Cowry and Pyramid-shells 241 



flat (discoid), but after a time the new portions are 

 added in almost a straight line ; then the animal 

 constructs a conical division across the interior to 

 separate the straight portion from the spiral, which 

 soon falls off. Later another division is made in 

 order to get rid of a portion that is too narrow. So 

 that we have here a creature beoinnino: life with a 

 spiral shell, and arriving at maturity with one of a 

 cylindrical character like a Tooth-shell (Dentaliiini), 

 except that the exterior of this is marked off into 

 rings whilst that is plain. The ringed appearance 

 accounts for its specific name trachea as recalling the 

 structure of the windpipe. The round opening of 

 the brown shell is closed by a flat brown operculum. 

 It may be found in fair abundance in water from 

 15 to 50 fathoms deep on the coasts of Dorset, Devon, 

 Cornwall, Wales, Guernsey, the Clyde district, Bantry, 

 and Galway. The animal is extremely active, but 

 not so agile as that of the minute Smooth Blind-shell 

 (C. glahruni), which has a thin, smooth transparent 

 white shell closed by a convex operculum. It is 

 found all round these islands between the depths of 

 15 and 50 fathoms. 



The Pelican's-foot (Chenopus pes-iJelicani) when 

 fully developed brings to 

 mind the Strombs and 

 Wing-shells of the tropics, 

 and it is interesting to note 

 how easily this form may 

 be produced from a shell of 



,. , ,.™ , Pelican's-foot 



entirely dinerenb appear- 

 ance. In earlier life the shell is shaped like the 

 Auger-shell (Tai'ritella), but by successive additions 



