158 EOCENE AND LOWER OLIGOOENE CORAL FAUNAS. 



The costse are thick, low, equal, and have granulate edges. Looked at 

 superficially from above, each calice seems peripherally bounded by a wall; 

 and there appears to be a second wall where the costse from one calice meet 

 those of the next adjacent calice. But this is only an appearance. Syn- 

 a])ticul8e occur between both septa and costa\ These ai-e arranged in a 

 definite circle around each corallite cavity, and give the appearance of a 

 definite wall when viewed from above. There is another definite series of 

 synapticula3 at the costal junction of adjacent corallites. These features 

 were shown by breaking some of the specimens longitudinally to the ver- 

 tical axis of the corallites. Besides these definitely arranged synapticulse, 

 there are many others between the costse without apparent order. The 

 septa are arranged definitely in three cycles. The six of the first cycle are 

 slightly the largest and fuse by their inner ends to the columella. The 

 members of the second cycle also reach the columella. Those of the third 

 cycle fuse by their inner edges to the sides of the second. All of the septa 

 are decidedly thicker at the periphery of the calice, and have their edges 

 slightly elevated. None of the septa have the margins preserved, but they 

 are without doubt dentate. The septa are composed of trabecules directed 

 upward and inward. Occasionally minute pits indicated the trabecular 

 courses, but no instance of a septum being undoubtedly originally perforate 

 could be found. Tlie septa, typically, are solid, imperforate. Synapticuloe 

 exist between the septa, but are not so abundant , as they are between the 

 .costse. Besides the synapticulae, there appear to be some small thin dis- 

 sepiments. Pali are present on the inner ends of the septa of the second 

 cycle; and in the best-preserved calice studied they seemed to be on the 

 inner ends of those of the first cycle also. The follo^\■ing•, apparently, is 

 the correct characterization: Pali well developed, moderately wide, with a 

 curved upper edge, in a single crown, on the inner ends of the first and 

 second cycles of septa. The precise nature of the columella can not be 

 made out with absolute certainty, because of chemical changes which the 

 specimens have undergone. The inner margins of the septa of the first 

 and second cycles fuse more or less compactly, making a well-developed 

 columella. Tliere appears to be in most calices a central, erect, more or 

 less styliform or compressed piece that is independent of the septa; and 

 apparently the columella in the worn specimens is composed of the two 

 elements — one essential, the other merely a reenforcement of the first l)v 



