. A manual of zoology. Zoology. 242 CWLKNTKRArA. Other common genera in American waters are, of hydroids, besides those mentioned, Jiudendriutn, Tnhularia, and Thamnocnida; of medusie, Tiaris, Turritopsis, Dipurena, Lizzia, Noiwpsis, and Hydrichthis. Order IV. Campanulariffi = Leptomedusae (Calyphoblastea). These forms are readilj' distinguished from the last by the fact that they are always colonial and possess hydrothecce, the meduste always being Leptomedusae (p. 239). A peculiarity of the group is the existence of gonothecse, closed perisarcal envelopes, inside which the gonophores arise f
. A manual of zoology. Zoology. 242 CWLKNTKRArA. Other common genera in American waters are, of hydroids, besides those mentioned, Jiudendriutn, Tnhularia, and Thamnocnida; of medusie, Tiaris, Turritopsis, Dipurena, Lizzia, Noiwpsis, and Hydrichthis. Order IV. Campanulariffi = Leptomedusae (Calyphoblastea). These forms are readilj' distinguished from the last by the fact that they are always colonial and possess hydrothecce, the meduste always being Leptomedusae (p. 239). A peculiarity of the group is the existence of gonothecse, closed perisarcal envelopes, inside which the gonophores arise from the blastostyle, a specialized polyp, without moutli or tentacles (fig. 174,/â ). The typical Campanularia? produce medusae, while some forms, like Thaumantia* iViid jEquoria* liave no hydroid stage, and on the other hand Sertidaria * and Pluinulariu * have no medusa Fig. 186.âAmerican Campanularians. (After Verrill.) A. Clytia noliformis; B, CaUjceJla syriufjii; C, Olwlia dtchotonta ; />, OpercuJareUa pumila. Other common genera, Clytia * Dijjhusia* and Aglaoplienia* among hydroids ; Ohelia* I'ima,* lihegmatodes* Among meduate. Possibly the fossil group of belongs near here. Only the perisarc is known, and this is composed of hydrolheca', in wliicli it is supposed the hydranths occurred. Order V. Trachymedusae. These medusas, mostly from warmer seas, have no hydroid stage. The characters are given on p. 239, Tnirhi/)ii'iii(i, Liriope* {fig. 183), and Cam- panella in our own waters, Geri/ouia, iu Europe. Order VI. Narcomedusae. In addition to the characters on ]>. 239 may lie added the fact that the tentacles arise from the outside aliove the rim of tlie bell. Ciniomntha * (tig. 183), and Cunina * iu our warmer waters, ^Egina in 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
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