. A manual of zoology. PHYLUM CCELENTERATA 97 The mouth (Figs. 41, C, D, and 43, mth) leads into an enteric cavity which occupies the whole interior of the manubrium, and from its dilated base sends off four delicate tubes, the radial canals (rad. c), which pass at equal distances from each other through the substance of the umbrella to its margin, where they all open into a circular canal (cir. c), running parallel with and close to the margin. By means of this system of canals the food, taken. Fig. 43. — Dissection of a medusa with rather more than one-quarter of the umbrella and manubrium c
. A manual of zoology. PHYLUM CCELENTERATA 97 The mouth (Figs. 41, C, D, and 43, mth) leads into an enteric cavity which occupies the whole interior of the manubrium, and from its dilated base sends off four delicate tubes, the radial canals (rad. c), which pass at equal distances from each other through the substance of the umbrella to its margin, where they all open into a circular canal (cir. c), running parallel with and close to the margin. By means of this system of canals the food, taken. Fig. 43. — Dissection of a medusa with rather more than one-quarter of the umbrella and manubrium cut away (diagrammatic). The ectoderm is dotted, the endo- derm striated, and the mesoglcea black, cir. c, circular canal; end. lam, endoderm lamella; gon, gonad; /, lithocyst; mtto, manubrium; jnth, mouth; rad. c, radial canal; vl, velum. in at the mouth and digested in the manubrium, is dis- tributed to the entire medusa. The edge of the umbrella is produced into a very narrow fold or shelf, the velum (Fig. 43, vl), and gives off the tentacles (/), which are sixteen in number in the newly-born medusa (Fig. 41, D), but which are very numerous in the adult. At the bases of eight of the tentacles — two in each quadrant — are minute globular sacs (/), each containing a H. 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 Parker, T. Jeffery (Thomas Jeffery), 1850-1897; Haswell, William A. (William Aitcheson), 1854-1925. New York, The Macmillan Company; London, Macmillan & Co. ,Ltd.
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