162 



ZOOLOGY 



SECT. 



is divided into eight long bifid arms (a.) with deep (adradial) 

 notches : it has of course carried away with it a segment of the 

 stomach with the gastric ridges of the Scyphula : during the process 



Fio. 116. Aurelia aurita, development. A, planula ; B, C, formation of stomodseum ; D, 

 transverse section of young Scyphula ; E, Scyphula ; F, longitudinal section of same : the 

 section passes through a per-radius on the left of the dotted line, through an inter-radius on 

 the right ; G, division of Scyphula into ephyrulre ; H, ephyrula from the side ; L, the same 

 from beneath. In A D and F the ectoderm is unshaded, the endoderm striated, and the 

 mesoglcea dotted, a. lobes of umbrella; nmb. manubrium ; mth. mouth; s.f. septal funnel; 

 st. stomodseum ; t. tentacle ; in. tsenioles. (From Korschelt and Heider's Embryology.) 



of constriction this becomes closed in on the proximal or ex- 

 umbrellar side, while on the sub-umbrellar side it remains open, 

 and its edges grow out to form a manubrium. On each gastric 



