NIAGARA GROUP. 
147 
I have referred this species to Callopora, from its possessing the essential characteristics of 
the preceding, differing perhaps in the character of the intercellular spaces, which appear to 
be solid upon the upper surface. The apertures of the cells are smaller, and often only tri- 
petaloid or formed by segments of three or four curves. The coral is, to the naked eye, 
apparently quite solid, but the minute cylindrical tubes penetrating the mass are very distinct 
under a magnifier. The spaces between the tubes, though appearing to be of uniform texture, 
still show, when highly magnified, the lines of the transverse septa, giving a kind of cellular 
appearance to the mass. The structure and mode of growth do not, therefore, differ in any 
degree from the preceding species. 
There is no appearance of the minute spinulose or papillose points around the aperture which 
occur in the preceding and following species, but it is possible that these have been removed 
by abrasion, which has likewise obliterated the marks of intercellular tubes; still the surface 
gives no evidence of having been worn. This coral, from its apparent structure, could be re¬ 
ferred to Stromatopora, without doing violence to the essential characters of that genus. 
Fig. 3 a. The surface showing the openings of the natural size. 
Fig. 3 b. A section showing its mode of growth in concentric laminae. 
Fig. 3 c. The lower surface, showing the concentric striated membranous covering. 
Fig. 3 d. A portion of the surface enlarged, showing the form of the mouths of the cells. 
Fig. 3 e. A section enlarged, showing the vertical tubular cells and transverse septa. 
Position and locality. In the shale of the Niagara group at Lockport. 
537. 4. CALLOPORA ASPERA (n. sp.). 
Pl. XL. Fig. 4 a - i. 
Coral growing in solid or hollow cylindrical stems, often incrusting other bodies in broad 
explanate or foliate expansions; stems usually thickened or clavate at their extremities ; cells 
tubular, openings circular or slightly oval, with finely reticulate interspaces; margins of the 
aperture surrounded by minute points, which give the entire surface an asperato-granular 
appearance ; vertical section tubular or columnar; intercellular spaces septate; the form of 
apertures and intermediate spaces often very irregular towards the margin of an incrusting mass. 
In unworn specimens, the minute points surrounding the apertures of the cells give a very 
peculiar and characteristic appearance to the surface. The apertures are smaller and of different 
form, and the intermediate spaces more finely reticulate than in the two first species; and in 
worn specimens the appearance and texture is more delicate, though it assumes a greater 
variety of appearance than either of the preceding species. In its growth it often surrounds 
the stems of crinoids, probably while the latter are in a living state ; in other instances the 
centre of the stem is filled with amorphous mineral matter, while the coral forms an en¬ 
veloping hollow cylinder. This feature may arise from the mode of growth, the coral first 
enveloping the stem of a crinoid, and afterwards growing on beyond its extremity while the 
