Circulars Volume 20-22

Circulars Volume 20-22

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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. 1903 edition. Excerpt: ... dorsal pore. P., dorsal pore. Per. and Pel., right and left pore canals, aer. and ael., right and left anterior enterocoeles. oe., oesophagus. S., stomach, rpa. and Ipa., posterior arms of the pluteus. series of preserved material representing the various stages from the egg to the adult form. The larvae were reared and preserved during the Summers of 1900 and 1901, in the U. S. Fish Commission Laboratory at Beaufort, N. C, while the detailed study of the material has been carried on in the Zoological Laboratory at the Johns Hopkins University. A Muscular Apparatus of the Pluteus. When the plutei were swimming undisturbed in an aquarium it was noticed that the four long posterior arms which join the body of the larva near its middle, would occasionally be quickly spread far apart at the top then more slowly resume their normal position. When confined under a cover glass the plutei Dent. 5-1. Dent. 1-2. A reconstruction of the structures found on the left side of a young pluteus. (The ectodermic pouch is omitted). M., mouth, oe., oesophagus of pluteus. S., stomach. /., intestine. Sph., sphincter, ael., left anterior enterocoelo. Pel., left pore canal. P., dorsal pore. St., stone canal. 1,2,3.4, and 5, radial water canals, he., hypogastric euterocoele. Dent., 1-2, 2-3, 3-4, 4-5, and 5-1, pouches from the hypogastric cooiom for the formation of the dentary apparatus. exhibited the same motions with much greater frequency than when free, which may indicate that the motion may serve the larva as a means of escape when caught. The movements seem, however, to have mainly to do with the removal of the faeces from P Fig. 5. Transverse section of a fully developed pluteus in a plane almost the same as that in Fig. 4. stomach into the intestine...
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Product details

  • Paperback | 358 pages
  • 189 x 246 x 19mm | 640g
  • United States
  • English
  • black & white illustrations
  • 123674148X
  • 9781236741486