154 MOLLUSCA OF THE 



Locality: Cavern on Mount Liang Koeboeng, 800 M., 

 March 1894 (Büttikofer). 



One fine specimen, larger than the type described by 

 Bock, measuring 38 instead of 30 mill., but agreeing with 

 it in every other respect. 



16. Dyakia densestriata , n. sp. 

 (Plate 3, fig. 2). 



Shell dull reddish brown , discoid , narrowly umbilicated , 

 sharply keeled ; sculpture : above remote rib-like folds, with 

 hair-like intermediate raised striae , scarcely visible without 

 a lens; these striae are waved and granular, the granula- 

 tion giving the appearance to the shell of being spirally 

 striate; under surface with the same sculpture, but less 

 developed and accordingly more smooth and shining, mo- 

 reover with a few scattered grooves; apex blunt; spire 

 moderately elevated , with 7 slowly increasing , nearly flat 

 whorls; suture shallow, in some parts showing the keel, 

 which is sharp and prominent in the last whorl ; the shell 

 is slightly excavated above and below the keel; aperture 

 semilunate, slightly oblique; peristome thin, with a short, 

 curved upper margin and a regularly rounded lower one , 

 which is slightly produced in the middle ; columellar margin 

 very oblique, slightly reflected on and partly covering the 

 umbilicus. 



Diam. maj. 37, min. 33, alt. 19 mill.; apert. lat. 18, 

 alt. I3I/2 mill. 



Localities: Mount Liang Gagang, March 1894 (Hal- 

 lier). — Mount Tiloeng, May 1894 (Büttikofer). — Sintang 

 (Büttikofer). 



In the first named locality one dextral and some sinistral 

 specimens have been collected ; on Mount Tiloeng one 

 sinistral. Most of the specimens have also spiral and obli- 

 que grooves on the upper part of the shell. The specimen 

 from Sintang is incomplete; though slightly differing in 

 sculpture, I think it may be merely a variety. 



Notes from the Leyden JMusemn, Vol. XVII. 



