CLINTON SEOUP. 



45 



around the stipe, and arranged between longitudinal elevated lines ; cellules apparently reach- 

 ing to the centre, and diverging and radiating from a central imaginary axis. 



This little coral is extremely abundant in the thin calcareous layers in the lower part of the 

 Clinton group. The entire surface, often for several inches square, is covered with these mi- 

 nute fragments, of the length of from i to i of an inch, and rarely longer. The least worn of 

 these will be found, on examination with a microscope, to be poriferous, while others are nearly 

 or entirely smooth. Whenever the termination is distinctly visible, it appears thickened or 

 swollen ; but this character is only of specific importance. In worn specimens, where the 

 pores are visible, they are distinctly oval ; the angular form being apparent in more perfect 

 individuals, from the longitudinal lamellae separating the pores. Some of the specimens are 

 branched, but this is a rare feature. 



Fig. 3 a. Fragment of the ordinary character. 

 Fig. 3 5. A fragment showing the thickened termination. 



Fig. 3 c. A specimen having a single branch, the stipe and branch both having enlarged ex- 

 tremities. 

 Fig. 3 d. The specimen 3 h enlarged. 

 Fjg. 3 e. A portion of another specimen enlarged. 

 Fig. 3 /. A small specimen of limestone with fragments of this coral upon its surface. 



Position and locality. This coral is abundant in the thin semi-calcareous layers above the 

 Pentamerus oblongus at Rochester ; it is less abundant in Wayne county, and at Reynale's 

 basin and Lockport in Niagara county ; and is again abundant at Flamborough head, Canada 

 West. 



424. 7. STICTOPORA CRASSA (n. sp.). 



PL. XVIII. Fig. 4 fl, 6, c. 



Frond branching ; branches numerous, somewhat thick ; openings of the cellules oval, about 

 ten in the width of the stipe or branches ; each opening margined by a shallow groove, which 

 gives the surface a striated appearance. The non-celluliferous margins of the branches narrow 

 and smooth 1 



This species is more robust than any heretofore described. The number of rows of cells on 

 the stipe and branches is ten or upwards, and the openings are well defined. In worn speci- 

 mens the striated surface of the intercellular spaces is not obvious, but in more perfect speci- 

 mens is quite conspicuous. 



This species differs sufficiently from any heretofore described, to be readily recognized. 

 The margins may perhaps, in better specimens, prove to be striated. 



Fig. 4 a & 5. Two fragments, natural size. 



Fig. 4 c. A portion enlarged, showing the striated surface of the intercellular spaces. 



Position and locality. In the lower part of Clinton group, Wayne county ; and at Flam- 

 borough head, Canada West : also, more rarely, at Rochester and Reynale's basin. 



