64 



below the muldle of the last whorl : plicately and transversly ribbed 

 on the middle of .the whorls ; with a very broad moderately elevated 

 spiral ridge along the middle of the whorls ; with a slight linear spi- 

 ral ridge at the summit of the whorls, and a third spiral ridge of in- 

 termediate size at the lower part of the whorls : apex subacate : spire 

 with the outlines nearly rectilinear: whorls about seven, scarcely con- 

 vex, with an indistinct suture : aperture small, but rather wide : sinus 

 moderate, near the upper end of the labrum : canal very short. 



Mean divergence about 28°; length of spire .11 inch; total length 

 .19 inch ; breadth .07 inch. 



Pleuroto.aia nodata. Shell fusiform, elongated : brown, with 

 white tubercles : with a spiral series of large obtuse undivided 

 scarcely elongated tubercles, which are connected by a small elevated 

 spiral line ; whorls slightly shouldered ; anteriorly with a few distant 

 elevated spiral lines : apex acute : spire with the outlines nearly 

 rectilinear : whorls seven, a little convex, with a moderately im- 

 pressed suture : aperture rather narrow : sinus rather shallow : canal 

 not very short. This species resembles P. alhinodata Rv., which has 

 the tubercles divided by a deeply impressed spiral line. 



Mean divergence 33°; length of spire .2 inch; total length .31 

 inch ; breadth . 1 inch. 



Pleurotoma quadkilineata. Shell clavate-pyramidal : white, 

 with one or two fine spiral lines of brown along the suture, and four 

 similar lines just below the periphery of the last whorl, all of which 

 lines are interrupted by the ribs, and with similar but paler lines at 

 the upper part of the whorls and anteriorly : with obtuse moderately 

 elevated transverse ribs, about eleven on each whorl ; with many 

 excessively minute finely gi-anose spiral elevated lines, which are 

 more conspicuous where colored as above described, and which are 

 obsolete at the summit of the ribs : apex acute : spire with the out- 

 lines nearly rectilinear ; whorls seven, subangular above the middle, 

 with a well impressed suture : aperture long-obovate, subacuminate 

 at both extremities : labrum well excurved : sinus shallow : canal 

 short. 



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

 •21 inch ; breadth .08 inch. 



Pleurotoma fusiformis. Shell fusiform : white, with a tinge of 

 brown along the suture and in the intercostal spaces : with large ob- 

 tuse pliciform ribs, about nine on each whorl, and numerous unequal 

 inequidistant spiral raised lines, of which one a little above the pe- 



