GASTEROPODA. 93 



PATELLA INORNATA. Plate XII, figs. 11, 11. 



P. Testa elliptica, lavissimd, lateribus subcompressis ; apice elato, erecto, subaculo, et 

 postmediano; latere antico concavo, postico recto. 



Shell elliptical, very smooth, the sides rather compressed; the apex erect, elevated; 

 subacute, and situated posterior to the middle of the shell ; anterior side concave, posterior 

 straight. 



The figure is a lengthened oval, the anterior side being rather depressed and pro- 

 duced ; the concavity anterior to the apex, presents some resemblance to P. nitida 

 (Deslongchamps); but in that shell the anterior side is much the shortest. P. nitida is, 

 likewise, much more nearly orbicular and conical, the vertex being distinctly curved 

 forwards. The smaller specimens have a more depressed figure, the anterior cavity being 

 scarcely perceptible. 



Longer diameter 10 lines, shorter diameter 8 lines, height 5 lines. 



Locality. It occurs in all the shelly beds, but is not very common in the Minchin- 

 hampton district. 



PATELLA NAN A, Sow. Plate XII, figs. 10, 10a. 



PATELLA NANA, Sow. 1824. Min. Con., t. 484, fig. 3. 



Fleming. 1827. Brit. Anim., p. 288. 



Morris. 1843. Cat. Brit. Foss., p. 155. 



Brown. 1849. Illust. Foss. Conch., p. 105, t. xlviii, figs. 24 26. 

 HELCION NANA, D'Orb. 1850. Prod. Pateont., p. 303. 



P. Testa parvd, elliptica, conicd, leevissimd; apice submediano, erecto, obtuso. 



Shell small, elliptical, conical, very smooth ; apex nearly mesial, erect and obtuse. 



The figure approaches near to P. cingulata, but it is usually a longer oval, and slightly 

 compressed at the sides ; in the young state the apex is more obtuse and depressed, the 

 form being then a longer oval. Many of the larger specimens are scarcely to be distin- 

 guished from P. cingulata, except by the absence of encircling stria3; and in badly 

 preserved specimens the striae are nearly obsolete. P. nana may, therefore, possibly be 

 only a variety of P. cingulata; they occur in the same beds, and are equally numerous. It 

 is true that good specimens of each species are sufficiently distinct; but knowing the 

 variations to which the shells of this genus are subject, we have thought proper to allude 

 to the possible specific affinity. The size never equals that of the larger specimens of 

 P. cingulata. 



Locality. Minchinhampton Common : found also in the Oolite of Ancliff, near 

 Bradford, Wilts. 



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