140 PEOr. p. MAETIJ^ DUNCAI^'S REVISION OE THE 



Grenus Eeussastr^a, d'AcJiiardi, Goralli Bocen. del Friuli 



(Pisa, 1875), p. 67, tav. 13. fig. 2 ; amended. 

 Colony in tlie shape of a lamina more or less thick. Calices 

 distinct, numerous, varying in their distances, shallow. Septa 

 confluent with those of neighbouring calices. Columella lamellar 

 and essential. Calicular wall ill defined. Dissepiments well 

 developed, arched. Synapticula exist ; and the solid septal laminse 

 are very granular. 



Distribution. — Fossil. Eocene : Europe, Sind, Asia. 



Grenus Dimorphastr^a, d'^Orhigny, Bev. et Mag. de Zool. p. 177 

 (1850), amended ; Milne-Fdwards 4" Jules Haime, Hist. Nat. 

 des Gorall. vol. ii. p. 585 (1857). 

 The colony is pedunculate or not, flat on the upper surface, 

 rarely convex, more or less circular in outline. Corallites 

 arranged around a large central parent in distant concentric 

 circles. Columella papillary and small. Septo-costse confluent. 

 Synapticula exist. Common wall striated or not, naked. 



Distrilution. — Fossil. Cretaceous : Europe, Hindostan, Asia. 



Grenus DiMOEPHOccEifiA, de Fromentel, Polyp, foss. de V Stage 

 Neocomien, p. 55 (1857). 



Colony in a tolerably thin lamina. Corallites disposed in con- 

 centric rows around a central parent. Plateau naked and costu- 

 lated. The septa are entire, and almost all radiating from the 

 centre to the circumference. There is no columella. 



M. de Eromentel states that this genus corresponds in the 

 Eusmilian family with the genus Dimorphastrcea, the distinction 

 being the entire nature of the septa in tbe first-named genus and 

 the absence of a columella. There are synapticula. 



Grenus Sttlom^A]S"dra, F. de Fromentel, Fal. Fran^., Terr, 

 cret. p. 457 (1877). 



The genus Stylomcsandra, according to M. de Fromentel, is 

 clearly allied to the genus Latimcsandra, and is only really dis- 

 tinguished by having a styliform columella in the centre of the 

 calices. 



The figure shows (pi. 113. fig. 3) a broad colline covered 

 by confluent costse. It appears that this genus is hardly near 

 Latimceandra, and that it is possibly one of the Thamnastrsean 

 alliance, where it is placed with doubt. 



