tions, but cases of somewhat easily misunderstood metamor- 

 phosis. Such, for exami'le, v/as the case of Liriope, which 

 has been studied by Metschnikoff (1874) and Brooks (1886). 

 T?ie larva is a true hydra, although its free swimming mode 

 of life and its siiperficial aspect caused it to be mistaken, 

 formerly, for a gonosome. 



My investigations of a jelly-fish which Haeckel in- 

 cludes in his order "Trachomedusae" show that the first part 

 of Haeckel's statement also requii-es revision, and that 

 metagenesis does occur in the "Trachomedusae". Although 

 there may bo some differ*ence uf opinion as to the exact 

 definition of the terms "metagenesis" and "hypogenesis" ,the 

 following notion of the process of alternation of genera- 

 tions !nay be safely acr-epted as tliat generally held. The 

 prodTzction by a lai-va of offspring unlike itself, and its 

 own ultimate death without undergoing metamorphosis, are 

 frequent accompaniments of the intermediate as of the pri- 

 mary process of multiplication; but they are by no means 

 essential to the process of metagenesis or alternation of 

 generations. Creatures which multiply sexually at one 

 point of their life-history, and at another point nonsex- 

 ually by budding or fission, are said to have a metagenetic 

 development. In Gonionema (Figs. 3 - 23) a large number 

 of adult individuals are produced from a single egg through 



