254 BULLETIN OF THE 



Tentaculata and Nuda, accordingly as tentacles exist or are wanting. If this 

 feature alone be used in classification, Ocyroe would be placed in the group of 

 Nuda side by side with medusa; like Beroe, with which it has few other ana- 

 tomical likenesses. If his classification be followed, Ocyroe must be regarded 

 as a connecting form between Ctenophora tentaculata and Ctcnophora nuda. 



Ocyroe renders necessary some modification in the phylogenetic tree which 

 Dr. Chun suggests, for the different genera of comb-bearing medusae. The 

 Beroids may have come from Bolina like jelly-fishes through Ocyroe rather 

 than directly from other tentaculated Ctenophores. A. Agassiz has pointed 

 out that this medusa has " structural characters of the Lohatce, Saccatre, and 

 Eurystomw" * It is the intermediate form connecting Beroe with Ctenophores 

 like Mucmiopsis or Bolina. Although most closely related to the Lobatoe, it 

 resemljles genera of the Eurystoniatcc in tlie absence of tentacles and the course 

 of the lateral tubes. The resemblance to the Saccata; is more distant. 



DISCOPHORA. 

 Cassiopea frondosa, Lamarck. 



Plate I, Figs. 7 - 19. Plate II. Figs. 1, 3. Plate III. Figsv 1-3, 9, 10. 



Cassiopea frondosa f is very common in the moat outside Fort Jefferson on 

 Garden Key (Tortugas Islands). Specimens were also found in the still 

 waters and protected shallows in the lee of the Mangrove Keys, near Key 

 West City. 



Cassiopea frondosa is found lying on the coral mud at the sea bottom, with 

 its bell reversed and the oral region turned uppermost (PI. I. fig. 7.). When 

 transferred to the aquarium it assumes a similar position, exhibiting little 

 power of locomotion, but flapping the disk-shaped bell in a sluggish manner. 

 This motion seems to be confined almost wholly to the margin of the bell. 

 While it cannot be said to be fixed to the bottom in such a way that movement 

 is impossible, it Avill be found, if its position from time to time be carefully 

 observed, that it does move from place to place, although the amount is very 

 small. It generally lies on its aboral region,^ sluggishly flapping the bell 

 maigiu in a monotonous manner, in general appearance, when seen from the 

 boat floating above it, resembling a small cluster of nullipores. The habit of 



* Hull. Mus. Comp. Zool., IX. 3. 



t I regard tliis the same as Pohjclonia frondosa, Agass. Polyclonia according to 

 L. Agassiz has twelve marginal sense bodies and twelve radial markings. Tlie speci- 

 mens of C. frondosa studied by me had generally sixteen such structures. Tliis is 

 true of young as well as of adult Cassiopea^, except in abnormal specimens. 



C. frondosa is closely related to C. Andromeda, Esch. 



t A similar posture lias already been oliserved in Cassiopea by Mortens ; in Poly- 

 c'onin, by L. Agassiz ; and in Medusa aquorea, Forsk, 1>y McAndrew. (Ann. Nat. 

 Hist., IV., 1869, p. 295.) 



