41 

 Distribution hitherto unknown. 



Remarks. This species differs from D. dispar in the simple primary ribs, lack of fine 

 even lontjitudinal striation, and persistance of the sculpture to the aperture. D. qiiadrapicale is 

 allied, but has a much more oblique aperture, more rapidly tapering tube, and though far 

 smaller, a greater number of much finer longitudinal riblets. (P. & Sh.). 



The specimen obtained by the Siboga is not full-grown Ijut it oft'ers all the characters of 

 D. dipsycha. It measures 23 mill., with a greatest diameter of 2 mill, and is much attenuated. 

 At the aperture there are 16 riblets, the last set of interstitial riblets having not yet appeared. 

 The four primary ribs though acute near the apex, become rapidly rounded, together with the 

 other ribs. They remain however very narrow. 



*48. Dentaliiini qitadi'icostatiint Brazier. 



1877. Dentaliwn quadricostatum Brazier, Proc. Linn. Soc. N. S. Wales II, p. 58. 



1897. Dentaliiiiii qiiadricostatutn Brazier. PiLSBRV & SHARP, Man. of Conch, vol. XVII, p. 33. 



Diagnosis. Shell white, very slightly arched, four angled, keel or rib at each angle, 

 rounded, finely serrated, interstices flat, marked with transverse lines; apex perforated, perforation 

 entire; aperture angled. Length 16 mill., diam. of base 2 mill. (Br.\zier). 



Distribution. Princess Charlotte Bay, North East Australia, 13 fms. York Island, 

 Torres Straits, 13 fms. Katow, New Guinea 8 fms (Chevert Exp.). 



Remarks. If this species is laid upon its side it forms a true square; when resting 

 with the arched part of the apex down, it forms four angles, with a serrated rib on each angle. 

 The 1 I specimens from Katow, 1 6 from Princess Charlotte Bay, and i from York Island, all 

 have the same character. (Br.\zier). 



49. Dentalium tctj-apleiirtim n. sp. PL VI, fig. 37. 



Stat. 4. 7°42'S., 1 14° 12.6 E. Anchorage off Djankar (Java). 9 Metres. Coarse sand, i Spec. 

 Stat. 279. Ruma-Kuda bay, Roma Island. 36 Metres. Mud and sand, i Spec. 



Diagnosis. Shell moderately curved, white, rather .stout, square at the apex, rounded 

 at the aperture. Sculpture: four primary ribs at apex, soon followed by secondary and tertiary 

 ribs, giving a total number of 16 equally strong, rounded longitudinal ribs near the aperture. 

 Intervals concave and longitudinally striated throughout their e.xtent. About 20 fine microscopical 

 striae in each undivided interval at the apex. Tube subcircular, a very little laterally compressed. 

 Aperture not very oblique. xA.nal orifice round, with a slight rim, the ribs not slit. 



Length 22, greatest diameter 3 mill. 



Remarks. The specimens obtained by the Siboga are not yet full-grown. Probably an 

 older individual would show one more set of interstitial striae, as in D. dipsvcha. Is the o-eneral 

 system of sculpture in both species the same, still they can easily be distinguished by the inter- 



SIBOGA-EXPEDITIE LIV. 



