1921] NATURAL SCIENCES OF PHILADELPHIA. 341 



Mitra barbadensis (Gmelin) 



The single .specimen is rather worn, but agrees well with recent 

 specimens. 



Mitra mesolia Pils. and Johns. Plate XXIV, fig. 10. 

 Proc. A. N. S. Phila., 1917, p. 166. 



Vexillum tortuosellum (Pils. and Johns.) Plate XXIV. fig. 9. 



Mitra torluosella Pils. and Johns., Proc. A. N. S. Phila. 1917, p. 165. 



Vexillum tortuosellum frater (Pils. and Johns.) Plate XXIV, fig. 13. 



Mitra tortuosclln frater Pils. and Johns., Proc. A. N. S. Phila. 1917, p. 166. 



Vexillum tortuosum (Gabb) Plate XXIV. fig. S. 



Mitra tortuGsa Gabb, Tr. Am. Philos. Soc, xv, 1873, p. 220. 



There are about fifteen sharp, axial ribs on the last, eleven or 

 twelve on the penult whorl. Between them are many impressed 

 spiral lines, eleven or twelve on the penult whorl, parted by convex 

 intervals which become spiral cords towards the anterior end of the 

 shell, the axial ribs disappearing there. There are four columellar 

 plaits, and the outer lip is closely lirate within. 



Length 32.3, diam. 11.5 mm. 



Type and 4 other specimens are no. 3284 A. N. S. P. 



Plochelsea crassilabrum Gabb. Plate XXIV, fig. 6. 



PluchchFi crussilabra Gabb, Proc. A. N. S. Phila. 1872, p. 272, pi. 11, fig. 5 



(Feb. 11, 1878 ) 

 Plochekea crasailabrum Gabb, Tr. Am. Philos. Soc. xv, 1873, p. 216. 



The shell is smooth, oblong, widest above the middle, soUd; spire 

 straightly conic; suture scarcely impressed, ascending in front. 

 Last whorl swollen above, the anterior two-thirds slowlj^ tapering: 

 terminating in a massive but low and rounded varix. The aperture 

 is sinuous, the upper half narrow, lower half dilated; lip thick, blunt, 

 the outer margin inflected, widest in the middle, dilated near the 

 base. Anterior canal deep. Columella crossed by an emerging 

 callus which is thickened in the lower half; bearing five low, round- 

 ed, parallel and contiguous entering plaits, the third one slightly 

 the strongest. 



Length 44.2, diam. 19.8 mm. Length of aperture measured 

 from base to the end of the suture, 35.4 mm. 



The type, represented by Gabb's figure and ours, is no. 3289 

 A. N. S. P. The eroded seat of an Hippofiix scars the spire. Inhis 

 later specific description, Gabb confused this species with the fol- 

 lowing one; his measurement and the phrase relating to the columellar 

 plaits relating to the latter. 



