86 THE MOLLUSCA OF THE FIRTH OF CLYDE. 
Foreign localities.-— Northern, western, and southern 
Europe, from Norway (Loven) to the Mediterranean and Sea 
of Marmora (Spratt). M‘Andrew records it from Mogador, 
Madeira, and Canaries. 
Triroris, Deshayes. 
Triforis perversa, Linné. 
Trochus perversus, Linné; Murex adversus, Montagu ; 
Terebra perversa, Fleming ; Cerithium adversum, Forbes 
and Hanley. 
Habitat.—Dead specimens in the Coralline zone not 
uncommon. I have not taken it alive, but Mr. Norman 
states that he has found it living in rock pools; rare. 
British distribution.—Chiefly on the southern and western 
coasts of England, and all Ireland. It occurs more or less 
sparingly throughout the west and north of Scotland as far 
as Shetland, and on the east coast it is recorded from Aber- 
deenshire and Dunbar. 
Foreign localities—From Norway (Lovén, and others) to 
Spain, Portugal, Mogador, Madeira, and Canaries (M‘ Andrew), 
as well as the Mediterranean and Aigean (forbes). 
ORDER SIPHONOBRANCHIATA. 
Famity Ceriruropsip®, P. P. Carpenter. 
CERITHIOPSIS, Forbes and Hanley. 
Cerithiopsis tubercularis, Montagu. 
Murex tubercularis, Montagu; Terebra tubercularis, Fleming; 
Cerithiopsis tuberculare, Yorbes and Hanley. 
Habitat—Under stones and in rock pools at Battery 
Point, Cumbrae; rare in a living state. Dead shells are not 
uncommon down to a considerable depth throughout the 
whole district. 
British distribution—South and west of England, all 
Ireland, and west of Scotland as far as the Shetland Islands.. 
My. Fryer has taken a specimen on the Northumberland 
coast, and Captain Laskey records it from Leith; but these 
east coast specimens may have been brought in ballast. 
Foreign localities—From Norway and Sweden (Lovén, 
and others) to the Canaries (M‘Andrew), and throughout the 
Mediterranean. In America, Gould records it (as Cerithium 
Greenii) taken in Dartmouth harbour by Professor Adams. 
