Lower Helderbero Bryozoa and Corals. 95 



Fenestella crebripora n. sp. 



Bryozoum forming frond-like expansions on the surface of weath- 

 ered slabs, undulated or folded from the rapid increase of the 

 branches from bifurcation ; base not known. Branches slender, 

 rounded and smooth on the non-poriferous side, not perceptibly stri- 

 ate : poriferous side of the branch carinate with a range of large, 

 closely approximate pores on each side. Dissepiments slender, dis- 

 tant, widening at their junction with the branch, carinate on the 

 poriferous side, and rounded on the opposite. Fenestrules elongate, 

 quadrangular, wider than the branch, and their length often double 

 their width. Pores large, often appearing polygonal on the surface 

 but rounded within, from three to four in the length of a fenestrule : 

 the partition walls narrow, often sharp on the outer edge, that on 

 the inner side dividing the two ranges and forming the carina fre- 

 quently tortuous. At the junction of the dissepiment with the 

 branch, there is commonly a cell pore within the dissepiment and 

 out of the line of the regular range; sometimes one in each axil, and 

 in these cases the pores are triangular at the surface. Branches from 

 three to four in a tenth of an inch : dissepiments one and a half to 

 two in the same space. 



This species is a somewhat coarser form than either of the preced- 

 ing, with slender and more distant branches and dissepiments; and 

 pores differing from those in size and position. 



J^m'mation and locality. — On weathered slabs of Lower Helder- 

 berg Limestone ; Albany county, New York. 



Fenestella Idalia n. sp. 

 Bryozoum forming broadly spreading cup-shaped bodies, attached 

 by the base to other substances ; celluliferous on the inside. 

 Branches slender, very closely arranged, frequently bifurcating, longi- 

 tudinally striate on the outer surface, strige granulose, from three to 

 five or six on each branch ; inner surface of branches densely 

 crowded with small slightly oval pores in two ranges, except for a 

 short distance below each bifurcation, wliere the branch gradually 

 widens and an intermediate range appears which divideb at the bifur- 

 cation ; a slight ridge often separates the rows of pores, but this is 

 often obsolete. Dissepiments slender, striated on the inner sur- 

 face ; their distance from each other equal to or greater than the 

 width of the branch; about four in the space of one-tenth of an inch. 

 Fenestrules small, elongate elliptical, appearing quadrangular on the 



