on each side of the branch regularly alternating curvatures and concavities; the convexities of adjacent branches approach each other, but very seldom unite, being connected by dissepiments; on nonporiferous side the branches are rounding or slightly angular and have along the middle a carina; carina thin, slightly elevated and connected with similar carinæ 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 carina 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 principal branches being a little wider than the secondary ones; the sinuosity of the branches and the connecting carinæ of the branches and dissepiments present the appearance of fenestrules enclosed by a hexagonal 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 distinguish them.

Formation and locality. Hamilton group; New York.

FENESTELLA SCALARIS, n. sp.

Bryozoan consisting of large infundibuliform fronds; largest fragment seen seven centimetres long and nearly four centimetres wide. Branches slender, very gradually. increasing in size to the bifurcations, which are distant from each other from five to thirty millimetres, 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 millimetre; on some fronds the nodes are more distant, and the rest of the branch is granulose.

Dissepiments comparatively slender, less than .25 mm. in width, six in the space of five millimetres; on non-poriferous side, on, a plane with the branches, rounded, carinated; carina similar to the carina of the branch.

Fenestrules oval, length about .66 mm., width from one-half to twothirds the length.

Cells in two ranges, opening nearly directly upward; apertures minute, circular, about .20 mm. in diameter, distance apart equal to and slightly more than the diameter of an aperture, about twenty in the space of five millimetres; margins slightly elevated, and indenting the border of the fenestrule; space between the ranges of apertures elevated, carinated; carina thin, elevated, nearly equal to the thickness of the branch, the upper half slightly expanded, and having a sharp, thin crest, the carinæ connected by their lateral projections or bars, which are very thin and extend down the side of the carinæ obliquely about .20 mm., or a little more, about eighteen bars in the space of five millimetres.

Where the poriferous face is seen this species can be easily distinguished by the very thin lateral bars connecting the carinæ, and their comparatively great distance apart. The species of the genus Fenestella are so similar in appearance, that without both poriferous and non-poriferous faces, it is sometimes very difficult to assign a specimen to the right species.

Formation and localities. Hamilton group; Bellona, N. Y., and West Williams, Ontario.

FENESTELLA EXORNATA, n. sp.

Bryozoan probably infundibuliform, though occurring only in fragments in the present collections; largest fragment seen five centimetres long and three wide.

Branches moderately slender, appearing more slender on non-poriferous side than on poriferous, gradually increasing in size to the bifurcations, which are distant from each other generally from five to seven millimetres; branches from .33 to .50 mm. in width; space between the branches on non-poriferous side more than the width of branches, on poriferous side about equal to the width, five or six branches in the space of five millimetres; on non-poriferous side flat, with a comparatively thin, sharp elevation around the edge of the fenestrules; the space between these elevations flat or slightly concave, with frequent, short, broad, conical spines, about .20 mm. in height.

Dissepiments strong, frequently as wide as, or wider than the branches, there are four in the space of five millimetres, greatly expanding at their junction with the branches, on a plane, and having the same appearance in every respect as the branches on their non-poriferous side; on poriferous side very much depressed and flattened.

Fenestrules, on non-poriferous side, appearing broadly oval, on poriferous side elongate-oval; length from three-fourths to one millimetre; width on poriferous side .5 mm.

Cells in two ranges, opening slightly laterally; apertures small, circular; diameter about 16 mm.; distance apart equal to or a little more than the diameter of an aperture, about twenty in the space of five millimetres; margins slightly elevated; space between the rows of apertures carinated; carina thin, sharp, consisting of two plates, which coalesce near the crest; height of carina .75 mm., or nearly twice the width of the branches.

This species is very characteristic and is easily recognized from either surface, from non-poriferous by the flat branches, with elevation around the fenestrule; and from the poriferous face by the thin greatly elevated carina, in which respects it differs from any other known species of this formation.

Formation and locality. Hamilton group; Alden, Erie county, N. Y

FENESTELLA QUADRANGULA, n. sp.

Bryozoan probably infundibuliform in shape though, so far as observed, occurring only in small fragments; frond rigid in appearance. Branches slender, very gradually increasing in size to the bifurcations which are distant from each other from five to fifteen millimetres, generally from ten to twelve millimetres; width of branches from .33 to nearly .50 mm. space between the branches more than the width of the branches; nine branches in the space of five millimetres; on non-poriferous side, branches rounded and frequently having a node or spine opposite the dissepiments; striated; striæ fine; sometimes entirely concealed by fine granules.

Dissepiments slender, less than .25 mm. in width; seven in the space of five millimetres, expanding at their junction with the branches; on non-poriferous side on a plane with the branches, rounding; poriferous side depressed, angular; slightly carinated.

Fenestrules broadly oval or sub-quadrangular; length from .50 to .66 mm.; width from .33 to .50 mm. Cells are in two ranges, opening slightly laterally; apertures minute, .16 mm. in diameter, very closely arranged; distance apart about one-half the diameter of an aperture; twenty-two in the space of five millimetres; margins slightly elevated; space between ranges of apertures, angular, carinated; carina moderately strong; very slightly elevated and having a row of nodes; nodes moderately strong, about four in the space of one millimetre.

Formation and locality. Hamilton group; Darien, N. Y.

FENESTELLA EMACIATA, n. sp.

Bryozoan occurring only in fragments, the form of the whole frond is not certainly known, but probably infundibuliform; largest fragment observed five centimetres long and three wide.

Branches moderately slender; not increasing in size, except just below the bifurcations, which are distant from each other from four to twenty-four millimetres- generally about fifteen millimetres; width

of branches from .33 to .50 mm.; space between about equal to the width of the branches; seven branches in the space of five millimetres; on non-poriferous side, rounded, striated; striæ moderately strong, from three to five on a branch; finely granulose; sometimes the central stria resembles a narrow carina.

Dissepiments about .25 mm. in width; six in the space of five millimetres; slightly expanding at their junction with and oblique to the branches; angle of obliquity from ten to twenty degrees; on nonporiferous side moderately depressed, rounded, transversely striated, granulose; on poriferous side, very much depressed, slightly angular, carinated; carina slight.

Fenestrules oval or subquadrangular; length .66 mm.; width from .33 to .50 mm.

Cells in two ranges opening laterally; apertures small, .20 or .16 mm. in diameter, closely arranged, frequently nearly contiguous; from twenty to twenty-five in the space of five millimetres; margins elevated and indenting the border of the fenestrule.

Space between the ranges of apertures elevated, height equal to onehalf the thickness of the top of the branch; slightly rounding; not acutely angular, having a row of nodes; nodes minute; frequently wanting.

This species differs from F. marcida by having stronger, more widely separated branches; dissepiments farther apart and oblique to the branches; on the poriferous side the cells open more laterally; the space between the cells is elevated, not carinated, and comparatively thick, and without the closely arranged, prominent nodes of that species.

1

Formation and locality. Hamilton group, shore of Seneca lake, N. Y.

FENESTELLA CURVATA, n. sp.

Bryozoan infundibuliform; largest fragments seen four millimetres in length and of about the same width.

Branches slender, scarcely increasing in size to the bifurcations, which are distant from each other from four to fifteen millimetres, generally about ten millimetres; width of branches from a little less than .25 to .33 mm., occasionally slightly more; transverse section subcuneiform in outline; space between branches greater than the width of the branches; seven branches in the space of five millimetres; when the dissepiments on opposite sides of the branches alternate, the branch is flexuous, but not when the dissepiments are opposite each other; on non-poriferous side the branches are rounder, in well-preserved specimens showing fine, granulose striæ, from five to seven on a branch; generally opposite the dissepiments there is a prominent, conical spine about .25 mm. in height.

Dissepiments comparatively strong; width nearly or quite equal to that of the branches; thirteen in the space of ten millimetres; not expanding at their junction with the branches; on non-poriferous side slightly depressed, rounding; on poriferous side scarcely perceptible.

Owing to the sub-cuneiform shape of the branches the fenestrules of the poriferous and non-poriferous face present an entirely different appearance; on non-poriferous face they are broadly oval or subquadrangular; .66 mm. in length; width from .50 to .66 mm.; on the poriferous side they frequently appear merely as narrow slits; sometimes the branches are apparently contiguous.

Cells in two ranges, opening slightly laterally; apertures minute, circular, diameter about .20 mm., closely arranged; distance apart from one-half to one diameter of an aperture, about twenty in the space of five millimetres; margin distinctly elevated and indenting the border of the fenestrule; space between ranges of apertures carinated; carina thin, slightly elevated and having prominent nodes or short spines, two in the space of one millimetre.

When both the poriferous and non-poriferous faces of this species can be seen, it will be very easily distinguished from any other species of this formation.

Formation and locality. Hamilton group; Moscow, Livingston county, N. Y.

FENESTELLA BREVILINEA, n. sp

Bryozoan probably infundibuliform, largest fragment seen seven centimetres wide and five long.

Branches moderately strong, a transverse section sub-cuneiform in outline the widest portion on poriferous side— gradually increasing in size to the bifurcations, which are distant from each other from seven to twenty millimetres; width of branches from .33 to .66 mm.; space between branches greater than the width of the branches, five or six in the space of five millimetres; or when the dissepiments on opposite sides of the branches alternate, which is generally the case, the branches are sinuous; on non-poriferous side rounding or slighty angular, carinated; carina thin, but slightly elevated, sinuous; surface pustulose.

Dissepiments from .50 to .66 mm. in width, three in the space of five millimetres on non-poriferous side, on a plane with the branches, rounded, with a semi-circular carination; pustulose.

Fenestrules oval; owing to the sub-cuneiform shape of the branches, the fenestrules on poriferous and non-poriferous sides present a widely different appearance; on non-poriferous side 1.33 mm. in length, .50 mm. or slightly more in width; on poriferous side they appear much smaller, both in regard to length and width.

Cells in two ranges minute, circular or lunate, opening slightly laterally; diameter .20 or .16 mm.; space between the apertures longitudinally, equal to or more than the diameter of an aperture; ranges of apertures separated by a carina, which is very much elevated; height about .75 mm., or more than the thickness of the branch; at the base it is nearly .25 mm. in thickness, continuing of that thickness for about one-third the height of the carina, where it abruptly narrows and for the rest of the height the carina is extremely thin. Owing to the sudden contraction of the carina it appears to have a ridge upon the side when viewed from above; apparently the dissepiments sometimes have