24 SUPPLEMENT TO GREAT OOLITE MOLLUSCA. 



PLEUROTOMARIA GRANULATA, Sow., sp. Tab. XXXI, fig. 8, 8 a. 



TROCHUS GRANULATUS, Sow. Min. Con., t. 220, fig. 2. 



PLEUROTOMAKIA GRANBLATA, Deslong. M6m. Soc. Linn., yiii, pi. 16, figs. 6 8. 



D'Orb. Prodrome, p. 267. 



Morris. Cat. Brit. FOBS., 1854, p. 271. 



Quenstedt. Der Jura, p. 414, tab. 57, figs. 5 7. 



Testa trochiformi subturrita, apice acufa, anfractibus convexiusculis, in media angulaiis, 

 subgradatis, supernc planiusculis, in/erne convexiusculis, transverse et longitudinaliter 

 sfriatis ; sinu anyusto, fascia sinus prominentc> transverse tenuissime sfriato, in media 

 anfractuum sita ; ultimo anfractu ad basin suhangulato, basi subconvexa, concentrice striata ; 

 umbilico minima out subnullo ; apertura subquadrata labro sinistro crassiori reflecto. 



Shell trochiform, subturreted; apex acute ; volutions rather convex, angulated in their 

 middle portions, or somewhat step-like, the upper half of each volution being flattened, the 

 lower half rather convex ; the surface is longitudinally and transversely striated, the decus- 

 sations of the striae forming granules or tubercles, of which there are usually five rows 

 above and four beneath the mesial angle, the uppermost row having the tubercles more 

 prominent and separated than the others ; the sinus is narrow, and of moderate depth ; 

 the fascia of the sinus is prominent, with fine, transverse striations, and placed in the 

 middle of the volution ; the last volution has the base somewhat angulated ; the base is 

 convex, and concentrically striated ; the umbilicus is very small or almost none ; the 

 aperture is subquadrate, the left lip being thickened and reflected. 



A beautiful species, not very regular in the disposition of the longitudinal and transverse 

 striations, but for the most part those beneath the mesial fascia are more strongly marked 

 than above. 



The height of the entire shell and diameter of the last volution are equal in the 

 specimen figured; others have the height somewhat greater; 16 lines is a medium size. 



Geological Positions and Localities. The Inferior Oolite of the south-west of England 

 and the Cornbrash of the coast of Yorkshire. Our specimen is from Gristhorpe, in the 

 collection of Mr. Leckenby. It is moderately abundant. 



CYLINDRITKS EXIGUA, Lye. Tab. XLIV, fig. 14. 



Testa parva, subcylindricd, spira elata conica, apice obtitso, anfractibus 5, latis, paulu- 

 lum convcxis, spira vero lateribus subconcavis ; anfractu ultimo margine rotundato, aper- 

 tura angimtissimo. 



Shell minute, subcylindrical ; spire elevated, conical, its sides being, however, slightly 

 concave, and its apex obtuse ; the volutions are five in number, moderately wide and 



