This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1901 edition. Excerpt: ...thick investing test, in which lies the darker stained kernel-like body. At five points the test is broken through; three of these are where, at the anterior end, there pass an equal number of THE COMPLEX NERVOUS SYSTEM OF ASCIDIAN LARV.E. 69 tiny rod-shaped papillae spreading into wide heads on their ...
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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1901 edition. Excerpt: ...thick investing test, in which lies the darker stained kernel-like body. At five points the test is broken through; three of these are where, at the anterior end, there pass an equal number of THE COMPLEX NERVOUS SYSTEM OF ASCIDIAN LARV.E. 69 tiny rod-shaped papillae spreading into wide heads on their emergence. These are glandular in function, secreting a tough glutinous cement whereby the larva when tired of a free life, attaches itself to a rock or weed. The other two points where the test is pierced, are upon the dorsal side, and in the larva of Aplidium elegavs are situated far back. The anterior is the opening of the mouth (o), and is separated by only a short interval from the posterior, which is a depression indicating where the atrial aperture breaks through. The mouth opens into a wide pharynx occupying a great part of the larval body space. In the stage figured, the stomach is just beginning to be apparent as a thick walled canal in a ventral position towards the hinder part of the body, and connection is just being made between the atrial cavity and the intestine. In the advanced larva several openings pierce the pharynx and allow water entering through the mouth to pass into the atrial cavity without having to traverse the stomach and intestine. Such openings are obviously the same as are so numerous and so apparent in the adult. In Fig. 4, Pl. x, they show as two rows of disc-shaped thin places in the pharyngeal walls. The nervous system, of the most extreme simplicity in the adult, has in the larva a complicated and highly developed arrangement. As in the Vertebrata, it takes its origin as an open furrow stretching longitudinally along the dorsal side of the body. The edges gradually grow upwards and inwards to meet, and..
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Add this copy of Microscopical Studies in Marine Zoology to cart. $63.29, good condition, Sold by Bonita rated 4.0 out of 5 stars, ships from Newport Coast, CA, UNITED STATES, published 2016 by Palala Press.
