. A manual of zoology. Zoology. PORIFERA 203 Sponges of this simple ascon type are few. As a rule sponges are more massive and have a more comphcated canal system (figs. i6i, 162). The tirst step tovi^ards complication is seen in the Sycon type, in which the gas- tral cavity consists of numerous radial chambers or avijni-UcB which alone. 'â Mik Fig. 162.âSection of cortex oiChondrilla nucula, the skeleton omitted fatter Scliulze). c', afferent canals; c-, effereni canals; g, ampuUas; m, cloaca; 0, osculum. contain the collared cells, while the central cavity, now called cloaca, is lined with p
. A manual of zoology. Zoology. PORIFERA 203 Sponges of this simple ascon type are few. As a rule sponges are more massive and have a more comphcated canal system (figs. i6i, 162). The tirst step tovi^ards complication is seen in the Sycon type, in which the gas- tral cavity consists of numerous radial chambers or avijni-UcB which alone. 'â Mik Fig. 162.âSection of cortex oiChondrilla nucula, the skeleton omitted fatter Scliulze). c', afferent canals; c-, effereni canals; g, ampuUas; m, cloaca; 0, osculum. contain the collared cells, while the central cavity, now called cloaca, is lined with pavement epithelium. By increase of mesoderm and corre- sponding thickening of the body wall the ampullie become separated from external and cloacal surfaces (Leucon t}fpe). They nevertheless retain their connection with both surfaces by means of cavities which may 'f (sis Fig. 163. Fig. 163.âSurface'. 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, ed. and tr. New York, H. Holt
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectzoology, bookyear1912
