PROSOBRANCHIATA. 271 
Size.—If the shell were perfect the axis would be about 1 inch and 4-12ths 
(34 millim.); diameter, 5-12ths of an inch (11 millim. nearly). 
Localities —Southend, Nuneham. /rench: Bos d’Arros (fide Rovault. 
Additional Species*.—Subdivision a. Canal elongated. 
No. 194. Prevroroma Lenonu. ouault. Tab. XXXI, fig. 13, a, 4. 
Pievrotoma Levonit. Rouwault. 1848. Foss. du Terr. Eocéne des Env. de Pau; (Mém. Soe. 
Geol. de France, vol. iii, 2d ser., p. 485, t. 16, fig. 26.) 
P. testé elongato-fusiformi, transversim lineatd, longitudinaliter costellatd : anfractibus 
convexiusculis ; marginibus posticis declivis, ad suturam leviter crenulatis ; ultimo anfractu 
spiram in longitudine superanti; costellis obliquis, angustis ; lineis transversis tenuibus, 
erebris, sub-regularibus : aperturd ovato-angustd, in canalem longum, angustum, sub-rectum, 
productd ; sinu lato, sub-trigono, in margine collocato. 
Shell long, narrow, fusiform, longitudinally ribbed, and ornamented with concentric, 
raised lines ; the spire is moderately produced, not equalling the last whorl in length. 
The whorls are slightly convex, with rather wide, slanting margins, slightly thickened, 
and very finely crenulated by the lines of growth along the sutural edge. The 
longitudinal ribs are rather prominent, narrow, not very distant, oblique, and curved, 
corresponding with the lines of growth, short in front, barely passing beyond the 
middle of the whorls, but reaching backwards to the very suture; the concentric 
lines extend over the ribs, and are fine, close-set, regular, and nearly equal. The 
aperture is of a narrow, ovate form, and terminates in front in a long, narrow, and 
nearly straight canal; the sinus is wide, sub-trigonal, and placed in the margin. 
The English shells agree so well with the description and figures given by Rouault, 
that there does not appear to be any reasonable doubt of their identity with the 
species described by that author. 
Size.—Axis, 7-12ths of an inch, nearly (14 millim.); diameter, 2-12ths of an inch 
(4°5 millim.) 
Localities.—Highgate Archway. French; Bos d’Arros (fide Rowault). 
No. 195. Pxrevroroma macrura. LF. 2. Hdwards. Tab. XXXIIL, fig. 8. 
P. testa elongato-fusiformi, sub-turritd, longitudinaliter costellatd, omnino concentrice 
lineata: spird breviusculd, in longitudine trientem totius teste vix superanti: anfractibus 
* The following three species, Nos. 194, 195, and 196, have been obtained since the publication 
of the first subdivision of the section distinguished by the sinus being placed in the margin; they are now 
added in order that the present monograph may contain descriptions of all the known English Pleurotome. 
