This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1898 Excerpt: ...prepared transverse sections of the pharyngeal region (as fig. 107), a large number of gill-arches and slits are seen, and the whole pharynx-section appears somewhat heart-shaped instead of narrow-elliptical. 7. Endostyle. The lattice-work of gill-arches forms the whole surface of the pharynx except for the narrow ...
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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1898 Excerpt: ...prepared transverse sections of the pharyngeal region (as fig. 107), a large number of gill-arches and slits are seen, and the whole pharynx-section appears somewhat heart-shaped instead of narrow-elliptical. 7. Endostyle. The lattice-work of gill-arches forms the whole surface of the pharynx except for the narrow dorsal and ventral areas, which form continuous grooves--dorsally the hyperpharyngeal groove, ventrally the endostyle. Anteriorly, in the velum, these two grooves are united by a Fig. 107.--Transverse Section Of Amphioxus In Pharyngeal Region. (Altered from Marshall and Hurst.) pair of grooves, curving round right and left of the mouth. These grooves are lined by an epithelium that is partly ciliated, partly glandular. In the endostyle there are four longitudinal rows of gland-cells, separated by rows of ciliated cells. The gland-cells secrete a slimy fluid which the cilia drive along the groove. To this slime most of the solid particles brought in by the water-current will adhere, and while the main part of the water passes out through the gill-slits into the atrium, whence it is expelled by the atriopore, the solid particles (mostly food) are carried on into the digestive region. Thus the water-current is at once nutritive and respiratory. In Amphioxus we find for the first time a reason for that utilization of the anterior part of the alimentary canal for respiration which is so marked a characteristic of the Vertebrata. As we ascend to the dogfish, frog and rabbit, we find the respiratory portion of the canal becoming smaller and smaller, until in the rabbit the courses of the air and of the food are almost completely separated. 8. Intestine and Liver. Behind the last gill-slits the canal becomes more nearly circular in section, ...
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PLEASE NOTE, WE DO NOT SHIP TO DENMARK. New Book. Shipped from UK in 4 to 14 days. Established seller since 2000. Please note we cannot offer an expedited shipping service from the UK.
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PLEASE NOTE, WE DO NOT SHIP TO DENMARK. New Book. Shipped from UK in 4 to 14 days. Established seller since 2000. Please note we cannot offer an expedited shipping service from the UK.
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PLEASE NOTE, WE DO NOT SHIP TO DENMARK. New Book. Shipped from UK in 4 to 14 days. Established seller since 2000. Please note we cannot offer an expedited shipping service from the UK.
