COCKLES. 199 



Roman Catholic countries the valves of this huge shell are sometimes em- 

 ployed as " benitiers" or vessels for containing holy water. A pair so used 

 may be seen in the church of St. Sulpice, in Paris, which weigh five hundred 

 pounds, and are more than two feet across. Specimens attain even larger 

 dimensions than these, and are the largest shells known. The byssus is so 

 thick, and its attachment to the rock so strong, that it is frequently necessary 

 to cut it with a hatchet in order to obtain the animal. 



FIG. 201. CLAM-SHELL. 



These are the shells alluded to by Captain Flinders, who observes : 

 ' ' Many enormous cockles were scattered upon different parts of the reef. At low water 

 this cockle seems most commonly to lie half open ; but frequently closes with much 

 noise, and the water within the shells then spouts up into a stream three or four feet 

 high. It was from this noise, and the spouting of the water, that we discovered them, 

 for in other respects they were scarcely to be distinguished from the coral rock. A 

 number of these cockles were taken on board the ship, and stewed in the coppers, but 

 they were too rank to be agreeable food, and were eaten by few." 



The fourth family of Conchiferous Mollusks embraces 



The Cockles (Cardiacea}. These are distinguished by the mantle being 

 open in front, and, moreover, by having two separate apertures, one serving 

 for respiration and the other for the discharge of effete materials ; these are 

 prolonged into two tubes (Fig. 202), which are sometimes distinct from each 

 other, but occasionally conjoined. As a general rule, those species provided 

 with long tubes burrow into mud or sand. As examples of this family, we 

 may instance 



The Common Cockle (Car&uiii), met with upon sandy shores in great 

 abundance, where, under the name of " red noses," they constitute an important 

 article of food. In the cockles " the foot " is an organ of considerable size, 

 assuming all sorts of shapes. Sometimes it is used lor burrowing, for which 



