Corals and Bryozoans of the Lower Helderberg. 153 



This is a very distinct and well-marked species, characterized by its large cells 

 and slender branches. A single branch, apparently belonging to the species, 

 has been found in the Niagara shale at Lockport. 



Formation and localities. In the shaly limestone of the Lower Helderberg 

 group, at Catskill, Greene county ; near Clarksville, and at Schoharie, N. Y. 



Callopora macropora, var. si gnat a, n. var. 



(PLATE XI, FIGS. 30, 31.) 



Trtmatopora signata. Hall. Twenty-sixth Rep. of the N. Y. State Mus. Nat. Hist., 



p. 104. 1874. 



This variety differs from the usual form of C. macropora in the more dis- 

 tinctly polygonal cell-apertures, and in having but very few intercellular pits. 



Formation and locality. Lower Helderberg group, near Clarksville, N. Y. 



Callopoba heteropora. 



(PLATE XI, FIGS. 32, 34, AND PLATE XIII, FIGS. 5-8.) 



Callopora heteropora, Hall. Twenty-sixth Rep. of the N. Y. State Mus. Nat. Hist., 



p. 102. 1874. 



Bryozoum ramose, solid ; branches one mm. in diameter ; cell-apertures oval, 

 about .25 mm. in length, irregularly arranged, distance from each other varying 

 from contiguity to the length of an aperture ; cell-margins elevated, and in 

 well-preserved specimens spinulose ; intercellular spaces occupied by minute, 

 angular pits, of about .15 mm. in length. 



Formation and locality. Lower Helderberg group, near Clarksville, N. Y. 



Callopora unisplna. 



(plate XI, FIGS. 35-39 and ? 40, 41.) 

 Callopora unispbia, Hall. Twenty-sixth Rep. N. Y. St. Mus. Nat. Hist., p. 101. 1874. 



Bryozoum ramose, solid ; diameter of the larger specimens two mm. ; branches 

 infrequent, widely diverging ; cell-apertures oval ; length about .25 mm ; width 

 a little more than half the length ; distance from each other varying from con- 

 tiguity to a little more than twice their width ; cell margins elevated, and 

 generally having, at the base of each aperture a comparatively large, obtuse 

 spine, though this feature is by no means invariable — in some specimens but 

 few of the cells having spines ; intercellular spaces occupied by small polygonal 

 pits, in from one to three ranges, with sharply elevated margins. 



Formation and localities. In the shaly limestone of the Lower Helderberg 

 group, at Catskill creek, and near Clarksville, N. Y. 



