60 MOLLUSCA FROM THE GREAT OOLITE. 



PILEOLUS PLICATUS, Sow. Plate IX, figs. 36, 360, 6,c. 



PILEOLUS PLICATUS, G. B. Sow. 1823. Genera of Shells, No. 19, figs. 14. 



Sow. Min. Con., t. 432, figs. 14. 



Bronn. Leth. Geogn., p. 392, t. 27, fig. 6. 



Brown. Illust. Foss. Conch., p. 92. 



D'Orb. 1850. Prod. Pal6ont., p. 299. 



Bronn. Index Palseont., p. 973. 

 PATELLA COSTATULA, Goldfuss. Petref., t. 177, fig. 9. 



P. Testa turbinatd; amditu orbiculari; vertice elato, subacuto, erecto; costis radiantibus 

 majoribus (16) acutis, minoribus intermediis ; costis posterioribus maasimis ; margine 

 dentatd; basi in media convexiusculd, ad peripheriam subconvexd; peripherid integrd aut 

 subsinuatd. 



Shell turbinated, suborbicular, summit elevated, erect, and rather acute; ribs radiating, 

 the larger series (16 in number) are acute, with smaller ones between them; the posterior 

 ribs are the largest and most distant ; the margin is toothed, the base is convex in its 

 middle part, and slightly convex at the periphery ; the periphery is entire, and slightly 

 sinuated. 



Four of the posterior ribs occupy one third of the circumference; they are more elevated 

 and distant than the others. The specimens of this species in the Great Oolite never 

 occur of so large a size as those of P. lewis ; the usual basal diameter being about 

 3 lines, and very rarely exceeding 4 lines. Pileolus plicatus is scattered, indifferently, 

 over the shelly beds, but in fewer numbers than the other species; the shell being very 

 thick and strong, is usually entire and uncompressed ; both species are always found in 

 the upright position. 



Locality. Minchinhampton Common ; Ancliff, Wiltshire ; Langrune, France. 



PILEOLUS L^EVIS, G. B. Sow. Plate IX, figs. 37, 37, b. 



PILEOLUS L^EVIS, G. B. Sow. 1823. Genera of Shells, No. 19, figs. 5 8. 

 Sow. Min. Con., t. 432, figs. 68. 



Brown. Illust. Foss. Conch., p. 92, t. 44, figs. 16, 17. 



D'Orb. 1850. Prod. Paleont., p. 299. 

 Bronn. 1848. Index Palseont., p. 973. 



? PATELLA MAMILLARIS, Goldfuss. Petref., t. 177, fig. 10. 



? PAPYBACEA, Bronn. Letheea Geogn., pi. 27, figs. 7, a, b. 



P. Testa pared, conico-depressd, Icevi, aut sulcis raris, obsoletis notatd; basi in media 

 convexiusculd. 



Shell small, conical, but much depressed ; sometimes discoidal, smooth, or with a few 

 faintly-marked longitudinal irregular sulcations ; base rather convex in the middle part. 



