Scarabus), I came to the conclusion that the form really 

 belongs to the family of Auriculacea. In the other inland 

 genus, Carychium, the spiral column is intact, except close to the 

 summit, although in the littorine genera Alexia, Auricula, Me- 

 lampus, and Cassidula I find the internal structure of the spire 

 similar to that of Coilostele and Pythia. 



In C. scalaris the aperture has some resemblance to that of 

 Jaminia, Say, a North-American marine operculate genus, which 

 Kiister included in the Auriculacea, but which is now referred 

 to the Pyramidellidse. 



Shortly before 1853, Capt. T. Hutton collected specimens of 



