UPPER, OR FLINTY CHALK. 195 



sion ; a portion of the original shell is attached to one of the volutions. 

 This species sometimes attains two inches and a half in height, and 

 four inches in diameter. 



Fig. 21. View of an interesting example of the base, exhibiting 



the structure of the umbilicus. 



Localities. Upper, and Lower chalk of the South Downs ; rare in the 

 latter deposit. 



47. Cirrus depressus. Tab. xviii. figs. 18. 22. 



Spire depressed ; volutions transversely ovate, spirally striated ; aper- 

 ture ? umbilicus ? 



This shell might be referred to the genus Euomphalus of Sowerby, but 

 is so clearly related to the preceding species, that I cannot hesitate to 

 retain its present appropriation. 



It differs from C. pe7'spectivus, in the spire being scarcely elevated 

 above the margin of the outer volution, the umbihcus must consequently 

 be very shallow. 



In a large specimen in my collection, the width of the base is 3*5 

 inches, while the height of the shell is 13 inch; some allowance, it is true, 

 may be made for the effects of compression, but the circumstance is too 

 constant to be the result of accident. The form of the aperture, and the 

 structure of the umbihcus, are at present unknown. 



Tab. xviii. fig. 18, represents the appearance of a specimen viewed 

 from above. 



Fig. 22. A perspective view of another example. 



Locality. Upper chalk, near Lewes. 



48. Cirrus granulatus. 



Conical, volutions five or six, obscurely quadrangular, ornamented with 

 regular, transverse, granulated striae ; umbihcus ? 



I have but very recently discovered this elegant shell, and only four 

 imperfect casts are at present known : its characters are however sufficiently 

 defined to identify the species. The volutions are depressed on the 

 upper and under surface, and broad and sKghtly convex on the outer 



c c 2 



