72 



OCEAiV^IA LAKGUIDA. 



reproductive calycles in March, April, or September ; I am therefore 

 unable to state whether it is the Hydrarium of our common Oce- 

 ania. 



A very young Oceania (Fig. 96), soon after its escape from the 

 re^iroductive calycle, has a very deep bell (Fig. 96), two long tentacles 

 and two rudimentary ones at the base of the chymiferous tubes. It 

 resembles in its general appearance and motion the Medusa of Clytia 

 bicophora ; the bell is covered with large lasso cells, scattered irregu- 

 larly over the surface ; it can at once be distinguished from the latter 



Fig. W. 



Medusa by the absence of ovaries, the two long tentacles {t, Fig. 97), 

 and by what characterizes at once this genus, the position of the mar- 

 ginal capsules (c. Fig. 97) on each side of the primary tentacles {t, t', 

 Fig. 97), at the base of the chymiferous tubes, while in Clytia they are 

 placed on each side of the secondary rudimentary tentacle, half-way be- 

 tween the chymiferous tubes. The young Medusa, in more advanced 



stages, has become quite conical (Fig. 98), 

 the ovaries are forming, and, besides the two 

 original long tentacles, we have the two ru- 

 dimentary primary tentacles fully fomied, as 

 well as eight others half-way between the 

 chymiferous tubes, and rudiments of eight 

 additional tentacles half-way between these 

 and the chymiferous tubes. The proboscis 

 has likewise somewhat lengthened. In still 

 older specimens, in which the fourth set of 

 rudimentary tentacles has developed {t*. Fig. 

 99), and in which Ave can trace the position of 

 the remaining sixteen tentacles {t", Fig. 99), 

 the ovaries have also taken a greater development, and are now ellipti- 



Fig. 96. Young Medusa of Oceania languida, immediately after escaping from the reproduc- 

 tive calycle. 



Fig. 97. The same, seen from the actinal pole, to show the position of the marginal capsules, 

 c, on the sides of the tentacles, t, I'. 



Fig. 98. Somewhat more advanced Mi'dnsa, in which traces of the ovaries can be detected. 



Fig. 99. Quarter of the disk of a still more advanccil Oceania, where the remaining tentacles 

 of the a<lult (t") are developing between the tentacles, l\ l\ t\ l\ t"; as well as additional marginal 

 ca|)sules, c. 



