. Outlines of zoology. Zoology. Nervous system and sense organs. 401 nervous system consists merely of a ganglionic mass lying between the two apertures, giving off a few nerves forwards and backwards. A structure of doubtful sensory, but of considerable morphological, Fig. 174.—Diagram of Ascidian.—After Herdman. The arrows indicate the two openings ; the dark border the test. Ph., pharynx, with gill-slits; G., reproductive organs; H., heart, with blood vessels; , genital ducts; R., rectum, ending in cloacal chamber. Surrounding the pharynx the peribranchial cavity is shown. importan
. Outlines of zoology. Zoology. Nervous system and sense organs. 401 nervous system consists merely of a ganglionic mass lying between the two apertures, giving off a few nerves forwards and backwards. A structure of doubtful sensory, but of considerable morphological, Fig. 174.—Diagram of Ascidian.—After Herdman. The arrows indicate the two openings ; the dark border the test. Ph., pharynx, with gill-slits; G., reproductive organs; H., heart, with blood vessels; , genital ducts; R., rectum, ending in cloacal chamber. Surrounding the pharynx the peribranchial cavity is shown. importance, is the small sub-neural gland which lies beneath the ganglion, and communicates by a ciliated duct with the pharynx. The opening is usually complex, and forms the so-called dorsal tubercle, which is very distinct on the wall of the pharynx. It lies at the point where the two halves of the ciliated groove, or peripharyngeal band, 26. 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
