. Elementary text-book of zoology. Zoology. i;fcj<J COELEISTTERATA. i acteristic of the group. The striped muscles of the sub-umbrella are strongly developed to correspond with the great size of the body : and beneath them the supporting lamella is usually thrown into a number of closely aggregated circular folds, thus causing a consider- able increase in the surface on which the muscular epithelium with its circularly arranged fibres are placed. The generative organs have the form of horse-shoe shaped frills which project into four widely open cavities in the sub-umbrella, the sub-genital
. Elementary text-book of zoology. Zoology. i;fcj<J COELEISTTERATA. i acteristic of the group. The striped muscles of the sub-umbrella are strongly developed to correspond with the great size of the body : and beneath them the supporting lamella is usually thrown into a number of closely aggregated circular folds, thus causing a consider- able increase in the surface on which the muscular epithelium with its circularly arranged fibres are placed. The generative organs have the form of horse-shoe shaped frills which project into four widely open cavities in the sub-umbrella, the sub-genital pits. These cavities are not developed in some ex- ceptional cases (Nausithoe, Discomedusa}. The germinal epithelium, GA-. RK. FIG. 200.—Aurelia in/ritu, seen from the oral surface. MA, The four oral arms with the mouth in the centre; 6'fr, The genital frills ; GH, Openings of the sub-genital cavities ; Hk, Marginal bodies ; HO, Radial vessels ; T, Tentacles on the margin of the disc. which is always embedded in the gelatinous substance, is covered with an entodermul layer, and is probably itself an entodermal product (fig. 200). Development takes place by alternation of gene- rations. In rare cases (Pelagia) the development is simplified, and the larva passes directly into the Eplti/ra, missing out the attached Scyphistoma and the Strobila stage (Krohn}. 1. tfemceostomew. Discophora with large central mouth sur- rounded by four large often nmlti-lobed oral arms. The form 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 Claus, Carl, 1835-1899; Sedgwick, Adam, 1854-1913; Sinclair, F. G. (Frederick Granville), b. 1858. New York : Macmillan
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectzoology, bookyear1884
