. A text-book of invertebrate morphology. Invertebrates. TYPE CCELENTERA. 101 {Tessera) or line {Lucernaria) of adhesion. The depressions of the subumbrellar surface, the funnels (/), are very deep in I/ucerTuxria, extending almost to the summit of the bell. 2. Order Peromedusae. In this order the adult medusse are always free-swimming, and are characterized by the bell being pointed in shape and about its middle marked with a distinct constriction. The coelenteron is obliterated at only four points, as in Tessera, and they differ from the Stauromedusse by possessing four sense-organs, the fou
. A text-book of invertebrate morphology. Invertebrates. TYPE CCELENTERA. 101 {Tessera) or line {Lucernaria) of adhesion. The depressions of the subumbrellar surface, the funnels (/), are very deep in I/ucerTuxria, extending almost to the summit of the bell. 2. Order Peromedusae. In this order the adult medusse are always free-swimming, and are characterized by the bell being pointed in shape and about its middle marked with a distinct constriction. The coelenteron is obliterated at only four points, as in Tessera, and they differ from the Stauromedusse by possessing four sense-organs, the four interradial of the primary series of eight becoming modified to form these structures, while the radial ones retain their original character. 3. Order Cubomedusse. This order, of which Oharyhdea (Fig. 53) is a typical example, is characterized by the bell being of a cubical shape. The interradial obliterations of the ccelenteron are linear, and, as in the pre- ceding order, four of the primary ten- tacles, these being the only ones which develop, are modified to form sense- organs. In this order, however, it is''i.—Charybdeamar- the four radial tentacles which form the sense-organs {so), the four interradial per- sisting as tentacles {t).. supialis (after Glaus). so = sense-organ. i = tentacle. 4. Order Discomedusae. In this order, which includes the majority of the known Scyphomedusse, all the eight primary tentacles are converted into sense-organs, a number of secondary tentacles usually developing at the margin (Fig. 54). The primary interradial obliterations of the coelenteron do not develop, but on the other hand secondary obliterations frequently make their. 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 McMurrich, J. Playfair (James Playfair), 1859-1939. New York, H. Holt and Compa
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Keywords: ., bookcentury1800, bookdecade1890, bookpublishernewyo, bookyear1894
