156 Thirty-Second Report on the State Museum. 

 Callopora maculosa. 



(PLATE XIV, PIGS. 1-8.) 



Trematopora ponderosa, Hall. Twenty-sixth Rep. N. Y. State Mus. Nat. Hist., 



p. 106. 1874. 

 Trematopora maculosa, Hall. Twenty-sixth Rep. N. Y. State Mus. Nat. Hist., 



p. 106. 1874. 



Bryozoum lamelliform, free or incrusting, generally occurring in masses com- 

 posed of numerous successive layers of growth ; thickness of separate layers 

 from less than one mm. to three mm. or more ; celluliferous on one side ; lower 

 surface covered by an epitheca, with strong concentric wrinkles and radiating 

 striae ; cell-tubes round or oval, generally opening at right angles to the sur- 

 face ; diameter of apertures about .25 mm. ; distance from each other a little 

 less than the diameter of the aperture, with frequent maculae destitute of 

 cell-apertures, the cells around these being larger than the ordinary cells, fre- 

 quently radiating, and opening obliquely ; cell-margins elevated ; on the thinner 

 fronds and near the margins of others, the cells open quite obliquely, the poste- 

 rior margin frequently extending over and constricting the aperture, forming an 

 elevated, projecting lip, and sometimes presenting very much the appearance 

 of a Ceramopora. Intercellular spaces channeled, smooth or rugulose from 

 the intercellular pits ; sometimes the pits themselves are visible. In a vertical 

 section the intercellular spaces are shown to be strongly vesiculose, the trans- 

 verse septa being arched. 



A critical study of numerous specimens has shown that the species originally 

 described as Trematopora ponderosa and T. maculosa are not distinct, and the 

 internal structure of both are like typical forms of Callopora. 



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

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



Callopora ponderosa. 



(PLATE XIV, PIGS. 9-12.) 



Callopora ponderosa, Hall. Twenty-sixth Rep. N. Y. State Mus. Nat. Hist., 



p. 103. 1874. 



Bryozoum explanate, either free or incrusting, generally growing in large 

 masses composed of numerous successive layers ; thickness of separate layers 

 two mm. or more ; lower surface covered by an epitheca, marked by strong, 

 concentric wrinkles and radiating striae ; cell-apertures round, .25 mm. in 

 diameter, distance from each other variable, frequently less than their diameter ; 

 cell-margins thin, elevated, having one or more comparatively large spines, 

 causing the surface of well-preserved specimens to present an echinate appear- 

 ance ; intercellular spaces occupied by minute polygonal pits, in from one to 

 three ranges. 



F&rmat-ion and locality. In the shaly limestones of the Lower Helderberg 

 group, at Schoharie, N. Y. 



