THE SCYPHOMEDUSAE 



adradial canals grow into them. The mesenteries lose their attach- 

 ment to the body wall and are probably converted into phacellae. 



Fin. 10. 



Fin. 11. 



9. Surface view of the subumbral or oral aspect of Aurelia auritc, to show the 

 position of the openings of the subgenital pits, (IP. In the centre is the mouth, with four 

 p^rradial anus corresponding to its angles, or. The four subgenital pits are seen to be inter- 

 radial. x t indicates the outline of the roof (aboral limit) of a subgenital pit ; ?/, the outline of 

 its floor or oral limit, in which is the opening ; Tc, tentaculocyst. (After Lankester.) 



10. Tentaculocyst of Aurelia nurita from the oral aspect. CC, circular canal ; 77, tho 

 aboral hood ; 7,, the protective lateral lappets ; T, tentacles ; T, tentaculocyst, carrying an 

 ocellus, and a terminal mass of otoliths ; TC, endodermal canal of the tentaculocyst ; V, the 

 " velarium," or thin edge of the bell. The outline of the endodermal canals is dotted. 



11. Tentaculocyst of AitrcUa aurita (longitudinal section). A, superior or aboral 

 olfactory pit ; B, inferior or adoral olfactory pit ; 77, bridge between th two marginal lappets ; 

 T, tentaculocyst; Knd, endoderm ; Ent, endodermal canal' continued into the tentaculocyst; 

 Con, endodermal concretion (auditory); or, ectodermal pigment (ocellus). The drawing repre- 

 sents a section, taken in a radial vertical plane so as to pass through the long axis of the ten- 

 taculocyst. (After Eimer.) 



Concrescence of the exumbral and subumbral endoderm of the 

 coelenteron into a gastral lamella ultimately gives rise to the com- 

 plicated system of gastric pouches and canals of the adult. 



