COELEXTERATA CXIDARIA 



SUB-BRANCH II 



of the thickened and fused septal edges ; sometimes it is invested with epitheca 

 and furnished with vertical rugae or root-like processes. A true coenenchyma 

 is absent. In a few genera the calice is provided with a lid or operculum, 

 which may be composed of one (Calceola) or of several plates (Goniophyllum). 



With the exception of a few genera whose systematic position is uncertain, 

 all the typical TetracoraUa are confined to the Palaeozoic rocks. They are 

 probably the ancestors of the imperf orate Hexacoralla. 



Family 1. Cyathaxonidae. Milne-Edwards and Haime. 



Turlinatc or horn-shaped coralla, occurring only simple. Septa with regt/In,- 



radial arrangement. Tabulae and dis- 

 sepiments absent. 



Cyathaxonia, Mich. (Fig. 106). 

 Acutely pointed, conical. Cardinal 

 septum in fossula. Septa numerous, 

 extending inward as far as the 

 strongly developed styliform and 

 considerably elevated columella. 

 Carboniferous Limestone ; Belgium 

 and England. 



Duncanella, Xich. Corallum top- 

 shaped. Septa nearly all of uniform 

 length and size, forming a spurious 

 columella in centre of the deep calice, 

 exsert at the base. Silurian ; North 

 America. D. lorenlis, Xrch. 



Petraia, Miinst, (Fig. 107). Tur- 

 binate or conical. Septa short, 

 reaching to the centre only at the 

 Columella absent. Ordovician to Carboniferous. 



FIG. 106. 



Cyathaxonia 



cnrnii, Mir.h. 

 ( 'a rlion ifVrnr.s 

 Limestone; 

 Toumuy. Cor- 

 allum" with 

 fractured theca, 

 showing open 

 interseptal 

 loculi. 2/1- 



Petraia 

 Must. Devonian; 

 Enkeberg, near 

 Brilon. Vl- a, Cor- 

 allum viewed from 

 the apex ; 6, Trans- 

 verse section below 

 the middle. 



FIG. 10S. 



PolycoeJw pro- 

 funda, Germ, 

 sp. Zechstein ; 

 Gera. l/i (after 

 Roemer). 



base of the very deep calice. 



Polycoelia, King. (Fig. 108). Horn-shaped. 

 Calice very deep; four principal septa reach 

 nearly to its centre, between which in each 

 quadrant are five shorter septa. Zechstein. 



Kanophyllum, Dyb. Ordovician and Silurian. 



Family 2. Palaeocyclidae. Dybowski. 



Coralla simple, discoidal, or bowl-shaped. Septa 

 numerous, stout, approaching radial symmetry in 

 disposition. - Tabulae and dissepiments wanting. 



rl<ieocijdus, E. and H. (Fig. 109). Discoidal 

 to depressed top-shaped, with epitheca. Septa 

 numerous, radially disposed, the larger ones 

 reaching to the centre. Silurian. 



Oombophyllum, Baryphyllum, E. and H. 

 Devonian. 



Hadrophyllum, E. and H. Cushion-shaped, with epitheca. 

 septal fossula, that of the cardinal septum being the largest, 

 and North America. 



FIG. 109. 



i>,Lin. Silurian; 

 Gottland. ". Tnp 

 view of calice; 

 b, Profile. 1/1. 



FIG. 110. 



M ic rocyct " > 

 discus, Meek and 

 Worth. Hamil- 

 ton (Devonian); 

 North America. 

 J/i. ", (.'i>rallum 

 from below; 

 I, from above 

 (after Nicholson). 



Calice with three 

 Devonian ; Eifel 



