14 THE MEDUSAE. 



I fully agree with Maas (: 07), indeed, I think that no actual student 

 of the Scyphomedusae will now dispute, that the Charybdeida are a very 

 aberrant group. But I think it very doubtful whether the three remaining 

 groups which he enumerates — Stauromedusae, Coronata, and Discophora — 

 do actually form a phylogenetic series as he suggests (: 07, p. 193). To 

 assume this seems unwise until we have a clearer idea of the affinities of the 

 Lucernarida. For even if we accept the view that the Lucernarida are 

 in reality not Medusae at all but Scyphistomata which attain sexual maturity, 

 and that their fixed habit is therefore a primary, not a secondary, character, 

 we cannot safely assume that they are necessarily ancestral forms. On the 

 contrary, it is entirely possible that they ought rather to be regarded as off- 

 shoots of one of the more highly developed groups. Furthermore, although 

 it will, I think, be generally admitted that the relationship between Coronata 

 and Discophora is closer than Vanhoffen's separation of the Scyphomedusae 

 into Cathammata and Acathammata suggests, yet there is strong evidence 

 against regarding these groups as connected by a direct genetic relationship. 

 Though we may not regard the presence or absence of septal nodes as of 

 the first importance in classification, yet these structures are of morphologic 

 importance and of regular occurrence among the Coronata; and there is con- 

 siderable evidence, as we know from the studies of Claus ('83) on the 

 development of Nausithoe, for regarding them in the Coronata at least, 

 even if not in the Charybdeida, as partly, if not wholly, homologous with 

 the original taeniolae of the scyphistoma. Like so many problems in 

 medusology, this is a question requiring further embryologic study; but 

 should the septal nodes of the Coronata actually prove to represent the 

 taeniolae, their phylogenetic significance in classification would, of course, be 

 very great. At any rate, their presence in the Coronata and absence in 

 the Discophora suggests a parallel, rather than a serial, relationship between 

 the two groups. 



Maas's provisional scheme shows an apparent shortcoming in that it 

 provides no place for the Tesserida, since he states that the Stauromedusae 

 are "Tesserida auszuschliessen " (: 07, p. 193); but in any formal classi- 

 fication of the Scyphomedusae some place must, of course, be found for 

 this group. Considering the fid thai their affinities, and even many points 

 in their structure, are very problematical, it seems to me as well, to 

 retain them provisionally among the Stauromedusae. Various ideas as 

 to theii ignificance have been entertained, li is by no means necessary to 



