156 Dr. C. Chun on the Siphonophora. 



batteries. Without going into detail upon the development 

 of these buds, I will only mention that the rudiment of the 

 bract becomes flattened, and, curving like a sickle^ begins to 

 grow round the stem. Its endodermal cavity forms the liquid- 

 receptacle, and the lateral parts, which grow out into wings, 

 embrace the genital nectocalyx. Tn the lowest groups of in- 

 dividuals therefore we remark first of all the mobile stomachal 

 sac with the ectodermal cell-pad at its base, and its yellowish- 

 red mouth often dilated in the shape of a funnel ; further, the 

 tentacle, with its amceboidally movable ectodermal cell-pro- 

 cesses, and the kidney-shaped urticating batteries, of a bright 

 yellow colour, attached to long accessory threads ; and finally 

 the genital bell, with its central manubrium, forming the 

 sexual products and the four vessels opening into an annular 

 canal. The umbrella of the genital bell grows rapidly to a 

 considerable size, and, assisted by a velum, begins to perform 

 pumping movements, until finally the group separates from 

 the stem at the point of insertion of the bract, in order to lead 

 an independent existence for a considerable time. 



These sexually maturing monogastric colonies (fig. 3) also 

 have not escaped the attention of the observers Will and 

 Busch, who have been already repeatedly mentioned, although 

 certainly they did not recognize their relations with Muggicea. 

 Will * describes a Siphonophore under the name of Erscea 

 pyramidcdis which is evidently identical with the Eudoxia 

 Eschscholtzii so accurately studied by Busch f* But Eudoxia 

 Eschscholtzii represents the sexual generation of Muggisea. 

 From the most highly developed individual groups of Mug- 

 gicea it differs externally only in the form of the bract, which 

 has become considerably thickened, and, as the last indicatio 

 of its wing-like dilatation, exhibits two angles, which extena 

 from the apex towards the genital calyx. The latter has 

 attained its full size, shows in transverse section four wing- 

 like edges of unequal size, and always allows the four vessels 

 with their annular canal, which were overlooked by Busch, to 

 be recognized. That the Eudoxice are of separate sexes and 

 produce semen and ovum in the manubrium, representing the 

 stomachal peduncle of a Medusa, we first learned from Busch. 

 He further called attention to the fact that, besides this necto- 



calyx, a second is produced, the significance of which, how- 



ever, was not clear to him. Leuckart % ai *d Gegenbaur§ first 



* Hora Tergest. p. 8, Taf. ii. fig. 17. 

 t Zoc. cit. p. 33, Tafs. iv. and v. 

 X Zoc. cit. p. 47. 



§ 4t Beitrage zur naheren Kenntniss der Schw immpohpen/' 1854, 

 Zeitschr. f.wiss. ZooL Bd. v. p. 290. 



) 



