G7 



Interstices smooth. Ground colour pale yellowish, obscurely 

 mottled with smoky brown. Bureas, Philippines. Mr. Cuming. 

 65. P. Pes-felis. (pL xvii. f. 162. pi. xx. f. 234.) Lin. 

 Syst. Nat. p. 1146. Bornii, Payr. O. corallina, Poll. 



T. ovali-subtrigona, compressa, scabra, radiatira sulcata, 

 tequivalvi, su1j-a?cpiilaterali, crassa; auriculis inccqualibus, 

 nodoso-sulcatis : posticis parvis, anticis magnis : costis 8, 

 crassis, latis, elevatis, sulcatis. Interstitiis latioribus, sulcatis. 

 Colore, fusco-rubescente, fasciis nigris, et maculis albis varie- 

 gate; variat purpureo. Long. 2. 50.; lat. 0. 72.; alt. 2. 90.; poll. 



A well known species from the Mediterranean and also 

 from the Persian Gulf. 



G6. P. PARVUS, (pi. XX. f. 227-8.) G. B. Soioerhj, Sen. 

 ZooL Proc. 1835. p. 110. 



T. subovata, depressiuscula, sub-sequivalvi, eequilaterali, 

 albicante : auriculis ineequalibus, graniferis : valvis radiatim 

 costatis; costis 8, ineequalibus, trans versim striatis: interstitiis 

 radiatim sulcatis et transversim striatis: Long. 0. 75.; lat. 

 0. 25.; alt. 0. 80.; poll. 



"Found in coral sand on the reefs." Lord Hood's Island. 

 Mr. Cuming. 



67. P. iMBRiCATUs. (pL xiii. f. 32-3.) Gmel. p. 3318. 

 No. 12. sauciatus Gmsl. Chem. t. 69. f. h. 



T. sub-trigona, complanata, sub-leevi, sub-eequivalvi : auri- 

 culis inaequalibus, complanatis, ad marginem nodosis : posticis 

 parvis, obiusis : anticis magnis, acutis : valva sinistra com- 

 planata : costis 9, rotundato sul3-angulatis, tuberculatis, forni- 

 catis, globosis ftrjntibus: alternis depressis : valva dextra, 

 sub-ventricosa, costis noduliferis fequalibus 10. Colore albo, 

 roseo-maculato, costis alternis rubro maculatis, intus ad mar- 

 ginem purpureo, medio luteo ; nonnunquam occurrit purpureo 

 immaculato. Long. 1. 35.; lat. tuberculis exclusis 0. 40; 

 alt. 1. 55 ; poll. 



This flat trigonal species is remarkable for the hollow 

 imbricated tubercles which are placed at nearly equal distances 

 on 9 alternating ribs. I believe that the figure in Chemnitz 

 referred to by Gmelim for P. sauciatus is only a variety of 

 this species in the state most common in collections, having 

 the knobs worn down. Red Sea. 



68. P. RUBROMACULATUS. (pi. xiii. f. 34.) nob. 



T. ovali-subtrigona, oequivalvi, sub-?equilaterali, sub-com- 

 pressa : auriculis iniequalibus, sca1:)roso-sulcatis : posticis 

 parvis; anticis magnis, costis 18, prope marginem squamosis, 

 alternis depressis, minoribus, interstitiis Iseviter striatis: costis 



