. Principles of economic zoo?logy. Zoology, Economic. Fig. 12.—Obe'lia flabella'ta. (Hincks.) Fig. 13.—Obe'lia commissura'lis Obelia (Figs. 12, 13) is a good representative of such colonies. The axis is made up of a creeping horizontal portion and of vertical axes. The short, alternate, lateral branches of these axes bear zooids at their extremities, or, again branching, the polyps or zooids are borne on the second set of branches. When these zooids are immature, they are little, club-shaped enlarge- ments. When mature, the polyps are surrounded proximally by a little glassy, protective cup, t
. Principles of economic zoo?logy. Zoology, Economic. Fig. 12.—Obe'lia flabella'ta. (Hincks.) Fig. 13.—Obe'lia commissura'lis Obelia (Figs. 12, 13) is a good representative of such colonies. The axis is made up of a creeping horizontal portion and of vertical axes. The short, alternate, lateral branches of these axes bear zooids at their extremities, or, again branching, the polyps or zooids are borne on the second set of branches. When these zooids are immature, they are little, club-shaped enlarge- ments. When mature, the polyps are surrounded proximally by a little glassy, protective cup, the hydrotheca, and distally bear about a score of tentacles. These are the nutritive zooids, for division of labor is found here. The tentacle-bearing indi- viduals procure the food, and since the tubes are all hollow 1 Hertwig's " Manual of Zoology," Kingsley, p. 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 Daugherty, Lewis Sylvester, 1857-; Daugherty, L. S. , Mrs. , 1859-. Philadelphia, London, W. B. Saunders
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