CALYCOPHORAE. 181 



have now been examined (p. 185) is a strong argument against this view, and, 

 furthermore, the essential difference between Prayids and Hippopodids on the 

 one hand, and Diphyids and AbyUds on the other with respect to the second 

 nectophores indicates clearly that the two groups have originated from different 

 Monophyid ancestors: i. e., the former from Sphaeronectids, the latter from 

 Muggiaea- and Halopyramis-like forms. Thus there are both structural and 

 phylogenetic reasons for adopting the Muggiaea-Diphyes, rather than the 

 Diphyes-Muggiaea sequence. For the case of Doromasia, and its relation- 

 ships to Diphyopsis, see p. 205. For this reason I have recognized Chun's 

 Monophyidae, but since Monophyes is undoubtedly a synonym of Sphaero- 

 nectes, the name of the family must be changed to Sphaeronectidae. 



The accompanying diagram will represent the probable relationships of 



Sphaeronectidae 



Diphyidae 



/\ \ 

 / Amphicary- Stephanoph- V Abylinae 



oninae yinae / ' 



/ 

 Hippopodiidae / Galeolariinae 



Prayinae Diphyopsiinae 



the Calycophorae better than a linear arrangement. The various families and 

 subfamilies may be defined as follows : — (the definitions of the subfamilies are 

 practically those of Chun, '97b, p. 12). 

 1. Sphaeronectidae — only one nectophore. 



1. Sphaeronectinae. With rounded nectophore probably representing 

 the ''primary" bell of the non complex Calycophorae. 



2. Muggiinae. With pyramidal nectophore of Diphyid or Abylid outline. 

 The definitive nectophore is a secondary bell. 



3. Nectopyramidiinae. With rounded nectophore : the somatocyst repre- 

 sented by a system of branching canals. 



Diphyidae Eschscholtz. With 2 (or temporarily 3 or 4 nectophores: the oldest 

 definitive nectophore differs from the one (s) subsequently formed in 

 the presence of a somatocyst. 

 1. Abylinae L. Agassiz. Superior nectophore prismatic and much smaller 

 than the inferior one. Free Eudoxids have prismatic bracts. 



