104 THE MEDUSAE. 



in addition eight adradial tentacles which are single. Each tentacle group 

 consists of two members, rising side by side from a single bulb (PL 30, 

 figs. 7-9) ; one about as long as the bell diameter, ringed with nettle cells, 

 solid, arising from the surface of the exumbrella some distance above the 

 actual margin, and connected with the ring canal by an endodermic root 

 just as are the exumbral tentacles of Olindias, with a nettle cluster at the 

 tip,- but no sucking disc (PI. 30, fig. 6) ; the 6ther is so short as to be hardly 

 more than a spur, and arises directly from the nematocyst pad. It shows, 

 however, the earliest stages in the development of nettle rings, and bears 

 at its tip a nettle pad, clearly visible in the photographs. Alternating with 

 these eight groups are eight simple tentacles, resembling in structure the 

 large members of the tentacle groups, though smaller than the latter. 

 Finally, alternating with these sixteen tentacles and groups are sixteen 

 swellings or papillae clearly seen in the photograph (PL 30, fig. 2). In 

 G. corynetes, according to Haeckel ('79), there are the same number of 

 groups of tentacles, i. e. eight ; but each contains three nearly equal 

 members, while Gosse's figures of younger specimens show three, two large 

 and one very small. It is evident, then, that the full number is not attained 

 until an advanced stage in development is reached. The single adradial 

 tentacles evidently correspond to the adradial cirri of O. corynetes, but are 

 much larger. The latter species appears to lack the rudimentary bulbs or 

 papillae seen in the present specimen. If Haeckel's ('79) account be 

 correct, another important difference between the tw^o species is in the 

 structure of the tentacles, for while he describes them as hollow in 

 G. corynetes, in the present species they are solid, with a core of chordate 

 endoderm cells (PL 30, fig. 10). 



Otocysts. — In spite of the good condition of the specimen I am unable to 

 give any account of the otocysts. Most careful search with the microscope 

 failed to reveal any on the bell margin, although both Gosse ('53) and 

 Haeckel ('79) agree that in G. corynetes two or three otocysts occur on the mar- 

 gin between every two groups of tentacles. In the present species, however, 

 they appear to be replaced by the rudimentary tentacular papillae, which are 

 solid and bear no resemblance to sense organs. In one case I distinguished 

 near the base of one of the primary members of a tentacle group what ap- 

 pears to be an otocyst (PL 30, fig. 5), so that, although I was unable to find 

 any in connection with other tentacles, it is not unlikely that the otocysts in 

 this species occupy the same position that they do in Olindias. 



