194 CATALOGUE OF THE MOLLUSCA 
Cullercoats, rare. South Shields sands—A.H. Dredged in 
60 fathoms off the Durham coast by Mr. R. Howse, who has also 
got it at Whitburn. “ Hartlepool.”—Sir OC. Sharp. 
Solen legumen is in Sir C. Sharp’s list of Hartlepool shells, 
and Mr. Winch’s for Lindisfarne. We have not heard of its being 
recently met with. 
Faminy. Gastrocua£nipa, Forbes. 
118. SAXICAVA, Lamarck. 
1. S. rugosa, Penn. 
Mytilus rugosus, Mont. Test. Brit. 164. 
Solen minutus, Mont. Test. Brit. 53, t. 1, fi 4. 
Tn limestone rocks, frequent. We have never found it boring 
into any other description of rock in this neighbourhood. It is 
often met with, attached by the byssus, at the roots of tangle 
(Laminaria digitata), and other large sea-weeds; as well as 
among zoophytes and old shells from deeper water. The varie- 
ties of form and size are very numerous, but we have not been 
able to make out more than one species. 
Faminy. Poouapipa, Cray. 
119. PHOLAS, Linneus. 
1. P. crispata, Linn. 
Pholas crispatus, Mont. Test. Brit. 23. 
In shale rocks, and occasionally in limestone, and the softer 
sandstones, on different parts of the coast, common. Mr. Hogg 
informs us that he found this and the following species living in 
decayed wood, below the sand, at Seaton. 
2. P. canpipa, Linn. 
Pholas candidus, Mont. Test. Brit. 24. 
In shale, &c., along with the last, frequent. 
The mode by which the Pholades perforate rocks has long been 
a subject of dispute, but from recent observations there can be 
little doubt that it is principally, if not entirely, mechanical; and 
that it is effected by the soft parts of the animal, namely, the 
foot and mantle, which appear to have minute crystalline par- 
ticles, probably siliceous, imbedded in their surface. 
