360 



MEDUSAE OF THE WORLD. 



canals, which increase with age. In young medusae 15 mm. in diameter, the centripetal vessels 

 ranged from 11 to 14 per sextant, about 78 in all; whereas in a mature medusa 75 mm. wide 

 the centripetal canals varied from 18 to 23 in the several sextants, or about 120 all told. 



The 6 gonads are foldings of the subumbrella walls of the 6 radial-canals and extend 

 throughout the greater portion of their lengths, leaving only a short proximal, and a much 

 shorter distal, extremity of the canal free. The young gonads are sinuously folded from side 

 to side of each canal, but later they give rise to numerous lobes, which may become secondarily 

 lobed, as in Olindias. 



The tips of the exumbrella tentacles are transparent lilac; their middle and proximal 

 lengths are smaragdine-green. The peronial strands and basal parts of those tentacles which 

 project from the exumbrella at a high level are ivory-black. The radial and circular canals 

 are deep scarlet and the centripetal vessels are of a lighter hue of the same color. There is a 

 small, green, triangular spot at each of the 4 corners of the base of the manubrium, on either 

 side of which there is a lilac area, and there are one or two somewhat irregular longitudinal lilac 

 streaks along the middle of each side of the manubrium. The tips of some of the filiform 

 tentacles are tinged with green and lilac. The gonads are egg-yellow. 



The medusa is found from December to June or July at Misaki and at other places in 

 the Bay of Tokyo, Japan. It is a bottom form and appears to be most abundant in water 

 20 to 30 fathoms deep. It is beautifully figured by Goto, who gives also a very detailed and 

 clear description of the medusa. 



204. 



Fig. 204. — "Dipelasus digonimus," after Haecke]. 



Fig. 205.— "Pelasus atavus," after Haeckel, in Syst. der Medusen. 



Fig. 206.— "Petasata eucope," after HaecUel, in Syst. der Medusen. 



206. 



