232 EOCENE MOLLUSCA. 



Localities. — Highgate, Hornsey, Potters' Bar, and Clarendon Hill, at which last 

 locality both varieties occur. 



The specimens represented by figs. 3 a and 3, form part of Mr. Wetherell's col- 

 lection. 



No. 156. Pleurotoma pyrulata, Beshayes. Tab. XXVII, fig. 7 a, b. 



Pleurotoma pyrulata, Desk. 1824-37. Descr. des coq. foss., &c, vol. ii, p. 449, t. 66, 



figs. 1—3. 



P. testa elongatd, angustd, piruliformi, spiraliter lineatd: spird mediocriter elevatd, 

 sub-conicd ; anfractibus angulatis, in medio convexiusculis, antice sensim attenuatis ; mar- 

 ginibus posticis declivis, vix cavatis, concenlrice tenuissime lineatis ; ultimo anfractu in 

 canali prce-longo terminanti ; lineis spiralibus acutis, irregularibus, incequalibus, lineis incre- 

 menti fortiter decussatis : aperturd elongaio-ovali ; labro parum arcuato ; sinu latiusculo, 

 prof undo, in margine collocato. 



Shell elongated, narrow, concentrically lined : the spire, formed of eight or nine 

 volutions, is pointed and moderately elevated, not equalling in length a third part of 

 the whole shell ; the whorls are convex at the middle, bluntly angulated at the 

 shoulders ; the posterior margins but slightly depressed, giving a nearly conical form 

 to the spire ; slightly thickened at the edge, where they present two strong, prominent, 

 raised lines, which run round the suture, and form a border to the whorls ; the space 

 between the suture and the shoulders is slightlv channeled, and covered with several 

 very slender, unequal, raised lines ; the body-whorl diminishes gradually towards the 

 base, and terminates in a very long and nearly straight canal. The gradual tapering 

 of the whorls, joined to the rather short, conical spire, gives to the shell somewhat of 

 the form of a long, narrow pear, from which appearance the specific name is taken. 

 The spiral lines over the middle and front parts of the whorls are numerous, irregular, 

 and unequal, slender thread-like lines alternating with thicker and more prominent 

 lines ; all are beautifully and regularly decussated by the strongly marked lines of 

 growth. The aperture is of a long, narrow, oval form ; the outer lip slightly expanded 

 towards the middle ; and the sinus, which is placed in the middle of the margin is deep 

 and not very wide. 



The French shells, in their typical form, are narrow, with a rather short spire ; 

 but, apparently, specimens from different localities present considerable variations, 

 not only in the relative height of the spire and width of the shell, but also in the stria- 

 tion. The specimens from Compiegne, for instance, as M. Deshayes has recorded, 

 have the spire more produced, the angle of the whorls more prominent, and the con- 



