. Elementary text-book of zoology [electronic resource]. Zoology. ARENICOLA. 185 region, from segment 20 backwards, there are regular trans- verse septa. Hence the ahmentary canal, from segment 4 to segment 19 inclusive, is free to move in the ccelom. The pharynx leads into a long oesophagus which widens out into the stomach. Just before the commencement of the latter there is a pair of oesophageal glands men ary. pockets, the lumen of which opens into the oesophagus. They are probably digestive glands. The Fig. III.—Transverse Section of Arenicola (Diagrammatic). Dorsal Blood-vessel receiving
. Elementary text-book of zoology [electronic resource]. Zoology. ARENICOLA. 185 region, from segment 20 backwards, there are regular trans- verse septa. Hence the ahmentary canal, from segment 4 to segment 19 inclusive, is free to move in the ccelom. The pharynx leads into a long oesophagus which widens out into the stomach. Just before the commencement of the latter there is a pair of oesophageal glands men ary. pockets, the lumen of which opens into the oesophagus. They are probably digestive glands. The Fig. III.—Transverse Section of Arenicola (Diagrammatic). Dorsal Blood-vessel receiving Efferent Branchial. Gill (7-13)-. \ - y Circular Muscles ' , . , ' with Ectoderm and - - Cuticle Outside. Ventral Vessel. '"''^ ' Nerve Cord. n the left is seen the arrangement of the first six branchial segments, on the right the last seven. stomach is wide, and is covered with yellow-cells^ intersected by a network or plexus of blood-vessels. At about the level of the seventh pair of gills the stomach passes into the intestine which terminates in an anus, Arenicola is perpetually employed in passing quantities of sand and food-particles through its alimentary canal, digesting the latter and egesting 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; Parsons, John Herbert, Sir, 1868-1957, donor; S. H. Lazarus (Firm); University College, London. Library Services. Edinburgh : E. & S. Livingstone
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectzoology, bookyear1901
