LONSDALE ON EOCENE CORALS FROM N. AMERICA. 



529 



disappeared in more advanced con- 

 ditions ; while in still older, the 

 aperture was depressed, and in the 

 most aged totally obliterated (see 

 figure). Other changes, dependent 

 upon age, consisted in the diminu- 

 tion in number and distinctness of 

 the pores, and in the increased 

 convexity of the surface, with a 

 corresponding greater depth in the 

 separating furrows, An exposed 

 dorsal surface was traversed by 

 fractured edges of the walls. 



In the accompanying figure 

 (which is magnified seventeen times 

 in linear dimensions) the greater 

 portion represents mature cells, 

 and the right lower part aged cells, 

 with obliterated mouths and nearly 

 closed foramina. 

 Locality. — Eutaw. 



21. ESCHARA INCUMBENS. (sp. n.) 



Foliaceous; cells oval, surface slightly convex, porous, boundary a very faint 

 furrow, mouth round or transversely oval, notched in mature state, and margin 

 slightly thickened ; a round foramen sometimes on one side of mouth ; interior 

 of cells, lateral walls slightly curved, terminal arched or nearly straight ; dorsal 

 surfaces not separable ; gemmuliferous (?) vesicle large, semi-globular, resting on 

 next succeeding cell ; connecting foramina near the base of side and terminal walls. 



In addition to the aggre- 

 gate of differential characters, 

 this species is distinguished by 

 the large overlying gemmu- 

 liferous ( ?) vesicle. From the 

 mode of blending with the 

 surface on which it rests, this 

 chamber might be mistaken 

 for an irregularly developed 

 cell ; but its true nature was 

 shown by the absence of dis- 

 tinct pores in the lamina form- 

 ing the outer covering, by the 

 great size and inclined position 

 of the opening, and by the true 

 mouth of the cell, being de- 

 tectable within the chamber, 

 in its right position. In the 

 oldest observed condition of 



The figure represents the general cha- 

 racters of the surface of Eschara incumbens, 

 magnified sixteen times, linear. The 

 unforaminated portions express the 

 chambers alluded to in the description ; 

 and the shaded part above the mouth of 

 the cell the entrance to the chambers, 

 the edges of the covering being, in these 

 instances, more or less removed by abra- 



sion, and the mouth of the cell exposed. 



the coral, the outer surface was greatly thickened, and the mouth 

 of the cells was partially or wholly obliterated. 

 Locality. — Rock's Bridge. 



N N 3 



