98 MEDrS.E (IF THE WORLD. 



It has been rescued from scientific oblivion through an able paper by Giinther, 1903, who 

 has carried out an elaborate study of its anatomy, life-history, and variations. 



The characters of the medusa are those of the genus of which it is the sole representative 

 (see genus Mnestra). 



Fewkes, 1884, describes this medusa upon Ph\lhrhoc on the Florida Reef. It is com- 

 mon at Naples and Messina, Mediterranean. 



Genus CTENARIA Haeckel, 1879. 



Clenaria, HAECKEL, 1X79, Syst. der Medusen, p. 107. GUNTHER, 1903, Mittheil. Zool. Sta. Nrapel, Bd. 16. p. 57. HARTLAUB, 

 1907, Nordisches Plankton, Nr. 12, p. 24. 



The type species is Ctenaria ctenophora Haeckel, from the coast of japan. This is the 

 sole representative of the genus, and Haeckel had but a single preserved specimen. 



GENERIC CHARACTERS. 



Cladonemidae with 4 bifurcated radial-canals. With 2 feathered marginal tentacles and 

 simple, unbranched, oral tentacles. There are 8 adradial, meridional lines of nematocysts 

 over the exumbrella, and a nematocyst tract above the base of each marginal tentacle. 

 Gonads on the sides of the stomach. There is an apical cavity above the stomach, but it is 

 not known whether this is an ectodermal brood-pouch, as in Eleutheria, or a mere extension of 



the stomach-cavity. 



Ctenaria ctenophora Haeckel. 



Ctenaria cttnttphora, HAECKEL, 1879, Syst. der Medusen, p. 108, taf. 7, figs. 5-7. HARTLAI-B, 1907, Nordisches Plankton, 

 Nr. 12, p. 126, fig. 119. 



Bell three-fourths-egg-shaped; 6 mm. high, 5 mm. wide. (Fig. 52.) Widest in a zone 

 slightly below the middle. 8 adradial lines of nettling cells extend up the sides of the 

 exumbrella from the margin nearly to the apex, and in addition to these there are 1 large 

 club-shaped clusters of nematocysts extending from the bases of the 2 tentacles half-way up 

 the sides of exumbrella. 



The tentacles are each 2 to 4 times as long as the bell-height and they taper gradually 

 from base to tip. There are no basal ocelli. A row of numerous, slender filaments arises from 

 the abaxial side of each tentacle. These filaments superficially resemble those of Ctenophorae, 

 and do not end in nematocyst capsules as in Zanclea. They are, however, covered with nema- 

 tocysts throughout their lengths. 



The velum is well developed. 4 main radial-canals arise from the stomach, but these 

 bifurcate so that 8 canals join the marginal circular vessel in the 8 adradii. The edges of these 

 radial-canals are serrated, being apparently beset with glands. 



The stomach is almost spherical and about half as long as the depth of the bell-cavity. 

 There are 16 short, simple, oral tentacles, each of which ends in a nematocyst-knob. 



Haeckel describes 4 swollen, radially placed gonads on the sides of the stomach, but 

 these are probably adradial or interradial ( '.) There is a well-developed apical cavity above 

 the stomach, but it is not quite clear whether this is a brood-sac homologous with that of 

 Eleutheria or whether it is simply an apical extension of the stomach. Haeckel supports the 

 latter view, but he made no sections, and the point can not be considered as determined. 

 Color ( ?) 



Haeckel describes this medusa from a single alcoholic specimen from Japan. 



Genus CLADONEMA Dujardin, 1843. 



Cladoncma, Dl'jARDlN, 1843, Anna!, des Sci. Naturelles, tome 20, p. 370. KROHN, 1853, Muller's Archiv. fur Anatomie und 

 Physiologic, p. 420. GEGENBACR, 1856, Zeit. fur wissen. Zoo]., Bd. 8, p. 230. VAN BENEDEN, 1866, Fauna Littor. 

 Belgique, p. 139. HINCKS, 1868, British Hydroid Zoophytes, p. 62. ALLMAN, 1871-72, Monograph Tubularian 

 Hydroids, pp. 216, 357. HAECKEL, 1879, Syst. der Medusen, p. 109. PERKINS, 1902, Johns Hopkins University Circu- 

 lars, No. 155, p. 21;, 1908, Papers from Tortugas Laboratory Carnegie Institution of Washington, vol. I, p. 136. 

 HARTLAI-B, 1887, Zool. Anzeiger, Bd. 10, p. 654; 1907, Nordisches Plankton, Nr. 12, p. 131. GUNTHER, 1903, 

 Mitt. Zool. Sta. Neapel, Bd. 16, p. ^7. 



Stauridium cladontma (hydroid), or PLESSIS, 1888, Recueil Zool. Suisse, tome 4, p. 536. 



GENERIC CHARACTERS. 



Cladonemidae with 4 or 5 or more bifurcated radial-canals or 8 to 10 or more simple 

 canals, or with some bifurcated and some simple canals. With 8 to 10 or more tentacles which 



