EEPORT ON THE SIPHONOPHOR^E. 101 



directly into Cucubalus eschscholtzii ( = Eudoxia eschscholtzii), the monogastric generation 

 of Muggisea kochii. 



Scarcely different from this is the ontogeny of another Monophyid [Cymbonectes 

 huxleyi (PI. XXVII. figs. 8-11), which I observed in December 1881 during my residence 

 at Belligeinma, in Ceylon. The Calyconula here presents distinctly the character of a 

 bilateral Medusa, through the ventral fissure of which the siphon was protruded ; its 

 distal end opens through the mouth rather early. Its similarity to the young Eudoxia of 

 the same species is interesting. 



Metamorphosis. — All Calyconectse seem to undergo a metamorphosis, since the 

 gastrula, developed from the fertilised egg, develops into a larva differing more or less 

 considerably from the adult state. But the metamorphosis of the larva is very Httle 

 known, and has been observed in a few species only. Chun, who has observed accurately 

 the metamorphosis of some Monophyidse and Diphyidse (86-88), holds the opinion that 

 the primary umbrella of the medusiform larva is always lost and replaced by a hetero- 

 morphous secondary umbrella. More extended researches are required to prove whether 

 this supposition is generally true. 



Metagenesis. — The majority of Calyconectae are subject to a regular metagenesis, two 

 different generations alternating regularly, as in the majority of the AnthomedusEe. The 

 first generation is a monogastric and sexually developed cormidium — Eudoxia or Ersaea. 

 From its fertilised egg arises a larva, which is transformed by metamorphosis into the 

 second generation — Monophyid or Diphyid. Its body is a polygastric corm, the tubular 

 stem of which produces numerous cormidia by budding asexually. Each cormidium, 

 provided with a single siphon, afterwards becomes detached from the stem, and maturing 

 as a Eudoxid or Ersseid returns to the first generation. 



Hypogenesis. — -The minority of Calyconectse develop by hypogenesis (not by 

 metagenesis) ; the cormidia arrive at full sexual maturity whilst sessile on the common 

 stem, and are not detached from the latter. There is here, therefore, no free and 

 independent monogastric generation ; neither free Eudoxidae nor Ersasidse arise. The 

 ontogeny of these polygastric corms is in a strict sense a strophogenesis. 1 



The Calyconectse which are developed by hypogenesis are the following : — All the 

 Polyphyidas and Desmophyidse, some Diphyidae (Galeolaria, Lilyopsis, and Praya ?) and 

 several Monophyid* (Monophyes partly ?, Mitrophyes, and Cymbonectes). All the 

 other Calyconectse develop by metagenesis. There seem to be, however, some inter- 

 mediate forms of ontogeny, in some species the male gonophores becoming detached, 

 whilst the females remain attached to the stem, or inversely. These relations, as well as 

 the whole ontogeny of the Calyconectae, require further accurate examination. 



1 On the difference between metagenesis and strophogenesis, see my Generelle Morphologie, 1866, Bd. ii. pp. 104-109, 

 and on Hypogenesis, op. cit., p. 99. 



