808 INTRODUCTION TO CONCHOLOGY. 



Two genera belong to this family — Tridacna and Hijj- 



One species^ the Tridacna gigas, is by far the most gi- 

 gantic of all mollusks ; its muscular powers are said to be 

 very great, and the shell is so large and ponderous,, as to 

 exceed occasionally five hundred pounds in weight. This 

 gigantic shell is believed to have been noticed by Meander, 

 and some of the early Greek poets. 



The Tridacna gigas is doubtless referred to by Linnseus, 

 when he spoke concerning a specimen that weighed four 

 hundred and ninety-eight English pounds, of which the 

 inhabitant afforded a plentiful supply of food to a large 

 company of men, and the sudden closing of whose valves 

 was sufficient to snap a cable asunder. 



A manuscript in the library of the late Sir Joseph Banks, 

 also notices the dimensions of a specimen brought from 

 Sumatra, and preserved at Ano's Yale, in Ireland : the 

 weight amounted to five hundred and seven pounds ; the 

 largest valve measured four feet six inches in length, two 

 feet five inches in breadth, and one foot in depth. A shell 

 of the same species forms the baptismal font at the church 

 of St. Sulpice at Paris : it was presented by the Venetians 

 to Erancis the Eirst. 



