No. 5.] VARIATION AMONG HYDROMEDUSAE. 223 



distortion in the process, whereby minute variations of organs 

 often became difficult of detection, yet I was able to demon- 

 strate a fair degree of constancy in the general form of the 

 medusa, its radial canals, tentacles, etc. I desire to direct 

 attention to the number of tentacles. As stated by Agassi/, 

 there seems to be a single long tentacle arising from the mar- 

 gin of the bell at the terminus of one of the radial canals, from 

 the base of which arose later the proliferous medusae-buds, as 

 shown in the figure already cited. From these secondary medu- 

 sae other tentacles arose, giving to them the exact morpho- 

 logical equivalent of the primary or mother medusa. Hence, as 

 several of these proliferous specimens budded off from the 

 base of the primary tentacle, several tentacles would come to 

 be clustered near the same point, giving the impression of a 

 bunch of tentacles of the same nature. In several specimens 

 in which the medusae-buds had not yet appeared, or could be 

 detected as mere papilla-like bodies, these secondary tentacles 

 were nevertheless well developed, and of a length frequently 

 equal to that of the primary, one. Now whether this be a 

 variation, or whether it may not be rather fundamental, aris- 

 ing as a source from which the medusae are to spring, may 

 perhaps be an open question, to be settled by a more critical 

 examination of their development. Proceeding on the assump- 

 tion before stated, I venture to cite it as a case of varia- 

 tion, though it may later be found to be rather the normal 

 process. 



The rather unusual character of this medusa, both in its 

 origin and proliferous progeny, led me to suspect that it might 

 exhibit more than the usual phases of variation ; but in this I 

 have been disappointed, except in the point just cited, - - its con- 

 stancy in almost every morphological detail being quite marked. 

 As stated, however, in connection with observations upon 

 Coryne, the limited number of specimens examined, and further- 

 more their distortion due to preservation, are barriers which 

 should suggest reasonable caution in the formulation of any 

 conclusion. 



Pennaria. - - Of this medusa I have had an almost unlimited 

 number of specimens, having collected them during three 



