PLEUROTOMA.— Plate XIII. 



spiraliter tortuosd ; canalibrevissimo, leviter recurvo ; 

 labro subincrassato, intus eximie denticulato, sinu 

 parvo, distincto. 



The Rissoa-like Pleurotoma. Shell elongately oval, 

 smooth, shining, semitransparent, whitish, washed 

 with clouded yellow streaks ; whorls seven in 

 number, the first three longitudinally plaited ; apex 

 pink ; columella spirally twisted ; canal very short, 

 slightly recurved ; lip rather thickened, delicately 

 denticulated within, sinus small, distinct. 



Reeve, Pro. Zool. Soc, 1843. 



Hab. Island of Ticao, Philippines (found on the reefs) ; 

 Cuming. 



This species reminds me somewhat of the Rissoa de- 

 formis ; the first whorl or two are plaited as in that 

 shell, the surface is moreover smooth and shining, and 

 they bear a general resemblance to each other in size. 

 The apex of this shell is peculiar in being pink, whilst 

 there is not the least indication of that colour in any 

 other part. 



Species 112. (Fig. a & b, Mus. Cuming.) 



Pleurotoma Boholensis. Pleur. testd subelongatd, 

 tenui, subpellucidd, albidd, fulvo subindistincti vir- 

 gatd ; anfractibus octo, transversim linearis et liratis, 

 striis quoque subtilissime reticularis ; columelld spi- 

 raliter tortuosd; canali brevissimo, paululum recurvo ; 

 labro simplici, acuta, sinu parvo. 



The Bohol Pleurotoma. Shell rather elongated, thin, 

 somewhat transparent, whitish, rather indistinctly 

 streaked or waved with yellow ; whorls eight in 

 number, transversely lineated and ridged, very 

 finely reticulated also with stria?; columella spi- 



rally twisted ; canal very short, a little recurved 



lip simple, sharp, sinus small. 

 Reeve, Pro. Zool. Soc, 1843. 

 Hab. Island of Bohol, Philippines (found under stone: 



on the reefs at low water) ; Cuming. 



This shell, which is of a much thinner and slightei 

 composition than either of the two preceding ones, is 

 very finely reticulated over with striae ; and it has ■< 

 number of lines and ridges running transversely across 

 the whorls, but none longitudinally. 



Species 113. (Mus. Cuming.) 



Pleurotoma unizonalis. Pleur. testa ovatd, subtur 

 ritd, albido-grised, anfractu ultimo zona olivaceo 

 fused cincto ; anfractibus longitudinaliter costatis 

 costis in medio tuberculatis, superne evanidis ; colu 

 melld arcuatd, superne callositate munitd; aperture 

 ovali, fauce olivaceo-fuscd ; canali brevissijno. 



The zoned Pleurotoma. Shell ovate, somewhat tur 

 reted, greyish-white, last whorl encircled with ; 

 broad, distinct, olive-brown zone ; whorls longitu 

 dinally ribbed, ribs tuberculated in the middle 

 disappearing before they reach the suture; colu 

 mella arched, upper part furnished with a callosity 

 aperture oval, interior olive-brown ; canal very 

 short. 



Lamarck, Anim. sans vert., vol. vii. p. 92. 



Kiener, Icon. Coq. viv., pi. 22. f. 2. 



Hab. Island of Masbate, Philippines (found on the reefs 

 at low water) ; Cuming. 



In the figure above referred to, the ribs appear to re- 

 tain their greyish-white colour in passing through th< 

 olive-brown zone ; this is not the case in the specimer 

 before me, and I conclude therefore that the species 

 varies in this respect. 



