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Distribution. Philippines, Molluccas. 



Remarks. A beautiful specimen was obtained at Stat. 33, with all the characteristics 

 of a typical D. aprimim. Length 85, greatest diameter 6 mill. Anal orifice with a very 

 slight notch. 



The specimen of .Stat. 313 is strongly curved like the one figured in Sowerby's Thes. 

 Conch. Ill, fig. 5 ; here the anal orifice is circular. 



The specimens from Makassar and Djampeah are very much alike. I hold them for young 

 individuals. They measure 45 mill, and less and are characterised by being fragile, strongly 

 curved, and much attenuated. I hesitated at first before identifying them with the full-grown 

 solid specimens from the Zoological Museum of Amsterdam. Fig. 3 shows the anterior apertures 

 of some of the Siboga specimens. They show the same characters as a typical D. aprijuiui : 

 on the concave side the ribs are stronger and the intervals more concave than on the convex 

 side. This is characteristic for all the species, included in this group. 



\'ar. incolor n. v. PI. IV, figs 3, 4, 5, 6. 



Stat. 133. Anchorage oft" Lining, Salibabu-island. Mud and hard sand. 4 Spec. 

 Stat. 163. Anchorage near Seget, West-entrance Selee (Galewo) strait. Sand and stone, mixed 

 with mud. i Spec. 



Fig. 4. Anterior aperture of 

 D. aprinum var. incolor with i8 ribs. 



Fig. 5. ."Vnterior aperture of 

 D. apriitiiin var. incolor of Stat. 133. 



Fig. 6. Anterior aperture of 

 D. aprinum var. incolor of Stat. 163. 



Under this variety I include the specimens of Stat. 133 and 163. The specimens of 

 Stat. 133 can easily be recognised as belonging to D. aprimun. They only differ by their 

 absolute lack of the green colour which characterises that species. Near the apex the shell is 

 yellow, fading to ivory white near the anterior aperture, but of 4 specimens (none of them quite 

 fullgrown) one has 11, two have 12, one has iS ribs. The latter number may be an abnormal 

 one, but there is little doubt about identifying that specimen with the others of the same 

 station. (PI. IV, fig. 3). 



The single specimen of .Stat. 163 (PI. IV, fig. 6) has a more doubtful character. It also 

 lacks the green colour of D. aprhmm but is moreover straighter and by its lusterless appearance 

 looks rather like D. javamim. There are however 1 2 ribs, stronger on the concave side than 

 on the convex side, which fact reminds of D. aprimun, and indicates a nearer relationship to 

 that species. In the collection of the British Museum I also found some specimens of this 

 variety; they were labelled D. apriimin var. and included forms resembling specimens of Stat. 133 

 as well as of Stat. 163. 



