108 



PEOP. P. MAETIN DIJTS'CAN's EEYISIOIT OP THE 



the usual attributes of Plesiastrcda present, but the exotheca is 

 in excess and there is an epitheca. The columella is papillary 

 and more concentrated than is' shown in the drawing (pi. iv. 

 figs. 4« & 5). 



This group includes Plesiastrcea distans^P . glohosa, and P. ranea, 

 nobis. 



Another species, Plesiastrcea spongiformis, Duncan, op. cit. 

 p. 39, pi. iv. figs. Qa, 6&, requires a new generic environment. 



G-enus Aisttillaste^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, projectiag, endiag in exotheca, which is 

 cellular and well developed. Endotheca scanty. Epitheca rudi- 

 mentary. 



Distrihution. — Fossil. Miocene : San Domingo. 



II. Alliance PLACOCCENIOIDA. 



Massive budding Astrseidse, with corallites united by costse 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. 



Genus Placoc(enia, d'Orligny, Note sur les Polyp, foss. p. 7 

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



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

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

 three papillae. Septa entire, unequal, of the decameral or of hexa- 

 meral type. Costse thick and well developed, cristiform or 

 granular. Gemmation between the calices. 



Distrihution. — Fossil. Oolite and Cretaceous : Europe. 



^Genus Placophoea, F. de Fromentel, Pal. Fran^., Zooph. Terr, 

 cret. p. 495 (1879). 



Colony expanded, with a subplane surface formed by close 

 laminae, 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 



