222 EOCENE MOLLUSCA. 



Acy-en-Mulcien, Fosse-Martin, Ermenonville, Ver (fide Graves), Laon (fide 

 Mettev.), Bos d'Arros (fide Bouault). North American — Claiborne, Alabama (fide 

 d'Orb.)? 



No. 147. Pleurotoma textiliosa, Deshayes. Tab. XXVI, fig. 7. 



Pleurotoma textiliosa, Desk. 1824-37. Desc. des coq. foss., &c, vol. ii, p. 454, t. 62, 



figs. 5, 6. 

 D'Orb. 1850. Prod, de Paleont., vol. ii, p. 417, No. 1480. 



P. testa elongato-fusiformi, angustd, sub-tarritd, longitudinaliter costatd, spiraliter 

 subtilissime lineatd ; spird eievatd, acuminata: anfractibus sub-convexis, angulatis j margi- 

 nibus posticis angustis, concavis, ad suturam incrassatis ; costis distantibus, obtusis ; lineis 

 spiralibus confertis, inaqualibus, lineis incrementi sub-decussatis : aperturd ovato-angustd, 

 in canali mediocri exeunti ; labro acuto ; sinu lato, trigono, in margine collocate-. 



Shell elongate, fusiform, narrow, longitudinally ribbed and ornamented with 

 numerous, very fine, concentric, raised lines; the spire, which is formed of eight or 

 nine volutions exclusive of the pullus, is pointed and much produced, fully equalling 

 the last whorl in length : the whorls are slightly convex, and angulated at the shoulders ; 

 the posterior margins narrow, hollowed out, and thickened at the edges so as to form 

 an elevated border round the suture ; the whole of the margin is covered with very fine, 

 regular, closely set, concentric lines, of which those on the border are more conspicuous 

 than the rest. The longitudinal ribs are rather distant, round, thick, and short, barely 

 extending to the middle of the whorls, and terminating abruptly at the shoulders, 

 where they present a sharp keel-like edge, which gives somewhat of a turreted aspect 

 to the spire. The concentric lines over the front and middle parts of the whorls are 

 very numerous, unequal, and irregular ; some of them, slender and thread-like, are 

 prominent and more or less distant, and the intermediate spaces are covered with 

 exceedingly fine lines, scarcely perceptible by the naked eye ; the whole are roughened 

 by the lines of growth. The aperture is of a narrow, ovate form, and terminates in 

 front in a moderately long canal, slightly notched at the anterior extremity ; the outer 

 lip is thin, sharp-edged, and expanded behind ; the sinus which is wide, deep, and 

 somewhat trigonal in form, is placed a little in front of the middle part of the 

 posterior margin of the whorl ; the columella is slightly twisted and presents a con- 

 spicuous but not very prominent crest. M. Deshayes states that the columella is 

 " sub-perforated at the base," presenting there a narrow, shallow " umbilical opening, 

 partly covered by the inner lip ;" this opening, however, is not truly umbilical, but a 

 slight hollow caused by the ridge or crest being imperfectly overlapped by the inner 

 lip, and is a character very variable, and sometimes wanting. 



