82 EUCOPIDiE. 



identica. ; as, for example, the MedusfC of Eucojie polygena, UucojJe 

 diapliana, Eucojje 2}J/riformis, and JEucope articulata. The strongest 

 case we can cite is perhaps that of Syndictyon and Coryne, the adult 

 Medusae of which had long been distinguished by the difference of 

 color of the sensitive bulb ; but whether this was anything more than 

 mere individual differences could not be ascertained till we became 

 acquainted with the comjjlete development of the former genus, which 

 will be found given in its place in this Catalogue. Plincks, after 

 some observations limited to two genera of Hydroids, came to the 

 conclusion that we could have Medusas, generically identical, developed 

 from Hydroids generically distinct ; this is so entirely opposed to any- 

 thing known in the history of the development of these animals, and 

 so totally disproved by the examples of Campanularians here described, 

 that I believe that, when the complete history of the two MedusiB 

 described by Hincks is fully known, we shall find Ave have only a case 

 of very close afKnity at one stage of their development, and that, as 

 Ave become acquainted with their more advanced stages, differences will 

 be perceptible. 



The different species of Eucopida3 found on our coast, of Avhich Ave 

 knoAv the deA'elopment, explain many of the contradictory statements 

 of European Avriters concerning the mode of development of the dif- 

 ferent species of Eucope. It has been shoAvn only more recently that 

 many of the species, so closely allied as to be readily mistaken at any 

 time, except the breedmg season, were reproduced, on the one hand by 

 Planulte, and on the other by Medusje ; and noAV it is found that the 

 Medusae produced from Hydroids Avliich have been considered identi- 

 cal species, develop into A^ery different adult forms. See, for example, 

 the differences in the Medusae of Laomedea genicidata, figured by 

 Wright and Gosse ; one has ovaries and the other has none, imme- 

 diately after its escape from the reproductive calycle, as in our EucojJe 

 dicq)hana and Eucope articulata. The Laomedea gelatinosa of Van 

 Beneden has tAventy-four tentacles and ovaries, as in our Eucope p)yri- 

 formis, to which it is closely allied, while the Medusa of Laomedea 

 gelatinosa of English Avriters has sixteen tentacles at first, and is an 

 Obelia. The European Campanularians require a thorough revision in 

 order to ex:tricate them from the confusion existing in their synonymy, 

 and this can only be done after a thorough acquaintance AAith the de- 

 velopment of their Meduste. 



The Laomedea dichotoma of Dalyell is probably the same as the 

 Campamdaria gelatinosa of Van Beneden. The same confusion oc- 

 curs in the fourth volume of Professor Agassiz's Contributions ; the 

 Eucope which is there figured as Eucope diaphayia Agass., and the 

 Campanularian of that name (Plate 34), is not the Hydroid of Eu- 

 C02:)e diaijhana, as Avill be seen in the description of the latter-. The 



