182 TRIDACNA AND HIPPOPUS. 



arched scales, give a character to this species as distinguished 

 from the preceding. 



8. EUDis, f. 13, 14, Reeve. — Ovato-gibbosa alba, antice 

 subproducta, utrinque obtusa ; costis magnis rotundis inter 

 squamis valide liratis ; squamis maximis arcuatis latis, later- 

 aliter expansis ; interstitiis angustiusculis, rude liratis. — The 

 surface is roughly ridged, both upon and between the ribs. 

 The scales are large and saddle-like, extending at the sides so 

 as nearly to touch each other. The shell besides is not so deep 

 as T. squamosa, and has a much wider opening. 



