16 BRITISH FOSSIL CORALS 



Family— riJNGID^]. 



Ge}ws — Thamnastr^a. 

 1. THAMNASTRiEA Browni, Buiican. PI. II, figs. 1 — 5. 



The corallum is variable in shape, and appears in two series of orms : 1st, as a nearly 

 globular mass with a very small base ; 2nd, as a pillar-shaped corallum, terminating in a 

 knob. 



The calices are large, and have wide and rounded margins ; they are shallow, and do 

 not present any appearance of columellse. 



The septa are large, unequal, broadly dentate, arched, and not crowded. There are 

 six systems and four incomplete cycles. 



The costse pass down the base of the corallum in long, parallel, wavy lines ; they are 

 sub-equal, broadly dentated above, and most so below, where they become more equal 

 and more level. 



The epitheca is scanty, but covers the costee here and there. . 



Breadth of cahces i%ths inch. * 



Locality. Great Oolite, Cirencester. 



In the Collection of T. C. Brown, Esq., and in the British Museum, 



VII. Description of New Species from the Inferior Oolite. 

 Family— ASTRtEID^. 

 Genus — Montlivaltia. 

 1. Montlivaltia Holli, Duncan. PI. I, figs. 5 — 8. 



The corallum is cornute, tall, and slightly compressed laterally. 



The epitheca is very strong and plain, but marked with transverse folds and slight 

 costal strise. 



The calice is elliptical, rather deep, open, and has a thin margin. 



The septa are very unequal as regards the higher orders, but the primary and 

 secondary are equal, slightly exsert, and convex on the upper margin. They are mode- 

 rately prominent in the calicular fossa. The other septa are much smaller. There 

 are six systems and four cycles in each and part of the fifth. The appearance is that 

 of twelve systems of three cycles. 



