258 MARINE MOLLUSCS. 
Arca lactea.—Numerous on the beaches. Found 
alive in the interior of stones from deep water. 
Pectunculus pilosus.—Deep water. Rare. 
Pectunculus decussatus.—Not rare. Plymouth, 
(J.C. B.) Torbay, (Rev. H. F. Lyte.) 
Pectunculus nummarius.—Uncommon. 
Nucula nuclea.—Uncommon in deep water. 
Nucula minuta.—Rare. 
Avicula hirundo.—Not very rare on Gorgonia 
verrucosa, &c. 
Pinna ingens.—Only in small beds at certain 
parts. Falmouth harbour not uncommon, (J.C. B.) 
* Pinna papyracea.—Devon. (‘Turton.) 
Pinna fragilis.—(Turton.) 
Mytilus edulis._Mussel. Abundant on all shores, 
and also obtained in the young state from deep 
water. Are not the reputed pellucid young, separate 
species? 
Modiola vulgaris.—Rare. Deep water. Torbay, 
(Rev. Mr. Lyte.) 
Modiola discrepans.—Not uncommon in deep 
water. 
Modiola discors—Common at the roots of fuci, 
and in various marine substances. 
Modiola Gibsii.—(Turton and Kingston.) 
Tsocardia cor.—Rare. 
Lithodomus lithophagus.—(Turton & Kingston. ) 
Cardium aculeatum.—Not uncommon in bays, 
and at the mouths of rivers, and thrown up after 
storms. 
Cardium tuberculatum.—Common in deep water. 
Often dredged up in Plymouth Sound. Torbay, 
common. 
Cardium elongatum.—Devon. (Montagu.) 
Cardium exiguum.—Plymouth Sound. (J. C. B.) 
Cardium edule.—Common cockle. Collected in — 
April. 
Cardium fasciatum.—Common in deep water. 
tee 
