60 Thirty-sixth Report o:n" the State Museum. 



in width ; ten branches in the space of five millimetres ; on non-porif- 

 erous side the branches are rounded or circular, aud frequently have 

 a very narrow, slightly elevated keel or striation running along the 

 middle, which connects with a similar keel on the dissepiments, and 

 opposite each dissepiment is a prominent triangular node. 



Dissepiments slender, about .25 mm. in diameter, eight or nine in 

 the space of five millimetres, much expanded at their junction with the 

 branches ; on non-poriferous side depressed, and with a thin, slightly 

 elevated carina; on the poriferous side they are scarcely perceptible. 



On account of the cuneiform shape of the branches, the fenestrules 

 on the different faces of the frond have an entirely different appear- 

 ance ; on the non-poriferous side the fenestrules appear broadly oval, 

 or nearly circular, a little less than .5 mm. in length and of about the 

 same width ; the branches rapidly thicken to the poriferous side where 

 they are contiguous or nearly so, the fenestrule generally not showing 

 at all, and when showing appearing only as a narrow slit. 



Cells in two or three ranges, two ranges occur for only a short dis- 

 tance above the bifurcation, the greater part of the branch being occu- 

 pied by three ranges ; apertures small, circular, about .16 mm. in diam- 

 eter, closely arranged, frequently nearly contiguous, twenty-eight in 

 the space of five millimetres, the central row opening directly upward, 

 the two outer rows nearly upward, slightly lateral; margins distinctly 

 elevated and unusually thick ; the margins of the outer rows of adja- 

 cent branches are separated only by a narrow line, sometimes contigu- 

 ous ; the central row of apertures is elevated above the outer rows, 

 making the branch angular. 



This species is not common, and when the poriferous face is seen is 

 easily recognized ; like F. fistulaia, the cells are arranged in two and, 

 three rows and the branches are nearly of the same size, but it dif- 

 fers in having the cell apertures larger and much more closely arranged, 

 and the central row much elevated, making the branch angular, while 

 in that species the branch is nearly if not quite flat, the apertures being 

 on the same plane; the contiguity of the branches, or the poriferous 

 face, is also a distinguishing characteristic. 



Formation and locality. Hamilton group ; Bellona, New York. 



js/ Fenestella angustata, n. sp. 



$u £ r ^hW fUfo rt JM &*(?** r Pxf'H'o/-f, 



Bryozoan infundibuliform ; fronds large. 1 



Branches of nearly the same size throughout their entire length, 

 except immediatelv below the bifurcations, or increasing in size very 

 gradually; bifurcations at very irregular distances from each other, 

 varying from five to fifteen millimetres; width of branches from .33 

 to .50 mm.; distance apart less than the width of the branches; 

 from ten to thirteen branches in the space of five millimetres ; on 

 non-poriferous side the branches are rounded, with generally a single 

 range of nodes along the middle ; sometimes there are additional 

 scattering nodes with indistinct evidences of striations ; on other 

 parts of the frond the nodes are obsolete, either from wearing or some 

 other cause not apparent, and there are from three to five strong stria- 

 tions on a branch. 



