Title: The Biological bulletin
Identifier: biologicalbullet193mari (find matches)
Year: [1] (s)
Authors: Marine Biological Laboratory (Woods Hole, Mass. ); Marine Biological Laboratory (Woods Hole, Mass. ). Annual report 1907/08-1952; Lillie, Frank Rattray, 1870-1947; Moore, Carl Richard, 1892-; Redfield, Alfred Clarence, 1890-1983
Subjects: Biology; Zoology; Biology; Marine Biology
Publisher: Woods Hole, Mass. : Marine Biological Laboratory
Contributing Library: MBLWHOI Library
Digitizing Sponsor: MBLWHOI Library

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CATECHOLAMINES IN BIVALVE LARVAE 119
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Figure 2. Aldehyde-induced fluorescence in 22-day-old veligers of Placopecten maaellanicus. (A) Solid arrow indicates a squat, conical cell along a string of fibers on the rim of the velum. One to two fluorescent cells (out-of-focus) are located on each side of the mouth. Unfilled arrow indicates a small fiber that originates near the mouth and then terminates in what may be the apical ganglion located in the middle of the velum. (B) This shows another example of the squat conical shape of fluorescent velar cells (larger arrow). Fibers appear to exit at the base of the cell. Numerous varicosities (smaller arrows) are found along the lengths of the fibers. (C) In many cases two to three fibers with varicosities (smaller arrows) interconnect adjacent fluorescent cells (large arrows) in the velum. (D) Flask-shaped cells (larger arrows) and intercon- necting fibers (smaller arrow) are found around the mouth. Calibration bars in A, B. C. and E equal about 12 fjm. younger larvae, but strings of three to four fluorescent cells and interconnecting fibers could still be detected along each of the outer rims (Fig. 4A). Single fluorescent cells were also located at the tips of each of the two to three gill bars of these larvae, and a fiber tract could be detected connecting the most posterior gill arch with the abdominal ganglia (Fig. 3E). As with P. mai>ellanicus, visualization of fluorescence in such larvae was often obscured by the shell and growing body tissues. By 41 days, most M. edulis either had vela that were further reduced in size (Fig. 4B) or had completely lost their vela. Although the shell length changed little from earlier stages, new growth resulted in broader, less ellip- tical shells, indicating the addition of postmetamorphic dissoconch (Bayne, 1971). Prominent cells could still be seen around the mouth and within the abdominal ganglia and foot of each animal. Several of these specimens also contained fluorescent byssal fibers running along the ante- rodorsal margin of the foot from its base to apex. The gills contained a total of four to five arches, each with one to two fluorescent cells. (See Fig. 4B for a schematic summary of the distribution of fluorescent elements in post-settling specimens of M. edulis.) Immunocytochemical labeling of serotonin produced a completely different staining pattern than that induced by aldehydes in 34-day-old M. edulis. Compare Figure 5A, B (aldehyde-induced fluorescence) with Fig. 5C-F (sero- tonin-like immunoreactivity). The velum contained no in- trinsic serotonin-like immunoreactive somata but only varicose fibers (Fig. 5C-E). which appeared to originate from three somata located near the midline just behind the center of the velum (Fig. 5E). Likewise, the foot contained no intrinsic immunoreactive somata but only varicose fibers (Fig. 5C-E), which appeared to originate

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