242 PROCEEDINGS OF SOCIETIES. 



ON THE ACALEPH^J OP DUBLIN COAST, WITH DESCRIPTIONS OP SEVEN NEW 

 NAKED-EYED FORMS. BY JOSEPH R. GREEN, HON. SEC. DUBLIN UNIVER- 

 SITY ZOOLOGICAL AND BOTANICAL ASSOCIATION; ASSIS. SEC. ROYAL ZOOLO- 

 GICAL SOCIETY, IRELAND.* 



If we take any group of living beings and carefully observe the several 

 species which are found in any given locality, considerable service will 

 be rendered to science. This more especially applies to the Acalephae, 

 the distribution! of which interesting class has hardly received from na- 

 turalists the attention which it deserves. " Pelagic as these animals 

 are, there is reason to believe that the range of the species is extremely 

 limited, and that they afford a valuable means of denning zoological pro- 

 vinces in the open sea." — (Professor E. Forbes' s " Keport on Egean In- 

 vertebrata," 1843.) 



The Acalephae of the Irish shores have as yet been but little inves- 

 tigated, and it is highly probable that many rare and beautiful forms 

 yet await the notice of some patient observer. 



* Read before Section D at the Meeting of the British Association, Dublin, August 26, 

 1857. 



f Many details, too, in connexion with the development of several of these forms have 

 only recently been brought to light, and our knowledge of their history is still incom- 

 plete. Any classification of them in accordance with their real nature would probably 

 be considered premature. I, however, wish it to be understood that I agree entirely 

 with the views of Dr. Carpenter and others as to the true position which the Discoid 

 Medusae ought to occupy, and that they are not to be regarded as distinct animals, but 

 rather as the reproductive zoids of certain zoophytic structures. The discovery of the 

 beautiful analogy which exists between the flower-bud of a plant and the Medusoid of a 

 Zoophyte may justly be regarded as one of the most important steps which zoological 

 science has recently made. A modification of the above view is proposed by some natu- 

 ralists, who consider the Gymnophthalmata as divisible into two groups, namely — 

 1. True Naked-eyed Medusae, as Willsia, Thaumantias, which produce ova, to be deve- 

 loped into the likeness of their parents by continuous reproduction. 2. Medusoids, which 

 are merely generative zoids, as Steenstrupia, Cladonema, &c. But such a separation is 

 unsupported by facts, for no instance of a Discoid Medusae having been produced without 

 the intervention of a Zoophyte has yet been established. Moreover, the figures of the 

 Medusoids developed from some of the Campanularidae, as observed by Van Beneden on 

 the coast of 03tend, are stated by Professor Forbes to bear a striking resemblance to Tima 

 and Geryonia, which, certainly, cannot be ranked among the lower forms of the group; 

 nor can any essential difference be shown to exist between the forms thus widely sepa- 

 rated from one another. It is true that many observations are still wanting before the 

 evidence in favour of the necessity of entirely altering the present system of classification 

 can be considered complete; and the abolition of a large group of animals is a step of too 

 serious a nature to be carried into execution without much careful consideration. But 

 there can be little doubt that the researches of future observers, if properly conducted, will 

 ultimately show the necessity of such an alteration. Meanwhile, we are not to refrain 

 from recording the forms which present themselves to our view, nor even to give those a 

 name, even though we should feel sure that the latter must eventually be done away with. 

 These remarks are appended lest it might be supposed that I attach a false value to the 

 description of species as given in the text. With regard to the Ctenophora, there can be 

 little doubt as to their affinity with the Actinozoa ; not only their development, but also 

 their anatomical structure, entitle them to be ranked as a distinct class parallel with the 

 Actiniadae. 



