PECTEN. 



Plate III. 



Species 13. (Mus. Cuming.) 



Pecten Danicus. Pect. testa suborbiculari, inceqnivalvi, 

 tenui, mbcompressd, atiriculis siibaqualibus, striatis ; 

 valvd sinistra plano-convexd, costis quiiique ad sex vix 

 elevatis latiiiscnlis leviier angnlatis radiatd, costis 

 tenuiliratis, interslitiisque undique temiissinie deciissa- 

 tim striatis, fulvo-rtifd, punctis pallidis promiscue 

 dense aspersd ; valvd dextrd convexiore, costis sex de- 

 presso-coiivexis latioribus, laterihus subrugoso-liratis, 

 alba, ad umboneni rufescente. 



The Danish Pecten. Shell nearly orbicular, inequi- 

 valve, thin, somewhat compressed, ears nearly equal, 

 striated ; left valve flatly convex, rayed mth five to 

 six ribs but little raised, rather broad, slightly angled, 

 finely ridged, and, with the interstices, everj'where 

 vei-y finely decussately striated, fulvous red, promis- 

 cuously densely sprinkled with pale dots ; right valve 

 more convex, with six depressly convex broader ribs, 

 sides somewhat roughly ridged, white, tinged with 

 red at the umbo. 



Chemnitz, Conch. Cab. vol. xi. p. 265. pi. 207. f. 2043. 

 Pecten aspersns, Lamarck (not of Sowerby). 

 Ostrea triradiata, Midler. 

 Ostrea hybrida, DiUwyn. 

 Pecten pseudamiisium, Chemnitz (not of Klein). 

 Ostrea septemradiata, Gmelin. 

 Pecten glaber, Montagu. 

 Pecten nebulosus. Brown. 

 Pecten Jamesonii, Smith. 



Hub. Hebrides, Zetland, Scandinavia. 



Extremely variable in form and sculpture, but less vari- 

 able in coloui- and marking than many other species of this 

 genus. 



Species 14. (Fig. a and b, Mus. Ciuning.) 



Pecten TRANauEBAUicus. Pect. testa trigono-o?-biculari, 

 aquivalvi, aquilaterali, aimcuUs valde inaqualibus ; 

 valvis convexitisculis, costis octodecim lavibus elevatis 

 subquadratis, lateribus minute serratis, radiatd, inter- 

 stitiis subprofunde excavatis; colore varid, albd, nunc 

 castaneo marmoratd, nunc aurantio-rnfescente tinctd. 



The TKANauEBAR Pecten. Shell triangidarly orbicular, 

 equivalve, equilateral, ears very unequal ; valves rather 

 convex, rayed with eighteen smooth raised somewhat 

 square ribs, minutely serrated at the sides, interstices 



rather deeply excavated ; colour various, white, now 



marbled with chestnut, now tinged with orange-red. 

 Ostrea Tranqneharica, Gmelin, Syst. Nat. p. 3328. 



Pecten Tranquebaricus, Lamarck. 



Ostrea undulata. Born. 



Ostrea nucleus, DUlwyn (not of Born). 

 Hab. Tranquebar. 



Of au elegant symmetrical growth, extremely variable 

 in colour. 



Species 15. (Mus. Cuming.) 



Pecten nodosus. Pect. testa subcequivalvi, aquilaterali, 

 auriculis inaqnalibus ; valvis subplano-convexis, costis 

 novem ampliter nodosis radiatis, costis interstitiisque 

 undique nodoso-liratis, costis valves dextrm planioribus, 

 latioribus, vix nodosis ; valvd sinistra intense brunneo- 

 rubrd, dextrd pallidiore. 



The kkobbed Pecten. Shell nearly equivalve, equi- 

 lateral, ears unequal ; valves rather flatly convex, 

 rayed with nine largely knobbed ribs, ribs and in- 

 terstices nodosely ridged throughout, ribs of the right 

 valve flatter, broader, scarcely nodose ; left valve deep 

 brown-red, right valve paler. 



Ostrea nodosa, Linureus, Syst. Nat. p. 1145. 

 Pecten nodosus, Lamarck. 

 Ostrea decemradiata, Gmelin. 

 Pecten corallinus, Chemnitz. 



Hab. Gulf of Mexico. 



This fine and well-known species varies from a rich 

 brown-red to a deep coral-red colour. 



Species 16. (Mus. Cuming.) 



Pecten plica. Pect. testd trigono-ovatd, subeequivalvi, 

 eequilaterali, lateribus versus umbones compressis, auri- 

 culis parviusculis, cequalibus ; valvis undique striatis, 

 costis tribus ad quinque radiatis, costis valvce sinistra 

 rotundatis, elevatis, prope viarginem declivibus, valva 

 dextra latioribus, convexis, minus elevatis; valvd sinis- 

 tra fulvescente-albd, castaneo-rufo late marmoratd, dex- 

 trd albd, immaculatd. 



The folb Pecten. Shell triangularly ovate, nearly 

 equivalve, equilateral, sides compressed towards the 

 uraboes, ears rather small, equal ; valves striated 

 throughout, rayed with three to five ribs, ribs of the 



November, 1852. 



