100 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."— ^i> C. 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. 



Family. GASTROCH.ffiNiD^, Forbes. 

 118. SAXICAVA, Lamarck. 

 1. S. RUGOSA, Penn. 



Mytilus rtigosus, Mont. Test. Brit. 164. 

 Solen minutus, Mont. Test. Brit. 53, t. 1, f. 4. 

 In 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. 



Family. Pholadid^, Gi-ay. 

 119. PHOLAS, Linnceus. 



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. CANDIDA, Linn. 



Fholas 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. 



