G9 



72. P. i.iviDrs. (pi. xiii. f. Gl. pi. xiv. f. 89 et 91.) Lam. 

 Anim. s. Yert. vi. p. l^^- P- sulphureo. Lam. ct Ost. Tegulo, 

 Wood, incliisis. 



T. irregulari, sub-ovali, su])-fequivalvi, coinpress/i, foliacea; 

 auriculis infcqualibus, niagnis, aiiticis majoribus, valvae dextrce, 

 antica validissime emarginata; costis 16 ad 20, iiicequalibus 

 vixelevatis, squamas iiumerosas, acutas ferentibus; interstitiis 

 irregulariter radiatim sulcatis : colore, fusco variegato, squa- 

 mis luteis vel albis ; variat fusco paiilulum variegato, squamis 

 fere obsoletis ; variat quoque sulpbureo. Long. 2. 5.; lat. 0. 

 70 ; alt. 2. 25 ; poll. 



An irregular, compressed, foliaceus species, \\\t\\ 16 to 20 

 irregular, unequal ribs, having numerous thin scales which are 

 nearly obsolete in some varieties ; the ribs of the lower A-alve 

 are more numerous. The general colour is variegated purplish 

 brown, with the scales white or yellow; there is a variety scarcely 

 mottled, and another of an uniform sulphureous tine- 

 Red Sea and Japan. 



73. P. SQrAMOSus. (pi. xiii. f. 48, 49, 50. pi. xiv. f.^Ss, 

 92, 9.3.) Gmel. O. anonyma. Lam. et P. hybridus. Lam. inclu- 

 sis, O. hybrida, Gmel. exclusa. P. arausicanus, Chemn. 



T. irregulari, sulj-ovali, sub-asquivalvi, complanata, foliacea ; 

 auriculis inccqualibus, magnis, anticis majoribus, valvcB dextree 

 antica validissime emarginata; costis 12 ad 18, fere obsoletis, 

 squamiferis, ad umbones evanidis, valvae dextrte numerosis, 

 paululum angulatis ; colore vario, aliquando prope miibones 

 albo fulgurato. Long. 1. 85.; lat. 0. 50.; alt. 2. 10. ; poll. 



The figure in Lister referred to by Gmelin, leaves no doubt 

 of the identity of this species, which is remarkable among 

 the irregular foliaceus group, for a peculiar flatness, particu- 

 larly at the umbones. The varieties are numerous, many of 

 them being marked with fine zigzag lines of white. 



Northern Ocean. 

 And also brought from the Philippines by Mr. Cuming, 



74. P. SERRATUS. (pi. xiii. f. 56.) nob. 



T. oblique ovali, irregulari, postice sub-producta, sub-com- 

 pressa, auriculis inoequalibus, posticis minoribus, costis nume- 

 rosis, minutissime squamiferis ; colore sulphureo, maculis 

 magnis, fuscis, variegato, intus ad marginem purpureo. Long. 

 1. 20. ; lat. 0. 50; alt. 1. 40; poll. 



More ventricose, more oblique, with the auricles smaller 

 and the scales more minute than P. squamosus. Brought 

 from the Philippine Islands by Mr. Cuming. 



75. P. IRREGULARIS, (pi. xiii. f. 51-2.) nob. 



T. oblique ovata, irregulari, sub-eequivalvi ; auriculis in- 



