232 



umbilicus, others totally devoid of fiich a mark ; infide 

 pearlaceous. Length an inch ; breadth rather lefs. 



This fpecies varies a little in fliape ; fome are more conic, 

 and the volutions more round and tumid than others ; but 

 are always readily diftinguifhed from any other of the ge- 

 nus by the tooth, and the flat white fpace at the bafe. 



The outer coat is rather thick, but when removed, the 

 whole fliell except the apex, is of a beautiful mother of pearl. 



Da Costa, who firft noticed this (liell from Cornwall, 

 DevonJJiire, Dorfetjliire, CaernarvonJJiirc, Hampjliire, and 

 Norfolk, has placed it in the Turbo genus, from the fub- 

 orbicular fliape of the mouth. It is, however, fufficiently 

 angulated to rank it amongfl: the Jrochi. 



We have found it plentiful in many of the places men- 

 tioned by Da Costa, particularly on the rocks at Ma- 

 razion in Cornwall, not unfrequent near Falmouth, and 

 very common on many parts of the coafl; of South Devon, 



It is always found adhering to rocks, or loofe ftones, 

 and fcldom below mid-tide. 



Doftor PuLTENEY fcnt us the young of this fliell, ra- 

 ther more than half grown, for his Trochus lineatus. 



Animal dufky-cinereous, frequently fpeckled with white, 

 with tvy'o long, flender, pale tentacula, flreaked tranfverfe- 



