COELENTERATES IN GENERAL 



147 



A B 



Fig. 64. — Two scyphozoan jellyfishes. A, Rhizostoma pulmo Haeckel. B, Chrysaora 

 hyoscella. {From Lankester, "A Treatise on Zoology," by the courtesy of A. and C. Black.) 

 The first of these reaches such a size that the bell is 2 feet in diameter; in the second the 

 bell may be 6 inches across. 



Sfotrtocfeum feao/incr 



wfo en-/-eron i/p about moufh 



Tet^fcrcles 





Ostia 



acont/'un? 



Pn'tnary mesentery 

 Reproo/ucfi've or(yan 



A Edl^e of /nesentery 



Fig. 65. — A sea anemone, Metridium dianthus Ellis. {From Woodruff, "Animal 

 Biology," by the courtesy of The Macmillan Company.) A, view of polyp with one quadrant 

 removed. B, diagram of transverse section, reduced in size, showing the general plan of 

 the mesenteries. 



