Text-book of comparative anatomy . FIG. 06.— Diagrammatic transverse section of a Coral individual; to the left on the level ofoesophagus, to the right on the level of the gastric cavity. «-&, Direction of the plane of sym-metry. wall, and these compartments again are continued into the axial cavitiesof the tentacles, which are lined with endoderm (cf. Fig. 82, p. 107).The axial cavities of the tentacles occasionally open externally at thetip by a pore. The number of tentacles represents, generally, the number of thesepta. The Octocorallia have 8 septa, and 8 tentacles placed so asto alternate
Text-book of comparative anatomy . FIG. 06.— Diagrammatic transverse section of a Coral individual; to the left on the level ofoesophagus, to the right on the level of the gastric cavity. «-&, Direction of the plane of sym-metry. wall, and these compartments again are continued into the axial cavitiesof the tentacles, which are lined with endoderm (cf. Fig. 82, p. 107).The axial cavities of the tentacles occasionally open externally at thetip by a pore. The number of tentacles represents, generally, the number of thesepta. The Octocorallia have 8 septa, and 8 tentacles placed so asto alternate with them. The Tctracondlm generally have a largenumber of septa which are always a multiple of 4. The HexacoraUiapossess 6 or 611 partition walls and tentacles, arranged in a definiteorder which cannot here be described. We can only say, quite gener-ally, that the oldest septa project farthest, and the youngest septa leastfar, towards the axis. Most Corals have not a strictly radial structure; on the contrarywe often find
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectanatomycomparative
