380 



MEDUSiE OF THE WORLD. 



smaller tentacles are adradial and only about half as wide and as long as the other tentacles. 

 They are stiff and their outer ends are club-shaped and bear a ring of long, stiff bristles. The 16 

 lithocysts, near the bases of the adradial tentacles, are closed marginal vesicles, each contain- 

 ing a pear-shaped sensory-club, with a single spherical concretion. Velum- narrow. The 8 

 radial-canals and the ring-canal are quite wide and are simple and straight-edged. 



The most characteristic feature of this species is the great length of the stomach, which 

 is about 1.5 times as long as depth of bell-cavity. It is narrow, cylindrical, and has 4 large, 

 bluntly-rounded lips. The gonads are developed upon the middle points of the 8 radial- 

 canals and are restricted to the middle one-fourth to one-third of each canal. These gonads are 

 spindle-shaped and are developed upon both sides of each canal. Males only were found by 

 Haeckel. The medusa is glassy and colorless. Found in the Mediterranean, Sea of Marmora. 

 (See text-figure 220.) 



Rhopalonema coeruleum Haeckel. 



( ?) Dianaa juneraria, Quoy et Gaimard, 1817, Annal. des Sci. Nat., tome 10, plate 6, figs. 10-15 ( an abnormal specimen with 

 7 canals). 



Rhopalonema casruleum, Haeckel, 1879, Syst. der Medusen, p. 264, taf. 17, fign. 3-6.— Maas, 1905, Craspedoten Medusen der 

 Siboga Expedition, Monog. 10, p. 51, taf. 10, fign. 67, 68. — Browne, 1906, Trans. Linnean Soc. London, ser. 2, Zool., 

 vol. 10, p. 172; Fowler, Ibid., p. 182. 



(?) Rhopalonema funerarium, Maas, 1904, Result. Camp. Sci. Prince de Monaco, fasc. 28, p. 28. 



Rhopalonema funerarium, Vanhoffen, 1902, Wissen. Ergeb. deutsch. Tiefsee Expedition, Dampfer Valdivia, Bd. 3, Lfg. 1, 

 p. 61, taf. 9, fig. 2; taf. 10, fig. 17; taf. 11, fig. 31.— Bigelow, H. B., 1909, Mem. Mus. Comp. Zool. at Harvard Col- 

 lege, vol. 37, p. 132. 



Bell 17 mm. wide, 14 mm. high. Walls moderately thin, thicker at apex. 8 radial- 

 canals. 16 tentacles: 8 radial, 8 interradial. 16 adradial cirri and 32 marginal lithocysts at 

 equal distances between the tentacles and cirri. Stomach short, with 4 simple lips. 8 elongate, 



Fig. 218. — Rhopalonema velatum. A, mature medusa; B, enlarged view of half-grown medusa; C, sensory-club within its 

 wall-like capsule; D, part of tentacle; E, cunina larva ectoparasitic on subumbrella of Rhopalonema. From life, 

 by the author, Naples Zoological Station, December, 1907. 



