EUCOPE. 83 



Eucope diaphana of the fourth volume (not that of the Memoirs of the 

 American Academy) is probably identical with the English Eucope 

 geniculata of Wright, not that of Gosse, and it may hereafter be desig- 

 nated as Eucope alternata. 



EUCOPE GEGENB. 



Eucope GEGENB. Versuch eines System ; Zeit. f. "VViss. Zool., p. 241. 1856. 

 Eucope AGASS. Coat. Nat. Hist. U. S., IV. p. 351. 1864. 



Eucope diaphana AGASS. 



Eucope diaphana AGASS. (ex p.). Cont. Nat. Hist. U. S., IV. PI. 33, Fig. 2. Hydrarium. 1862. 

 Tftaumantias diaptiana AGASS. Mom. Am. Aca<l., IV. p. 300, Figs. 1, 2. 

 Eucope diaphana A. AGASS. Proc. Bost. Soc. Nat. Hist., IX. p. 02, Figs. 7-9. 

 Tltaumantias diaphana MO'UCH ; in Beskriv. af Gronland, p. 96. 1857. 



This is by far the most common of our Jelly-fishes ; it does not grow 

 to a large size, adult specimens not measuring Kig 115 . 



more than a quarter of an inch across the disk. 

 On escaping from the reproductive calycle, the 

 little medusa has but twenty-four tentacles, and is 

 constantly swimming with the disk turned inside 

 out, as in Fig. 115 ; at the base of two of the ten- 

 tacles (t f , t r . Fig;. 116), situated on both sides of the mid- 



Fig. 116. 



die tentacle, between the chymiferous tubes, are found 

 large spherical capsules ; there are no traces of ovaries 

 to be found in this early stage, it is not till the second 

 set of tentacles begin to develop (2, Fig. 117) that they 

 make their appearance. Young tentacles do not pos- 

 sess the root-like projection at their Fig 117 . 

 base ; this is only developed in older tentacles 

 of more advanced Medusae. (See Fig. 120.) With 

 advancing age the Medusae lose the habit of 

 swimming with the proboscis uppermost, and grad- 

 ually assume the usual mode of swimming of Jelly- 

 fishes. The young Eucope of Fig. 117 develops 

 rapidly additional tentacles, the ovaries increase in 

 size, and we soon have an adult Medusa, with large bag-like ovaries, a 



Fig. 115. A Eucope diaphana just after its escape from the reproductive calycle, seen in 

 profile. 



Fig. 116. One quarter of the disk of the same, seen from above. ?, tentacle opposite chymif- 

 erous tube ; (', <', tentacles with capsules. 



Fig. 117. A more advanced Eucope, in which the second set of tentacles (2) is developing 

 between the original tentacles (1). 



