MOLLUSCA. 
63 
spun yam gives way, and the rope pulls the head of the 
dreg backwards, and disengages the teeth from the tangles 
and stones. In transverse section the teeth form a trun¬ 
cated ellipse round the central iron rod. 
The nomenclature adopted is that of Dr. Gwyn Jeffreys in 
his valuable work on the British Mollusea ; and I am specially 
indebted to him for his great courtesy in frequently aiding me¬ 
in doubtful cases, and also carefully investigating shell-debris 
containing minute species, which otherwise might have been 
overlooked. 
Class CONCHIFERA. 
Order Lamellibranchiata. 
Fam. 1. Anomiidae, Gray. 
Genus Anomia, L. 
Anomia ephippium , L. Jeffreys, Brit. Moll. ii. p. 31, 
v. pi. 20. f. 1,1 a- 1 e. 
Not uncommon in the debris of the fishing-boats. 
Anomia patelliformis, L, Op. cit. ii. p. 34, v. pi. 20. f. 2,2 a-2 c. 
Common in the same region, as well as between tide-marks. 
Fam. 2. Ostreidse, Broderip. 
Genus Ostrea, L. 
Ostrea edulis , L. Op. cit. ii. p. 38, v. pi. 21. 
Living examples are rare. The u rock ” variety with 
purplish streaks, however, is occasionally found at the East 
Rocks on the under surface of stones in pools near low water. 
Fam. 3. Pectinidse, Lamarck. 
Genus 1. Pecten, Pliny. 
Pectenpusio, L. Op. cit. ii. p. 51, v. pi. 22. f. 1 & la. 
Common; the living specimens come from the deep water 
