MOLLUSCA. 
73 
Mya truncata , L. Op. cit. iii. p. 66, v. pi. 50. f. 2. 
Abundant off the mouth of the Eden, and on the beach 
after storms. 
Fam. 21. Saxicavidae, Swainson. 
Genus 2. Saxicava, Fleurian de Bellevue. 
Saxicava rugosa , L. Op. cit. iii. p. 81, v. pi. 51. f. 3 & 4. 
Common at low-water mark amongst the rocks in crevices 
and holes in sandstone and shale, as well as inside empty 
limpet-shells and Balani. Often firmly adherent to its cavity 
by a byssus. 
Fam. 23. Pholadidae, Gray. 
Genus 1. Pholas, Lister. 
Pholas Candida , L. Op. cit. iii. p. 107, v. pi. 52. f. 2. 
Rarely found in shale at the Castle Rocks; commonly met 
with on the beach after storms, sometimes in a perfect con¬ 
dition. 
Pholas crispata, L. Op. cit. iii. p. 112, v. pi. 53. f. 1. 
Abundant in the soft shale and sandstone at East and West 
Rocks, and especially opposite the castle. Occasionally the 
siphons are observed protruding through sand which coats 
some of the ledges. Young specimens are often cast ashore 
on the West Sands in water-logged and decayed wood, whence 
they are extracted by the sea-fowl. 
Genus 3. Xylophaga, Turton. 
Xylophaga dorsalis , Turton. Op. cit. iii. p. 120, 
v. pi. 53. f. 4. 
Not common; several living specimens occurred in the 
wood of a submerged thorn tree. 
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