CNIDARIA 



109 



The sti'uctures occurring between these [eight] radii are 

 designated as adradial. 



The lower free margins of the four septa soon become 

 continuous with the wall of the central stomach in the form 

 of four longitudinal folds, which ultimately extend through 

 the entire length of the scyphopolyp, even into the foot. 

 These folds are known as the kmgitttdinal folds, or tceniolce 

 (Fig. 52 F, t), and the sinuses of the central stomach limited 

 by them as gastral furrows. 



In the further metamorphosis of the larva the form clianges, 

 approaching more and more the shape of a goblet (Fig. 53). 



Fig. 53. — Diagrammatic loncritudinal section through a Scyphistoma (based on 

 Goktte). .^, perradial longitudinal section ; B, interradial longitudinal section; 

 pb, proboscis; f, tentacle ; tr, septal funnel ; ?ii, gastral pouches; g, mesogloea; s, 

 septum. The entoderm is represented as a dark layer. 



The lower narrow portion is called the stalk or peduncle 

 (Fig. 55 st), the prolongation of the centi-al stomach extend- 

 ing into it the peduncular canal. The upper part of the 

 body becomes flattened, and thus forms the oral disc ov peri- 

 stome, in the middle of which rises the cone-shaped proboscis 

 (Fig. 53 ph) with its central foux'-sided mouth-opening. 

 The four corners of the mouth are placed perradially (Figs, 

 54 G and 55). 



The first four tentacles now arise over the four gastral 

 pouches, and, in keeping with the successive appearance of 

 the pouches, those over the first pair of pouches arise first, 

 and then those over the second pair. A cylindrical ento- 



