172 Thirty-second Report on the State Museum. 



to bifurcations, striated, striae coarse, rounded, from two to three on a branch, 

 frequently entirely concealed by granules, the branch presenting only a granu- 

 lose surface ; bifurcations few near the base, becoming more frequent and regu- 

 lar above. 



Dissepiments about one-half the thickness of the branches, six or seven in 

 the space of five mm., expanding at their junction with the branches, sometimes 

 oblique to the branches ; on non-poriferous side granulose, on plane with the 

 branches ; on poriferous side depressed, not extending above the ranges of pores. 



Fenestrates from subquadrangular to oval, width varying from one-half to 

 equal the width of branches in different fronds, or different parts of the same 

 frond ; length varying from double to little more than double the width. 



Cell-pores in two ranges, opening directly upward or obliquely outward ; open- 

 ings circular, three in the space of a fenestrule, distant from each other more 

 than the diameter of an aperture ; margins elevated, very slightly indenting 

 the border of the fenestrules ; space between the ranges of pores carinated, car- 

 ina elevated more than the diameter of a branch, expanded above, and having, 

 in the middle of the wider portion, a thin, sharp crest, giving to the upper por- 

 tion of the carina very much the appearance of a branch ; the expanded portion 

 has, on each side, a row of pustules, which when worn, present the appearance 

 of ranges of minute cell-pores ; occasionally, either on account of the more perfect 

 condition of the frond or more advanced stage of growth, the pustules of con- 

 tiguous carinae are extended until they unite, forming slender bars connecting 

 the carinae ; there are five pustules in the space of a fenestrule. 



This species, when the pustules are extended into bars, has all the characters 

 of the genus Hemitrypa. 



Formation and localities. On the surfaces of decomposing shaly limestone of 

 the Lower Helderberg group, near Catskill and Clarksville, N. Y. 



Fenestella quadrula, n. sp. 



(PLATE XXI, FIGS. 19-22.) 



Bryozoum funnel-shaped, rapidly expanding. Branches comparatively broad, 

 nine in the space of five mm. ; non-poriferous side flattened, striated, striae 

 sharp, distinct, generally three on a branch. 



Dissepiments ten in the space of five mm., extremely slender, not expanding 

 at their junction with the branches. 



Fenestrules quadrangular, width about the same as that of the branches, 

 length but slightly more than the width. 



Cell-pores in two ranges, opening nearly directly upward ; cell-openings cir- 

 cular, two in the space of a fenestrule, counting those opposite the dissepiment ; 

 margin elevated, slightly indenting the border of the fenestrule ; space between 

 the ranges of pores carinated, carina sharp, strongly elevated, abruptly expand- 

 ing above, having in the centre of the wider portion a thin, sharp crest, and on 

 each edge a line of sharp pustules, which frequently have the appearance of 

 minute cell-pores, of which there are five in the space of a fenestrule. 



