108 THE MOLLUSCA OF THE FIRTH OF CLYDE. 
FAMILY TRITONIIDA, H. and A. Adams. 
TRITONIA, Cuvier. 
Tritonia Hombergi, Cuvier. 
Habitat—Cumbrae, dredged and at low tide (Robertson). 
Tritonia plebeia, Johnston. 
Habitat.——Rothesay Bay (Alder); Cumbrae, on stones at 
low water, common (Robertson) ; Skelmorlie Bank and Ascog 
(A. Brown). 
(SuB-ORDER ACANTHOBRANCHIATA. ) 
FAmILy POLYCERIDA. 
AiciRvS, Loven. 
Aigirus punctilucens, D’Orbigny. 
Habitat. Ardrossan and Lamlash (Alder); Cumbrae, under 
stones at lowest tides, moderately common (Robertson). 
TRIOPA, Johnston. 
Triopa claviger, J/iiller. 
Habitat—Common at Cumbrae in rock pools (Norman, 
Robertson, and A. Brown); dredged in 5 or 6 fathoms off 
Ascog (A. Brown); Lamlash (Norman). 
POLYCERA, Cuvier. 
Polycera quadrilineata, Miller. 
Habitat—Common at low tide and in the Laminarian zone, 
Cumbrae (Landsborough and Robertson) ; Lamlash (Greville 
and Miles); Ascog (A.Brown). 
Polycera ocellata, Alder and Hancock. 
Habitat.—Lamlash (Landsborough) ; Cumbrae, under 
stones at low water, moderately common (Robertson). 
ANCULA, Loven. 
Ancula cristata, Alder. 
Habitat-—Cumbrae, on stones at low tide, moderately 
common (Robertson); Kyles of Bute (4. Brown). 
‘Gonroporis, Forbes. 
Goniodoris nodosa, Montagu. 
Habvitat—Ardrossan, plentiful (Alder) ; Holy Island, Lam- 
