Corals and Bryozoans of the Lower Helderbkrg. 161 



at other times the arrangement is very irregular, as also the form and size of the 

 cells. Only two specimens have thus far been found, and both are fragments, 

 so that the entire form is unknown ; these fragments are each about twelve cen- 

 timetres long and three centimetres wide. 

 f£ Formation and locality. Lower Helderberg group, Clarksville, N. Y. 



STICTOPORA, Rail. 

 Stictopora papillosa, n. sp. 



(PLATE XIII, FIGS. 12, 13.) 



Bryozoum ramose. Branches moderately flattened, transverse section elon- 

 gate-oval or lenticular in outline ; width of branch two mm. ; thickness at the 

 middle one mm. Cell-apertures circular, about .20 mm. in diameter, generally 

 arranged in longitudinal rows ; distant from each other less than the diameter 

 of an aperture ; margins distinctly elevated and sloping. 



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



ESCHAROPOBA, Hall. 



ESCHAROPORA LIFvATA. 

 (PLATE XVII, FIGS. 1-6.) 



EscMropora lirata, Hall. Twenty-sixth Rep. N. Y. St. Mus. Nat. Hist., p. 100. 1874. 



Bryozoum small, ensiform, gradually enlarging from an obtusely pointed 

 striated base, for a short distance, the sides then becoming nearly parallel ; 

 width from one and a half to two mm.; transverse section lenticular in form ; 

 celluhferoiis on both sides; a thin epitheca dividing the cells of the two sides. 

 Cell-apertures large, arranged in longitudinal rows — five or six rows on each 

 side ; apertures elongate-oval ; three in the space of one mm. longitudinally, and 

 five in the same space transversely ; the cells of the two outer rows larger than 

 the others ; longitudinal partitions thick, elevated, granulose ; transverse parti- 

 tions thin, deeply depressed, widening at the junction with the longitudinal par- 

 titions, and having a pore on the expanded portion. 



This species differs from E. tenuis (plate xvii, figs. 7-13), in its smaller size, 

 proportionally larger cells, and the peculiar lirate appearance given to it by the 

 thick elevated walls separating the longitudinal rows of cell-apertures. 



Formation and locality. In the upper shaly portions of the limestones of 

 the Lower Helderberg group, Clarksville, N. Y. 



ESCHAROPORA TENUIS. 

 (PLATE XVII, FIGS. 7-13.) 



JSscharoj)ora tenuis, Hall. Twenty-sixth Rep. N. Y. St. Mus. Nat. Hist., p. 99. 1874. 



Bryozoum consisting of thin, elongate, narrow stipes, with a striated base ; 

 gradually enlarging from an obtuse point to a short distance above the com- 

 11 



