35 



TAB. CCCCXXVIU.— /o^5 1 and'L 

 CIRRUS perspectivus. 



Spec. Char. Obtusely conical, spirally 

 striated ; umbilicus deep, exposing one 

 third of each whorl; aperture transversely 

 oblong. 



Syn. Cirrus perspectivus, Blanteil Geoh SusseXy 

 p. 194. tab. 18./. 12 and'n. 



Not quite so hii^h as wide, with a flattish base, in the 

 centre of which is an acute conical umbilicus ; the in- 

 ternal portion of each whorl is regularly convex ; the 

 outer rather squared ; there is no canal around the 

 spire ; the inner surface is pearly. 



Not uncommon in the upper Chalk of Sussex, Kent, 

 Wiltshire &c. it is also found, but rarely, in the lower 

 Chalk ; the place of the shell is oiten supplied by a 

 green steatitic substance, that retains the cast of the 

 external striated surface. The specimen {fig. 1.) shew- 

 ing the internal pearly portion, is from Northfleet ; the 

 other was among a number sent from Wiltshire by <he 

 late Mr. Cunninjrton. 



Cirrus depressus. 

 TAB. CCCCXXVIIL— /o. 3. 



Spec. Char. Subdiscord, concentrically striated ; 

 umbilicus wide, exposing a small portion of 

 each whorl ; an angular canal runs round 

 the spire; aperture obtusely angular. 



Syn. Cirrus depressus. Mantell Geoh Siissexy 

 p. 195. t. 18/. 18atid'2'2. 



M. HE short spire and the canal around it, produced by 

 the prominent upper parts of the whorls, distinguish this 

 from the last, it is nevertheless possible that they may 

 be only varieties. 



Nearly as common as the C. perspectivus in the same 

 situations, we have received it with a similar green coat- 

 ing from Wiltshire ; the specimen figured is from 

 Bridgwick in Sussex, through the kindness of Gideon 

 Mantell, Esq. 



