. Outlines of zoology. Zoology. Fig. 120.—Development of Anodonta. (Alter Giktte.) 1. .Seclion of blaslosphere. sd., shell gland ; c,/., ciliated disc ; i:., beginning of endodermic invaginalion. Note mesoderm cells in the cavity. 2. Later stage, in. mesoderm. 3. Embr>'onic shell has appeared. 4. Glochidium larva; note byssus threads, and teeth on shell valves. " byssus," which moor the larva. If it manage to anchor itself on the tail, fins, or gills of a fish, the Glochidium shuts its valves and fixes itself more securely, and is soon surrounded by a pathological growth of its ho
. Outlines of zoology. Zoology. Fig. 120.—Development of Anodonta. (Alter Giktte.) 1. .Seclion of blaslosphere. sd., shell gland ; c,/., ciliated disc ; i:., beginning of endodermic invaginalion. Note mesoderm cells in the cavity. 2. Later stage, in. mesoderm. 3. Embr>'onic shell has appeared. 4. Glochidium larva; note byssus threads, and teeth on shell valves. " byssus," which moor the larva. If it manage to anchor itself on the tail, fins, or gills of a fish, the Glochidium shuts its valves and fixes itself more securely, and is soon surrounded by a pathological growth of its host's skin. In this parasitic stage a remarkable metamorphosis occurs. The sensory or tactile patches not unnaturally disappear ; the byssus and the embryonic byssus glands vanish, but a new byssus gland (which remains. 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; Newbigin, Marion I. (Marion Isabel), 1869-1934; Smith, Preserved, 1880-1941. fmo. New York, D. Appleton & Co.
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectzoology, bookyear1895
