90 



EUCOPE FUSIFORMIS. 



a larger pedicel, having from eight to ten rings. It is very common to 

 see the sterile Hydras, placed as in the figure (Fig. 131), in pairs at the 

 base of the reproductive calycle. The Hydrarium grows to about the 

 size of the Eucope iJiiriforiims, from three to four and even five inches 

 high, and is readily mistaken for the Hydrarium of Ohelia commissu- 

 ralis. It grows in pools on rocks at low-water-mark. 



Cat. No. 396, Nahant, June, 1862, A. Agassiz. Hydromedusarium. 



Cat. No. 397, Nahant, June, 1862, A. Agassiz. Hydromedusarium. 



Fig. 132. 



Eucope? fusiformis A. Agass. 



Eucope f A. Agass. ; in Proc. Bost. Soc. Nat. Hist., IX. p. 91, Fig. 6. 



From a Hydrarium, in which the cavity of the main stem passes 

 from one side to the other (s, s, Fig. 132), similar in its mode of 

 branching to that of Uiico2)e dia2:)hana, but in which the 

 Hydrae, remarkable for their small bell, 6, are attached 

 to the main stem by short branches, not having more 

 than three or four rings (Fig. 132), is produced a small 

 Medusa of a sixteenth of an inch in diameter, having, 

 when hatched, four long fusiform ovaries (Fig. 133), oc- 

 cupying nearly the whole length of the chymiferous 

 tubes, and forty-eight long, slender tentacles, having 

 well-developed rootlets, usually carried quite stiffly, with 

 two marginal capsules between each pair of chymifer- 

 ous tubes, occuj^ying the same position as in E. dia2:)ha- 

 na, when it has forty-eight tentacles. The digestive 

 cavity is quite long and movable, and differs from that 

 of the last species by the more marked lobes of the actinostome. The 

 different species of Eucopida?, thus far described, can easily be distin- 

 guished by the number of tentacles, the presence 

 or absence of the ovaries, and their jDOsition 

 when they escape from the reproductive calycles. 

 Among the many specimens of E. dia2:>hana 

 which I had occasion to examine, I have only 

 found two in which there were not twenty-four 

 tentacles on hatching, and in the Ohelia commis- 

 SKTcdis and E. 2^yriformis the same holds good ; 

 the number of tentacles at the time of escape 

 from the calycles being very constant. 

 Massachusetts Bay, Nahant (A. Agassiz). 

 Cat. No. 90, Nahant, July, 1861, A. Agassiz. Hydromedusarium. 



Fie. 133. 



Fig. 132. Hydrarium of Eucope fusiformis ; magnified. 



Fig. 133. Quarter of the disk of the Medusa of Eucope fusiformis ; greatly magnified. 



