. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 36 M. H. TEMK1N AND S. B. BORTOLAMI M. nieiiibriimicen colonies typically are functionally simul- taneous hermaphrodites, and sperm in spermatozeugmata are transferred from paternal to maternal zooids through the water column (Temkin, 1994). Like those of other gymno- laemate bryozoans. the spermatogonia of M. membranacea migrate into the perivisceral coelom from the peritoneum of the body wall, or funiculus (a network of strand-like ele- ments of the circulatory system), and form syncytial masses of spermatocytes around cyt
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 36 M. H. TEMK1N AND S. B. BORTOLAMI M. nieiiibriimicen colonies typically are functionally simul- taneous hermaphrodites, and sperm in spermatozeugmata are transferred from paternal to maternal zooids through the water column (Temkin, 1994). Like those of other gymno- laemate bryozoans. the spermatogonia of M. membranacea migrate into the perivisceral coelom from the peritoneum of the body wall, or funiculus (a network of strand-like ele- ments of the circulatory system), and form syncytial masses of spermatocytes around cytoplasmic masses or cytophores (see Reed, 1991; Franzen, 1998). Cells of a cytophore disassociate at the end of spermiogenesis in most gymno- laemates, but in species such as M. membranacea. sperm remain together, adhering to one another to form a sperma- tozeugma. Gymnolaemate spermatozeugmata are aggregates of 32 or 64 euspermatozoa in which the cells are arranged parallel to one another in a hexagonal array, with all the heads at one end of the aggregate and all of the tails at the other (Bon- nevie, 1907; Franzen, 1956. 1998; Zimmer and Woollacott, 1974) (Fig. 1). Spermatozeugmata of gymnolaemate bryo- zoans are held together by viscomechanical forces that tightly adhere sperm to one another along the head region, the tail-end half of the midpiece region, and almost all of the tail region (see Franzen, 1956, 1998; Temkin, 1994). The. AMTR TT - I. Diltcrcnlial inlcrlerenci- contrast image of u partial!) disas- .1. 'd spennatozcugnw adhcimg in a glass slide. The head-end hall ot the spermato/eugnia consists ol the elongate head regions (H) thai are adhering to one another and the iionadhcring portions of the midpiece regions (NAMR|. The tail-end hall 'consists ol the adhering portions ol the midpiece and tail regions I AMTR) and the tips ol the kills (TT). Sperm that ha\c become partially disassociated Irom Ihe aggicgalc gcnciale a variety ol waxclortns. Scale bar \2 ;uin
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
