98 



PEor. p. MAETiN Duncan's eevision or the 



Milne-Edwards and J ules Haime formed a subgroup of compound 

 or colonial corals, which they placed between the Astraeidse which 

 multiply by successive fissiparity and those which increase by gem- 

 mation only, the corallites in both instances being united by their 

 walls or by intermediate structures. This group, the Faviacese, has 

 genera the individuals of whose species increase by fissiparous 

 division, and do not form series or have meandroid calices, but 

 grow upwards independentlj' so soon as to give the appearance of 

 budding having taken place. The septa are always dentated and 

 not entire. Now this group has greater affinities with the fissi- 

 parous Astrseidse than with those which increase by budding, 

 and, moreover, a critical examination of its genera shows that it 

 is not homogeneous. 



The genus Mcemidrastrcea, d'Orb., clearly belongs to the alliance 

 in which Coeloria, Mwandrina, and Leptoria are placed, and it has 

 been noticed therein. 



The genus Favia, Okeu, with its intermural coonenchyma and 

 fissiparous and almost serial calices, is an ally of Dichocoenia, the 

 distinction of the septal-edge structure being insufficient to sepa- 

 rate the genera into subfamilies. 



On the other hand, Goniastrcea, Septastrcea, and AphrastrcBa 

 should form an alliance, and be placed amongst the fissiparous 

 Astrseidse. 



Eighteen genera are recorded, but only thirteen remain after 

 revision. 



Alliances : — Eavioida, Goniastrseoida. 



I. Alliance FAYIOIDA. 



Massive fissiparous Astrseidse. Corallites united by costse and coenen- 

 chyma. Calices projecting but slightly or not at all above the common 

 surface. Series very short, or only due to imperfect separation of the 

 fissiparity. Septa entire or not. 



Tribe I. Septa entire. 

 „ II. Septa dentated. 



1. Genus Dichoccenia, Ed. & H. 

 Genus Barysmilia, Ed. & H. 

 Genus Stenosmilia, E. de From. 

 II. Genus Favia, Oken. 

 Genus Favoidea, Reuss. 

 Genus Baryphyllia, E. de From. 

 Genus Spinellia, D'Achiardi. 



