116 



EMBRYOLOGY 



stages the marginal pouches become narrower and raoA-e 

 ajDart ; the sixteen regions of fusion [cathammata] thus 

 spread out into a bilaminar plate, which connects all of the 

 marginal pouches with one another : the tnedusoid, vascular, 

 or cathammal plate. 



The detachment, of the Ephyra now takes place, and from 

 this time on it moves about freely by rhythmical contractions 

 of its discoid body, the former point of attachment being 

 directed upwards, and the manubrium downwards (Fig. 51, 

 ii). The columellie, which are frequently the means of the 

 final connection with the nurse form, now degenerate. It 



Fig. 57. — Tutenadial longituditia section through an Ephyra monodisca, vrith 

 the Scyphistoma tentacle.s still retained (dingram moditied from Goette). ph, 

 proboscis; f)-, septal funnel ; g/, gastral filament ; so, septal ostium ; i/, constrict- 

 ing annular groove. 



is probable that the last metamorphosed remnant of the 

 septal infundibula can be recognized in the fonr sub-genital 

 cavities (p. 122) lying on the sub-umbi-ellar side beloAV the 

 gonads of the medusa. With the degeneration of the 

 columella' the boundary between the central stomach and the 

 perij)liural intestine entirely disappears, and the boundary 

 at which the ectoderm of the oesophagus is continuous with 

 the entodermal lining of the peripheral intestine is indicated 

 only by means of f(nir tentaculoid gastral filaments (Figs. 

 57, 58 r//), which have budded forth at the bases [oral ends] 

 of the columellae. 



