136 



K. KISHINOUYE. 



So fau as I know there are only two species of Thtjsanosto7)ia — Th. 

 melitea and Tli. tJujsamira. The present form, however, differs from 

 both of these species by having shorter lower arms, higher umbrella, 

 granulated exumbrella, etc. It also closely resembles in general ap- 

 pearance the medusae of the genus Gramhessa, but differs from them by 

 the possession of short and for the most part coalesced upper arms. 



Fig- 



Explanation of Plate. 



The figures were tlrawn from an alcoholic sf)ecimen. 



genital gland after the removal of the oral disc and oral 

 arms. Lower half shows the gastiovascular system. 

 8. Perradial section of the medusa. 



4. Oral disc. Upper surface. 



5. ,, ,, Lower surface (suctorial frills and whip-like 



filaments removed). 



6. ,, ,, Canal system. 



7. Upper arm. Cross section of the free portion. 

 8-10. Lower arms. Cross sections of the proximal portion. 



IL ,, ,, Cross section of the middle portion. 



12, 18. ,, ,, Cross sections of the distal portion. 



