142 BULLETIN OF THE 



Lizzia grata, A. Ag. 



Plate I. Figs. 1, 2, 3, 4, 5, 6, 7. 



Sars * described, many years ago, a jelly-fish closely allied to L. grata, which 

 he named Cytceis octopunctata. Forbes f refers to this jelly-fish of Sars a 

 form from the coast of England, which he called Lizzia octopunctata. Lizzia 

 grata, first described from our waters by JSIr. Agassiz, is closely allied to 

 L. octopunctata. "While in the figures which Forbes gives of L. octopunctata 

 there are but two tentacles in each of the clusters midway on the bell rim be- 

 tween the radial tubes, in the jelly-fish which I had there were three, as is 

 represented (Plate I. fig. 1). Forbes, however, in his descriptions, speaks o 

 specimens in which there were three members in the cluster as well as two, 

 mentioning it, however, as if rather after the nature of an abnormality. Three 

 is the normal number found in well-developed animals, and none were taken 

 in which it was exceeded, however far advanced the medusa had grown. The 

 number of tentacles, however, from the ocellus of the radial tubes, as Mr. 

 Agassiz figures is, in large specimens, five or six. Forbes, on the other hand, 

 says that in L. octopunctata only three tentacles arise from the radial ocellus. 

 (See Naked-eyed Aledusse, Plate XII. figs. 3 - 3,.) 



The adult and several of the younger stages of L. grata have been described 

 in the " North American Acalephse," by Mr. Agassiz. The process of budding 

 from the proboscis is mentioned by him in a paper before the Boston Society of 

 Natural History, in 1862 (p. 100, Figs. 28, 29). 



Haeckel J has formed a new genus called Margellium for the reception 

 of the Lizzia octopunctata of Forbes and L. grata of A. Agassiz, and looks 

 upon each as a separate species. In liis diagnosis of Forbes's species, Haeckel 

 makes no mention of the fact spoken of by Forbes, that the number of 

 tentacles in the intermediate cluster is sometimes three. This is rather as- 

 tonishing, as Haeckel considers the supposed inequality in the number of ten- 

 tacles in diff'erent clu.=:ters a generic characteristic. Haeckel also suggests the 

 genus Puithkea for Lizzia-like jelly-fishes, in which the number of tentacles in 

 radial and intermediate clusters is equal. The young Lizzia resembles so 

 closely the proposed genus that at least new characters must be pointed out 

 to distinguish the two. 



The Oceania Blumenbachii described by Rathke, and which suggested the 

 new genus Rathkea, which Haeckel proposes, has eight clusters of tentacles with 

 generally two members in each cluster. Rathke gives in his figure of U. 

 Blumenbachii eight chjTniferous tubes, an interesting condition, of which I shall 

 speak in considering a new genus which I have called Mabella. Four of these 

 tubes in Rathke's medusa are regarded by Haeckel as foldings, the result ot 

 muscular action in the bell walls. 



♦ Wiepn. Arch. 1837, Part V. p. 406, and Fauna Littoralis Norwegise. 



t Nakcd-evf'd Meduste. 



J Das System der Medusen, Erster Band, p. 95. 



