447 



This species is x'cr)- peculiar, il has sonu- icscmhlaiicc with riciii-oliuiicNa (Gyninobcla) 



extcnsa Pall [\\\\\\. Mus. Coinp. Zool. X'ol. WIN, iSSc), p. 126, I'l. 10, li(r. 2), IhiL differs 



iniu-h li\' iho spiral sculplun-, which seems not to exist in thai species, which is moreover 

 more sleiuler. 



7. PlcuroioDiclla abbreviata n. s]). Pi. XXX, fio'. 6. 



Stat. 178. 2°4o'S., 128'' 27'. 5 E. Ccram-sca. 835 I\I. Blue niucl. 2 Spec. 



Shell small, shortly biconical, thin, transparently white. Whorls about cS (nucleus sli<,rhtly 

 eroded), of which 4 forni a brownish (bleached) nucleus, of a])parently the same character as 

 in the preceding species. Stibsequent whorls (excepted last one), practically existing only of the 

 excavation, which is sculptured by curved, raised striae and is bordered, just below the suture, 

 by a conspicuous, spiral liration, with laterally compressed, fold-like beads, becoming fainter 

 towards the aperture, and, just above the suture, a second row of depressed, slightly pointed 

 tubercles, forming a keel below the excavation of last whorl, about 1 2 in number on that 

 whorl, where they form the top of short, oblique, axial ribs; lower part of last whorl, with 

 about 1 5 lirae and a few intermediate ones. Moreover fme growth-striae and excessively small 

 granules are visible on the whole shell, by the aid of a strong lens ; last whorl regularly attenuated 

 towards its base, only slightly convex, with a very short, broad canal. Aperture obliquely oblong, 

 with a sharp angle above and a narrow gutter-like canal below; peristome thin, with a wnde, 

 moderately deep sinus above; columellar margin slightly concave above, straighter and directed 

 to the left along the canal, with a thin layer of enamel, thicker below. 



Alt. 6, lat. 3^^; apert. alt. 3, lat. i Mill. 



This species is quite different from any of the preceding or elsew^here known ones by 

 its shape and sculpture. 



8. PlezLrotoinella pyriformis n. sp. PI. XXX, fig. 7. 



Stat. 178. 2°4o'S., 128° 37'. 5 E. Ceram-sea. 835 M. Blue mud. i Spec. 



Shell pyriform, with acute spire, ivory-white, thin, fragile. Whorls 8, of which 4 form 

 a light-brown nucleus, with convex whorls, remote riblets on the upper part, oblique, and less 

 stronger ones, which cross each other, in the lower part. Subsequent whorls scarcely convex, 

 wath only a trace of being divided into 2 parts on the upper two ; however, the upper part is 

 marked with elegantly curved, conspicuous riblets, being slightly bead-like just below the suture, 

 on a narrow, infrasutural spiral; lower part of last whorl, with numerous, faint, spiral striae, 

 stronger on the rather long, slender canal ; moreover the lower whorls display elegantly waved 

 growth-lines. Aperture oval, wnth a sharp angle above and a narrow gutter-like canal below, 

 which is directed to the right. Peristome much broken, probably with a wide, shallow sinus above; 

 columellar margin with a very thin layer of enamel, slightly stronger along the canal. 



Alt. 7Y0, lat. 37_i; apert alt. 4^^, lat. ly. Mill. 



The generic position of this shell seems to be somewhat doubtful, but the characters 



83 



