2 49 
primitive chaiactei, which is to be compared with the mesenterial character of the normal 
Actinia, especially in view of their relative position. But they are neither of the opinion of 
van Beneden that the Antipatharia ought to be combined with the Ceriantharia. If the latter 
are sepaiated from the lemaining Actinia in view ol their zone of growth, one must be 
consequent and separate them also from the Antipatharia, which in this respect are different 
from them. 
We find extensive discussions of these questions in Roule (13 and 14). In 13 Roule 
gives a leview ol former opinions, and joins van Beneden s opinion. In this respect Roule 
refeis to his examination of Stichopcithes- species, the bodywail of which, with its thick meso- 
gloea is pi ecisely like that ol young Cevianthus- larvae, before the ectodermal musclefibres 
appear. He emphasizes the primitive character of the Antipatharia, which through their faculty 
of budding and the lorming of fixed colonies have not disappeared as their ancestral types, 
and which are only higher developed in the shape of the colonies, while the individual polyps 
have presei ved their ancient character. Roule places the Rugosa, Antipatharia and Ceriantharia 
together as Protanthozoariae opposite the other Anthozoa, which form the Metanthozoariae. 
As to the thickness of the mesogloea with Stichopathes- species, the value, which Roule gives 
to it, is discussed by me and rejected in the review of the anatomical results. 
Roule gives more arguments in 1905 (14) in his more extensive publication. In the first 
place he advocates the relation between the Antipatharia and the Ceriantharia, opposite Delage 
and Herouard. According to Roule the likeness was not sought in the zones of growth but in the 
characters of the primary mesenteries, for, as to these mesenteries and their interseptal chambers, 
the situation is the same as in Cennula , so that there is an undoubted homology between these 
situations, lasting in the one, transitory in the other. Roule also sees a microscopical anatomical 
relation with the Ceriantharia; but it is to be regretted for his arguments that his own research 
on this point is not very convincing since his material is scanty and badly preserved, so that his 
conclusions are not always permitted. Roule points out that the Antipatharia and the Ceriantharia 
have in common: a homogeneous, thick mesogloea, no mesenterial musclefibres, a simple, not 
differentiated entoderm, all points in contrast with the other Anthozoariae. I have to add to 
this, that it is true that formerly the zones of growth were not used as an argument for com¬ 
bining the Antipatharia and the Ceriantharia, but that this fact makes it not less true that these 
zones are an obstacle for that union, when they are also used to keep other groups apart. — 
The homology ot the mesenteries with those of Cennula cannot be very great when we keep 
in view that other mesenteries may be fertile beside the transversal mesenteries, and also the 
entirely different arrangement of the musclefibres and the existence of mesenterial filaments on 
other mesenteries at the side of the transversal ones. All this indicates that there is an accidental 
likeness between both conditions ol the mesenteries, without a more fundamental connection., 
no more than that the twelve mesenteries of Leiopathes could be compared with those of the 
Halcampu /a-stage. - — As to the microscopical anatomical arguments, I have only to refer to the 
several Antipatharia with well developed musclefibres on their mesenteries, longitudinal fibres 
as well as transversal ones, and to the several cases, where cells were found in the mesogloea, 
oval ones or even stellate cells. — Even so the abundant pigmentation of the actinopharyngeal 
S1BOGA-EXPEDITIE XVII. 
