56 THE MOLLUSCA OF THE FIRTH OF CLYDE. 
* Trochus tumidus, Montagu. 
Trochus patholatus, Dillwyn; Trochus Racketti, Payrau- 
deau. 
Habitat.—On stony and shelly ground in 6 to 20 
fathoms everywhere throughout the district; a common 
shell. My finest specimens of this pretty but common 
species are from Loch Fyne, off Silvercraigs. 
British distribution —Everywhere on the British and 
Trish coasts from a fathom or two downward; it is pro- 
bably most abundant in from 10 to 15 fathoms, and is 
apparently more at home in western Scotland than else- 
where. 
Foreign localities—lIceland (Verkriizen, and others), 
Norway (Lovén, and others), Vigo Andrew), the Medi- 
terranean (Philippi, and others), Aigean (Forbes). 
* Trochus cinerarius, Linné. 
Trochus littoralis, Brown ; Trochus lineatus, Da Costa (but 
not his Turbo lhneatus, which is the true Trochus lineatus 
Da Costa, and is the Trochus crassus Pulteney.) 
Habitat.—Exceedinely abundant on stony and weedy 
shores from half tide down to 5 or 6 fathoms, and it is not 
infrequent at greater depths. Good specimens of a more 
conical shape than the type are obtained on the fronds of 
Laminariz in 8—6 fathoms. These may perhaps be the 
Trochus electissima of Bean. 
British distribution—Abundant everywhere throughout 
our seas; one of our commonest shells. 
ix oreign localities—Everywhere throughout northern 
and western Europe; also in the Mediterranean, Adriatic, 
and Black Seas. M‘Andrew records it from Mogador, 
“ frequent.” 
Trochus umbilicatus, Montagu. 
Trochus umbilicalis, Da Costa; Trochus umbilicaris, Pen- 
nant; Trochus cinerarius, Pulteney. 
Habitat—Local but not uncommon on stony beaches at 
about half tide. The east side of Battery Point, Cumbrae, 
and the Ascog shore, Bute, are good localities for this 
species. 
As compared with the last the present species may be said 
to occupy a higher and much more restricted zone, and it is 
not by any means so common. It may sometimes be 
Vk 
