88 K. KTRHTNOUYE. 



along the 3 corners of the under arm and give off many fine l:)ranches (Figs. 

 5-8) ; but they are not connected with each other by any lateral branch. 

 These 4 principal canals again nnite into one at the distal end of the arm and 

 produce a strong blind canal of the appendage (Fig. 9). 



The genital organ is a greatly folded liand at the floor of the stomach 

 cavity (Figs. 1,2). 



The largest specimen in alcohol is about 100 mm. broad. Fishermen 

 tell us that a large specimen attains a size more than 800 7}im. in the 



umbrella-diameter. 



J. 



Exumbrella in light In-own with numerous, round, dark brown spots. 



This medusa is often found al)undantly in summer at the coasts of the 

 provinces of Shiuia and Sagami. 



Materials of my examination were kindly collected by Mr. U. Takakura, 

 and I wish to express my best thanks to him. 



Fig. ]. Mastigas physophora. A little smaller than the natural size. 



Fig. 2. Subumbrella. 



Fig. 8. Oral disc. Upper surface. 



Fig. 4. ,, ,, Under surface. 



Fig. .5. Oral arm. Dorsal view. 



Fig. ('). ,, ,, Side view. 



Fig. 7. Under arm. Cross-section at the middle portion. 



Fig. 8. ,, ,, . Cross-section near the distal end. 



Fig. 9. Club-shaped appendage. Cross section. 



Fig. 10. Octant of the umbrella margin of a larva about 10 ww. in 

 diameter. 



Fig. 11. Octant of the umbrella margin of a larva about 20mm. in 

 diameter. 



Fig. 12. Octant of the umbrella margin of a larva about 40m7». in 

 diameter. 



Fig. 18. Conical vesicle between oral crisps. 



