78 



CLYTIA BICOPHORA. 



Fig. 108. 



Clytia bicophora AGASS. 



Clytia bicopJiora AGASS. Cont. Nat. Hist. U. S., IV. pp. 304, 354, PL 27, Figs. 8, 9 (as C. cylin- 



drica) ; PL 29, Figs. 6-9. 1862. 



Clytia bicophora A. AGASS. Proc. Boston Soc. Nat. Hist., IX. Figs. 14, 15. 

 Clytia cylindrica AGASS. (p.p.). Cont. Nat. Hist. U. S., IV. Fig. 14. 1862. 



Under the name of Eucope campanulata, Eucope Thaumantoides, and 

 EuQOpe affinis., Gegenbaur lias described three species, which, to judge 

 from the development of a similar Medusa of our coast, Clytia 'bicoph- 

 ora, are probably only different ages of the same species. 

 The difference in shape of the ovaries in the different 

 stages of the males and females, as seen in our Oceania, 

 may account for the difference of form which Gegenbaur 

 has found in the genital glands : I have been able to 

 observe the same differences in our Clytia. The differ- 

 ence in the shape of the bell of his species is similar to 

 what we find at different periods in our Clytia. When 

 hatched from the calycle, the bell is globular (Fig. 108) ; 

 the digestive cavity is a simple cylinder ; the ovaries are 

 hardly visible, as very short narrow lines on both sides 

 of part of the upper half of the radiating tubes ; there are only four 

 tentacles. As it grows older, the actinal portion of the bell bulges out ; 

 the second set of tentacles, which were small bulbs, have now grown 

 out, and there are traces of eight other tenta- 

 cles (Fig. 109); the ovaries are also larger. At 

 this stage the bell has the shape of a segment of 

 a sphere, and has entirely lost its globular out- 

 line, the marginal capsules have not increased 

 in number, there are only two between each 

 radiating tube, just as we have them in the young Medusa at the time 

 when they are freed from the reproductive calycle. In the next stage 

 of the Medusa the rudimentary tentacles of Fig. 109 have developed 



into long flexible lashes, usually carried curled 

 up, as in Fig. 110. In the adult of this Medusa 

 there are no traces of any additional tentacles ; 

 though not measuring more than a quarter 

 of an inch in diameter, yet they are very con- 

 spicuous on account of the accumulations of 

 black pigment-cells in the bulb of the tentacles ; 

 two additional marginal capsules have also been formed, one on each 

 side of the four primary tentacles ; the ovaries are brownish purse-like 



Fig. 108. Clytia bicophora, immediately after its escape from the reproductive calycle. 



Fig. 109. A somewhat older Clytia bicophora. 



Fig. 110. An adult Clytia bicophora, measuring one quarter of an inch. 



Fig. 109. 



Fig. 110. 



