. Outlines of zoology. Zoology. SEGMENTED WORMS OR ANNELIDA. Nervous system and sense organs.—The nervous system mainly consists of a pair of dorsal ganglia lying above the pharynx, and of a double nerve-cord, with twenty-three ganglia, lying along the middle ventral line. The dorsal (or supra-cesophageal) ganglia are connected with the most anterior (or sub-oesophageal) pair on the ventral chain, by a. Fig. 91.—Transverse section of leech.—After Bourne. £., Cuticle ; e., epidermis ; cm., dermis and outer muscles (circular and oblique) ; , longitudinal muscles (the peculiar connective tiss
. Outlines of zoology. Zoology. SEGMENTED WORMS OR ANNELIDA. Nervous system and sense organs.—The nervous system mainly consists of a pair of dorsal ganglia lying above the pharynx, and of a double nerve-cord, with twenty-three ganglia, lying along the middle ventral line. The dorsal (or supra-cesophageal) ganglia are connected with the most anterior (or sub-oesophageal) pair on the ventral chain, by a. Fig. 91.—Transverse section of leech.—After Bourne. £., Cuticle ; e., epidermis ; cm., dermis and outer muscles (circular and oblique) ; , longitudinal muscles (the peculiar connective tissue is hardly indicated); , radial muscles; , lateral blood vessel; , dorsal sinus; ventral sinus enclosing nerve-cord (m);^-., median part of crop, with lateral pockets(/.) ; r., testis;/;, nephridial funnels ; , vas deferens. narrow nerve-ring surrounding the beginning of the gut. From the dorsal centres nerves proceed to the " eyes " and anterior sense spots, from the ventral centres the general body is innervated, and from the beginning of the ventral chain special nerves supply the alimentary canal, forming what is called a visceral system. The sense organs of the leech are ten so-called " eyes," besides numerous sense spots usually occurring on every. 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 Thomson, J. Arthur (John Arthur), 1861-1933. Edinburgh, Glasgow and London, H. Frowde and Hodder & Stoughton
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Keywords: ., bookauthorth, bookcentury1800, bookdecade1890, booksubjectzoology
