218 



there must remain some doubt as to whether there may not have 

 been an error in the locality, or whether the solitary specimen 

 procured was not the young of some better-known shell. Two 

 specimens from Theobald's Collection, now in the British Museum, 

 do not agree satisfactorily with the original description. 



b. Aberrant form. 



*326. Durgella khasiaca, Godivin-Austen, Mol Ind. i, 1883, p. 145, 



pi. 39, figs. 7, 7 , 7 b, 8, 8 a, 8 b (shell, jaw, and radula). 



" Shell depressedly ovate, thin, horny, shiny, smooth, with 

 close, fine, transverse lines of growth ; colour pale ochraceous 

 olive ; spire very depressed, flatly convex, suture shallow ; 

 whorls 3, rapidly increasing ; aperture oblique, flatly ovate ; 

 columellar margin but weakly developed." (Godwin-Austen.) 



Major diam. 6*7, min. 5, height (from figure) 3 mm. 



ffab. West Khasi Hills. 



The radula is very remarkable ; it contains 250 . 1 . 250 teeth in 

 120 rows : the rhachidian is elongate, with three terminal equal- 

 sized points ; the lateral teeth are all alike, much curved and 

 terminally bicuspid, the outer point slightly in advance of the 

 inner. All decrease gradually in size outwards. Jaw thin and 

 horny, nearly straight in front. 



There is some slight resemblance to the radula of this species in 

 Girasia crocea, but both shell and animal are very different. 



Genus IBYCUS. 



Ibycus, Heynemann, Mai. Bliitt. x, 1862, p. 142. 

 Leptodontarion, subg. of Helicarion, described by Paul 8f Fritz 

 Sarasin, Land-Mollusken von Celebes, p. 124 (1899). 



Type, I.fissidens, Heynemann. 



Range. Sikhim. 



The original type of this genus was a spirit-specimen in very 

 bad condition, all the posterior half of the body, half the mantle, 

 and part of the shell having been lost. The radula shows re- 

 markable characters. There is no median row of broader plates 

 as in so many LimacidsD ; the rhachidian tooth is much broader at 

 the base than at the point, the shovel-like point rising up like a 

 spoon. The side teeth have two cusps, each projecting forward 

 and connected with a plate behind, and pass gradually into rather 

 smaller but similar teeth, each side of a row running backw*ard 

 from the middle tooth, " so as to resemble a flight of cranes." 

 The jaw has a projecting median process, as generally seen in 

 Macrochlamys, thus differing from other species of the Durgellince. 



With this remarkable form Col. Godwin- Austen's Durgella 

 minuta may perhaps be connected, as it has a somewhat similar 

 radula. 



[The shell of the type species is very different from that of minuta. 



