3rd 







6 





4tli 







6 



a ; 



5tli 







9 



}} } 



6th 







14 



}) J 



18 PEOCEEDINGS OF THE GEOLOGICAL SOCIETY. [DoC. 4, 



tertiary septa are very small. None of the septa are exsert. The 

 columella is essential^ stoloniform, large and projecting. Diameter 

 of calices -^ inch. 



Locality. Eocene Shales, Jamaica. 



Placoteochtjs SATVKZNrsi, spec. nov. Plate II. fig. 2 a, 2 h. 



The coraUnm is short, turbinate, adherent, and compressed. The 

 epitheca is delicate, and permits the costse to be seen near the calice. 

 The costse are distinct, rather unequal, and are faintly dentate. The 

 calice is deep, and the margin is blunt. The septa are wide apart, 

 the primarj^ are large, slightly exsert, and have a straight inner 

 edge. 



The septal arrangement is very irregular. Thus in the 

 1st system there are 8 septa, or 4 cycles 



incomplete. 



and part of 5th cycle 



49 septa. 



The higher orders of septa are very small ; but their costae are 

 larger. The laminae are ornamented with granules. The columella 

 is small, central, slightly projecting, and lamellar ; about 18 septal 

 ends reach it, and become more or less adherent. 



Height of the coral | inch. Length of the calice | inch. 



Loc. Bowden, Jamaica. 



Siderastrcea grandis, Duncan, becomes under the latest nomen- 

 clature Astrcea grandis, Duncan. 



9. JRemarhs on tlie Antiguan Fossil Corals, and Descrijptions of 

 new species. — The genus Astrcea gives way to that of Eeliastrcm, and 

 the genus Siderastrcea becomes Astrcea. Hence all the Astrseans 

 with thick septa become classified under Heliastrcea crassolamellataj 

 Duncan. 



One of the varieties of this species, var. pidcliella, nobis, is in Sir 

 Charles Lyell's collection of Miocene fossils fi^om Madeira, in the 

 British Museum. There is, moreover, a Heliastrcea in the collec- 

 tion of recent corals in the British Museum, with thick septa at the 

 calicular margin, but it has a low septal number ; nevertheless it 

 renders the existence in the present Coral-fauna of some of these 

 large Miocene Heliastrcew very probable. 



In a former communication, the alliance of Heliastrcea Rochettina, 

 Mich., sp., with the species crassolamellata was omitted to be 

 noticed. Michelin's delmeation of the H. Eocliettina is perfectly in- 

 comprehensible. The species has not four complete cycles, but is 

 larger as regards its corallites than H. Guettardi ; there is no other 

 distinction, however, between these species. The costal structures of 

 H. Guettardi distinguish it from H. axissolcunellcda, nobis ; and the 



