445 



iiiofo allt'iiuakHl towards its l)asc> aiul (-(Hisiclcral)!)- in sc-iilpturc, as will he seen liy comparin^.f 

 tlu' clcscri[)ti(,Mis. 



-i. Plcurotomclla si''<^data n. si). PI. XXX, (Ilt. 2. 



Stat. 159. o°59'.iS., I29°48'.8E. Ilalmahcra-sca. 411 AT. Coarse sand, i Spec. 



Shell fusiform, gradate, moderately strong-, white. Whorls S (ii|)]HM-m()st brokcnj, (jf whicdi 

 2 form a reddish-brown nucleus, with convex whorls (their number probably will have been 4 

 of which 2 are wanting), sculptured by curved riblets, crossed by oblicjue fmer ones in the lower 

 part, which is consequendy finely reticulated. Subsequent whorls convex, angular, gradate by 

 a conspicuous excavation of the upper part, lower part perpendicular. .Spirals consisting of a 

 keel and a few, rather strong, slightly flattened lirae on the lower part, 4 in number on ])enult- 

 iiuate whorl and 2 narrow^ ones at the base of excavation, just above the keel; last whorl with 

 numerous stronger, flat lirae, eventually divided by a very fine groove, and some intermediate 

 ones. The axial sculpture consists of numerous fine growth-striae and curved riblets in the upper 

 part of excavation, less pronounced on last whorl, not quite extending to the keel. Last whorl 

 convex, regularly attenuated towards the rather long canal. Aperture elongate, angular above, 

 ending in a long, gutter-like canal below. Peristome broken, probably with a moderately wide, 

 shallow sinus. Columellar margin concave, with a rather strong layer of enamel along the canal. 



Alt. loYo, lat. 4Y1; apert. alt. 5Y3, lat. \^\, Mill. 



Still allied to the preceding 2 species, but less biconical in shape, with more slender 

 canal and very difl'erent in particulars of sculpture. 



4. Pletirotomella ceraineiisis n. sp. PI. XXX, fig. 3. 



Stat. 178. 2°40'S., I28°37'.5E. Ceram-sea. 835 M. Blue mud. 2 Spec. 



Shell shortly fusiform, transparently white. Whorls 8, of which 4 form a yellowish-brown 

 nucleus, with convex whorls, the uppermost broken, the other ones with curved riblets, crossed 

 by oblique, slightly finer ones, over a large part of their breadth. Subsequent whorls rather 

 convex, angular, with a broad, excavated, upper part, a rather narrow, nearly straight, lower 

 part, this lower part wath narrow^, obtuse, axial ribs, occupying also the lower part of excav- 

 ation, about 17 in number on last whorl, where they are fainter near aperture; these ribs are 

 crossed by 2 strong spirals on upper 2 whorls, 3 on penultimate and numerous ones on last 

 whorl, the upper spiral forming a keel, which is tuberculiferous by the intercrossing of the ribs; 

 moreover there are fainter spirals in some of the interstices and just above the keel, in tRe 

 basal part of excavation, 3 in number in penultimate whorl; the excavation is crossed by curved 

 riblets or plicae in its upper part, and the w^hole shell is covered with fine growth-striae. Last 

 whorl regularly attenuated below, with a rather short canal. Aperture angular above and at 

 the end of keel, with a probably shallow sinus, below the suture; peristome broken; columellar 

 margin with a thin layer of enamel; canal a little broken, probably gutter-like. 



Alt. 67^, lat. 3; apert. alt. 37,, lat. 17^ Mill. 



81 



SIBOGA-EXrEDITIE XLIX^ l?. 58 



