82 ACALEPIIS IN GENERAL. Paut I. 



several pendent 3Ic(hiS((iia. The dinerent genera ol' the family ma}' then be 

 characterized In' the peenliarities ol' tlieir Ilydnv and of their Medusie. The Cam- 

 panuhtri((iis as a family may ))e described as II//Jraria with two kinds of IL/ilrce : 

 some being sterile and more nnmerons, while others are fertile and produce Medusna 

 from their prol)oscis. The diil'erent genera may easily Ijc distinguished Ijy the 

 peculiarities of the two kinds of Ilydra^, as well as by their Medusa\ Similar 

 differences exist among the Si})hono[)hora'. The Vclclliihv are simply Ilijih-ana arising 

 from a single IL/dra which grows larger and larger until it produces other Ili/clrw 

 of a diflerent form, and from these single Medusae buds spring forth and finally 

 free themselves. The P/i//S(i//(hc, on the contrary, are IT//dro-3L'Jusaj-k(, arising, like 

 the At'lellida', from a single Ih/dru, which also grows larger and larger, and even 

 acquires an enormous size, forming in the end the large swinnning-bag, from which 

 single additional Ilydra^ at first arise, and afterward a larger and larger number, 

 forming sexeral distinct IL/draria suspended from the original eidarged Hydra. These 

 Hydraria themselves consist of heterogeneous Hydra, though of Hydras only. Others 

 produce 2L'dtimria, and thus become IL/div-Mcduxai'ia ; so that a Physalia community 

 is reall}' made up of many heterogeneous communities attached to a gigantic 

 Hydra. The Dljihyida' are also IL/dro-3Icdnsi(riii, Init of a Acry different kind from 

 those of the Physalida\ Here the community Ijegins with a medusoid individual, 

 from which arises another Medusa, thus forming Medusa^ twins. This twin community 

 produces a stiiug of medusoid Ilydi'oids, from each of which arises another kind of 

 Medusa-, in close connection with tlieir Hydroids, thus forming secondary twin com- 

 munities, each of which consists of a medusoid Hydra and a genuine Medusa. In 

 the I'lii/sophoridic, the comliinations are still dilferent. The connnuuity constitutes 

 also ;i Ihidro-Medmarium ; Ijut it arises fronr a single ILfdra, from the ujnier part 

 of whicli laid sterile 3It'dusa\ while other Ilijdnc arise from its lower part, between 

 which, finally, a. iiumber of Mcdimu-la make their aj^pearance. 



As soon as it is conceded that the so-called sexual organs of the Siphonophora! 

 are themselves individual animals provided with ovaries and spermaries, there is no 

 possiljility of avoiding the conclusions presented in the ju'cceding paragraphs 

 respecting the structural constitution of the Acalephs, and the close aftinity of the 

 Siphonophora' and Hydroids proper becomes very striking. For, notwithstanding 

 the extraordinary diversity of the Ibiiu of these animals, there are, properly speaking, 

 only two kiuils of individuals among them: the stei'ile ones, for which the name 

 Illjdnv is most ap[iropriate ; and the fertile ones, which we may best call Mi'dnsa\ 

 I must, however, (jualily this statement somewhat, in order to avoid every possible 

 misapprehension. There are fertile Ilydra^ if the production of Ijuds constitutes 

 fertility, for most Hydra^ ])roduce Medusa^ buds; but Hydne are themselves desti- 

 tute of sexual organs, there being neither males nor females among them ; and 



