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. 1906 Excerpt: ...overarches it. There is typically an enlarged muscular pharynx which is often eversible, followed by a narrow tubular oesophagus. Often there is no further differentiation, the remainder of the tube being fairly uniform and called the intestine. Frequently however special enlargements occur, chief among which is the ...
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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. 1906 Excerpt: ...overarches it. There is typically an enlarged muscular pharynx which is often eversible, followed by a narrow tubular oesophagus. Often there is no further differentiation, the remainder of the tube being fairly uniform and called the intestine. Frequently however special enlargements occur, chief among which is the stomach. In the leeches the alimentary system is much modified in accordance with the blood-sucking habit of the animal. The crop is capable of great enlargement and may contain enough blood to nourish the animal for a long time. The mouth is sometimes armed with special cuticular outgrowths which serve as teeth. Glands either unicellular or compound occur in various regions of the digestive tract. In the earthworm F1g. 102. Transverse section of the intestine of the Earthworm, ty, typhlosole, an infolded longitudinal ridge in the gut in which the gland cells (g/.) are especially aggregated. Other letters as in Fig. 101. Questions on the figure.--Of what conceivable gain is the typhlosole? What is it analogous to in the higher types of animals? and related forms there in a dorsal longitudinal fold of the intestinal wall into the lumen of the tube, thus increasing the exposed surface. This is called the typhlosole (Fig. 102) and is supplied with cells which have been described as digestive. The entodermal epithelium may secrete a cuticle or may be ciliated. This layer is surrounded by a connective tissue and muscular fibres. 262. Respiration is effected for the most part through the general body wall, into which the blood capillaries or the lacunae of the coelom may penetrate. In some forms there are special thin places and outpocketings of the body-wall (branchiae) by which the exchange of gases is facilitated. These are characteristic of the Po...
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Add this copy of First Course in Zoology: a Text-Book for Secondary to cart. $62.50, good condition, Sold by Bonita rated 4.0 out of 5 stars, ships from Newport Coast, CA, UNITED STATES, published 2011 by Nabu Press.