CORALS AND BRYOZOA. 
147 
branches, strong; width .33 to .38 mm., angular, slightly carinated, seven 
in the space of 5 mm., on a plane with the branches or elevated above them; 
sometimes continuing across the branches and uniting with adjacent dissepi¬ 
ments, forming irregular, continuous elevations, which are very prominent, 
but do not obscure the branches. Fenestrules oval, length from .33 to .38 
mm., width .25 mm. 
On the celluliferous face the branches are straight: dissepiments rounded 
or sub-angular, slightly carinated, depressed. Fenestrules much narrower 
than on the opposite face, the length being frequently as much as three times 
the width. Cell apertures in two ranges, opening directly outward, twenty- 
five in the space of 5 mm., separated by less than half the diameter of an ap|r- 
ture: margins remarkably elevated, attaining a height of .10 mm., indenting 
the borders of the fenestrules; carina .40 mm. high; summit sometimes 
sharp, at other times .10 mm. wide. Scalae and pseudo-carinse, usually slightly 
narrower than the carinse, twelve scalse in the space of 5 mm. Interstices 
nearly circular or sub-quadrangular; frequently the summits of the carinse 
are sharp and irregular, this face of the frond then having the appearance 
of some form of Paleschara. (In fact, some authors have mistaken similar 
forms for incrusting corals.) The carina is apparently formed from the con¬ 
necting of a row of small columns by a thin plate; when this is removed 
there is no evidence that the thinner portion proceeded from the branch, the 
base having very much the appearance of a row of nodes or cell apertures. 
This face of the frond with the carinse removed, might be very easily mis¬ 
taken for some form having three rows of cell apertures. 
The non-celluliferous face of this species so closely resembles F. ( TJnitrypa ) 
stipata , that it is not possible to satisfactorily distinguish them. The celluliferous 
faces are, of course, very different. From F. ( Hemitrijpa ) favosa or F. (H .) nana, 
it is distinguished by its stronger branches and very much stronger dissepi¬ 
ments ; from F. (II.) cribrosa by its much stronger dissepiments; from F. (II.) 
biordo, by its more slender branches, more closely disposed branches and dis¬ 
sepiments and much smaller fenestrules. 
Formation and locality. Upper Helderberg group, Walpole, Ontario, Canada. 
