312 TROCHID^. 



Hebrides the throstle feeds on this kind of Trochus, as 

 well as on the common periwinkle, holding one in its 

 beak and breaking the shell by sharp and repeated strokes 

 against a stone. A small living specimen which I 

 dredged in Loch Alsh was thin, pearly, and lustrous, 

 owing to the greater part of the outer layer having been 

 removed by some natural cause. Some have no um- 

 bilicus or perforation. Those on Laminaria saccharina 

 in Shetland are remarkably large, nearly an inch in 

 breadth. The fry are not angulated at the base. 



T. cinerarius of Born is an Indian shell, and that of 

 Olivi appears to be a variety of T. varius. The present 

 species is the Trochus (not Turbo) lineatus of Da Costa, 

 and Gibbula striata of Leach. T. littoralis of Brown is 

 scarcely a variety ; and his T. perforatus was probably a 

 specimen encrusted with a zoophytic growth, which he 

 mistook for an epidermis. The variety variegata cor- 

 responds with the description and figure of Payraudeau's 

 T. (sgyptiaca ; but it is not Lamarck's species of that 

 name. This variety was described by Recluz as T. 

 Philberti. 



T. cinereus of Da Costa has the inner or pillar lip 

 plaited, and is a species of Clanculus. It is " said to be 

 from the South Seas " (Donovan) and " a native of the 

 West Indies" (Forbes and Hanley); but assuredly it is 

 not British. Mr. Dillwyn possessed and gave me one 

 of the original specimens. 



..v 7. T. UMBILICA TUs*,(Montagu.) 



N. umbilicatus, Mont. Test. Brit. p. 286 ; F. & H. ii. p. 519, pi. Irri. f. 1-4 

 (as T. umbilicalis). 



BODY light yellowish-brown, marked transversely with 

 purplish lines, and tinged in front with fleshcolour: mantle 

 thin, edged with short purplish streaks ; lappets leaf-like, the 



* Umbilicate. 



