NARCOMEDUS.E — SOLMISSUS. 



483 



Fig. 324. — Solmissus albescens, after Gegenbaur, 

 in Zeit. fur wissen. Zool., Bd. 8. 



Bell flat, lenticular, 25 to 30 mm. in diameter. The central part of the bell is a doubly 

 convex lens, quite thick at the center, whereas the bell-collar is thin, flexible, and contractile. 

 The exumbrella over the collar region is thickly besprinkled with pnckle-like tubercles and 

 with flat, discoidal nematocyst-warts. 



There are about 14 to 16 marginal lappets and an equal number of tentacles which alter- 

 nate with these lappets. When expanded, each lappet is nearly rectangular, but with rounded 



angles on its outer margin; and it is about 

 1.5 times as long as it is wide. They can, 

 however, contract so as to become some- 

 what wider than they are long. There are 

 5 to 8 sensory-clubs on the margin of each 

 lappet. There are neither otoporpae nor 

 exumbrella sensory tracts above the 

 sensory-clubs. Each sensory-club is short 

 and widens outwardly, with a cup-shaped 

 entodermal cavity in its outer end within 

 which there is a vesicle containing a 

 spherical concretion. Theouterhalf of the 

 sensory-club bears sensory bristles. 



The annular velum is broad and has 

 powerful circular muscles. The 14 to 16 

 tentacles are each nearly as long as the 

 bell-diameter. They taper gradually from 

 the sides of the bell to their tips and are 

 not very flexible, bending commonly only 

 near their bases. The central stomach is 

 a wide space with a very widely-gaping, 

 circular mouth-opening. The convex lower floor of the central disk projects downward into 

 the stomach-cavity; and indeed the stomach-wall simply forms an annulus around it, the 

 mouth being constantly open. The marginal stomach-pouches are pentagonal in shape and 

 somewhat wider than they are long. Their outer angles lie under the roots of the tentacles. 

 Sections stained in Delafield's haematoxylin show there is no marginal canal-system. The 

 gonad is developed over the subumbrella ectoderm of the stomach-pouches and stomach. 



The gonads and tentacles are slightly milky in color, the concretions are garnet-red, and 

 all other parts are colorless. 



This medusa is quite common in the Mediterranean, having been found frequently at 

 Naples and Messina. 



The dimensions, in mm., of a specimen studied by me at Naples are as follows: Diameter 

 of bell, 28; width of central stomach, 18.5; width across stomach and stomach-pouches, 22.5; 

 tentacles 25 ± long. (See text-figures 325 and 326.) 



Solmissus incisa Bigelow. 



Salmarh incisa, Fewkes, 1886, Report Commiss. Fish and Fisheries U.S. A. for 1884, p. 954, plate 9; 1889, Ibid., p. 529.— Maas, 



1893, Ergeb. der Plankton Expedition, Bd. 2, K. c, p. 47. 

 Solmissus incisa, Billow, H. B., 1909, Mem. Museum Comp. Zool. at Harvard College, vol. 37, p. 67, plate 21, figs. 1-3, 5. 



Bell 75 mm. wide, flat, exumbrella smooth. Gelatinous substance very soft and thinner 

 than in .9. marshalli. 18 to 32 stiff, tapering tentacles, longer than the bell-diameter. Not 

 more than 2 to 5 sensory-clubs per lappet. Clubs similar to those of S. albescens. Tropical 

 Pacific and Atlantic Gulf Stream. Distinguished from S. marshalli by its soft, gelatinous 

 substance, fewer sense-clubs, and greater number of tentacles. It is possibly identical with 

 S. faberi and S. bleeki of Haeckel. 



Solmissus faberi Haeckel. 



Solmissus jaberi, Haeckel, 1879, Syst. der Medusen, p. 350. 



Bell lenticular, biconvex, 20 mm. wide and 7 mm. high. 24 tentacles hardly as long as 

 bell-radius. 72 sensory-clubs without otoporpae. 3 on each bell-lappet; the 24 lappets form a 



38 



