. A manual of zoology. Zoology. UTDROZOA. 233 Usually the colony is strengthened and protected by the perisarc, a cuticular tubular secretion of the ectoderm. In some (fig. 175) the perisarc stops at the base of the hydranth; in others (fig. 176) it expands distally into a wide-mouthed bell, the hydrotheca, into which the hydranth may retract at times of danger. In rare cases. Fig. 176.—Campanularia geiiiculata. f/i", ectoderm; f?), entoderm; p, perisarc, ex- panded around hj'dranth to a li>-drotlieca: .s-, supportinj^ layer. this perisarc may he greatly increased and calcified, formin
. A manual of zoology. Zoology. UTDROZOA. 233 Usually the colony is strengthened and protected by the perisarc, a cuticular tubular secretion of the ectoderm. In some (fig. 175) the perisarc stops at the base of the hydranth; in others (fig. 176) it expands distally into a wide-mouthed bell, the hydrotheca, into which the hydranth may retract at times of danger. In rare cases. Fig. 176.—Campanularia geiiiculata. f/i", ectoderm; f?), entoderm; p, perisarc, ex- panded around hj'dranth to a li>-drotlieca: .s-, supportinj^ layer. this perisarc may he greatly increased and calcified, forming large coral-like masses with openings from which the hydranths may protrude (fig. 177).. 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 perfectly resemble the original Hertwig, Richard, 1850-1937; Kingsley, J. S. (John Sterling), 1854-1929. New York, H. Holt and Company
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectzoology, bookyear1902
