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convex whorls and 2 other ones with rather coarse, slightly oblique ribs, which are not crowded 

 and a spiral, just above the suture. 



18. PleiLrotoma (Geimmila) trttncata n. sp. PI. XXVI, fig. i. 



Stat. 221. 6°24'S., 124° 39' E. Banda-sea. 2798 M. Solid bluish grey mud with foraminifera, 

 covered by a 5 cM. thick layer of brown mud. 4 Spec. 



Shell shortly fusiform, very thin, whitish under a yellowish epidermis. Upper whorls 

 wanting by erosion, remaining whorls 5, angularly convex, separated by a conspicuous undulated 

 suture; upper part of whorls concave, lower part slightly convex, sculpture consisting of strongly 

 waved ribs, more conspicuous in upper whorls, becoming fainter in last one, where they nearly 

 disappear and have more the character of strong growth-lines below the periphery; on the 

 upper whorls these ribs form tubercles on the fasciole, becoming more foldlike on the lower 

 ones ; the whorls are crossed by numerous spirals, forming a subsutural rib, which on upper 

 whorls is more conspicuous and adorned with small beads, corresponding to the upper ends ot 

 the ribs, the excavation and fasciole are finely lirate; on the basal half of each whorl, the lirae 

 are coarser, especially on last whorl, where they are irregular, with some intermediate ones. 

 Last whorl strongly contracted below periphery, ending in a short, wide canal, slightly directed 

 to the left. Aperture oval, with a moderately sharp angle above and a very wide but not deep 

 sinus at the periphery ; peristome thin ; columellar margin with a conspicuous white layer of 

 enamel. Operculum thin, corneous, with basal nucleus. 



Alt. 19, lat. 8; apert. alt. 9, lat. 3Y3 Mill. 



This remarkable species is more or less variable in sculpture, as far as concerns the 

 strength of ribs, tubercles and spirals, but three of them agree in every important particular, 

 in the fourth, a young shell, some characters are obliterated. Though the species may belong 

 to the alliance of P. praesignis Smith and rotatilis v. Marts., it is impossible to combine it 

 with any of the described species. 



19. Pleurotoma (Gemimda) Sibogae n. sp. Tl. XXVI, fig. 2. 



Stat. 137. Channel between Makjan and Halmahera. 472 M. Fine dark muddy sand, i Spec. 



Shell broadly fusiform, with acute, conical spire and strong, angular last whorl, thin, 

 whitish, faintly yellowish on the keel, between the nodules. Whorls 11, but the number may 

 be considerably more, as the upper nuclear whorl seems to be wanting and the shell has the 

 appearance of being not adult. One upper nuclear whorl (or 2) smooth, convex, followed by 

 nearly another whorl, with rather remote ribs; subsequent whorls concave above the keel, with 

 a moderately strong infrasutural keel and i or 2 other spirals in the excavation between suture 

 and keel ; the infrasutural keel becomes fainter and is scarcely if at all traceable on lower 

 whorls, where on the contrary the number of spirals increases, so that on last whorl of the 

 specimen their number amounts to 6 and two very narrow ones just above the keel; this latter 

 is rather narrow, composed of 3 narrow superficial spirals, more conspicuous between the nodules, 



40 



