1863.] DUNCAN WEST INDIAN COEALS. 423 



but the transverse view of the corallites is excellent. If the speci- 

 men had been found in Oolitic rocks, it would have passed for a small 

 variety of Isastrcea tenuistriata. 



12. ISASTEiEA TUKBINATA, Spec. n0V. PI. XIV. figs. 1 rt-1 C. 



Corallum 7 inches high, subplane and irregularly convex above, 

 broad and gibbous at the sides, small and conical at the base, whence 

 the corallites radiate ; upper surface ridged with the elevated mar- 

 gins of more or less polygonal, close calices. Corallites very long, 

 slender, and prismatic, excessively crowded. Walls united, simple 

 throughout. Calices very numerous, irregularly pentagonal, not 

 deep, and not packed geometrically. Margins existing as sharp 

 ridges, not marked by the septa, but faintly ragged ; united, crowded, 

 not deep. Septa small, not exsert, not arched, but slanting irregularly 

 downwards and inwards, except the primary, which stand up in the 

 fossa, and are easily seen ; they are laminar, delicate, and crowded, 

 slightly toothed near the internal end, ragged above, and granular 

 on the sides. The primary septa sometimes meet by their inner 

 ends ; the secondary and tertiary are subequal when there are 

 others. They are disposed in six systems. In fully developed 

 calices there are four cycles in four systems, and three in the rest ; 

 in other calices three cycles with an occasional fourth order ; the 

 fourth cycle is very small. Septa straight, not crenulate, but slightly 

 ragged ; no external spines. Endotheca tolerably developed. From 

 the condition of the base, which has been rolled, no epitheca can be 

 seen. Reproduction by submarginal (close to the Avail) gemmation. 

 Diameter of the calices from 2 lines to 3^- lines. 



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



Fossilization very like that of Isastrcea oblonga in the British Port- 

 land Oolite. 



The affinities of these two Corals with the Isastrcece are not to be 

 mistaken; and their occurring in the Chert of Antigua, where they are 

 associated with the Miocene Astrocoenia ornata, is very remarkable. 



13. Stephanoccenia tenuis, spec. nov. PI. XIV. figs. 3 a, 3 b. 



Corallites very long, slender, nearly straight, prismatic, and closely 

 approximated; sometimes less prismatic than cylindrical. "Walls 

 thin. Calices wanting; but there are several polished sections of 

 the corallites which show a pentagonal or hexagonal outline ; occa- 

 sionally a circular outline is seen. Columella obscurely preserved, 

 but well enough to be recognized as styliform. Pali long, distinct, 

 like prolongations of the septa to the columella ; opposed to all the 

 primary septa, and to the secondary where the third cycle is com- 

 plete. Septa delicate, straight, very little thicker at the wall than 

 elsewhere ; slightly granular, and not crowded. They are disposed 

 in three cycles, the third being often wanting in some systems, or in 

 some half- systems, in imperfectly developed corallites. The primary 

 and secondary septa are nearly equal when the third cycle is com- 

 plete ; the tertiary do not reach halfway to the columella, and are 

 straight. Reproduction by marginal budding. 



