102 MF.nrs.K UK TIIK WORLD. 



This medusa, together with its hydroid stage, was found in great numbers by Prof. 

 Henry F. Perkins in the salt-water moat of Fort Jefferson, Tortugas, during the summer of 

 1905. The hydroid is a minute Stauridiu which grows upon algae. The same medusa was 

 described by Fewkes, 1883, as being in association with Cassiopea at Fleming's Key, near 

 Key West, Florida. 



Genus DENDRONEMA Haeckel, 1879. 



Dtmlronema, HAFCKEL, 1879, Syst. der Metlusen, p. MO. GUNTHER, 1903, Mitth. Zool. Sta. Neapel, Bil. 16, p. 57. 



The only known form is Dendronema styludendron Haeckel, from the Canary Islands, 

 Atlantic Ocean. 



GENERIC CHARACTERS. 



Cladonemidae with branched oral tentacles and branched marginal tentacles, the 

 branches ending in nematocyst-knobs or adhesive disks, or both. With bifurcated radial- 

 canals. Gonads in the stomach-wall. 



There is an apical cavity above the stomach, but we do not know whether this is a mere 

 extension of the stomach itself, or a reproductive sac similar in anatomy to that of Eleutkena. 



Dendronema stylodendron Haeckel. 



])?rnlionetiiti st \lrjiletidT on, HAVCKKL, 1879, Syst. iler Medusen, p. no, taf. 7, fi^. 8. 



Bell miter-shaped, with pointed conical apex. 9 mm. high, 6 mm. wide. Stomach spindle- 

 shaped. There are apparently 4 radially placed oral tentacles each of which branches dichot- 

 omously 6 to 7 times and terminates in (50 to 60) nematocyst-knobs in each quadrant. 

 Haeckel's description is, however, vague upon this point. Haeckel states that there are 4 egg- 

 shaped "gonads" on the 4 perradial sides of the stomach. These may, however, be homol- 

 ogous with the protuberances seen in Cladonema ( ?) HaeckePs figure shows them distended 

 with ova. 4 principal radial-canals, 90 apart, leave the stomach and bifurcate so that 8 

 vessels reach the ring-canal 45 apart. There are 8 marginal tentacles, one at the base of each 

 radial-canal. There is an ectodermal abaxial ocellus at the base of each tentacle. Each ten- 

 tacle gives off a stout, short branch on its inner (velar) side, .and this branch bifurcates twice 

 and terminates in 4 nematocyst-bearing, knob-like "suckers," or adhesive organs. The main 

 shaft of the tentacle also branches dichotomously many times and is besprinkled with nettling 

 warts, and the ends terminate in large knobs. There is a spindle-shaped cavity in the apex 

 of the bell, above the stomach, but its anatomical character is unknown. The mouth, stomach, 

 apical cavity, and gonads are reddish-yellow. Tentacles, radial-canals, and ring-canal brown- 

 ish-red. Ocelli black. 



This medusa was found by Haeckel in the Canary Islands, Atlantic Ocean, in February, 

 1867. 



Family OCEANIDjE, sens. Vanhoffen, 1891. 



OeeaniiLr (in part), ESCHSCHOLTZ, 1829, Syst. der Acalephcn, p. 96. FORBES, 1848, British Naked-eyed Medusa-, p. 21. 



GEGENBAUR, 1856, Zeit. fur wissen. Zool., Bd. 8, p. 219. 



Tiarid.e+ Margt'lid l p + Cannotidtf (in part), HAECKEL, 1879, Syst. der Medusen, pp. 40, 68, 1^6-159. 

 Ocrnniiir, VANHOFFEN, 1891, Zool. Anzeiger, Bd. 14, p. 443. 



FAMILY CHARACTERS. 



Anthomedusa? with 4, or 4 pairs of, isolated gonads upon the interradial or adradial sides 

 of the stomach. The marginal tentacles may arise singly or in clusters, but are neither 

 branched nor feathered. 



The Oceanidae constitute the third family of the Anthomedusae, and they are more com 

 plex and more highly differentiated than the simple and more primitive Codonidae. 



