. Amphioxus and the ancestry of the vertebrates. Amphioxus; Sea squirts; Hemichordata. 262 THE PROTOCHORDATA. a U-shaped alimentary canal. Both are deep-sea forms, Cephalodiscus having been dredged during the Challenger Expedition, from the Straits of Magellan, at a depth of 245 fathoms ; while Rhabdopleura was first dredged indepen- dently, off the Shetland Islands, at 90 fathoms, by the Fig. 125. — Cephalodiscus dodecalophus, from the ventral side. (.\fter M'iNTOSH.) Actual length of poh'pide from extremity of branchial plumes to the tip of the pedicle is about 2 mm. hj. Buccal shield;

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. Amphioxus and the ancestry of the vertebrates. Amphioxus; Sea squirts; Hemichordata. 262 THE PROTOCHORDATA. a U-shaped alimentary canal. Both are deep-sea forms, Cephalodiscus having been dredged during the Challenger Expedition, from the Straits of Magellan, at a depth of 245 fathoms ; while Rhabdopleura was first dredged indepen- dently, off the Shetland Islands, at 90 fathoms, by the Fig. 125. — Cephalodiscus dodecalophus, from the ventral side. (.\fter M'iNTOSH.) Actual length of poh'pide from extremity of branchial plumes to the tip of the pedicle is about 2 mm. hj. Buccal shield; the shading on its surface indicates pigment-markin'^s. At the tip of the pedicle, buds are produced. Canon Norman, and off the Lofoten Islands, at 200 fath- oms, by Professor G. O. Sars (i866-68). Rhabdopleura is the name given by Allman (1S69), who published a short account of it; and it has since been described by ^, Laxkester, and G. H. 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 Willey, Arthur, 1867-. New York, London, Macmillan

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Keywords: ., bookcentury1800, bookdecade1890, bookpublishernewyo, bookyear1894