Fariations Among ScyphojneduscB. 577 



His most remarkable observations are concerned with the 

 marginal lobes and sensory bodies of the ephyrae. He finds 

 these to vary in number from eight, the normal, to twenty-four. 

 While this extreme of variation is large it is not, however, improb- 

 able. The most remarkable feature of the case is the interpreta- 

 tion which Lendenfeld gives. He claims that during metamor- 

 phosis these larvae pass from the ordinary condition of octamerism 

 through stages of, first twenty-four, later sixteen and finally 

 emerge to the adult stage with the normal eight-merous condition. 

 "So habe ich gefunden, dass die Ephyren von Phyllorhiza punctata 

 acht, spatere Stadien vierundzwanzig, noch spatere sechzehn und 

 endlich die ausgebildeten Medusen wieder bloss acht Randkorper 

 besitzen." 



Though it is not expressly claimed that these phenomena are 

 involved in the observed ontogeny of these medusae, it is neverthe- 

 less, clearly implied. If this inference be correct then the results 

 must be accepted unless other observations may serve to discredit 

 the account given. If, on the other hand, as I am strongly inclined 

 to believe, these several stages have been observed in connection 

 with the general phases of metamorphosis such as one might find 

 among a given series of larvae, then the conclusion I should incline 

 to draw is that these phenomena are but larval variations similar 

 to those described in the earlier portions of this paper. Moreover, 

 when we are farther advised that these peculiar variations are due 

 to injuries the suspicion is still greater that the observed variations 

 are not normal processes during metamorphosis, but in fact, true 

 variations as above suggested. 



Furthermore, my own experiments upon regeneration in 

 Rhizostoma {op. ci't.), would seem to preclude the factor of injury 

 as of any importance in relation to variation. In these experi- 

 ments there was not the slightest evidence to support the view pro- 

 posed by Lendenfeld. We may, therefore, accept these instances 

 as but further extension of our knowledge of the wide prevalence 

 of variation among the Scyphomedusae, which the more critical 

 attention given to the subject during the past few years has brought 

 to light. 



FOSSIL MEDUSA. 



It will not be without interest in this connect'on to call attention 

 to the occurrence of variations among fossil medusae. In a recent 



