TRACHYMEDUS/E — GONIONEMUS. 349 



very contractile, and are armed with many incomplete, ring-like nematocyst-warts. Near the 

 outer end on the inner side of each tentacle is a prominent, elliptical, adhesive pad composed 

 of thickly-crowded, long, cylindrical, ectodermal cells. Beyond this adhesive pad the tip 

 bends sharply at an angle with the main shaft of the tentacle. 



On the margin, close to the base of the velum, there are basal bulbs which correspond both 

 in number and position to the exumbrella tentacles. These basal bulbs are believed by Goto 

 to be homologous with the flexible, hollow, marginal tentacles of Olindias and Olindioides. 

 Their ectoderm is clogged with developing nematocysts, and their entoderm consists of simple, 

 hollow prolongations of the cavity of the ring-canal. There is a pair of lithocysts, each with 

 one concretion at the base of each of the exumbrella tentacles. The lithocysts are thus twice 

 as numerous as the tentacles. They are small, closed vesicles, buried in the gallert near the 

 outer nerve-ring on the outer side of the ring-canal. 



The manubrium is quadrate, without a peduncle, and has 4 simple, unf ringed lips which 

 are at about the level of the velar opening. There are 4 radial-canals and a simple ring-canal 

 without centripetal diverticula. The 4 gonads are developed upon nearly the entire lengths 

 of the 4 radial-canals and are simple, linear thickenings which, being longer than the canal 

 upon which they develop, are sinuously folded from side to side of the axial line of the radial- 

 canal. This medusa may eventually prove to be identical with G. agassizii (see fig. 198.) 



The radial-canals, basal bulbs, and adhesive disks of the tentacles are translucent chestnut 

 brown. Tentacles, gonads, circular canal, and the larger part of manubrium are lighter brown. 

 Mouth pale-green. At the base of each tentacle there is a speck of brilliant emerald-green. 



Found among the eelgrass around the wharves of Yokohama, Japan. Its habits appear 

 to be identical with those of G. murbachti. It is beautifully figured and elaborately described 

 by Goto. 



Gonionemus suvaensis Agassiz and Mayer. 



Goriioneinus suvaensis, Agassiz and Mayer, 1899, Bull. Mus. Comp. Zool. at Harvard College, vol. 32, p. 164, plate 5, figs. 



14-16. — Bigelow, H. B., 1909, Mem. Museum Comp. Zool. at Harvard College, vol. 27, p. 107, plates 3 and 32. 

 Gonionemus pelagicus, Bigelow, H. B., 1904, Bull. Mus. Comp. at Harvard College, vol. 39, p. 256, plate 4, figs. 12-14. 



Bigelow, 1909, whose opportunities for the study of the Pacific species of Gonionemus 

 far exceeded those of any other observer, has decided that G. suvaensis, G. pelagicus, and 

 G. hornelli are only local varieties of one and the same species of medusa which is char- 

 acterized by having but 16 lithocysts and by its gonads being confined to short lengths on 

 the outer ends of its radial-canals. 



Bell 8 to 20 mm. wide, flatter than a hemisphere, with only moderately thick walls. 

 About 50 to 80 stiff", sucker-bearing tentacles not quite as long as the bell-radius. These ten- 

 tacles all project from the exumbrella side of the margin and their distal tips bend sharply at 

 right angles to shaft of tentacle. 16 freely projecting marginal lithocysts, each containing 

 a single concretion; 4 of these lithocysts in each quadrant. Velum well developed. There 

 are 4 straight radial tubes, upon the -lower portions of which, near to the circular tube, the 

 gonads are situated. The gonads are folded in a sinusoidal curve alternately to the right and 

 left of the radial tube, resembling those of Gonionemus mwbachit. Manubrium cruciform in 

 cross-section, the lips prominent. 



Green pigment-spots are found in the ectoderm of the basal bulbs of the tentacles and 

 upon the radial tubes close to their junction with the stomach. Entoderm of radial tubes in 

 region of gonads tinged with green. The ectoderm of bell-margin is of a delicate rose-color, 

 manubrium and gonads brown in specimens from the Fiji Islands, but in Bigelow 's medusae 

 from Suvadiva Atoll, Maldive Islands, Indian Ocean, the manubrium and tentacles were 

 yellowish-green, with Vandyke-brown pigment at the bases of the tentacles. Gonads rose- 

 pink. In 12 specimens found by Bigelow in Mangareva Harbor, Paumotos Islands, the 

 tentacles and tentacle-bulbs are pale yellowish, without green pigment, and the gonads 

 brownish-red. (See text-figures 199 and 200.) 



The medusa is evidently widely distributed, although only locally abundant, and may 

 be considered as the tropical Pacific Gonionemus where it occurs in coral lagoons or in 

 the sea near land. 



This medusa was common in Suva Harbor, Fiji Islands, late in December, 1897. 



