NARCOMEDUSjE — CUNOCTANTHA. 



465 



equal size and are somewhat larger than the cells of the outer layer, but there is no giant cell, 

 such as Metschnikoff, 1881, and Woltereck, 1905, observed in the center of the larva of Cunoc- 

 tantha parasitica. 



All of the cells increase in number and a central cavity appears. Meanwhile the larva 

 elongates. The tentacles appear one by one, starting with a single tentacle and ending with 



at least 12. 



These Cunina larvae are possibly parasites which enter the gastrovascular cavity ot the 

 Cunoctantha when young planulae and there develop until the 12-tentacle stage. They are, 

 however, not found in medusae less than 3 mm. wide, but as they are said to appear in male as 

 well as in female medusas of C. kollikeri, it is improbable that they develop from eggs of the 

 same species. Nevertheless it is possible that the statement that male medusas develop these 

 larvx is mistaken and that we have here a three-generation cycle, such as has been studied 

 by Stschelkanowzeff in Cunina probosadea. 



Cunoctantha actinulas are often found in the Mediterranean attached to the subumbrella 

 of Aglaura or Rho palonema . 



I believe that a "stolon larva" found floating in the Ocean at Tortugas, Florida, in July, 

 1904, is probably one of the generations of Cunoctantha kollikeri. It was producing numerous 

 8-rayed medusas by asexual budding (see plate 54, figs. 4 to 9). 



Cunoctantha polygonia Haeckel. 



Cunoctantha polygonia, Haeckel, 1879, Syst. der Medusen, p. 317, taf. 19, fig. 3. 



This medusa is described by Haeckel from the Mediterranean. It is about twice the size 

 of C. octonaria, its bell being 16 mm. wide and 6 mm. high. The 8 marginal lappets are "hex- 

 agonal" and the 8 stomach-pouches "pentagonal." The 8 tentacles are shorter than in C. 

 octonaria, being hardly as long as the marginal lappets. Also, there are 7 sensory-clubs on 

 each of the 8 lappets, instead of 3 to 5 as is commonly the case in C. octonaria. The median 

 sensory-club of each lappet is much larger than the others, whereas in C. octonaria they are ot 

 about a uniform size. The central stomach is wide and conical and is as long as the diameter 

 between the tentacle-bases. There are 4 well-developed lips. The gonad forms a ring around 

 the peripheral, ectodermal, subumbrella wall of the stomach and also extends out under the 8 



pouches. 



Haeckel figures a peronial, peripheral canal-system in this medusa, but it does not appear 



that he cut sections to determine this point. 



Found by Haeckel at Corfu and Messina in 1877 and 1878. 



Cunoctantha parasitica Metschnikoff. 



Cunoctantha parasitica, Metschnikoff, E, .88., Zeit. fur wissen. Zool., Bd. 36, p. 437, taf. 28, fign. 7-16 (development of the 

 larva); .886, Arbeit. Zool. Inst. Wien, Bd. 6, pp. 252-253, taf. 23, fign. 27, 28.-Korotneff, .891, Ze.t. fur w.ssen. Zool., 

 Bd. 51, p. 6.8, taf. 31, fign. 15-19. 



Cunina, sp., Maas, .892, Jahrb. Zool., Abth. Anat., Bd. 5, p. 271, taf. 21, 22, fign. I to 26. 



Cunina (Cunoctantha) parasitica, Woltereck, .905, Verhandl. deutsch. Zool. Gesell., .5 Jahresvers p. 117, fign. 12-14. 



( >) Cunoctantha sp., Mayer, 1904, Mem. Museum Brooklyn Institute, vol. 1, p. 27, plate 4, fign. 36-42 (budding larva;. 



( >) Cunina, sp., Fewkes, 1884, American Naturalist, vol. 18, p. 302, fig. 7 (°n Florida Reef, paras.t.c on Geryoma). 



Mature medusa.— Bell 7 mm. wide, quite flat, walls not very thick, 8 tentacles alternating 

 with 8 marginal lappets. The tentacles are somewhat longer than bell-radius. There are 5 

 marginal sense-organs on the margin of each of the 8 lappets. Each sense-club has one large 

 or 2 small concretions. An elongate otoporpa is found above each sense-club. Mouth a round 

 opening. Stomach flat, with 8 wide pouches in the radii of the tentacles. No peripheral canal- 

 system. Stomach and pouches rose-red, tentacles decided green. 



This species is parasitic, when young, in the gastric cavity of Geryoma. It is abundant in 

 the Mediterranean, and its larva, or one exactly like it, was found at Tortugas, Florida 



The larvae of Cunoctantha parasitica attach themselves to the bell-margin or lips of Gery- 

 oma proboscidalis, and then they enter the gastrovascular cavity of the Geryoma, apparently 

 wandering in through the mouth, in order to undergo their further development in the stomach 

 or peripheral canals of the Geryoma. 



The development of these parasitic larvae has been most carefully studied by Metscnmkott , 

 KorotnefF, Maas, and Woltereck; but although they were first observed within the gastrovas- 



