63 



•with very close-set rather co.arse spiral striae, which are elegantly de- 

 cussated on the lower whorls by excessively minute lines of growth : 

 apex acute : spire with moderately convex outlines : whorls seven, 

 or eight, rather convex, with a well impressed suture : aperture large : 

 labrum well excurved and produced in its lower half: sinus rather 

 deep at the upper extremity of the labrum : canal short and very 

 wide. 



Mean divergence 32'' ; length of spire .27 inch ; total length .55 

 inch; breadth .2 inch. 



This species much resembles P. lymneiformis Rv., for which it has 

 been mistaken. It also closely resea^bles in form, but not in sculp- 

 ture, P. patula Rv. 



Pleukotoma albella. Shell long ovate-fusiform : opaque snow 

 ■white in the intercostal spaces, otherwise of a chalcedonic white : with 

 strong wide transverse ribs, about thirteen on each whorl, nearly in 

 continuous lines from the summit to the last whorl, and becoming ob- 

 solete anteriorly ; with one or two raised spiral lines, at the base of 

 each whorl and numerous well rounded revolving ridges on the ante- 

 rior half of the last whorl : apex acute : spire with slightly convex 

 outlines, long and regularly conic: whorls seven, slightly convex, with 

 a moderately impressed suture : aperture nearly in the form of a i!:j ; 

 labrum denticulate within ; sinus rather wide and shallow near the up- 

 per end of the labrum : canal very short. 



Mean divergence about 30°; length of spire .12 inch; total length 

 ,2 inch ; breadth .07 inch. 



Pleurotoma pygmjea. Shell ovate-fusiform, much elongated: 

 with a broad ii'regular band of yellowish brown along the upper part 

 of the whorls and below the middle of the last whorl : with small 

 transverse approximate ribs, about fifteen on each whorl, and rather 

 distant spiral elevated lines, the intersections being developed into 

 large nodules : nucleus smooth and opaque white : apex subacate : 

 spire with convex outlines : whorls about'six, moderately convex, with 

 a, lightly impressed suture : aperture rather narrow : sinus rather 

 large and deep, near the upper end of the labrum : canal very short. 



Mean divergence about 30°; length of spire .075 inch; total 

 length .13 inch; breadth .055 inch. 



Pleurotoma flavocincta. Shell ovate-conic, much elongated : 

 white, with a spii'al band of yellowish brown on the upper and on the 

 lower parts of the whorls, with spots of the same descending from the 

 upper band into the intercostal spaces ; with linear bands of the same 



