The gastral filaments eight adradial (fig.
JG, Adradial gastral canal.
The gastral filaments have increased to three in each of the four sets.
Gh and Fg, Gastral filaments (phacellae).
E, Young ephyra just liberated, showing the eight bifurcate arms of the disk ' and the interradial single gastral filaments.
C,C', D,D', two types of medusa organization; C and D are composite sections, showing a radius (R) on one side, an interradius (IR) on the other; C' and D' are plans; the mouth and manubrium are indicated at the centre, leading into the gastral cavity subdivided by the four areas of concrescence in each interradius (IR).
Muscle of the gastral ridge.
Hence the gonads are found on the manubrium in Anthomedusae generally; on the base of the manubrium, or under the gastral pouches, or in both these situations (Octorchidae), or under the radial canals, in Trachomedusae; under the gastral pouches or radial canals, in Narcomedusae.
The development, on the contrary, shows unequivocally that the endodermlamella arises as a local coalescence of the endodermal linings of a primitively extensive gastral space.