SOWEEBr : ON THE SPECIES OF TRIDACXA. 



31 



irregular waved ridges. Hinge as in other Tridacnm, the principal 

 cardinal tooth in each valve being moderately thick. Length 125, 

 height 68 mm. 



Hah. — Philippines. 



This species differs from T. elongata chiefly in the angularity of its 

 ribs, the absence of lamellae, and the very different character and 

 small size of the scales on the ribs. 



All the species mentioned in this paper, with the exception of 

 T. mntica (which I have not seen), were received from the Philippines 

 in the year 1898, when I described T. ohesa; most of them, however, 

 are pretty generally distributed in the Indian and Pacific Oceans. 



1 am much indebted to Mr. E. A. Smith, I.S.O., for his valuable 

 assistance, and particularlj- for his insertion in my paper of references 

 to works on the subject. 



