201 



about one-third the total length of the shell, consisting of five 

 whorls, ending in a small, blunt, turbinate pullus of two and 

 a-half smooth rounded whorls. 



Spire-whorls slightly convex, separated by a well-defined linear 

 suture ; ornamented by six flat spiral ribs, the three posterior 

 ones separated by flat shallow sulci of about equal width, the 

 three anterior ones by linear grooves sometimes almost obsolete ; 

 the interstitial furrows are punctulatedly impressed. 



Body-whorl obtusely angled at the periphery, regularly attenu- 

 ated anteriorly ; ornamented with flat spiral ribs (about 30), 

 separated by narrow furrows, crossed by sigmoidal lines of 

 growth which produce the appearance of punctations in the 

 interstitial furrows. 



Aperture narrow, broadly emarginate in front ; outer lip thin 

 and sharp on the edge, smooth within, much ecurved medially. 



Dimensions. — Length, 16-5 ; greatest width, 6*5 ; length of 

 aperture, 10. 



Locality. — Clayey greensands, Adelaide-bore. 



Compared with actual specimens of C. do7initor, from the 

 Eocene of Hampshire, it has a narrower outline and a longer 

 spire, but especially differs by the ornamentation which consists 

 of engraved, punctated, spiral lines, and not of raised threads 

 with elegantly tessellated interspaces. 



By its sulcate sculpture and greatly arched outer lip it is more 

 allied with C. alatus, F. Edwards, of the Hampshire basin ; but 

 it seems to differ by its blunt-pointed apex and rounded shoulder 

 to the whorls, whilst the proportional measurements indicate a 

 narrower shell with a shorter aj)erture. 



FAMILY CYPR^IDJE. 

 Genus Cype^a. 



I have not been successful in arranging the species in confor- 

 mity with the sectional subdivision of the genus as employed by 

 recent conchologists. Those sections are largely based on external 

 shape, and as some of our fossil species show extensive-enough 

 variability as to necessitate the inclusion of the same species in 

 two sections, I have been induced to group them in respect to 

 themselves. Some of them are wholly unprovided for in the 

 scheme of recent species, such as C. gastrojjlax with its wing-like 

 base ; and the group typefied by C. eximia, which though having 

 a near ally in C. nmhilicata of the same geographic region, yet 

 markedly differs by the dental-sulcations of, and widely extending 

 upon, the inner lip, though in one individual-specimen, through 

 extreme age, the normal dentition is acquired. 



