. Elementary text-book of zoology. Zoology. GASTROPODA. 33 connected together by a transverse band, and each of them gives off a commissure to the pedal ganglia (P g), and a second commissure to a pair of visceral ganglia (Pig}. The latter ganglia, which are known as the commissural or pleura! ganglia, are also connected with the pedal ganglia (fig. 497). There are thus two nervous com- missures round the oesophagus—the direct cerebro-pedal, and the cerebro-pedal by way of the pleural or commissural ganglia. The pleural ganglia may lie directly on the cerebral or pedal ganglia. Br-. FIG. 510.—
. Elementary text-book of zoology. Zoology. GASTROPODA. 33 connected together by a transverse band, and each of them gives off a commissure to the pedal ganglia (P g), and a second commissure to a pair of visceral ganglia (Pig}. The latter ganglia, which are known as the commissural or pleura! ganglia, are also connected with the pedal ganglia (fig. 497). There are thus two nervous com- missures round the oesophagus—the direct cerebro-pedal, and the cerebro-pedal by way of the pleural or commissural ganglia. The pleural ganglia may lie directly on the cerebral or pedal ganglia. Br-. FIG. 510.—Nervous system of ffaliotis (diagrammatic, after Spensel). C/, cerebral ganglion ; Pg, pedal ganglion; Pig, pleural ganglion (commissural ganglion); Ag, abdominal ganglion ; O and O', olfactory organs ; PC, pedal cord; S and -$', lateral nerves ; Br, gills, b, Nervous system of Limnceits (aftei Lacaze-Duthiers). The pleural ganglia are part of the third typical group of ganglia, viz., the visceral group. They are connected with each other by a long commissure, the visceral commissure, which often extends into the hinder part of the body, and contains several ganglia in its course; the latter ganglia, which also constitute part of the visceral group of ganglia, send off nerves to the sexual organs, kidney, heart, gills, olfactory organs, and mantle (fig. 497, Gs b, Vg, Gsp; fig. 510 a, 0,0', A g; fig. 510 b, A g). The visceral ganglionic system of Gastropods is therefore broken VOL. ii. 3. 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 Claus, Carl, 1835-1899; Sedgwick, Adam, 1854-1913; Sinclair, F. G. (Frederick Granville), b. 1858. New York : Macmillan
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectzoology, bookyear1884
