422 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 6, 



From the Upper Parian of Trinidad (Wall & Sawkins's Coll.), and 

 the Marl-formation of Antigua. Coll. Geol. Soc. 



9. Asthma costata, spec. nov. PL XIII. fig. 9. 



The specimens of this species which I have examined present 

 polished longitudinal and transverse sections of corallites, but I have 

 seen no calices. Corallites long, parallel, sometimes deformed, 

 generally circular in transverse outline, not crowded, but close, vary- 

 ing in size. Intercorallite spaces very distinct. Walls thin, not 

 thicker than the delicate septa. Costaa large alternately, both sizes 

 equally produced; wedge-shaped at the wall, pointed, and often 

 bent at the free end. Septa all delicate and linear near the columella 

 and in the middle ; at the wall their base is narrower than that of 

 the costaa. They are arranged in six systems, the cycles being very 

 irregular. In three systems there are three cycles, and in the rest 

 an incomplete fourth ; rarely there are two systems with four com- 

 plete cycles ; the fourth and fifth orders often curve towards the 

 third order. Lamellae rather cribriform, joining the columella by 

 oblique processes. Columella lax, small, and formed by dissepiments 

 from the septa and a central spongy mass. Endotheca very abun- 

 dant, vesicular, and horizontal, with four or five dissepiments in 

 -^inch. Exotheca abundant, nearly equal to the endotheca. Repro- 

 duction by extra- calicular budding. Diameter of the corallites from 



T 3 o to A incl J- 



This species is closely allied to the Astrseans with great endothe- 



cal development, and especially to Astrcea vesiculosa, Edwards and 



Haime, from Dax, as well as to A. Antillarum, nob., and A. endothe- 



cata, nob. 



10. SoLENASTRiEA Tttroxexsis, Michelin. 



Some imperfect specimens of this species from Antigua are con- 

 tained in the collection of the Geological Society, but they add 

 nothing to our knowledge of the species. 



11. ISASTILEA COXFERTA, Spec. nOV. PI. XIV. fig. 2. 



Corallites very close, tall, slender, straight, and prismatic ; a 

 transverse section shows the wall to be very thin. The breadth of 

 the corallites varies from -^ to -^ inch. Septa very numerous, 

 linear ; the primary extend to the centre of the corallite, the second- 

 ary less so, and the others join the larger septa at a very acute angle ; 

 all are very slender and excessively crowded. There are eighty-two 

 septa in the larger corallites, sixty in the smaller. The septa of one 

 corallite do not join those of the next, but end sharply at the wall. 

 Endotheca plainly exists, linear, appearing, in transverse section, to 

 divide the interseptal loculi into several cells. The reproduction is 

 by submarginal budding. The sclerenchyma has been replaced by 

 dark homogeneous silica, and the interspaces by porcellanous and 

 opaline silica. 



From the Chert-formation of Antigua. Coll. Geol. Soc. 



This is a very remarkable form. Unfortunately no calices exist ; 



