444 PKOCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 6 } 



meila largely developed, consisting of nearly horizontal trabecule 

 from the lace-like septa, and of its special tissne. Tissue spongy, 

 filling up much of the lower part of the calice, and projecting a little 

 at the bottom of the shallow fossa. Septa delicate, a little thicker 

 at the calicular margin than elsewhere, barely projecting; they slant 

 rapidly downwards and inwards, being slightly dentate. Laminae 

 perfect and granular at the wall, but perforate and cellular else- 

 where. In six systems of three cycles. The primary septa are a 

 little projecting at the margin, arched inwards, then become concave, 

 and finally reach the columella ; the secondary either do not reach 

 the columella, or do so by the trabecule, and are a little smaller 

 than the primary ; tertiary often barely developed. Endotheca 

 greatly developed, extending even to the calicular floor; seen, in 

 longitudinal sections, as faint lines on the septal laminae, curved and 

 often oblique, and as cross-bars between the septa at very short in- 

 tervals ; near the calice the dissepiments become oblique, and form 

 complete floors between two septa, or simply join the septal laminae 

 by cross-bars. Exotheca greatly developed, that between the calices 

 formed by wide dissepiments, and marked out into checkered spaces 

 by the costae ; in the spaces a little papillary eminence is now and 

 then seen ; lower down and in longitudinal views the dissepiments 

 are stout, project more than the costae, and form cells generally 

 higher than broad, but occasionally very broad and less high ; they 

 are nearly on the same plane throughout the corallum. There are 

 six dissepiments to y 1 ^ inch. The young buds have not the tertiary 

 septa. Diameter of the calices from -^L- to -^ inch. 



The perforate laminae of the septa, the exothecal development, 

 and the density and compactness of the walls determine the genus. 

 Only one recent West Indian form has been described, differing 

 widely, however, from any other species. The Cyphastrcea oblata 

 from St. Thomas's has few costae and almost confluent walls. The 

 other species inhabit the reefs of New Holland, the Eejees, the Sand- 

 wich Islands, and the Red Sea. There are two Corals doubtfully 

 referred to Cyphastrcea by Milne-Edwards ; they are both from the 

 Lower Chalk, and were originally noticed by Eeuss. 



From the hard superficial limestone. Coll. Geol. Soc. 



VI. Baebadoes. 

 1. Astk^a Baebadensis, spec. nov. PI. XV. figs. 6 a, 6 b. 



Corallum tall, subplane, with tall and slender corallites, which 

 are crowded, but distinct. Calices circular, but slightly prominent 

 and very shallow. Costae well developed, not much produced, ex- 

 cept the primary, which now and then join those of neighbouring 

 corallites ; they are slightly spinous and inclined at the surface, and a 

 little wavy in their longitudinal course, but are distinct and strong at 

 their base. Primary and secondary costae equal, the primary being 

 now and then most produced ; the tertiary do not vary much in size 

 from the others, but are less produced. Septa stout, projecting up- 

 wards considerably from the calicular margin, especially the primary ; 



