^3 



4. magus. 



Trochus magus, Lin. — Gibbula magus, Risso, 

 Animal having the sides of the foot marked with 

 purplish brown, and bordered with yellow ; head 

 black ; tentacula yellowish, annulated with black ; 

 inter-tentacular lobes orange, bordered with yellow ; 

 eye-peduncles orange above, white beneath ; eyes 

 blue-black ; great lateral lobe and filaments yellow, 

 the former with an orange spot at the side nearest the 

 head. 



On the north coast. Frequently cast on shore. 

 Rarely taken alive by the dredge. Inhabits gravelly 

 ground at a depth of twenty fathoms, 



5. tumidus. 



Trochus tumidus, Mont. — Trochus umbilica- 



tus. Walker. 



Animal white, with the sides of the foot marked 



with black ; head black ; tentacula, eye peduncles, 



intertentacular lobes, lateral lobes, and filaments, 



white. 



In deep water. Common on all the coasts. 



6. cinerarius. 



Trochus cinerarius, Lin. — " T, lineatus, De 

 Gerv!''' Cherres. 

 Animal yellowish white, head and sides of the foot 

 marked with black ; tentacula annulated with black, 

 margin of the mantle with a black edge. 

 At low water on stones. Common. 

 7- umbilicatus. 



Trochus umbilicatus, Mont. — T. umbilicaris, 

 Penn. 



