GASTEROPODA. 43 



The narrowness of the base, narrow subangular whorls, obtuse apex, and subcylindrical 

 figure of the last whorl, are the prominent features. 



It has been named in compliment to Sir Thomas Tancred, Bart., the founder of the 

 Cotswold Naturalists' Club. 



Locality. The fine specimen figured was obtained in the hard white limestone of the 

 upper portion of the Great Oolite formation near Minchinhampton, but it likewise occurs 

 in the planking, being rare in both situations. 



NATICA GLOBOSA, JRoem. Plate VI, fig. 14. 



NATICA GLOBOSA, Roemer. 1836. Nordd. Oolith., p. 156, pi. 10, f. 9. 



Bronn. 1848. Index Paheont., p. 783. 

 t 



N. Testa globosd, obliqua, ovato-orbiculari, hemisphericd ; spird laid, prominuld; 

 aperturd subreniformi ; umbilico amplo. 



Shell globose, oblique, ovately orbicular, hemispherical ; spire large, but not much 

 elevated ; aperture kidney-shaped ; umbilicus large. 



All our specimens have been obtained from the upper or limestone portion of the Great 

 Oolite ; we have, consequently, been able to obtain only portions of the shell. The figure 

 approaches so near to some of the casts of Purpuroidea Moreausia, that it is difficult, in 

 the absence of nodules, to distinguish them. Our species is, however, more depressed, and 

 the preserved portions of the shell are thicker than in the Purpuroidea -, but we should 

 always expect to find some traces of nodules in well-preserved casts of the latter genus. 

 Length 14 lines, breadth 16 lines. 



Locality. Minchinhampton. 



NATICA NERITOIDEA. Plate VI, fig. 4. 



N. Testa oblique-ovatd ; spird parvd, obtusd, dcpressd ; anfractu ultimo clongato ; 

 aperturd anyustatd, obliqud ; labio inferno calloso. 



Shell smooth, oblique, ovate ; spire small, depressed, and obtuse, the last whorl 

 elongated and narrow at the base ; the aperture narrow and oblique, the inner lip 

 thickened. 



Two examples, with the shell partially preserved, are our authority. They are remark- 

 able for the rounded and depressed form of the spire, which gives it a truncated aspect : it is 

 likewise turned to one side simulating a Nerita. The form of the aperture and base is more 

 narrow or contracted than any other Great Oolite species. Length 13 lines, width 9 lines. 



Locality. A bed of sandy limestone, about 100 feet above the Fullers-earth. 



