CORALS AND BRYOZOA. 67 



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

 group, Schoharie, N. Y. 



MONOTRYPA, Nicholson. 1879. 



MONOTKYPA ? SPINOSULA, n. Sp. 



PLATE XVI, FIG. 28. 



iSpecies undetermiiied. Report of State Geologist for J 882. Expl. pi. 16, fig. 25. 1883. 



ZoARiUM explanate. Cells polygonal; septa infrequent ; diameter of cell aper- 

 tures .25 mm. Surface marked by maculae composed of cells of nearly twice 

 the diameter of those on other portions of the zoarium. Centers of maculae 

 distant from each other 5 mm. 



Formation and locality. Tentaculite limestone. Lower Helderberg group, 

 Schoharie, N. Y. 



Paleschara concentrica, n. sp. 



PLATE XVI, FIG. 24. 

 Speeiet wtdetermlned. Report of State Geologist for 1S82. Expl. pi. 16, fig. 24. 1883. 



Zoarium foliate; cells polygonal, in contact ; walls thin ; diameter of apertures 

 .40 mm. ; disposed in a radiatingly concentric order. 



This species may be distinguished from P. incrustans by the more regular 

 arrangement of the cell apertures. 



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



