Medusae of the world . ow finds them in Pegantha smaragdina, and indeed Stschel- —CUNINA. 479 kanowzeff partially bridges the gap in his detailed account of the development of the oogoniaand the oocytes and their nuclear phases. (See Zoolog. Centralblatt, Bd. 13, p. 676.) The medusa larvawhich develops in the stomach is attached to the maternalentoderm by means of two of its own ectoderm cells which send out processes into the entodermof the mother medusa, thus constituting a very primitive placenta. The genital cells of the larval medusa, in the stomach of its mothe
Medusae of the world . ow finds them in Pegantha smaragdina, and indeed Stschel- —CUNINA. 479 kanowzeff partially bridges the gap in his detailed account of the development of the oogoniaand the oocytes and their nuclear phases. (See Zoolog. Centralblatt, Bd. 13, p. 676.) The medusa larvawhich develops in the stomach is attached to the maternalentoderm by means of two of its own ectoderm cells which send out processes into the entodermof the mother medusa, thus constituting a very primitive placenta. The genital cells of the larval medusa, in the stomach of its mother, originate from asingle cell in the entoderm of the larva. This cell wanders into the ectoderm of the larvaand there it divides to form the genital cells of the developing medusa. Stschelkanowzeffs researches may be accepted with more reliance than those of Metschni-koff, for he bases his conclusions upon the study of serial sections, whereas Metschnikoffcarried out his observations largely upon macerated Fig. IIQ.—Cunina prolijera. A, Side view of mature medusa, with expanded bell-collar. B, One of the sensory-clubs andits otoporpa. C, Bell-margin; t>, velum; p. c, peronial ring-canal system. D, View of tentacle. E, F, G, Suc-cessive stages in growth of first sexual generation in stomach-cavity of swimming medusa. Drawn from life, by theauthor. Zoological Station, Naples, winter of 1907-08. 480 MEDUSJE OF THE WORLD. Cunina prolifera Gegenbaur. Cunina prolifera, Gegenbaur, 1854, Generationswechsel bei Medusen und Polypen, p. 56, taf. 2, fign. 24-31, Wiirzburg; 1856, Zeit. fur wissen. Zool., Bd. 8, p. 262.—Haeckel, 1879, Syst. der Medusen, pp. 313, rubiginosutn, Kollikfr, 1853, Zeit. fur wissen. Zool., Bd. 4, p. rosea, Gegenbaur, i8c6, Zeit. fur wissen. Zool., Bd. 8, p. 261, taf. 10, fign. 6, rhododaetyla +C. rubiginosa, Haeckel, 1864, Jena. Zeitschr. fiir Naturwissen., Bd. I, p. 335; Bd. 2, p. 263, taf. 9; 1865, Familie
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