.'524 PROCEEDINGS OF THE ACADEMY OF [Oct. ; 



has a very narrow, dull, minutely pitted border, within which the 

 nacreous layer is finely, almost regularly grooved at right angles to 

 the edge, with some coarse, unequal and irregularly placed wrinkles 

 in the same direction. The cartilage pit is deeply excavated, the 

 tooth stout, erect and triangular. 



Length 67, alt. 65|, semidiameter 21 mm. 



Near Sibuko Bay, Borneo. 



This species is much larger than any of the known Poromyaceous 

 clams. It is far larger and shorter than the Hawaiian Euciroa 

 pacifica Dall. 1 



A very similar, perhaps identical species from the Philippines is 

 contained in the collections made by Dr. Paul Bartsch while on the 

 ■"Albatross," which I was able to inspect through the kindness of 

 Dr. William H. Dall. 



1 Report on Mollusca and Brachiopoda dredged in Deep Water, chiefly near 

 the Hawaiian Islands, Proc. U. S. Nat. Mus., XVII, p. 688, 1895. 



