160 EDIBLE BRITISH MOLLUSKS. 



far for the operation of boring; but how to account for 

 the holes fitting the shape of the animal inhabiting 

 them ? To this I fearlessly answer, that this is only 

 the case when the Pholas is found in the rock which 

 it entered when small. This mollusk evidently bores 

 merely to protect its fragile shell, and not from any love 

 of boring ; and in this opinion I am borne out by my 

 own specimens. The young Pholas, having found a 

 substance suitable for a habitation, ceases to bore imme- 

 diately that it has buried its shell below the surface of the 

 rock, etc. It remains quiescent until its increased 

 growth requires a renewal of its labours. It thus con- 

 tinues working deeper and deeper, and, should the sub- 

 stance fail or decay, it has no alternative but to bore 

 through, and seek some fresh spot where it may find a 

 more secure retreat.^' 



At Amroth, near Tenby, is a submerged forest, the 

 trees of which are completely perforated by the Pholas; 

 and at spring-tides fine specimens may be collected. 

 Montagu remarks that, whilst it is the general habit of 

 shipworms {Teredo navalis, or Teredo norvegica) to bore 

 parallel with the grain, the Pholas perforates the wood 

 across the grain.* 



Mr. J. G. Jeffreys mentions that Redi, in a letter to 

 his friend Megalotti, describes the Teredo as being not 

 only eatable, but excelling all shellfish, the oyster not 

 excepted, in its exquisite flavour. Nardo also praises it, 

 and wonders why the Venetians, who call it bisse del 

 legno, do not eat it.f 



The German name for the Pholas is very appropriate, 

 viz., die bohrmuschel, sieinbohrer, or pierce-stone ; in 



* Forbes and Hanley, Brit. Mollusoa. 

 t Brit. Conch, vol. iii. p. 159. 



