304 



ZOANTHARIA. 



fluent with those of neighbouring cups by means of septo-costal 

 prolongations. The septa appear to be sometimes perforated, 

 sometimes imperforate (Duncan), and both dissepiments and syn- 

 apticula are developed, a variably shaped columella being also 



Fig. 184, 

 Surface of 

 Zittel.) 



— A, Surface of Thamnastreea agaricites, from the Cretaceous deposits of Gosau ; rs, 

 Comoscris conferta, from the Oligocene Tertiary of Vicenza, enlarged twice. (After 



present. Closely allied to Thamnastreea is the Jurassic genus 

 Clausastrcea. 



Family 2. Fungidce. — In the true Fungidce the corallum is simple 

 or compound, the interseptal loculi showing numerous synapticula, 

 but there being no dissepiments. The septa are usually imperfor- 

 ate, and the basal wall is generally perforated. As restricted by 

 Duncan, this family comprises no other fossil genus than the Micra- 

 bacia of the Cretaceous rocks. In this genus the corallum is of 

 small size, free and unattached, of lenticular form, with a convex 

 base covered with a perforated basal plate. 



Family 3. Lophoserida. — In this family the corallum may be 

 simple or compound, the wall being imperforate, and the septa also 

 usually solid. There are synapticula, but no dissepiments. The 

 simple forms of this family may be turbinate, discoid, or attached 

 by a wide base, and are represented in Secondary and Tertiary 

 deposits by various generic types (Trochoseris, Cycloseris, Fodoseris, 

 &c.) The composite types have their calices united by confluence 

 of the septo-costae, and usually possess a thin laminar or frond-like 

 corallum. Besides such recent genera as Lophoseris and Mycedium, 

 we have here a number of fossil types, some of which (such as 

 Frotoseris and Comoseris, fig. 184, b) are found in rocks as ancient 

 as the Jurassic. 



Family 4. Anabacidce. — This small family includes only the two 

 genera Anabacia and Genabacia, the former being simple and the 

 latter composite, and both being confined to the Jurassic rocks. 

 The septa in these genera are perforated, and the wall is indistinct, 



