168 PEOP. p. MAETIN DTJNCAN's KETISION OF THE 



rudimentary or absent. Septa very numerous, close, unequal, 

 often uniting, denticulate where free, trabeculate in construction, 

 witli regular nodules, partly solid and often perforate, then 

 forming a latticework. Synapticula feebly developed, or elon- 

 gate and visible. Dissepiments exist. 



Distribution. — Fossil. Jurassic, Cretaceous : Europe, India. 



II. Alliance MICRCSOLENOIDA. 

 Colonial Plesioporitidae, polymorphous, massive, dendroid, lobed or sub- 

 plane. A wall often present, with costse. Septa trabeculate and perforate. 

 Synapticula present. 



Genus Microsolena, Lamour. 



Genus Polyphylloseris, E. de From. 



Genus Thamnar^a, Etallon. 



Genus DiPLAR^A, Milas. 



Genus Disar^ea, E. de From. 



Genus Dimorphar^a, E. de From. 



Genus LatimjEandrar^ea, E. de From. 



Genus Mkandroseris, Rousseau. 

 The genera Denprar^a, d'Orb., Actinar^a, d'Orb,, Dimorpho- 

 SERis, Duncan, and Meandrar^a, Etallon, are absorbed. 



Grenus Mickosolena, Lamourotix, Exp. MetTiod. des genres des 

 Polyp, p. G5 (1821) ; amended. 



Syn. Bendrarcea, d'Orb. ; Actinarcea, d'Orb. 



Colony massive, polymorphous, mamiiliform, conical, with a 

 broad base, nearly spherical, turbinate and pedunculate, and 

 lobed, gibbous, lamelliform, or digitiform and subramose. Basal 

 wall with delicate costse covered with a strong epitheca. Calices 

 shallow, close or distant without order. Septo-costge straight or 

 curved, delicate, close, confluent, in groups or not, minutely 

 pointed with small spinules above, and formed by vertical tra- 

 beculse swollen regularly and forming a regular latticework of 

 perforations. Columella very small or absent. Synapticula 

 abundant, small. No calicular walls. 



Distribution. — Fossil. Jurassic : England, Europe. Trias : 

 ? Europe. 



Genus Poltphtlloseeis, de Fromentel, Pol. Foss. de Tetage 

 Neocomien, p. 67 (1857). 



Colony massive and convex. Corallites united by a costal 



