442 GASTEROPODA OF THE INFERIOR OOLITE. 



throughout, but the radial decussation is so slight that the shell is merely 

 subgranulate. 



The sinus-band is below the middle and not conspicuous, owing to the 

 resemblance of its spiral lines to the general spiral system ; there is a strong central 

 line and a fine one on each side. The body-whorl is bluntly angulated at the 

 periphery and carries an obtuse carina with about three subgranulate spirals, 

 corresponding to the basal keels in the spire whorls. Base extremely convex, with 

 well-marked spirals only faintly decussated by radii ; umbilicus small. Aperture 

 ovate to subrhomboidal. 



N.B. — The three following " species " represent the Granulata-growp in the 

 Parkinsoni-zone, and exhibit a sequence of forms from the flat and delicately- 

 sculptured PL PalcBmon to the turrited and rugose PL trapeza, the species next 

 described occupying the middle position. 



383. Pleurotomaria plicopunctata, Deslongchamjjs, 1848. PI. XL, figs. 2 a, 2b, 2 c. 



1848. Pleurotomaria granulata, var. plicopunctata, Beslongchamps. Vol. 



cit., p. 102, pi. xvi. figs. 7 a, b. 

 Syns. — ornata, Defrance. Diet. Sci. Nat., vol. xli, p. 382, 



pi. lxxxvi, fig. 2. 

 — Deshayes, Coq. caract., p. 179, pi. iv, 



%■ 3. 



— QB.A.xvi,A.TA,Deslongchamps. D'Orbigny, Terr. Jur., vol. ii, 



p. 466, pi. ccclxxx, figs. 1 — 6. 



— ornata, Defrance. Morris, Cat., p. 271. 



— Defrancii, Hudleston and Wilson. Cat. Brit. Jur. 



Gast., p. 102. 



BibliograjiJii/, Sfc. — Owing to the original misapprehension of Defrance in 

 identifying this member of the 6rra?mZaia-group with Sowerby's Trochus ornatus, 

 there has been a considerable amount of confusion in the nomeuclature. 

 Endeavouring to escape from the labyrinth of "granulatas" and " ornatas " 

 which invested it, Messrs. Hudleston and Wilson proposed the specific name 

 "Defrancii" This had, however, been already applied by d'Archiac and 

 de Verneuil (' Trans. Geol. Soc.,' 2nd series, vol. vi, p. 360) to a palasozoic 

 Pleurotomaria. In order to distinguish this species it seems best to fall back on 

 Deslongchamps' varietal name. 

 Description : 



Height ..... 16 mm. 



Basal diameter . . . .35 mm. 



Spiral angle ..... 12-5°— 130°. 



