T R I D A C N A . 



Plate III. 



Species 3. (Fig a, Mus. Brit., and PI. IV. Fig. 6, c, d, 

 Mus. Cuming.) 



TKlD.-kCNA SQUAMOSA. Trld. testd ovatci, qtiadri- ad quui- 

 que-co-itald, costis elevato-coiwexis, dktanlibus, fini- 

 briato-squamatls, squaiiiis peramplis, didaiUibus, 

 erectis, foruicatis, costarum mterstitiis deciissatim 

 nmltislriatis ; alba vel croced, iiilerdum. rubeule 

 tincld. 



The scaled Tkidacna. Shell ovate, four- to five-ribbed, 

 ribs elevately convex, distant, firabriately scaled, 

 scales very large, distant, erect, vaulted, interstices 



between the ribs decussately many-striated ; white 

 or saffron-yellow, sometimes tinged with red. 



Lamakck, Anim. sans vert. vol. vii. p. 10. 



Ilab. Moluccas. 



This well-known species is characterized by a much 

 more symmetrical growth than T. gigus. It has no ten- 

 dency to radiate obliquely, and the scales are developed 

 throughout with amplitude and precision. The ribs are 

 raised and tumidly convex, whilst the interstices between 

 them are spacious and decussated throughout with im- 

 pressed striae. 



June, 1862. 



