427 



S. testa ponderosa, niinime libera, plerumque ad umbonem 

 rubra; area cardinali plerumque elongata, fusco fasciata; varva 

 inferiori concamerata. Testa juniori lsevi, triangulari, costis dis- 

 tantibus, noduliferis radiata. Testa matura maxima, ovali, ple- 

 rumque squamis lingularibus, laevibus, depressiusculis, ornata. 



From the circumstance of water being retained between the 

 laminae of the shell in old specimens, this has commonly been 

 called the " Water Spondylus." The young is of a three-cornered 

 shape, smooth, and of an orange or purple colour, with five or six 

 beaded ribs, and a very elongated area. The age to which this 

 form is retained, depends partly upon the period at which the 

 lower valve becomes free. The full-grown shell is oval, generally 

 white, except at the umbones, and has numerous long, rather flat- 

 tened and depressed spathulae. 



This species was first decided by Mr. Sowerby, Sen., after a com- 

 parison of the various ages and forms exhibited in the beautiful 

 series of specimens brought from the Polynesian Islands by Mr. S. 

 Stutchbury. 



25. Spondylus limbatus (pi. lxxxviii. f. 51.), Sowerby, Jun., 

 Proc. Zool. Soc. May, 1847. 



S. testa ovali, vix costata, squamis depressis, laevibus, palmatis, 

 brevibus, in seriebus irregularibus, inaequalibus 6 ad 11 dispositis; 

 interstitiis minutissime striatis; cardine magno; colore squama- 

 rum croceo, interstitiarum obscure violaceo, intus limbo pur- 

 pureo. 



The specimen figured is in the collection of M. Gruner, and 

 there is also another fine specimen in the British Museum. The 

 shell is of a loose texture, with seven or eight rows of smooth, 

 flattened scales, of a brownish orange colour. The interstices are 

 obscurely ribbed, with occasional imbrications, and are of a dull 

 purple colour ; which colour constituting the principal pigment, is 

 shewn in a broad, bright, purple band round the border of the 

 interior. The hinge-teeth are remarkably large. M. Gruner, G. 

 B. Sowerby, Sen., and the British Museum have specimens from 

 the Persian Gulf. 



26. Spondylus Sinensis (pi. lxxxvii. f. 32, 33, 34.), nobis. 



S. testa lsevi elongato-ovali, area cardinali plerumque elongata ; 

 costis 5 ad 7 principalibus, vix elevatis, squamis laevibus, depres- 

 sis, palmatis ; interstitiis lsevibus, costis inaequalibus et squamis 

 minoribus ; colore pallide fulvo vel roseo vel albo, prope umbonem 

 fusco variegato. 



