TECTUS. 413 



Species of Trochns. 



acutaugulus, Chem. maximus, Koch. 



asperulus, Lam. Niloticus, Ldnn. 



Cumingii, A. Adams. spinosus, Chem. 

 fastigiatus, A. Adams. 



Genus CARDlNxVLlA, Gray. 



Shell conical, axis imperforate, last whorl angulatcd at 

 the periphery ; columella simple superiorly, without any 

 transverse canal, and ending below in a simple point. 



Ex. C. virgata, Gmelln, pi. 46, fig. 8. 



In this genus the axis is imperforate, nor is there any 

 appearance even of a false umbilicus, the columella not 

 forming a spiral fold at the upper part as in many genera 

 of the Trocliidoi ; there is consequently no posterior 

 canal as in Trochus ; the arcuate columella ends in a 

 tooth-like point below, thie whorls are flat and granular, 

 and the last whorl is angulated at the circumference. 



Genus TECTUS, Montfort. 



Shell conical, axis imperforate ; whorls numerous, 

 smooth or tubercular, the last angulated at the circumfer- 

 ence ; aperture much wider than long ; columella short, 

 anteriorly spirally twisted, ending in a point. 



Syn. Pyramis, Schiim., not Bolt, or Brown. Pyra- 

 midea, Swains. 



Ex. T. fenestratus, Gmelin, pi. 47, fig. 1. Opercu- 

 lum, T. fenestratus, fig. 1, a. 1, b. Shell, T. pyramis. Born, 

 fig. l,c. 



