GASTEROPODA. 39 



Ceritella mitralis. Plate V, fig. 15. 



C. Testa conicd, apice acuminata, anfractibus (7) angustatis, plants, marginibus sub- 

 tumescentibus ; aperturd parvd, obliqud ; canali brevi. 



Shell conical, apex acute, whorls (7) narrow, flattened, their upper margins slightly 

 tamed ; aperture small, oblique ; canal short. 



This species is unusually short and conical. Axis 5 lines, transverse diameter 3 lines. 



Locality. The planking of Minchinhampton Common, where it is rare. 



Ceritella conic a. Plate V, figs. 10, 10«, 10(5, 10c. 



C. Testa turritd, acuta; anfractibus angustatis plants (8) ; coslis longitudinalibus, a 

 dextro ad sinistram obliquis ; aperturd angustatd, canali obliquo. 



Shell turreted, acute ; whorls narrow, flattened (8), with longitudinal oblique ribs, 

 passing obliquely from right to left ; aperture narrow, canal oblique. 



The upper margin of each whorl has a slight encircling rib, which is united to the 

 oblique costae. The character of the markings in this species resembles C. gibbosa ; but in 

 that species, although the whorls are equally numerous, the spire is very small, and the 

 canal is almost obsolete. The length of the last whorl is two fifths of the entire shell. 

 Axis 6^ lines, transverse diameter 3 lines. 



Locality. The planking of Minchinhampton Common and white stone of Bussage 

 have furnished it but rarely. 



Ceritella gibbosa. Plate IX, fig. 17. 



C. Testa parvd turritd, spird mediocriter elatd, apice acuto, anfractibus plan a fix, angus- 

 tatis et angulatis, longitudinaliter costatis ; costis numerosis, a dextro ad sinistram obliquis ; 

 anfractu ultimo, magno ; aperturd obliqud, angustatd et elongatd. 



Shell small, turreted ; spire moderately elevated ; apex acute ; whorls flattened at the 

 sides, narrow, and angulated at their upper portions ; longitudinally costated ; costse 

 numerous, directed obliquely from right to left ; the last whorl large ; aperture oblique, 

 narrow, and elongated. 



The angle of the whorls is slightly thickened and prominent ; the costse are distinct 

 immediately beneath it, but are not discernible upon the lower portion of the whorls. The 

 length of the aperture is equal to the remaining portion of the shell. The specimen figured 

 is rather more gibbose than usually obtains, for the proportions vary, but in point of size 

 there is no considerable difference. It is somewhat rare, and occurs in the soft shellv 

 Oolite which underlies the planking. Axis 3 lines. 



Locality. Minchinhampton Common. 



