CYCLOSTREMA. 405 



stellate at the periphery, or angulated and keeled ; peritreme 

 more or less varicose. 



cruentata, Miihlf. Tamsiana, Dkr. 



muricata, Humph. 



Sub-gen. ilaira, H. and A. Adams. 



Shell discoidal ; spire depressed, whorls angulated, detached, 

 the last entirely free ; aperture quadrate, peristome sub-acute. 



evoluta, Reeve. 



Genus CYCLOSTREMA, Marryatt. 



Eye-peduncles very short, tentacles ciliated ; foot with 

 long, curved, linear auricles in front, the sides with three 

 ciliated filaments. 



Shell orbicular, depressed, widely umbilicatcd ; spire 

 very short, whorls rounded, smooth, cancellated, trans- 

 versely striated, or grooved; aperture orbicular, not pearly 

 within, peristome continuous, acute. 



St/n. Delphinoidea, Brown. 



Ex. C. serpuloides, Montagu, pi. 45, fig. 6. Shell, 

 C. cancellata, Man-yatl, fig. 6, a. 



The interior of the aperture in these shells is not 

 pearly as in Liotia. The animal of Skenea divlsa, 

 Fleming, which is the same as Cyclostrema serjniloides, 

 has been described by Mr. Clark, as well as that of C. ele- 

 gantula or Culleriana, and the existence of neck-lappets 

 and of filaments on each side of the foot show the posi- 

 tion of the genus to be among the Trochidce. Should 

 the smaller British species require to be separated from 



