i8 



Diagnosis. Shell rather slender, the length about lo times the greatest diameter, 



well curved, white or bluish white ; nearly 

 lusterless or shining. Sculpture 8 (rarely 9) 

 longitudinal rounded ribs, extremely strong 

 and prominent toward the smaller end, 

 often lower toward the aperture, parted 



Fig. 12. The .interior apertures of three diffeient specimens of/). ('<-A7«^-/^A7/««/. \^y (-Jggp concave intervals, SmOOth in the 



young, but usually with several or many unequal longitudinal striae in adult specimens at least 

 toward the larger end; growth-lines slight. Aperture somewhat oblique, octagonal, a trifle longer 

 than wide.' Anal orifice minute, a little channelled on the convex side but without a slit. 

 Length 50, greatest diam. 5, least i mill. 

 Length 52, greatest diam. 5,3, least 0,8 mill. (P. & Sh.). 



Distribution. China Sea (authors); Japan, Nagasaki and Bay of Jeddo (Lischke) ; 

 Hakodate (Schrenck); Kii coast (Stearns); Ceylon (Tennent); N. Australia at Cape York, 

 Princess Charlotte Bay, Katow, New-Guinea, Darnley Island, Torres Strait (Chevert Exped.); 

 generally distr. from Bushire to Karachi (Melv. & St.). 



To this diagnosis IVIessr Pilsbry and Sh.vrp add: "Out of 32 specimens before us from 

 Japan, 2 have nine equal and equidistant ribs and in another one rib is replaced by two 

 contiguous smaller ones. The young are much more curved than adults ; and in the latter the 

 larger half of the length is scarcely arcuate. The number of the ribs is practically the chief 

 character separating this from D. scxcostatiLin. 



In some specimens the primary ribs become much lower toward the aperture, which, 

 while still octagonal, has the angles rounded off, not projecting as in the typical form". 



No specimens were obtained by the Siboga Expedition. 



16. Dentalium javatunn Sowerby. Pl. I, fig. 6. PI. IV, fig. 7. 



i860. Dentalium javanuin Sowerby, Thes. Conch. Ill, p. 102, pl. 223, fig. 12. 



1872. Dentalium javanuin Sowerby, Conch. Icon. XVIII, pl. 3, fig. 14. 



1886. Dentalium javanuin Sowerby. Watson, Chall. Rep., p. 12. 



1897. Dentalium javanuin Sowerby. PiLSBRY & Sharp, Man. of Conch., vol. XVII, p. 4, 

 pl. 4, fig. 49. 



Stat. 162. Between Loslos and Broken islands, West coast of Salawatti. iS Metres. Coarse 



and fine sand with clay and shells. 4 Spec. 

 Stat. 33. Bay of Pidjot, Lombok. 20 Metres. Coralsand. 



Diagnosis. A large shell, well curved, the length about 10 to 13 

 times the diameter, tawny and nearly lusterless. Sculpture of eight longitudinal 

 prominent ribs separated by flat or slightly concave intervals. Intervals smooth 

 with slight growth striae only. Aperture rather oblique, dorso-ventral diameter a 

 F'g- '3- trifle longer than the transverse diameter. Apex entire, anal orifice rather wide. 



Anterior aperture 



ai D. javanum. Peristome thin, the ribs internally excavated, specially on the concave curve. 



