94 Twenty-sixth Report on the State Museum. 



surface, rounded or sub-oval within, the length but little exceeding 

 the breadth ; appearing longer on the outer side, from the thickening 

 of the dissepiment on the inner. 



Pores rounded, three or four on each side of the fenestrule, dis- 

 tance from each other equal to or greater than their own diameter ; 

 in well preserved specimens they have a slightly upward direction, 

 with the outer margin projecting. This feature is, however, seldom 

 preserved, and the cells appear as slight protuberances with a central 

 perforation. 



This is an abundant form on weathered slabs of the shaly lime- 

 stone of the Helderberg group, two miles north of Clarksville, 

 Albany county, JSTew York. 



Fenestella pr^cuksor n. sp. 

 Bryozoum forming narrow, deep, funnel-form bodies, attached by 

 their bases to foreign substances. ISTear the base the cup expands at 

 an angle of not more than forty degrees, spreading more rapidly 

 above. Branches slender, with few bifurcations below, the number 

 increasing above. Outer surface with a series of cell pores on each 

 side of a narrow, elevated carina, which widens above, forming 

 another branch parallel with the principal one, and having a sharp 

 crest with a line of obtuse nodes on each side, giving the appearance 

 of a second range of cell pores. Inner surface of the branch rounded, 

 marked by numerous small pustules which, when worn away, show 

 openings into the interior tube, presenting the characters of the pori- 

 ferous surface of Polypora. Dissepiments somewhat thickened, 

 rounded, spreading at their junction with the branch, on the same 

 plane in the inner side and not extending above the range of pores 

 on the outside. Fenestrules varying from subquadrangular to elon- 

 gate oval, about as wide as tlie breadth of the branches. Pores circu- 

 lar, three, or four to each fenestrule, opening outwardly and slightly 

 upwards, forming lobes on the sides of the branches. The obtuse 

 nodes are arranged somewhat more closely than the pores, five nodes 

 occupying a space equal to four pores. In much weathered speci- 

 mens the nodes are often worn away so as to exhibit a small perfora- 

 tion, and in this condition they might be mistaken for another range 

 of pores. . In one specimen the wearing of the carina has left a 

 groove between the ranges of pores. 



Formation mid locality. — On decomposed surfaces of the shaly 

 limestone of the Lower Helderberg group, near Catskill, Kew York. 



