108 POPULAR CONCHOLOGY. 



valve, and some, indeed, have been said to 

 weigh 500 lbs. In Roman Catholic countries, 

 the shells are sometimes used as receptacles for 

 the holy water in the churches, and formerly 

 they were considered sufficiently valuable to 

 form a present to a monarch, those in the 

 church of St. Sulpice at Paris having been pre- 

 sented to Francis the First by the republic of 

 Venice. The animal is correspondingly large, 

 and it has been stated that more than one 

 hundred persons can make a meal upon that 

 which inhabits the Tridacna gigas : this may 

 be an exaggeration, but there is no doubt the 

 architect of so extensive a dwelling must be 

 exceedingly large.* The Tridacna adheres to 

 the rocks by a stout and strong byssus with so 

 much tenacity as to require the aid of a hatchet 

 to separate them. A specimen of this shell, 

 brought from Sumatra, is now in Arno's Vale, 

 Ireland, and weighs 507 lbs., each valve being 

 four feet six inches in length, and two feet five 

 and a half inches in breadth. The interior of the 

 shell is of an opaque white, and very beautiful. 



* The valves are so large as probably to require cen- 

 turies to complete their growth. Reeve's Conchologia 

 Systematica. 



