73 



valve are numerous, unequal, rather undercut, crenulated, the 

 alternate ones most prominent : those in the under valve 

 are doubled. The colour is nearly white, variegated with 

 undulating banded patches of deep red ; these patches are 

 generally interrupted by three of the ribs being white ; a 

 variety occurs in which the dark red is spread nearly over the 

 entire surface of the shell. Atlantic Ocean. 



85. P. albolineatus. (pi. xiv. f. 69.) nob. Zool. Proc. 

 1842. 



T. ovali subtrigona, compressa, sequivalvi ; auriculis in- 

 sequalibus, posticis minimis, anticis magnis, acutis, sulcatis : 

 costis numerosissimis, eequalibus, subquadratis. Interstitiis 

 lsevibus. Colore palidissime ; luteo valvte dextrae, costis 

 griseo maculatis, valvae sinistrse, costis griseis, lineis albis 

 interruptis, costis tribus albis. Long. 0. 9.3. ; lat. 0. 25 .; 

 alt. 1. 19; poll. 



Differing from P. ornatus in having the ribs more numer- 

 ous and more equal in both valves. The shell is nearly white, 

 with grey spots on the under valve, and in the upper valve, 

 the tops of all the ribs, excepting three, are grey, the spaces 

 between the white ribs being crossed by narrow lines of 

 white. Brought by Mr. Cuming, from Guimaras, Philip- 

 pines. 



8G. P. sanguinolentos. (pi. xiii. f. 59.) Gmel. p. 3322. 

 No. 41. 



T. ovali subtrigona, scabra, subsequivalvi, subsequilaterali ; 

 auriculis inajqualibus, noduloso-sulcatis, acutis, posticis mi- 

 noribus ; costis 9, crassis, valde elevatis, subquadratis, nodu- 

 loso-sulcatis,, lateribus serratis. Interstitiis magnis, noduloso- 

 sulcatis : cardine oblique plicato. Colore albo, roseo-tincto, 

 supra costas fasciis rubris, latis, distantibus, variegato. Long. 

 1. 60.; lat. 0. 50.; alt. 1. 75.; poll. 



This species bears some resemblance to P. Pallium, but it 

 is more triangular in form, and the ribs are fewer, much more 

 deeply undercut, and more elevated ; the angles of the ears 

 are much more acute. Red Sea. 



87- P. Pallium, (pi. xvii. f.148— 150. pi. xviii . f. 167— 

 68.) Lin. Syst. Nat. p. 1145. O. regia, Gmel. 



T. Subrotundata, compressa, sequivalvi, subsequilaterali : 

 auriculis insequalibus, noduloso-sulcatis: costis 14 ad 16, tri- 

 partitis, elevatis, crassis, subquadratis, concentrice squamatis, 

 squamis plerumque tripartitis, imbricatis, numerosis, tenuis ; 

 interstitiis squamoso-sulcatis ; intus ad marginem dentatis. 

 Colore albo, purpureo fasciatim maculato ; intus albo, marginibus 



i 



