GASTEROPODA. 53 
Shell turreted, turbinated, acute; whorls (6—7) convex and costated ; coste oblique, 
directed from right to left. 
The cost are rather more elevated than in &. acuta, and the entire figure is more 
turbiniform, the whorls being much more convex. Length from 25 to 3 lines. 
Locality. Ancliff; also very rarely at Minchmhampton Common, in the planking. 
Rissorna acuta, Sow. Plate IX, fig. 9. 
Rissoa acura, Sow. 1829. Min. Con., t. 609, fig. 2. 
—- — Brown. Illust. Foss. Conch., p. 79, t. 38, figs. 25, 26. 
— —  Bronn. Index Paleont., p. 1090. 
Rissorna acuta, D’Orb. Prod. Paléont., p. 297. 
R. Testé parva, turritd, acuta; anfractibus convexiusculis 6, costulis angustatis subre- 
motis longitudinalibus; apertura ovata; labio dextro expanso. 
Shell small, turreted, acute; whorls (6) slightly convex, with narrow, rather remote, 
longitudinal ribs ; aperture oval; right lip expanded. 
The surface is nearly smooth; the longitudinal ribs, or rather lines, scarcely affecting 
the evenness of the surface ; it is the most slender example of the genus which the Great 
Oolite has produced. Length, 3 lines. 
Locality. Ancliff; and very rarely Minchinhampton Common, in the planking. 
RIssOINA CANCELLATA. Plate IX, figs. 12, 12a. 
R. Testa turbinatd, turritd, acuta; anfractibus convewis (8), angustis, transverse costatis; 
costis (6—7) inequalibus, lineis longitudinalibus decussatis ; apertura lata. 
Shell turreted, turbinated, acute; whorls convex (8), narrow, transversely costated ; 
costae (6—7) unequal, decussated by longitudinal lines; aperture wide. 
The upper costz of each whorl are smaller and more approximated than the lower ; the 
convexity of the whorls is chiefly upon their lower portions; the fine longitudinal lines 
crossing the narrow encircling costz give to the surface a cancellated aspect ; the aperture 
is acute above, rounded beneath. 
Locality. The soft Oolite beneath the planking of Minchinhampton Common furnished 
this pretty little shell, of which we have not seen another example. 
RissoInA TRICARINATA. Plate IX, fig. 13. 
R. Testa pared, turbinatd, acutd; anfractibus convexis; tricarinatis; carinis crenulatis; 
carind superiore apud suturam positd; aliis in medio et approaimatis; anfractu ultimo ad 
basem lineis tenuissimis notato; apertura parvd, suborbiculari. 
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