. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. FIGURE 2. Diagrams showing the structure of sea urchin gonads during early development in a juvenile urchin (A) (after Tahara and Okada, 1968), when fully developed in an adult Centrostcphamts coronatus ( B, C, D), and the effect on the gonad when infected by juvenile Echinocephalns psettdouncinatus encysted near the end of a peripheral tubule (E), in the main tubule leading to one of the flukes of the gonad (F), and in the main tubule (gonoduct) near the middle of the gonad (G). All of the gonads are shown from their perivi
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. FIGURE 2. Diagrams showing the structure of sea urchin gonads during early development in a juvenile urchin (A) (after Tahara and Okada, 1968), when fully developed in an adult Centrostcphamts coronatus ( B, C, D), and the effect on the gonad when infected by juvenile Echinocephalns psettdouncinatus encysted near the end of a peripheral tubule (E), in the main tubule leading to one of the flukes of the gonad (F), and in the main tubule (gonoduct) near the middle of the gonad (G). All of the gonads are shown from their perivisceral coelomic sides with the oral portion down; abbrev.: c, perivisceral coelomic epithelium; ge, germinal epithelium; gp, position of gonopore; gs, hemal strand; h, "hemal sinus"; in, muscle; n, encysted nematode; p, "perihemal ; spaces of the gonadal wall. Larger worms displaced most of the germinal epi- thelium in the infected tubule and thick, fibrous connective tissue encysted both the worm and associated germinal epithelium. Cysts with large juveniles protruded into the perivisceral coelom; large juveniles, probably nearly full-grown, broke through the wall of the gonadal cyst and extended free into the coelom. Although gonadal tubules adjacent to those with the worms usually contained well-developed spermatogenic or oogenic cells, most of the tissue within the cysts in the infected tubules consisted of nongametogenic accessory or connective cells. Moreover, gametogenesis within infected tubules distal (oral) to the worm also seemed suppressed. \Yhen the infection occurred near the end of a side tubule, as was usually the case, there was little effect on the overall gametogenic state of the gonad (Fig. 2E). Occasionally, however, infection occurred within a main. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not p
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
