SEMAEOSTOMEiE — CHRYSAORA . 



579 



♦Development through alternation of generations with strobilization (Claus). 



j-Development as in C. mediterranea. Haeckel found a specimen 160 mm. wide, with 40 tentacles, and 48 marginal lappets 

 as in Dactylometra. 



JOne of Vanhbffen's specimens had 4 tentacles in one octant. See also L. Agassiz, 1S62, Cont. Nat. Hist. U. S., vol. 4, pp. 

 127, 166. 



Chrysaora hysoscella Eschscholtz. 



Urtica tnaritia, etc., Borlase, 175S, Nat. Hist. Cornwall, p. 256, plate 25, figs, vil and \in. 



Medusa livsoscella^ Linne, 1766, Systema Naturae, Ed. 12, p. 1097. 



Chrysaora cyclofialay aspilonota, spilogona^ spiUtetnlgonaj pleurophora, lesueuriiy macrogona, heptanema, mediterraneay PtRON et 

 Lesueur, 1809, Annal. du Mus. Hist. Nat., tome 14, pp. 365, 366. 



Chrysaora hysoscella, Eschscholtz, 1829, Syst. der Acal., p. 79, taf. 7, fig. 2. — Claus, 1877, Denksch. Wien. Acad., p. 33, taf. 

 6, 7. — Krukenberg, 1880, Zool. Anzeiger, Jahrg. 3, p. 306 (the medusa contains 95.75 to 96.3 percent of water). — Graeffe, 

 1884, Arbeit. Zool. Inst. Wien., Bd. 5, p. 342. — Vanhoffen, 1908, Deutsche SUdpolar Expedition, Bd. 10. Zoo!. 2, p. 39. 



Chrysaora medUerranea+ C. isosceles, Haeckel, 1880, Syst. der Medusen, pp. 511, 513, taf. 31, llgn. 1-3 (list of literature). 



Chrysaora mediterranea, Vanhoffen, 1888, Bibliotheca Zoologica, Bd. I, Heft 3, p. 14. 



Chrysaora hysoscella^ C, mediterranea, Vanhoffen, 1906, Nordisches Plankton, Nr. 11, p. 47, fign. 9-10 a, b. 



Chrysaora isosceles, Del.'^p, M. J., 1901, Irish Naturalist, vol. 10, p. 27 (rearing the larva in an aquarium). 



For a synopsis of the characters of C. hysoscella, see table of characters of Chrysaora. 



There appear to be no definite distinctions between Chrysaora " mcJiterranea" of the 

 Mediterranean and C. hysoscella of the .Atlantic coasts of France, England, Germany, and 

 Holland, and in the entrance to the Baltic Sea. It is probable that the Chrysaora of the 

 Chesapeake Bay, in America, is identical with that of Europe, but I believe the Chesapeake 

 medusa to be only a brackish-water variety of Dactylometra qianquectrrha, which becomes 

 mature in the 24 tentacle stage. Judging from Haeckel's figures the Mediterranean medusa 

 is more highly colored than that of the northern shores of Europe. In the Chesapeake the 



