84 DISCOPHORiE. Part III. 



name of Aurelia flavidula, given by Peron and LeSuenr to the Medusa aurita of 

 Fabricius, knowing that our species extends at least as fai' north as Labrador, and 

 it is not hkely that that searcoast will prove the limit of another Acalephian 

 fauna, when it is known that other marine animals, having a similar range as 

 our Aurelia, occur also on the coast of Greenland. The differences between the 

 figures of the Aurelia aurita, published by Ehrenberg, which I would consider as 

 specific, consist in the less numerous anastomoses betAveen its radiating tubes, Avhich 

 are so frequent in our species as to form a net-work of meshes near the mar- 

 gin. The space occupied by the sexual pouches in Aurelia aurita is, also, much 

 less than in Aurelia flavidula. In our species, the diameter of the area occupied 

 by these organs is fully one third of the total diameter of the disk ; in no one 

 of the figures of Ehrenberg does it amount to that, and in most of them it is 

 much less. The crescentrshaped sexual organs themselves ajDpear also further aj^art 

 in the European than in the American sjjecies. The sexual organs are every- 

 where i-epresented as rose-colored or purple in the European, while in our species 

 they are so only in the males, and have, in the females, a rather yellowish tint, 

 varying to yellowish brown. I have already alluded to the difference in the form 

 of the fringes along the rim of the mouth and the margin of the oral appen- 

 dages. All these differences belong to the category which I have found to indi- 

 cate specific differences, whenever I have had the materials to make satisfactory 

 comparisons. I think, therefore, that it may safely be admitted that the Aurelia 

 flavidula is the North American Atlantic rejiresentative of the Aurelia aurita of 

 the northern shores of Europe. 



Since Aureliae have been found in every part of the globe, I may be per- 

 mitted here to make some further remarks upon the sjiecies described by different 

 authors, and referred to this genus. The first question which I would submit to 

 zoologists is the following. Is there but one species of Aurelia upon the European 

 coasts, or are there more than one ? All modern authors, Ehrenberg, Milne-Edwards, 

 Sars, Loven, Gegeubaur, who have described the common Medusa of the European 

 shores, call it Aurelia aurita, while older writers, and among them those who have 

 contributed most to give a scientific character to the study of Acalephs, Peron 

 and LeSueur and Eschscholtz, mention several species as found upon the coasts 

 of Euroj^e. Eschscholtz enumerates Medusa aurita, surirea, campanula, granulata, 

 radiolata, tyrrhena, globularis, and crucigera; while Peron and LeSueur enumerate 

 Aurelia suriray, campanula, roseaj melanospila, lineolata, phosphorica, amaranthea, 

 purpurea, and rufescens, to which Lesson adds Aurelia Reynaudii (Biblis Rey- 

 naudii Lesson). Now it is evident to me, that the different stages of growth of 

 our species, and the different states of preservation in which specimens are frequently 

 found at sea, or stranded on the shore, might furnish the means of distinguish- 



