GONIONEMUS VERTENS. 



129 



disk touches the top of the water, the Medusa mverts itself, and sinks, 

 with its tentacles full.y expanded, until it reaches the bottom, or an- 

 other piece of sea-weed, where it attaches itself, and after remaining 

 suspended a little while, repeats the same operation ; when attached, 

 it requires strength enough to break the tentacles to make them loose 



their hold. I have never found single individuals, but have always 

 seen them in large numbers swiuaming among the sea-weed in the 

 manner described. The form of the spherosome is that of an oblate 

 spheroid, cut in two by a plane passing through the north and south 

 poles, the plane of intersection containing the circular tube ; there are 

 sixty-four tentacles, fifteen between each chymiferous tube, placed so 

 closely together that they seem all to unite at the Fig. i98. 



base. The tentacles, when contracted, resemble a 

 scythe fastened by a band to the circular tube 

 (Fig. 199) ; the pigment-cells are numerous, and 

 give the circular tube the appearance of having 

 a large row of violet knobs, to which the tentacles 

 are attached. There is one part of the tentacle, 

 near the tip, which seems to be more thickly cov- 

 ered by lasso-cells, and by which the Jelly-fishes 

 attach themselves ; when the tentacles are fully 

 expanded, they always make an angle at that point, as if they had 

 been broken, and the parts joined together again. (Fig. 197.) The 



Fif;. 1!)7. (Jonioni'iims vcrtons, as it appears wlicii attached by its teutacles. 

 Fig. 198. Gonidiicmvis vurtuns, in motiou ; uaturul sizu. 

 NO. ir. 17 



