Medusae of the world . ast of Australia under the name JEquovea pleuronota. GENERIC CHARACTERS. ./Equoridae with forked or branching radial-canals, which arise at equal intervals from theperiphery of the stomach. With 8 or more lips. Manubrium without a peduncle. Develop-ment unknown. Haeckel distinguishes Zygocanna with 16 or more branched radial-canals and Zygocan-nota with 12 branched radial-canals. It seems best to unite these genera, adopting Haeckelsfirst name, Zygocanna. Haeckels system makes no allowance for the possible discovery ofmedusae with 8 to ii, or 13 to 15, branched radial-ca
Medusae of the world . ast of Australia under the name JEquovea pleuronota. GENERIC CHARACTERS. ./Equoridae with forked or branching radial-canals, which arise at equal intervals from theperiphery of the stomach. With 8 or more lips. Manubrium without a peduncle. Develop-ment unknown. Haeckel distinguishes Zygocanna with 16 or more branched radial-canals and Zygocan-nota with 12 branched radial-canals. It seems best to unite these genera, adopting Haeckelsfirst name, Zygocanna. Haeckels system makes no allowance for the possible discovery ofmedusae with 8 to ii, or 13 to 15, branched radial-canals. Very little is known of these medusae. Their radial-canals arise at equal intervals fromthe periphery of the stomach and almost immediately bifurcate. The gonads are developedupon the peripheral branches. Zygocanna is separated from Zygocannula by its lacking a gelatinous peduncle, which isfound in Zygocannula, but I am inclined to believe that Zygocannula is the mature stage ofZygocanna. 338 MEDUSA OF THE Zygocanna pleuronota Haeckel. Mquorea pleuronota, Peron et Lesueur, 1809, Annal. du. Mus. Hist. Nat. Paris, tome 14, p. (Pohxenia) pleuronota, Eschscholtz, 1829, Syst. der Acalephen, p. 119. Zygocanna pleuronota + Z. costata, Haeckel, 1879, Syst. der Medusen, pp. 214, 215, taf. 15, fign. 7, 8. Zygocanna pleuronota, Bedot, 1901, Revue Suisse de Zool., tome 9, p. 488; Ibid., 1905, tome 13, p. 153 (citation of all litera-ture to 1850). Our knowledge of this medusa is very imperfect. Peron and Lesueurs description isinadequate for modern requirements, and Haeckel states that the hell-margin of his Z. costata, which certainly seems to be identical withPeron and Lesueurs pleuronota, is par-tially restored in his figure. The onlydifference between Peron and Lesueurspleuronota and Haeckels Z. costata isthat Haeckels species has somewhatlonger tentacles. The so-called disparityin numbers of radial-canals, lips, andtentacles is no greater than one wouldexpect
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