BIGELOW: MEDUSAE FROM THE MALDIVE ISLANDS. 247 
shown in the following table. The mark 0 signifies that the species 
is represented by an exceedingly closely allied, if not identical form. 
Species, Atlantic. | Pacific. | Indian. 
? Dipurena fragilis Mayer. 0 - 
Messonema coerulescens Brandt. + + 
Rhopalonema typicum Maas. 0 a - 
Aglaura prismatica Maas. 0 + + 
Aeginella dissonema Haeckel. + + + 
Nausithoe punctata Kolliker. + 0 -- 
Porpita lutkeana Brandt. + 
Diphyopsis appendiculata Agass. & 0 ob ao 
[Mayer 
Physalia megalista Péron. 0 “+ 
Considered from the standpoint of morphology, many of the new 
species are of interest, since they differ from their nearest allies in 
important structural characters. Such species are : Euphysa tetrabrachia, 
the only Euphysa possessing three prominent short tentacles ; Timoides 
agassizii, the only Leptomedusa possessing blind centripetal canals in 
the bell wall; Aurelia maldivensis, the only Aurelia with long pendent 
mouth parts. Taken as a whole, the new species uniformly show a 
very decided separation from their near allies in the Atlantic and 
Pacific, and there is only one, Dipurena fragilis, which seems to be 
a geographic race of a well-known Atlantic form. 
The Maldive islands form in every respect a typical tropical coral reef 
region, and a comparison of their Medusa fauna with that of similar 
regions in the Pacific and Atlantic is therefore of interest. Such other 
regions, of which the Medusae have been studied, by A. Agassiz and 
A. G. Mayer (see Mayer, Bull. Mus. Comp. Zodl., vol..37, and Agassiz 
and Mayer, Bull. Mus. Comp. Zodl., vol. 32, no. 9), are the Fiji Islands 
and the Tortugas. 
Taking first Fiji, we find the following conditions. The two areas 
have in common the following thirteen genera: Aeginella, Aglaura, 
Bougainvillia, Kirene, Eutimeta, Gonionemus, Liriope, Oceania, Aure- 
lia, Nausithoe, Beroe, Diphyopsis, and Physalia. But of these thirteen 
only four are represented by the same species. These are Aeginella 
