36 



Diagnosis. Shell moderately curved, sculptured with ii — 13 rather strong rounded 

 longitudinal ribs; intervals microscopally longitudinally striated over the whole surface, sometimes 

 with one or two interstitial riblets. Sculpture becoming weaker toward the anterior aperture. 

 Colour white or pinkish, or white becoming rosy towards the apex, with faint maculation on 

 the ribs. Of the three specimens in the British Museum two have the apex entire, while one 

 has a supplemental tube, a little transversely compressed. 

 Length 31, greatest diam. 4 mill. 

 Length 24, greatest diam. 3,5 mill. 



Distribution. East Indian Archipelago (Sowb.). 



*4i. Dcntalium variabile Deshayes. PI. I, fig. 17. 



1825. Dcntalium variabile Desh., Mem. Soc. Hist. Nat. Paris, II, p. 367, pi. 16, fig. 30. 

 i860. Dcntalium variabile Desh. SOWERBY, Thes. Conch. Ill, p. loi, pi. 224, fig. 30. 

 1872. Dcntalium variabile Desh., Conch. Icon. XVIII, pi. 4, fig. 26. 

 1872. Dentalium variabile Desh. Martens, Journal Linn. Soc. Lend. XXI, p. 200. 

 1897. Dentalium variabile Desh. PiLSBRY & Sharp, Man. of Conch, vol. XVII, p. 60, pi. 14, 

 figs 26- — 28. 



Diagnosis. Shell rather small, moderately arcuate, not much attenuated posteriorly, 

 solid; white, with numerous encircling grayish-translucent zones, more pronounced on the ribs, 

 which appear articulated with grayish and white. Sculpture of 10 or 11 strong narrow ribs with 

 concave interstices, at and near the apex; a median thread soon arising in each interval, and 

 becoming nearly equal to the primary ribs, and later other interstitial riblets arise in some 

 intervals, so that at the aperture there are about 22, 24 or more riblets. Aperture round, 

 slightly polygonal. Anal orifice small and circular with thick margin. No slit or notch. 

 Length 19, diam. aperture 2, diam. apex 1,1 mill. 

 Length 18, diam. aperture 2, diam. apex i mill. (P. & Sh.). 



Distribution. Mergui Archipelago at Mergui on mud-flats and Sullivan I. in 7 — lofms 

 (Anderson); Philippine Isl. (Sowb., Acad. Coll.) found at a dealers with mainly small Indian 

 shells (Desh.). 



Differs from D. Bclclieri in being narrower and less rapidly enlarging. The dotted ribs are 

 characteristic, but their number varies considerable. It sometimes reaches 30 mill, length (P. & Sh.). 



Subgenus Fissidentalium Fischer 1885. 



1885. Fissidentalium Fischer, Manual de Conchyliologie, p. 894. Type D. ergasticum Fisch. 

 1894. Scliizodentalium Sowerby, Proc. Malac. Soc. Lond. I, p. 158. Type S. plurifissuratum Sowb. 

 1897. Fissidentalium Fischer. PiLSBRY & Sharp, Man. of Conch., vol. XVII, p. 63. 



.Shell large and solid, sculptured with many longitudinal riblets, the apex typically with 

 a long slit, but often simple, sometimes with a slit divided into a series of fissures. (P. & Sh.). 



