FAMILIES AND GEIfEKA OP THE MADEEPOEAEIA. 



165 



lY. Family ANABAOIAD^. 



Madreporaria Fungida simple or coloDial. Septa trabeculate 

 and fenestrated. Synaptic ula small. Dissepiments absent. 

 "Wall indistinct. 



Genus Anabacia, d'Orb, 

 Genus Genabacia, Ed. & H. 



Grenus Anabacia, d'Orhigny, Note sur les Folyp. foss. p. 11 

 (1849). 



Corallum simple, free and without a trace of adherence, plano- 

 convex or biconvex in sbape. The upper surface bas a central 

 shallow fossette without a true columella. The septa are very 

 numerous, close, uniting, and are continued over the edge to tbe 

 base, wbere their free edges are in the position of costse. Tbey 

 extend from the base vertically to tbe upper surface, are tra- 

 beculate and perforate, and delicately spined or crenulate at their 

 free edge. There is no basal wall, and the septa unite by 

 synapticula. 



Distrihution. — Fossil. Jurassic : England and Europe. 



Genus Genabacia, Milne- Edivards Sf Jules Haime^ Compt. Hend. 

 Acad, des Sci. t. xxix. p. 71 (1849). 



Colony sublenticular, base naked and perforate. A central 

 calice surrounded by one or two circles of smaller size with con- 

 fluent septo-costse. Septa trabeculate, perforate, thin, close 

 rather numerous, crenulated where free. Calicular fossette not, 

 deep. No basal wall. 



Distrihution. — Fossil. Middle and Inferior Oolite ; Europe. 



Transitional group. 

 V. Family PLESIOPOEITID^. 



Eungida with trabeculate and regularly perforate septa. 

 Synapticula between the septal laminae in the iuterseptal loculi. 

 Sclerenchyma trabeculate. Dissepiments may or may not exist. 

 Wall existing or not, and imperforate. Epitheca may exist and 

 be well developed. 



