66 Thirty-sixth Keport osr the State Museum. 



on each side of the branch regularly alternating curvatures and con- 

 cavities ; the convexities of adjacent branches approach each other, 

 but very seldom unite, being connected by dissepiments; on non- 

 poriferous side the branches are rounding or slightly angular and 

 have along the middle a carina ; carina thin, slightly elevated and 

 connected with similar carinse on the dissepiments. 



Dissepiments strong, of about the same width as the branches, five 

 in the space of five millimetres; on non-poriferous side on the same 

 plane as the branches; rounded or slightly angular ; carinated ; carina 

 thin, slightly elevated and connected with the carinae of the branches. 



Fenestrules small, oval, slightly more than .5 mm. in length ; width 

 two-thirds to three-fourths the length. 



Cells in two ranges, opening directly upward ; apertures minute, 

 nearly circular, about one-sixth or one-seventh of one millimetre in 

 diameter, closely arranged, distance apart less than the diameter of an 

 aperture, occupying the dissepiments as well as the branches, and 

 forming an oval arrangement; the margins are distinctly elevated and 

 indent the borders of the fenestrules ; the space between the apertures 

 both on the branches and dissepiments is carinated; carina thin and 

 elevated about the thickness of the branch, when it expands and forms 

 secondary non-celluliferous branches and dissepiments; branches 

 .33 mm. in width, round, and having a carina; carina thin, but 

 slightly elevated, though very distinct; branches regularly sinuous ; 

 dissepiments of the same width as the branches, round, carinated; 

 carina similar to and connected with those of the branches. 



Fenestrules oval or circular ; the circular form has a diameter of 

 about .66 mm.; the oval forms are .66 mm. (sometimes a little more) 

 in length and about .5 mm. in width. 



The two faces of the frond are very similar in appearance, the prin- 

 cipal branches being a little wider than the secondary ones; the sinu- 

 osity of the branches and the connecting carinae of the branches and' 

 dissepiments present the appearance of fenestrules enclosed by a hexa- 

 gonal angular elevation; the dissepiments being of the same width as 

 the branches on the same plane and similarly carinated, and the 

 branches being quite irregular, it is sometimes very difficult to dis- 

 tinguish them. 



Formation and locality. Hamilton group; New York. 



Fenestella scalaris, n. sp. _ _, • 



Bryozoan consisting of 'large infundibuliform fronds ; largest frag- 

 ment seen seven centimetres long and nearly four centimetres wide. 



Branches slender, very gradually increasing in size to the bifurca- 

 tions, which are distant from each other from five to thirty milli- 

 metres, generally from fifteen to twenty millimetres ; width of branches 

 about .33 mm. ; distance between branches less than the width of the 

 branches, from nine to eleven branches in the space of five millimetres ; 

 on non -poriferous side branches rounded, carinated ; carina slightly 

 elevated and finely nodose, about seven nodes in the space of one mil- 

 limetre ; on some fronds the nodes are more distant, and the rest of 

 the branch is granulose. 



