Figure 1. — Calico scallop, showing left valve (top) and 

 right valve (bottom). 



Description 



A thorough description of the calico scallop 

 shell was given by Waller (1969). He noted 

 that this species generally reaches 40 to 60 mm 

 in shell height (a straight line measurement of 

 the greatest distance between the umbo and the 

 ventral margin). Maximum size reported is 

 about 80 mm in shell diameter (a straight line 

 measurement of the greatest distance between 



the anterior margin and the posterior margin) 

 (Roe, Cummins, and Bullis, 1971). Shell di- 

 ameter is about the same as shell height in in- 

 dividual small scallops. As height increases, 

 however, diameter increases more rapidly." The 

 height-diameter relationship for calico scallops 

 ranging from 43 to 61 mm in height was shown 

 by Wells, Wells, and Gray (1964). 



Both valves are well inflated and according to 

 Waller (1969) "generally equiconvex to slightly 

 left-convex." The disk outline is "roughly equi- 

 lateral to slightly produced posteriorly." There 

 are 17 to 23 ribs on the right valve. Waller noted 

 that the color of the left (upper) valve is var- 

 iable, usually with red or maroon mottling or 

 banding on a white or yellow background. The 

 right (lower) valve is more lightly pigmented 

 with the same colors as the left valve. 



Distribution 



The calico scallop apparently is restricted to 

 the western North Atlantic Ocean. Distribution 

 of this species is shown in Figure 2. Its known 

 range extends from the northern side of the 

 Greater Antilles and throughout the Gulf of 

 Mexico to Bermuda and slightly north of Cape 

 Hatteras (Waller, 1969; Kirby-Smith^ Mer- 

 rill'). According to Waller, however, the "pre- 

 cise southern limit" of the calico scallop is ob- 

 scured by confusion with other species. Calico 

 scallop shells, but no living animals, were found 

 off Delaware Bay (Merrill, see footnote 4). Al- 

 though this species might be expected from the 

 Bahama Islands, its occurrence there has not 

 been verified. 



This scallop, generally found on continental 

 or insular shelves, was reported from depths less 

 than 2 m (Kirby-Smith, see footnote 3) to 370 m 

 (Waller, 1969). The depths of occurrence vary 

 with locality. Near the southern end of its range, 

 on the northern side of the Greater Antilles, this 

 species was caught in depths of 22 to 26 m 



- Unpublished data on file at the National Marine 

 Fisheries Service, Southeast Fisheries Center, Miami 

 Laboratory, Miami, Fla. 33149. 



^ William W. Kirby-Smith, Duke University Marine 

 Laboratory, Beaufort, N.C. Personal communication, 

 1971. 



* Arthur S. Merrill, Laboratory Director, National 

 Marine Fisheries Service, Northeast Fisheries Center, 

 Oxford Laboratory, Oxford, Md. Personal communica- 

 tion, 1971. 



