EXPLANATION OF PLATE XVIII. 



Cn'uJouema hni^irelli, Brio-^s. 



REFERENCE LETTERS. 



C.C., Cifcnlar canal, n.r., Nematocjst ring, r.c, Radial canal, s. nm. c, 

 Subumbrellar cavity. /., Testis, c, Velnni. 



Fig. 1. Male Medusa; niicro-[)hotograpli of a vertical section passing 

 through inter-radial region. X 64. 



„ 2. Male Medusa ; vertical section passing through inter-radial 

 region. The section shows the testes (t.) occupying almost 

 the whole of the subumbrellar cavity, extending from the 

 velum (r.) upwai-ds alongside of the stomach and to a 

 considerable extent above it. X 64. 



,, 8. Male Medusa ; micro-photograph of a transverse section passing 

 thi-ough the circular canal on the right, and below the 

 circular canal on the left. X 64. 



„ 4. Male Medusa; veitical section passing through a radial canal 

 (r.r.) on the right. X 64. 



,, 5. Male Medusa; transverse section above the stomach showing the 

 testes (/.) in the form of a continuous ring. X 64. 



