NIAGARA GROUP. 141 
Fig. 2 a. A fragment of a frond having the cells filled and solid, separating in prismatic forms. 
Fig. 2 b. A portion enlarged, showing the structure. 
Position and locality. In the lower part of the Niagara limestone at Lockport. 
530. 7. CLADOPORA RETICULATA (n. sp.). 
Pl. XXXIX. Fig. 3 a - e. 
Coral expanded into a broad reticulate frond ; branches roundish or slightly flattened, coa¬ 
lescing at frequent intervals, and forming meshes of various form and size, poriferous on al] 
sides i openings of the cells upon the surface roundish or oval, distant from each other rather 
more than their diameter, often arranged in parallel longitudinal lines; interior showing the 
cells reaching to the centre from, all sides, and, in solid specimens, becoming prismatic. Cells 
distant from each other of an inch. 
This species has the general aspect of a Retepora, but a slight examination proves it pori¬ 
ferous on all sides, having round tubular cells, which, in perfect specimens, open upon the 
surface by nearly circular mouths, having a projecting lip on the lower side. In slightly worn 
branches, the openings are quite circular; and in those more worn, they become somewhat 
angular. From unequal wearing, the openings sometimes appear oval; and from other causes, 
specimens often present a variety of appearance. The spaces between the mouths of the cells are 
slightly greater than the width of the openings themselves, and, in longitudinal sections, this is 
distinctly seen penetrating to the axis, while the cell appears like a gradually enlarging tube 
from the centre to the surface of the branch. In specimens wholly crystalline, it is impossible 
to distinguish any thing beyond a general prismatic or fibrous structure. 
Fig. 3 a. A part of a large frond, showing the branches and reticulations of the natural size. The 
branches, in their circumference, have seven distinct rows of pores, arranged in 
nearly regular longitudinal rows. 
Fig. 3 b. An enlarged portion, showing the form and arrangement of the cells upon the surface. 
Fig. 3 c. A similar enlargement where the surface is worn. 
Fig. 3 d. A longitudinal section enlarged, showing the interior arrangement of the tubular cells. 
Fi.g 3 e. A fragment of another frond having only six longitudinal rows of pores on the branches, 
which, gives a greater lateral distance between the openings on the surface, though 
presenting no appreciable difference in the longitudinal distance. In other respects 
this specimen preserves all the characters of the preceding one, and of others of the 
same species. 
Position and locality. The specimens figured were found, associated with Catenipora escha- 
roides , near Louisville, Kentucky. I have found small fragments of the same or a very similar 
species at Lockport; but the evidence of the geological position of the specimens figured rests 
chiefly on their association with Catenipora, and that the limestone containing both is below 
the limestone containing the fossils identical with those of the Onondaga and Corniferous lime¬ 
stones of New-York. 
