Buccinnm. 



88 NASSA. RICINULA. PURPURA 



Ricinula Murejc. 



Purpura, \ 

 Monoceros, 

 Concholepas 

 Harpa, \ 



Do Hum, ^ 

 Buccinuni, 

 Eburna, 

 Terehra, J 



" To these genera another has been added, 

 called Nassa, of which Buccinnm ai'vularia 

 will furnish an example. The columella has a 

 callosity very evident in the species Pullus and 

 Thersites. 



'' Ricinula horrida has a ringent aperture of 

 a fine violet colour ; the shell is thick, and co- 

 vered with large black tubercles. The genus 

 takes its name from a resemblance to the seeds of 

 Rici7ius. 



" Purpura is a large genus : in certain of the 

 species the colouring-matter exists of which the 

 ancients form.ed their famous purple dye. It is 

 the last genus that offers any appearance of a 

 canal at the base of the aperture. 



" P. patula, the scoop, from the Atlantic and 

 Mediterranean, has the aperture remarkably di- 

 lated, the margin sulcated. 



" P. lapillu^ is a common British shell among 



