. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 432 JOSEPH D. CASSIDY AND ROBERT C. KING The interconnections between cystocytes were localized in 156 such composites. Transversely-sectioned ring canals were observed on rare occasions, and three such canals from cystocyte clusters located within the anterior, middle and posterior portions of the germarinm were chosen for study at higher magni- fication. The appropriate negatives were selected, and enlargements were made using Kodak positive sheet film. The result was a series of positive transparencies .showing t
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 432 JOSEPH D. CASSIDY AND ROBERT C. KING The interconnections between cystocytes were localized in 156 such composites. Transversely-sectioned ring canals were observed on rare occasions, and three such canals from cystocyte clusters located within the anterior, middle and posterior portions of the germarinm were chosen for study at higher magni- fication. The appropriate negatives were selected, and enlargements were made using Kodak positive sheet film. The result was a series of positive transparencies .showing the canals at 38,000 X. The transparencies from serial sections were •oriented one above the other and viewed simultaneously in order to grasp the three- dimensional morphology of the canal rim. Eventually a X model was made •of a canal rim using the malleable plastic, Polyform (see Koch and King, 1969 for the details of Polyform model construction). RESULTS AND CONCLUSIONS Each canal connecting sister cvstocytes in the Habrobracon germarium is in the shape of a laterally flattened right cylinder with an altitude ranging between and ^ (Fig. 1). ^'hen viewed in a perfect transverse section the canal from which the model was constructed formed an ellipse with major and minor axes of and p., respectively (Fig. 2). The rim surrounding each canal was made up of eight leaves arranged in four pairs. The leaves of each pair overlapped with the leaves of adjacent pairs. The arrangement of the leaves is easily grasped after viewing Figure 1. \Yhen the ring is sectioned in the longitudinal or frontal plane one obtains the image seen in Figure 3. CN •--••. >3J ^. --^-j^-j FIGURE 3. A canal rim cut in longitudinal (or frontal) section. The vast majority of the -canal rims seen in electron micrographs are sectioned in this manner: C, centriole; CN, nuclei of sister Please note that these images are extracted from scanned page images that
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
