Chap. II. THE DIFFERENT RADIATA. 55 



protected by a flattened, scale-like, gelatinous body {Fig. 37 a a), and between the 

 scale and the Polyp hangs a complicated tentacle, c d. These 

 individuals I consider to be identical with the Hydroids of 

 the Physalia, the so-called Polyp representing the proboscis, as 

 we oljserve it in Coryne and Clava, only that each is pro- 

 vided with a single tentacle and surrounded by a protecting 

 scale. Now, if I am not greatly mistaken, that protecting 

 scale must be considered as a sort of bell, analogous to that Two twin individuals of the 



. . . , pendent string of the com- 



of Campanularia, but gelatinous, and split open on one side ; munity of 



1 ., n n 1 / TT o^- \ i> il 11 1 DlPHYES SlEBOLDII, KijU. 



and the so-called sexual organs (-tie/, di hi) ot these so-caiieu „, , ^^^^ 



O \ <J I an Thcso-calleilscales. — S6 The 



Polyps are genuine Medusae buds, with a proboscis, four radi- so.caiied Poiyps. - m iheso- 



•^ -L o ^ i. -' called sexual capsule. — c Ex- 



atina; tubes, and a circular tube, with a diaphragm around the tcmai feder. «ith lasso ceiis. - 



^ ^ ^ i- ^ d Feeler contracted. 



I'im, exactly as in naked-eyed Medusa^, producing eggs or sper- 

 matic cells upon the proboscis, according to the male or female character of 

 the different individuals, exactly in the same manner as in Sarsia or Hippocrene. 



We have, then, in a Diphyes community, three kinds of individuals.^ First, 

 one or two, or sometimes three, Medusoid individuals at the base of the stock ; 

 secondly, a large number of more Hydroid-like individuals hanging connected with 

 the pendent string, but differing from the common Hydroids in having an open, 

 gelatinous, somewhat Medusoid bell, commonly called scale ; and, thirdly, arising 

 from the base of the proboscis of these Hydroids, genuine Medusa3 buds that are 

 either male or female, and which can no more ha considered as the sexual organs 

 of these so-called Polyps, than those of the types already considered, since they 

 are themselves provided either with an ovary or a spermary. 



The Diphyes community presents another peculiarit}-, highly important with 

 reference to a correct appreciation of the Medusoid character of the genuine 

 Hydroids. In most of these, we find that every individual consists chiefly of a 

 bell-shaped or trumpet-shaped or club-shaped sac, with tentacles around the central 

 opening, or upon its sides or around its l)ase, comparable, indeed, in every respect, 

 to the proboscis of the naked-eyed Medusa? as it exists in Sarsia. But though 

 the body of the individual Hj^droids appears more or less Itell-shaped, as in Tubu- 

 laria and still more in Campanularia, yet that bell is not hyaline and gelatinous 

 like the bell of the Medusa) proper, while the so-called scale of the Diphyes is 

 so, thus forming a sort of transition to the so-called swimming-liells, in which the 

 radiating and circular tubes are fully developed, as in ordinary Medusa^, but at the 

 expense of the proboscis, which is wanting. This would at once explain w^hy the 



* For illu,stration.s of tliis and the following bauer, Huxley, Kolliker, Leuckart, and Vogt, quoted 

 families I would refer to the pajiers of Gegen- page 27, notes 5, 10, 11, 12, and 13. 



