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PROCEEDINGS OF THE 



[April, 1857. 



acter. The tentaculiform individuals are probably of three sizes, 

 as described by Gluatrefages ; but, the transparent ones of the 

 smallest size described by Gluatrefages, were either entirely ab- 

 sent from the specimens I have examined, or so injured as to 

 make it impossible to obtain any reliable result from their exami- 

 nation. Those which I have called above the greater tentaculi- 

 form individuals are of two sizes and bear each on one side a row 

 of elongate transversely arranged pads of netting cells, which 

 being highly colored give a colored appearance to the organism. 

 They are of cylindrical form, and of two sizes differing in diame- 

 ter. Contrary to what it would seem natural to expect, the pads 

 of thread-cells are relatively more numerous and crowded on the 

 greater than on the smaller individuals, and the former, at least, if 

 not the latter, are so extensile, as to be capable of acquiring a 

 length of three feet and probably considerably more in large spec- 

 imens; in addition to this I have reason to believe that, all these 

 tentaculiform individuals in my specimens had been considerably 

 curtailed in their normal length by the rough usage to which they 

 had been subjected. It is possible, therefore, that a perfect speci- 

 men floating freely in the water may have these individuals some- 

 times outstretched to the length of five or six feet. 



The sexual medusae are, as has been said, arranged in grape- 

 like clusters of a full rounded form. They seem to be always at 

 the extremities of the branches of the digestive trunk of the basal 

 medusa, but in the specimens examined when uninjured, they 

 appeared usually to be carried close under the bladder, though in 

 one instance, a cluster hung nearly an inch lower than usual, 

 making it inferable that the stems which bear appendages are 

 contractile. The sexual individuals in one and the same cluster 

 are of three forms and sizes. The smallest which are nearest the 

 main stem, are of a round form, and appear to be composed of an 

 outer homogeneous transparent uncolored envelope, correspond- 

 ing to the bell-wall of a perfect medusa, and within is a round 

 colored sexual organ, in course of development. The second 

 size are the most numerous and occupy the greater portion of the 

 ramifying stems of the cluster. Their longitudinal diameter is 

 decidedly greater than that even of the third size, to which be- 

 longs the most highly developed medusae in the community. They 

 are thus of a much elongated ellipsoid form, and contain within 

 what is probably a prolongation of the nutritive canal of the stems, 

 representing in them the digestive trunk of a free medusa. The 



