64 
GASTEROPODA. 
Family — Ciiitonid.e. 
Genus — Chiton. 
C. cinereus, Linn. 
Common, in the laminarian zone. 
C. marginatus, Penn. 
Very common, between tide marks, and very variable in colouring. 
Family — Patellid.e. 
Genus— Patella. 
P. vulgata, Linn, (the common limpet). 
Common, on all rocks between tide marks. 
Genus — Helcion. 
H. pellucidum, Linn. 
Patella p., F. and H. 
Very common, on Laminaria digitata, on all parts of the coast. 
It feeds on the fronds of the sea-weed when young, but gradually 
working down the stem ultimately buries itself in the roots. I have 
also found it, when in its fully developed condition, adhering to the 
rocks like Patella vulgata. 
H. pellucidum, var. l.evis, Jeffr. 
Patella hcvis, Penn. 
Not common, with Patella vulgata. 
Genus — Tectura. 
T. testudinalis, Mull. 
Not uncommon, especially in the north of the county. 
T. virginea, Midi. 
Lottia v., Aid.? 
Not common. 
Family — Capulid.e. 
Genus — Capulus. 
C. HUNGARICUS, LilVl. 
Not common. From deep water. Minute. 
Family — Trochid.e. 
Genus — Trochus. 
T. tumidus, Mont. 
Frequent, on gravelly ground, in deepish water. 
T. cineraiuus, Linn. 
