rnyuwr c(EJ.EsrKu.\T.\ 81 



(line by niciins of which ihu animal c:ui aLlach ilsclf Icmporaiily 

 to vegetation or other objects in the water. 



Turn a spooinicn witli the vchiiii side toward tht; observer and 

 stud}' the edge of tlie body for the two kinds of sense organs. 

 The low objective may be necessary to render these distinguish- 

 able. At the base of each tentacle and coniniuiiicating with the 

 circumferential canal is a noticeable round body which is made up 

 of strongly pigmented cells. These are considered as light- 

 perceiving organs. Other smaller transparent outgrowths between 

 the bases of the tentacles are the datocysi'i which serve as 

 balancing (static) organs. The jelly-like consistency of the 

 medusie is duo to the enormous dcvclopiiioTit of the mesoglea. 



Upon the plate of Gonionemus label all the parts to which 

 attention is called in the outlines. 



