574 SYDNEY J. HICKSON. 



are occasionally found in Tubipora, exactly similar to the flat 

 tabulse of Favosites, the convex tabulae of Michelinia, the 

 lappet- or tongue-shaped incomplete tabulae of Pachypora, 

 and the funnel-shaped tabulae of Syringolites, and that tabulae 

 are quite unknown amongst the Poritidae — the family which is 

 supposed to be most nearly related to the Favositidae — we must 

 look upon these structures as evidence, if any, in favour of 

 the Favositidae being Alcyonarians. But the evidence in favour 

 of the Alcyonarian affinities of the Favositidae does not come 

 entirely from the side of Tubipora, for, as Professor Moseley 

 (17) has pointed out, there is strong evidence of close relation- 

 ship between Heliopora and Favosites. 



Professor Moseley also points out that the signs of Favosites 

 forbesi being dimorphic is also in favour of this affinity ; and 

 this point becomes of greater importance as our knowledge of 

 the Alcyonarians increases. KoUiker has pointed out that in 

 such closely allied genera as Heteroxenia and Xenia, the former 

 is dimorphic, the latter is not. Again, in such closely allied 

 genera as Paragorgia and Briareus the former is dimorphic 

 and the latter is not; and I have just been informed by Mr. S. 

 Ridley, who has been investigating the Alcyonarians brought 

 back by H.M.S. '^ Alert,'' that the genus Melitodes is also 

 dimorphic, whilst, as far as I am aware, the genera most 

 nearly allied to it are not dimorphic. Thus, a tendency for 

 various genera to become dimorphic seems to be a characteristic 

 feature of the Alcyonaria, a feature, moreover, which, as far as 

 I am aware, is entirely unknown amongst the Zoantharia, and 

 consequently the evidence bearing upon the question afforded 

 by Favosites forbesi, which was apparently dimorphic, is not 

 without considerable weight. 



Thus, I think that taking all things into consideration, the 

 evidence at our command tends to prove that the Favositidae 

 are really Alcyonarians, and that Syringopora is also an 

 Alcyonarian allied to Tubipora. 



