108 PROi'. p. MAETiisr dttncan's bevision" op the 



the usual attributes of Plesiastrcea present, but tbe exotbeca is 

 in excess and tbere is an epitbeca. Tbe columella is papillary 

 and more concentrated tban is sbown in tbe drawing (pi. iv. 

 figs. 4» & 5). 



Tbis group includes Plesiastrcea distans,P. glohosa, and P. ranea, 

 nobis. 



Anotber species, Plesiastrcsa spongiformis, Duncan, op. cit. 

 p. 39, pi. iv. figs. Qa, 65, requires a new generic environment. 



Grenus Antillaste^a, gen. nov. 



Colony very convex above, pedunculate and attached. Calices 

 close, barely projecting ; fossula shallow. Columella cylindrical 

 and flattened in young, styliform in old calices. Septa sub- 

 equal, few, well developed. Pali before all cycles except the 

 last. Costse subequal, projecting, ending in exotbeca, which is 

 cellular and well developed. Endotbeca scanty. Epitbeca rudi- 

 mentary. 



Distribution. — Fossil. Miocene : San Domingo. 



II. Alliance PLACOCCENIOIDA. 



Massive budding Astrseidae, with corallites united by costae or by exo- 



theca. Septa entire. Columella lamellary, or a septum reaches the axial 



space. 



Genus Placoccenia, d'Orb. 



Genus Placophora, E. de From. 



Genus Pleurostylina, E. de From. 



Grenus Placoccenia, d''Orbigny, Note sur les Polyp, foss. p. 7 

 (1849) ; Goldfuss, Petr. Germ. pi. 24. fig. 2. 



Colony massive. Calices largCj circular, or oval, rather distant, 

 united by costse. Columella lamellar and well developed, or in 

 three papillge. Septa entire, unequal, of tbe decameral or of hexa- 

 meral type. Costse thick and well developed, cristiform or 

 granular. Gremmation between the calices. 



Distribution. — Possil. Oolite and Cretaceous : Europe. 



^Grenus Placophoba, E. de Fromentel, Pal. Frang., Zooph. Terr, 

 cret. p. 495 (1879). 



Colony expanded, with a subplane surface formed by close 

 laminse, slightly granular on the surface, on which the calices are 

 free to a slight extent. Calices round or slightly oval, distant 

 (5-8 mm.). Columella large, lamellar. Septa well developed 



