Fig. 119. — A diagram of a vertical section 

 through one of the large jelly-fishes, 

 such as Aurelia. The section is divided 

 by a dotted line into two halves, in one 

 of which it is supposed to pass through 

 a radial canal, and in the other through 

 the endoderm lamella. 



can.c, Circular canal; can.r., radial canal J en.L, 

 endoderm lamella; ex.u., exumbrella ectoderm ; 

 g., gonad; g.f., gastral ■ filament : hd., hood 

 covering sense tentacle ; /., jelly or mesoglea ; 

 ml>. t manubrium; ces., oesophagus; s.g.fi., sub- 

 genital pit ; s.ten., sense tentacle ; st., stomach ; 

 ten., tentacle. 



Fig. 120. — The life-history of Aurelia. 

 A, Planula ; B-H, stages in the development of the hydra tuba ; /, ephyra, 

 13 



