328 



THE OCEAN WORLD. 



effected by the simple mechanical action of the " hydraulic apparatus, 

 rasp, and syringe." 



" If you examine the living molluscs," says Gosse, " you will see 

 that the fore part of the shell, where the foot protrudes, is set with 

 stony points arranged in transverse and longitudinal rows, the former 

 being the result of elevated ridges, radiating from the hinge, the latter 

 that of the edges of successive growths of the shell. These points 

 have the most accurate resemblance to those set on a steel rasp in a 

 blacksmith's shop. The animal," Gosse adds, " turns in its burrow 

 from side to side when at work, adhering to the interior by the foot, 

 and therefore only partially rotating to and fro. The substance is 



Fig. 132. — Pholas papyracea (Solander). 



Fig. 133. — Pholas melanoura (Sowerby). 



abraded in the form of a fine powder, which is gi'adually ejected from 

 the mouth of the hole by contraction of the efferent siphon." 



The Pholads are met with on ever)^ sea-shore, and are plentiful 

 in the Channel ; on the French coast they are called Dails, and 

 sought for for their fine flavour. As examples of the genus, we may 

 quote Pholas dactyhis (Fig. 130) ; Pholas Candida, found in the 

 Channel and in the Atlantic Ocean, which lives buried in the mud 

 or in decayed wood; Pholas crispata (Fig. 131), also found in the 

 Channel; Pholas papyracea (Fig. 132); and Pholas melanoura 



( FiS;, 133)- 



The bodies of many genera of Mollusca have the property of 

 shining in the dark, but none emit a light more brilliant than that of 

 the Pholads. Those who eat the Pholads in an uncooked state 

 (which is by no means rare, for the flavour of the mollusc does not 



