16 THE MOLLUSCA OF THE FIRTH OF CLYDE. 
coast (De Folin); Mediterranean and Aigean (Nares, and 
others). 
Montacuta, Turton. 
Montacuta substriata, Montagu. 
Mya substriata, Montagu. 
Habitat—I have frequently taken this species on the Tan 
Spit, and west side of Little Cumbrae, in 8 to 25 fathoms, 
sandy mud, living on the ventral spines of Spatangus pur- 
pureus. It has also occurred to me off Otter, Loch Fyne. 
Dr. Landsborough and others report it from Lamlash Bay. 
British distribution.—On all parts of our coast parasitic 
on Spatangus, and (occasionally) on Amphidotus. 
Foreign localities—Norway (Sars, and others); northern 
France (Petit); Spain (M‘Andrew); Mediterranean (Nares, 
and others). 
* Montacuta bidentata, Montagu. 
Mya bidentata, Montagu; Petricola bidentata, Gray; 
Mesodesma exiguum, Lovén. 
Habitat—On a muddy gravel bottom, in § to 25 fathoms, 
throughout the district, but generally dead. Very common 
at Lochgoilhead, opposite Douglas Pier, in about 6 fathoms 
water, where fine live specimens were obtained. I have 
also taken this species living at Little Cumbrae, off “The 
Hawk,” and at Ardrishaig, off the Pier. Single valves and 
dead pierced shells are very abundant almost everywhere. 
British distribution —Throughout all our seas from Shet- 
land to the Channel Islands. 
Foreign localities.—Norway (Sars), Sweden (Malm), 
northern Spain (M/A ndiew), Mediterranean (Nares, Jeffreys, 
and others), Madeira (Johnson). 
* Montacuta ferruginosa, Montagu. 
Mya ferruginosa, Montagu; Montacuta tenella, Lovén ; 
Tellimya elliptica, and T. glabra, Brown. 
Habitat—In 6 to 15 fathoms, on muddy bottom; scarce 
in a living state, but single valves are rather common in 
many localities in the district. I have taken living and 
fine examples of this species off the pier at Ardrishaig, in 6 
fathoms, or rather less; also off Garroch Head, Bute. Mr. 
Norman met with it in Millport Bay on the beach after 
storms. 
British distribution.—V ery scarce, but widely distributed. 
