ACTIVE MOVEMENTS AND OTHER ASPECTS OF THE BIOLOGY OF ASTICHOPUS AND LEPTOSYNAPTA (HOLOTHUROIDEA) 1 PETER W. GLYNN Institute f Marine Biology. University of Puerto Rico, Wayaguez, 1'ncrto Rico The ability of certain benthic sea cucumbers to execute relatively rapid move-ments has not been gem-rally recognized or given adequate treatment in compre-hensive accounts of the Holothuroidea (e.g., Ludwig, 1892; Cuenot, 1948; Hyman, 1955). In some bathypelagic species the performance of rapid progressive move-ments is regarded a normal means of locomotion. Ludwig (1892) and Hansen and Maclsen (1956) have noted the remarkable swimming movements, first observed by M. Sars (1868), of Juilliyplotcs natans (=Stichof>us natans), an aspidochirotid of the typically deep-sea family Synallactidae. Gilchrist (1920, p. 381) observed that ". . . some of the Holothurians procured in deep water off the South African coasts have the power of swimming about freely in the water by an undulatory movement of the body " He further surmised that ". . . such deep-sea Holothurians do not bury themselves in the soft mud of the floor of the ocean, but flit more or less readily over its surface." More recently, Hansen and Madsen (1956, p. 55) have suggested, "Probably a powder of swimming, though often awkward, may be attributed to a considerable number of Holothurians of the family Psychropotidae within the order Elasipoda and of the genera Bathyplotes and Paelopatides within the Synallactidae of the order Aspidochirota." These authors remarked that of the known bathypelagic holothurians, Galatheathnria uspera is probably the best adapted for active swimming, which in this species is effected through undulatory movements of the lateral brim much as in the swim-ming of the cuttlefish, Scf>ia. The elasipodid, Bcnthodytes typica, with a wide brim all around the body, is also well adapted for swimming. 1 The portion of the study dealing with Astichopus was supported by National Science Foundation Grant GB-888; observations on Lcptosynapta were made by the author while employed with the California Cooperative Oceanic Fisheries Investigations. Appreciation is expressed for the aid rendered by the following persons and institutions: Charles E. Cutress, Smithsonian Institution, \Yashington, D. C., who supplied information on the swimming be-havior of Astichopus and made available pertinent literature; David L. Fawson, also of the Smithsonian Institution, who made available-pertinent literature and reviewed the manuscript; Alfred II. Hummel, SCUBA instructor at K'anu \ \\\-Force Base, Aguadilla, Puerto Rico, who assisted in the collrclion of specimens of Astichopus; Frank Fernandez, Research Assistant, Institute of Marine Biology, who helped with tin-fit-Id and laboratory studies; John Shoup, Bernice I'. Bishop Muslim, Honolulu, Hawaii, who helped with certain phases of the be-havior studies; Stan \Yiinherh-y, Geology Section, University of Puerto Rico, Mayagiiez, who aided in the analysis of sediment samples; I.uis M. Quiiiones-Rodriguez, Department of 1'hy.sics, I'niversity of I'uerto Rico, Mayagnex, who .supplied monochromatic lamps and fdters. Credit is also due Elisabeth Deicliniann, Museum of Comparative Zoology, Harvard University and Kenneth R. Jl. Read, Division of General Education, Boston University, for criticizing the manuscript. 106
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