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Bulletin of the United States Fish Commission 1889 Page 314 SECTION B. NATURAL HISTORY OF THE GIANT SCALLOP. ...(Next Section.) 1. The Common and Scientific Names. The large pecten of which this paper treats is known among fishermen and others by several names. In localities in which it is the only representative of the genus it is called simply "scallop." In other sections, where the small scallop (Pecten irradians) is also found, the designations "giant scallop " and "great scallop " are given with reference to its size, and "smooth scallop" to distinguish it from the conspicuously crenated shell of the common species; the latter name also suffices to differentiate it from the strongly-ribbed valves of P. islandicus, a comparatively large deep-water form occurring in abundance off the same coasts adjacent to which the smooth species is found. The name giant scallop is herein adopted as being expressive and appropriate. Capt. J. W. Collins states that at places on Penobscot Bay the fishermen call the species the "hen clam." The species, or a very closely related form, was first described by Say as a fossil from the Miocene of Virginia and called Pecten clintonius. Under various other names* recent specimens were described by Lamarck, Mighels, Linsley, Stimpson, and others. It is now held by some writers that the fossil and living forms are identical, and the name advanced by Say in 1824 has consequently been adopted by them. The following remarks on this subject are by Professor Verrill : A comparison of specimens of this Miocene species, from Surrey, Virginia, with the more strongly ribbed, deep-water form hitherto recorded by me as Pecten tenuicostatus, var. aratus, shows that they are in all respects essentially identical. In the fossil specimens the ribs are much stronger and more regular than in ordinary specimens of P. tenuicostatus, but not more so than in many deep-water specimens taken in 65 to 125 fathoms, off Martha's Vineyard; while among the numerous specimens dredged by us, all gradations [occur] between the strongly ribbed form and those forms common in shallow water, in which the ribs are much more slender, indistinct, or almost obsolete. The forms of the main shell and of the auricles are the same, however, in all these varieties. The fossils, like all the recent specimens, show the peculiar fine, oblique etriaa or vermiculations between the ribs, both on the body of the shells and on the auricles. In the fossil specimens the ribs, especially those towards the ends of the shell and on the auricles, are crossed by the raised lines of growth in such a way as to form small, rather close, distinctly arched, raised scales; this character, which is not usually seen in. the smoother, shallow-water form is found in many of the deep-water specimens quite as prominently or even more so than in the fossils. There being no doubt, therefore, of the identity of the fossil and the recent shells, the name Clintonsus should be adopted for this species, on account of its priority, while the name tenuicostatus may well be retained to designate the ordinary smoothish, mostly shallow-water variety, found on the New England coast. This name was originally given by Dr. Mighels to very young specimens of this smoothish variety, under the impression that they were a distinct species, but he afterwards recognized the fact that they were only the young of the common species, at that time generally known as the Pecten magellanicus Lam. "The principal synonymy of the scallop is as follows:
Trans. Conn. Acad., vol. VI. Catalogue of Mollusca of New England Coast, part 1, pp. 260-261 --------------------------- GIANT SCALLOP FISHERY OF MAINE PAGE 315 Prof. William H. Dall, the honorary curator of the department of mollusks in the U. S. National Museum; in his "Catalogue of the Shell-bearing Marine Mollusks and Brachiopods of the Southeastern Coast of the United States,"(Bull. U. S. F. C. 1889) gives preference to the designation of Lamarck, and, under date of October 22, 1890, in reply to an inquiry, writes: The name Pecten magellanicus is by far the oldest, and, in the uncertainty as to the standing of several fossils which have been referred to the species in question, is the one I have adopted. 2. GEOGRAPHICAL RANGE. Professor Verrill, in his "Report upon the Invertebrate Animals of Vineyard Sound" (2) gives the range of the giant scallop as extending from Labrador to New Jersey. He states that it is rare or local south of Cape Cod. Later explorations have disclosed the fact that the species occurs as far south as Cape Hatteras, and is abundant in many places off the southern coast of New England. Locally it has been found in the waters of Labrador, Nova Scotia, Bay of Fundy, Passamaquoddy Bay, Frenchman's Bay, Penobscot Bay, Bagaduce River, Sheepscot River, Casco Bay, Massachusetts Bay, George's Bank; Block Island, Connecticut, New York, New Jersey, Virginia, and North Carolina. The mollusk is thought to be most abundant in the Gulf of Maine, off the coasts of Maine and Massachusetts, where several thousand specimens have been brought up from deep water at a single haul of the beam-trawl on the U. S. Fish Commission exploring steamers Albatross and Fish Hawk. 3. BATHYMETRICAL RANGE. The depth at which the scallop has been ascertained to occur varies with the locality, but generally speaking may be said to range from 1 to 150 fathoms for living specimens; dead shells have been dredged at a depth of 400 fathoms. Verrill cites the depth in different sections as follows: Labrador, 2 to 15 fathoms; Frenchman's Bay, 3 to 10 fathoms; Passamaquoddy Bay and Bay of Fundy, 1 to 109 fathoms; Massachusetts and Casco Bays, 4 to 80 fathoms; George's Bank, 45 fathoms. Detailed figures showing the depth of the numerous beds of scallops on the coast of Maine that have been operated by the fishermen are given farther on under the head of "Fishing Grounds". 4. DESCRIPTION OF THE SCALLOP. Dr. R. E. C. Stearns, of the Smithsonian Institution, is to be credited with the following graphic account of the anatomy of the scallop; although it applies more strictly to the species with crenated valves, the description is no doubt almost equally appropriate to the one under consideration: The animal of the fan-shells is exceedingly beautiful. The mantle or thin outer edge, which is the part nearest the rim or edge of the valves, conforms to the internal structure of the latter, and presents the appearance of a delicately pointed ruffle or frill. This mantle is a thin and almost transparent membrane, adorned with a delicate fringe of slender, thread-like processes or filaments, and furnished with glands which secrete a coloring matter of the same tint as the shell; the valves increase in size in harmony with the growth of the soft parts by the deposition around and upon the edges of membranous matter from the fringed edge of the mantle which secretes it. This cover is (Note 2) Report U. S. Commissioner of Fish and Fisheries, 1871-172, pp. 295-747. ------------------------------------------------------------------------------------------- ================================== |