. Elementary text-book of zoology. i84 ANNULATA. dorso-laterally and are beautifully branched delicate organs of respiration. Through their thin walls the blood and outside water interchange carbonic acid and oxygen. The posterior part (3) consists of a great number (about 30) of Fig. III.—A Magnified Gill-Segment of Arenicola. (After ASHWORTH and Gamble.) Notopodial Setae. Branches of Gills. Nephridiopore. Torus Uncinatus (Neuropodium). compressed segments, on none of which are there any appendages or gills. Integu- "^^^ body is covered by a fine but definite mentar7 '^'^'^i'^'
. Elementary text-book of zoology. i84 ANNULATA. dorso-laterally and are beautifully branched delicate organs of respiration. Through their thin walls the blood and outside water interchange carbonic acid and oxygen. The posterior part (3) consists of a great number (about 30) of Fig. III.—A Magnified Gill-Segment of Arenicola. (After ASHWORTH and Gamble.) Notopodial Setae. Branches of Gills. Nephridiopore. Torus Uncinatus (Neuropodium). compressed segments, on none of which are there any appendages or gills. Integu- "^^^ body is covered by a fine but definite mentar7 '^'^'^i'^'fi secreted by the simple underlying ecto- derm in which there are unicellular glands. If the animal be cut open down the median dorsal line the whole internal anatomy is exposed, for Arenicola is a ccelomate animal and all the internal organs lie in contact with the coelom. The coelom is spacious, as in Polygordius, but it -is not completely divided up into compartments. The front part Coelom '^ divided by three transverse septa* between the first, second, third and fourth segments, which * The first septum has a pair of hollow septal pockets which are muscular, and probably assist in protrusion of the 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 Masterman, Arthur Thomas. Edinburgh, E. & S. Livingstone
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Keywords: ., bookcentury1900, bookcollectionbiod, bookdecade1900, bookyear1902
