. Amphioxus and the ancestry of the vertebrates. Amphioxus; Sea squirts; Hemichordata. 252 THE PROTOCHORDATA. From a morphological point of view a more striking- resemblance between the two larvae than that furnished by the longitudinal ciliated bands exists in connexion with the anterior body-cavity or cntcroccei. In the Echinoderm. Figs. 119 and 120. â Auricularia, lar\'a of Svnapta (after SemonI ; and Tomaria, lar\'a of Balanoglossus. (After MORGAN.) a. Anus. Apical plate, bc^. Anterior bodv-cavitv, communicating with exterior by the water-pore, be-, bc^. Second and third bodv-cavities
. Amphioxus and the ancestry of the vertebrates. Amphioxus; Sea squirts; Hemichordata. 252 THE PROTOCHORDATA. From a morphological point of view a more striking- resemblance between the two larvae than that furnished by the longitudinal ciliated bands exists in connexion with the anterior body-cavity or cntcroccei. In the Echinoderm. Figs. 119 and 120. â Auricularia, lar\'a of Svnapta (after SemonI ; and Tomaria, lar\'a of Balanoglossus. (After MORGAN.) a. Anus. Apical plate, bc^. Anterior bodv-cavitv, communicating with exterior by the water-pore, be-, bc^. Second and third bodv-cavities of Tomaria. Circular ciliated band of Tornaria. Contractile cord between apical plate and anterior body-cavity of Tornaria. ^^'â ./. Gill-pouches, Hydroccel of Auricularia (anterior body-cavity), /. Longitudinal (circumoral) ciliated band. /.e. Left enteroccel (body-cavity), w. Mouth, v. Lateral (paired) nerve-band of Auiicularia. Right enteroccel. s/. Calcareous spicules, sf. Stomach. wp. Water-pore. â In Auricularia, the margin of the mouth is surrounded bv a ciliated band discovered by Semox. and known as the aJoral ciliated band. The poste- rior, V-shaped portion of this band lies inside on the ventral floor of the larval cesophagus. larva this cavitv arises as a median pouch of the archen- teron, and there is every reason to suppose that it has a similar origin in Tornaria, although this point has not 3^et. 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
