102 7 WE NTT- SIXTH REPORT ON THE StATE MuSEUM, 



Formation and locality. — In the shaly limestones of the Lower 

 Helderberg group, on Catskill creek, New Fork. 



Callopora unispina n. sp. 

 Bryozonm forming slender, solid branches, with distant bifurca- 

 tions; the branches seldom more than a sixteenth of an inch in 

 diameter. Cells small, somewhat crowded, usually triangular except 

 at or near the bifurcation, where they become distorted ; distant from 

 each other about two-thirds of their own diameter. The intercellu- 

 lar space marked by small angular pits, with the ridges b'etween 

 sharply elevated, and rising into a short triangular spine at the basal 

 margin of the true cells ; giving to the branches under a magnifier 

 a sharply asperate appearance. 



The distinguishing feature of this species is the triangular cells 

 with the single spine at the base of each. 



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

 Helderberg group at Catskill creek, Greene county, and near Clarks- 

 ville, Albany county, New York. 



Callopoea peeelegans n. sp. 



Bryozoum growing in strong, solid, tortuous branches, three-six- 

 teenths of an inch, or more, in diameter. Cell apertures large, cir- 

 cular, with slightly elevated margins, somewhat irregularly disposed, 

 distant from each other usually a little less than their own diameter. 

 Intermediate spaces marked by comparatively large, polygonal pits, 

 which frequently extend from cell to cell, making their length much 

 greater than their breadth ; the partition walls between the pits ver- 

 tical, slightly flattened on the top. In a transverse section, the par- 

 titions across the intercellular spaces are strong and distant. Cell 

 tubes smooth. 



This exquisite species of Callopora is not equaled in beauty even 

 by the C. elegantula of the Niagara group ; it differs from that in 

 the form of the intercellular pits, which in the Q. elegantula are 

 smaller, more numerous, and more equal in size. 



Formation and locality. — In the shaly limestones of the Lower 

 Helderberg group, near Clarksville, Albany county. New York. 



Callopoea heteeopoea n. sp, 

 Bryozoum forming solid, comparatively slender branches, with 

 numerous irregular bifurcations. Cell apertures small, elongate-oval, 

 with frequent constrictions, which, in well preserved specimens, give 



