6 



Mr. S. J. Hickson. 



and, on the other, with the canals of the coenenchym. In fsome cases 

 there are only three of these coeca, in- others they are very irregular, 

 and again in others there are none. It is quite impossible to determine 

 with certainty what is the "typical " or "average " arrangement of the 

 canities of these medusae with the limited amount of material at my 

 disposal, but I think it is probable that the quadriradiate form ^Y^^l be 

 found to be the most frequent of the many variations. 



2. The mature female mednsce received in December, 1898. The 

 material sent to me being abundant, I have been able to examine a 

 large series of medusae at this stage before their escape from the 

 ampullae. I have also examined a few medusae which Mr, Duerden 

 collected in his aquaria after their escape from the ampullae. They are 

 decidedly larger than the immature medusae of the last collection ; 

 the diameter of the umbrella being about 0*6 mm. instead of about 

 0"4 mm. The variability is even more pronounced at this stage than 



in the last, and it is almost impossible to find two medusae exactly 

 alike. In most of the medusae (figs. 2 and 3) three or four large ova 

 are found, and the manubrium is usually iriradiate or quadriradiate 

 accordingly, but occasionally medusae with five, two, or only one 

 mature ova occur, and the manubria of these are more irregular. 



I mounted a piece of a decalcified specimen about 48 sq. mm. in area, 

 and found that it bore forty-one medusae ; of these, nineteen had four 

 ova, eighteen had three ova, two had two ova, one five, and one one. 

 In another piece I counted three with four ova, six with three ova, and 

 one with two. In another ^iece 15 mm. by 10 mm. in area I counted 

 forty with three ova, fifteen with four ova, five with two, and five with 



