360 



CANCELLARTAD.^. 



The genus Cancellaria, the type of this group inckides 

 numerous and beautiful species, but none of them are 

 inhabitants of the British seas. They are remarkable for 

 variety and elegance of outline and sculpture, and some- 

 times for colour. They, and all the members of the family, 

 have shells with very angular apertures, and an attempt at 

 the extremity of the columella towards the formation of a 

 siphonal canal. The mantles of the animals have a rudi- 

 mentary siphonal fold to correspond. Their tentacles are 

 subulate with eye-bulgings, as in the Muricid(£^ and their 

 heads furnished with a retractile proboscis mark their posi- 

 tion among the Gasteropoda, in the neighbourhood of the 

 same family, from which, however, their dentition, which 

 closely approaches that of Velutina and Natica definitely 

 separates them. 



The genus Admete, still existing in the Greenland seas, 

 had once a representative in Britain, the Admete crisjya, or 

 Cancellaria viridula of authors, still surviving as an inha- 

 bitant of the Arctic seas, and of the coasts of Boreal 

 America. 



TRICHOTROPIS. Broderip and G. B. Sowerby. 



Shell more or less turreted and fusiform, spirally ridged, 

 covered with an epidermis which is usually setose ; apex of 

 spire acute ; aperture pyriform, angulated below, so as to 



