. SCiPnOMEBUS.E. 



251 



their umbrella, the gelatinous connective tissue of which is richly 

 developed and contains a quantity of strong fibrillse and a network 

 of elastic fibres, which structures confer upon it a greater firmness 

 and rigidity. 



Another characteristic of the group is derived from the structure 

 OL the edge of the umbrella. This is divided by a regular uurubtr 



RK 



FIG. I9l.Aure!ia aurlfa, from the oral surface. MA, The four oral tentacles with the mouth 

 in the centre; <?, generative organs; GH, aperture of sub-si nital pit; -Et, sense 

 organ (marginal body); BG, radial vessel ; T, tentacle at edge of the disc. 



of indentations usually into eight groups of lobes between which the 

 sense organs are contained in special pits (fig. 194). 



The marginal lobes of the Acalephre, like the continuous velum 

 of the HydromeduscK, appear to be secondary formations at the edge 

 of the disc. In the young stage known as Ejihyra, which is common 

 at least to all the Discophora, they r.re jre eiit as eight pairs of 



Bars, " Ueber die Entwiddnng der Medusa aurita nnd Cyanea capillata," 

 Archil-. /Hi- .Yitfi/rt/fneh, 1811. H. J. Clark. ' Prodromns of the History, etc.. oJ 

 the Order Lucernarid" Journ. t\f B*t. Soe, of Xat. Jlixt.. 1803. C. Glaus, 

 " Stiidien liber Polypen und Quallcn der Adria," D<-nlwltrifh-n- der /. 

 Ahademie Ji-r Wixxrnxrh. HV/-, 1877. C. Clans, ' Untersuchung'en iibcr 

 Charvbdca inarsunialis," Arlcife/t, an* Jan /.od. J/i.-fi'uf. II ir/i, 1878. Also 

 E. Haeckel, 1. c. 



