Mr. J. W. Fewkes on Deep-sea Medusre. 255 



let me mention another new Medusa collected bj the 'Alba- 

 tross ' in the Gulf-stream. The genus NaujyJiantopsis is of 

 interesting affinities, since it has the same central disk as 

 Nauphauta and Atolla, the same coronal fossa and coronal 

 socles. It is most closely allied to Nauphanta, but has 

 thirty-two socles instead of sixteen, eight sense-bodies (?), and 

 twenty-four tentacles *. These tentacles are therefore 

 arranged in threes, the series of three alternating with the 

 eight sense-bodies — all with gelatinous socles. 



It is easy to interpret the three deep-sea Acraspeda, Atolla, 

 Nauphanta, and Nau2)han(opsts. At first sight they closely 

 resem.ble gigantic young Aurelice or Cyaneoi in a stage which 

 is called the Ephyra. This is especially true of Nauphanta, 

 which has the same number and arrangement of tentacles 

 as the young Gyanea or A urelia in the Ephyra stage. It is 

 so close in fact that at first sight tliey seem identical. In 

 Nauphanta we have mature ovaries, and this would seem to 

 indicate the adult form. The existence, however, of ova and 

 a sexual maturity is by no means an indication of the acqui- 

 sition of the adult form among Medusee, and many instances 

 might be mentioned of a jelly-fish with mature ova even 

 before embryonic appendages have been dropped. There is 

 nothing then to prove that Nauphanta is not the young of 

 some other Medusa, and on the other hand there is no proof 

 that it is not an adult. If it is an adult, it is a mature Me- 

 dusa with likeness to embryonic conditions of other Medusae. 

 It would then be nearer the ancestral form of Acraspeda than 

 any of the more common Medusai like Gyanea and Aurelia. 



At first study I was inclined to regard Atolla as a giant 

 Ephyra of some unknown Medusa. Its affinities are certainly 

 very close to Nauphanta, and through the latter genus it is 

 connected with Ephyra, the young of Gyanea. We may 

 therefore regard botii these genera as embryonic in their struc- 

 ture and as close allies of the young of a higher jelly-fish. It 

 is a most interesting fact that two genera with such marked 

 characters are considered deep-sea genera. Exactly what the 



* Naupliantopsis is an interesting genu3 in its relationship to the surface- 

 genus Feriphylla, which has four sense-bodies and twelve tentacles in 

 four series of three each. We likewise have in the same genus marked 

 coronal socles, sixteen in number, while Nauphaiitopsis has thirty-two. 

 Nauphantupsis then appears to be a connecting genus between Nauphanta 

 and Periphylla. I believe we are justified in regarding Nauphanta as an 

 adult, although when I tirst studied it I was strongly inclined to caiisider 

 it an immature animal. It must be confessed that, with the exception 

 that it has eight sense-bodies, while Feriphi/lla has but four, there ara 

 strong resemblances between a young Periphylla and the genus Nau- 

 phanta. 



18* 



