180 CALYCOPHORAE. 



form is only of minor significance in phylogeny, in the present case it assumes 

 unusual importance because there is a remarkable parallelism in this respect 

 between the various Monophjads and the other more complex Calycophorae. 

 Thus, one group of Monophyids, the Sphaeronectids, resembles the Prayids 

 both in nectophore and Eudoxid, a second, represented by Cuboides, is, 

 in both these respects, of the Abylid type, while the components of a third, 

 Muggiaea and Doromasia, parallel Diphyes and Diphyopsis to such a remark- 

 able degree that they might readily be mistaken for each other; and finally 

 there is a recently discovered genus, Nectopyramis (p. 191), where the somato- 

 cyst, represented by a series of branching canals, recalls that of Stephanophyes 

 and of Nectodroma (p. 205). 



Of course the important question is, are all these Monophyids primitive 

 types, as the simplicity of their organization suggests, or are some of them 

 primitive, others degenerate. The first view is the one which has generally 

 been held (Haeckel, '88b, Chun, '97b). Schneider has recently maintained how- 

 ever, that while the Sphaeronectids are primitive, Muggiaea is merely a Diphyes 

 with the second nectophore aborted. Sphaeronectes, judging from the adult, 

 has an excellent claim to be regarded, as ancestral, because its definitive necto- 

 phore so closely resembles the transitory primary nectophore of Hippopodius 

 that it may reasonably be considered homologous with that structure, though 

 whether or not correctly, can be determined only when the development of 

 Sphaeronectes is studied. The case of Muggiaea is not so easily settled. 



In the first place the definitive bell of Muggiaea is not the primary bell; 

 the latter is early lost just as it is in Hippopodius and in Galeolaria. Then too, 

 we must consider the parallelism between Muggiaea and Doromasia on the one 

 hand, and Diphyes and Diphyopsis on the other, which is complete even to 

 the most trivial details of nectophore and of Eudoxid. The resemblance is 

 too close to be accidental ; the only reasonable conclusion is that either Diphyes 

 has been derived from Muggiaea, or Muggiaea from Diphyes. Schneider's 

 conclusion that Diphyes is the parent, Muggiaea the derivative, can be justi- 

 fied only on the assumption that Muggiaea becomes mature before the appear- 

 ance of the second bell, which fails to develop, and of course, precisely the same 

 ground might be taken from which to argue that Cuboides, of which the develop- 

 ment is unknown, is an Abylid with the second bell aborted, though in this case 

 the parallelism in the form of nectophore and Eudoxid is much less close than it 

 is between Muggiaea and Dyphyes. The entire absence of even the trace of 

 a bud for a second nectophore in all the many specimens of Muggiaea which 



