EAST COAST MARINE SHELLS 



33 



GENDS PECTEN Osbeck 1765 (SCALLOPS) 



Generally large heavy shells with 

 valves very unequal; right valve strongly 

 convex, left valve flat or concave; radial 

 ribs interlocking on margin. 



PECTEN RAVENELI Dall (P. hemicyclica of 

 authors; P. medlus of authors, not Gmelln), 

 Ravenel's Scallop. Shell mostly white and 

 pinkish color, frequently with brown lines 

 in grooves of lower valve; usually white 

 inside with color around margin; about 

 twenty-five low rounded ribs; ears sub- 

 equal. Height 30-45 mm. 



Often confused with P. ziczac but 

 smaller, also color of convex valve and 

 sculpture quite different. Single valves 

 are not rare in Florida. Living examples 

 have been taken near the S. Inlet in Lake 

 Worth. It also occurs in the Pliocene of 

 Florida. 



PI. 55, Fig. 20 



PI. 22, Fig. 10 



North Carolina to West Indies 



PECTEN ZICZAC Linn§. Upper or left valve 

 slightly concave, with about thirty-five 

 radiating ribs and areas at sides where 

 same are lacking; lower valve radiated 

 with twenty-three grooves and additional 

 lightly impressed ones at sides, fine ra- 

 diating lines between these grooves; ears 

 nearly equal; interior upper valve mostly 

 smooth except at edge where ribs are dis- 

 tinct, purple brown except for light mus- 

 cle area of attachment; right valve white 

 except for portion adjacent to ears. 

 Height 3 inches. 



The description is based upon a 

 specimen from Bermuda in the writer's 

 collection. It has been taken living in 

 Lake Worth, Florida, during the summer 

 months. 



PI. 22, Fig. 11 



Southern Florida; West Indies 



SUBGENUS CHLAMYS Roeding 1798 



PECTEN ISLANDICUS Muller. Iceland Scallop. 

 Valves equal, upper slightly more convex, 

 covered with fifty to one hundred radiat- 

 ing ridges, bearing scales; the ridges in 

 groups forming ribs most noticeable inside 

 shell; valves closed except at notch; col- 



or orange or dark brown, lower valve light- 

 est; interior white and shining, left valve 

 with rose-colored spot near umbones. Height 

 3.5 inches. Range 10-179 fathoms. 



PI. 7, Fig. 2 



Greenland to Cape Cod, Massachusetts 



PECTEN ORNATUS Lamarck. White, thinly 

 spotted with purple or red, ribs strong but 

 often worn, covered with frail cup-like im- 

 bricating lamellae which are rarely intact; 

 ribs twenty, several unaffected by purple; 

 posterior ear almost obsolete. 



The largest example in the United 

 States National Museum measures about 1 

 inch across. 



PI. 8, Fig. 4 



Florida to West Indies 



PECTEN MUSCOSUS Wood. Rough Scallop. 

 Valves uniform in color, usually rose or 

 soft red; about twenty-one prominent ribs 

 which are cut by beautiful sculpture and 

 forming squarish projections when worn; 

 ears ornamented with wave-like imbrica- 

 tions; ear adjacent to opening usually the 

 most prominent; scallop edge distinct. 

 Length 31 mm. 



A beautiful form often foimd liv- 

 ing upon the Sanibel beach in shallow pools 

 left by the receding tide. The adult hinge 

 line shows, transverse corrugations with 

 great distinctness. 



PI. 8, Fig. 5 



PI. 9, Fig. 4 



PI. 7, Fig. 1 



North Carolina to Florida and Texas 



PECTEN SENTIS Reeve. Thorn Scallop. Valves 

 usually alike in color, commonly bright 

 scarlet, sometimes purple, rarely white. 

 Often confused with P. ornatus this form 

 has about forty ribs in the adult with 

 erect low scales connecting the ribs. These 

 scales, which bridge the interspaces are 

 often damaged but seldom entirely lacking 

 in beach specimens. Interior white, with 

 grooves corresponding to those outside; 

 notch wide and shallow. Average length 

 33 mm. 



This is one of the commonest forms 

 upon the beaches but only single valves as 

 a rule are seen. It lives imbedded in 

 corals. 



PI. 7, Fig. 3 



Southern Florida and West Indies 



