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<br />An Ultrastructural Examination of the Scolex and
<br />Tegument of Bothriocephalus acheilognathi
<br />(Cestoda: Pseudophyllidea)1
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<br />WILLARD O. GRANATH, JR.z, JON C. LEWIs3, AND GERALD W, ESCH
<br />
<br />Department of Biology, Wake Forest University,
<br />Winston-Salem, North Carolina 27109, U.S.A,
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<br />Abstract, Immature, mature, and gravid specimens of Bothriocephalus acheilogna-
<br />thi from mosquitofish (Gambusia affinis) were studied by scanning (SEM) and trans-
<br />mission electron microscopy (TEM), SEM of the heart-shaped scolex revealed long,
<br />deep, pear-shaped bothria, A bilobed apical disc was present, although it was not prom-
<br />inent, The scolex tegument possessed microtriches which were_morphologically distinct
<br />from those of the strobila, Microtriches had a more slender appearance within the bothria
<br />than on the surrounding tegument, SEM also revealed the presence of tumuli which
<br />were numerous and uniformly spaced on the scolex, but became less abundant poste-
<br />riorly along the strobila, TEM revealed that tumuli contained dense-staining inclusions,
<br />Sensory cilia extended through the tegument of mature and gravid proglottids, The distal
<br />cytoplasmic layer was connected to the perikarya by cytoplasmic bridges, Muscle bun-
<br />dles were observed in longitudinal and cross-sections within the perinuclear region,
<br />Various organelles, including ribosomes, endoplasmic reticulum, and Golgi bodies, were
<br />present and within the cytons,
<br />
<br />Ultrastructural aspects of cestodes have received the attention of many
<br />investigators during the last two decades. Many of these studies have focused
<br />on cestodes of medical or veterinary importance (e,g., Jha & Smyth, 1971;
<br />Mehlhorn et aI., 1981; Rothman, 1963; Specian & Lumsden, 1980; Thompson
<br />et ~I., 1979), although other cestodes have not been ignored entirely (e.g.,
<br />Hayunga & Mackiewicz, 1975; McVicar, 1972; Tedesco & Coggins, 1980). Gen-
<br />erally, these studies have concentrated on a few specific microanatomical
<br />features of the parasite in question (e.g" Berger & Mettrick, 1971; Coggins,
<br />1980; Lumsden & Byam, 1967; Morseth, 1967; Specian et aI., 1979); few
<br />exhaustive studies have been undertaken.
<br />The present study was part of an investigation of the biology of Bothrio-
<br />cephalus acheilognathi Yamaguti, 1934, a parasite of mosquitofish (Gambusia
<br />affinis) in a North Carolina reservoir. B. acheilognathi was introduced into
<br />the United States via grass carp in the early 1970's and since has become
<br />well established in the mid-south and southeastern states (Hoffman, 1980).
<br />Previous light microscopic studies have described the general morphological
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<br />1 We thank Mr. Tillman Prader and staff of the EM laboratory of the Pathology Department,
<br />Bowman Gray School of Medicine, for technical assistance, This research was supported, in part,
<br />by a grant from the Wake Forest University Research and Publication Fund,
<br />2 Present address: Department of Zoology, 730 Van Vleet Oval, University of Oklahoma, Nor-
<br />man, Oklahoma 73019, U,S,A,
<br />3 Department of Pathology, Bowman Gray School of Medicine, Wake Forest University, Win-
<br />ston-Salem, North Carolina 27103, U,S,A.
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<br />TRANS. AM, MICROSC, Soc., 102(3); 240-250, 1983,
<br />@ Copyright, 1983, by the American Microscopical Society, Inc.
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