INTRODUCTION. xxiii 



3. Genus Dendracis. 



Milne Edw. and J. Haime, Comp. rend., t. xxix, p. 70, 1849. 



Corallum arborescent ; ccenenckyma almost compact, with its surface granulated. Calices 

 sub-mammiform. No columella. Septa not exsert, or only very slightly so ; nearly equal. 



Typ. sp., Dendracis Gervillii, nob. ; Madrepora Gervillii, Defranee, Diet, des Sc. Nat., vol. xxviii, p. 8 ; 

 Michelin, Icon., Zooph., pi. xlix, fig. 8. 



4. Genus Aileacis. 



Milne Edw. and J. Haime, loc. cit., p. 70, 1849. 



Corallum massive ; ccenenchyma spongy, with its surface echinulate. Calices with a 

 thiu projecting margin. No columella. Septa unequally developed, entire. 



Typ. sp. Araacis sphceroidalis, nob. ; Astrea sphceroidalis, Michelin, pi. xliv, fig. 9. 



Family III. 

 ASTREIDtE. 



Dana, Exploring Expedition, Zooph., p. 194, 1846. 



Corallum composite or simple, circumscribed by imperforated walls, and often 

 increasing by fissiparity. Corallites becoming tall by the progress of their growth ; each 

 individual or series of individuals well defined, and separated from the others by perfect 

 walls. Ccenenchyma not existing, or being formed either by the development of the costee 

 and their dissepiments, or by the epithecal tissue alone, and not forming a compact mass 

 as in the Oculinidae. The visceral chamber never obliterated inferiorly by the growth of 

 the walls, but subdivided and more or less completely closed up by the interseptal dis- 

 sepiments, which are in general very abundant ; never any synapticulae like those of the 

 Fungidse. 



First Tribe— EUSMILINyE. 



Septa completely developed and entire (that is to say, with their apical margin neither 

 lobate nor denticulate). Costa always unarmed. Columella often compact, or even styliform. 



Section I.— EUSMILINtE PROPRIA. 



Corallum simple or composite, and in that case formed by distinct corallites, affecting 

 an arborescent disposition, fasciculate, or presenting a linear arrangement ; free laterally, 

 at least in a great part of their length, and never having their calices blended together. 

 Reproduction usually fissiparous in the compound species. 



