TROCHUS. 309 



on a stony or shelly bottom in deeper water^ in every 

 part of our seas from 4 to 95 f. ; off the Mull of Gallo- 

 way in 50-145 f. (Beechey). It occurs in all our upper 

 tertiary strata, from Fort William (J. G. J.) to the Red 

 Crag (S. Wood); Christiania district, in the higher and 

 older deposits, at a height of 400-440 feet above the 

 sea-level (Sars) . Its distribution in a recent or living 

 state extends from Iceland (Steenstrup and Torell) to 

 the ^gean (Forbes), at depths varying from 4 to 60 f. 

 M^ Andrew and Barrett found it living on the shore in 

 Upper Norway. 



The animal of this rather common species is active 

 and restless. Northern greatly exceed southern speci- 

 mens in size; but those from deep water in every 

 locality are invariably dwarfed. Some have no umbi- 

 licus; in others the spire is either pyramidal or depressed. 

 The fry are often marked with spiral pink lines. 



It is the T. Racketti of Payraudeau, and probably the 

 T. Nassaviensis of Chemnitz and T.patholatus of Gmelin. 

 The fry was figured by Walker as T. fuscus, and de- 

 scribed by Macgillivray as Skenea Serpuloides. 



6. T. cinera'rius"^, Linne. 



T. cinerarius, Linn. S. N. p. 1229 ; F. & H. ii. p. 516, pi. Ixv. f. 1-3, and 

 (animal) pi. D D. f. 1 & la. 



. Body purplish-grey minutely speckled with yellow, or 

 yellowish speckled with flake-white, and marked with purplish- 

 brown lines or streaks in front and blotches of the same hue 

 at the sides (in southern examples barred with violet and 

 white) : mantle rather thick, yellowish ; lappets thin, leaf-hke 

 and folded, that on the left being split into branched pectina- 

 tions, the other plain : head semicircular, finely scalloped at 

 the edges ; veil forming two fringed lobes above the tentacles, 



* For cinereus, ash-coloured. 



