IXr. P. M. Duncan on some Fossil Cor ak from Stnde, 303" 



18. Trochoseris aperta, n. sp. PL XIX. fig. 5. 



The corallum is simple, conical, and short ; it is circular and 

 nearly flat above, except at the fossa, but slightly pedunculated 

 inferiorly. The upper surface consists of a central, irregularly 

 circular, and deep fossula, surrounded by a subplane and wide 

 rim, which is marked by numerous and slightly exsert septal 

 prolongations. The external edge of the rim is sharp and is in 

 contact with the epitheca, which is marked slightly by the costal 

 continuations of the septa of the rim. The fossula contains the 

 projecting primary septa, a small flat columella, and the numerous 

 small septa. The septa are in six systems; and in calculating 

 the cycles the horizontal septa of the rim must be considered, 

 although all of them do not reach the fossula. The cycles are 

 in-egular, and there are five, with several septa of the sixth. 

 The primary septa are the thickest, and project most into the 

 fossula; but they and all the others are very slightly exsert, and 

 the spaces between them are either closed (as on the rim) by a 

 horizontal floor which hides the numerous synapticulse, or (as 

 in the fossula) by the synapticulae. The primary septa, where 

 projecting, are granulated laterally. The secondary septa are 

 distinguishable within the fossula, but not on the rim. The 

 septa of the highest orders extend only a slight distance from the 

 external edge of the rim, and all are more or less dentate. The 

 costse are faint elevations covered with epitheca. The synapti- 

 culse are very numerous. Height of coral 1 inch. Width of 

 upper surface 1^ inch., of the fossula -^ inch ; depth of fossula 

 -rV inch. 



From the Sinde Tertiaries, Kurrachee. Coll. Brit. Mus. 



The form would resemble a large pedunculated calice of a 

 Mycedium with a circular rim including the costse. I do not 

 consider, however, that it is the parent calice of a compound 

 species. It has only a slight affinity with Trochoseris distorta 

 of the French Eocene. 



19. Cyathoseris Valmondoisiaca, var., Edwards & Haime. 

 The variety has a broader base and a greater disposition to 

 run into series as regards the calices than the type. The synap- 

 ticulse are numerous, and the "collines" are well developed. 

 The species is found in the French Eocene at Auvert, Valmon- 

 dois, Assy, and Bouconvilliers. (See Michelin, Icon. Zooph. 

 p. 155 ; D'Orbigny, Prod. t. ii. p. 426, 1850.) The variety, which 

 resembles a Manicina, is from the Blagrove Collection of the 

 Geological Society, and is found in the Hala Mountains. 



20. Cyathoseris irregularis, n. sp. PL XIX. fig. 6. 

 The calices are separated by cristiform walls, and are large 



