178 Dr. H. A. Nicholson on new Species of Polyzoa 
As a general rule the polyzoary is simple, unbranched, and 
falciform. I have seen, however, in the fine collection of 
Mr. Dyer, of Cincinnati, some specimens in which the frond 
bifurcates at its distal extremity, and at least one example in 
which it splits into three divisions. I have also seen examples 
of what may probably prove to be a distinct species, in which 
the frond is very much wider than is normally the case. 
This beautiful species is allied to Ptilodictya (Escharopora) 
recta, Hall, on the one hand, and to P. lanceolata, Goldf., 
P. gladiola, Billings, and P. sulcata, Billings, on the other 
hand. The specimens from which the above description is 
taken were sent to me with the label of Hscharopora recta 
attached to them; and at first sight they certainly closely 
resemble this species, especially in the disposition of the cells 
in intersecting diagonals of great regularity. It is certain, 
however, that they are distinct from Hall’s species—the chief 
differences consisting in the fact that the frond of P. faletformis 
is greatly flattened, so that the transverse section is acutely 
elliptical instead of being “cylindrical or subcylindrical,” 
whilst the edges are sharp and non-celluliferous, and the 
entire frond is regularly curved and sabre-shaped instead of 
being straight. Hall states that Hscharopora recta is not 
branched, but possesses root-like processes. Judging, however, 
from his figures, it would seem probable that his specimens 
have been drawn and described in an inverted position, and 
that this form is in reality dichotomously branched (Pal. N. Y. 
vol. i. pl. xxvi. fig. 1 a). 
From Pitlodictya lanceolata, Goldf. (Petref. pl. xxxvii. fig. 2), 
the present species is readily distinguished, more especially by 
the disposition of the cells, which are in regularly intersecting 
diagonal lines ; whereas in the former there is a central series 
of longitudinally arranged cells, flanked on each side by 
diagonal rows directed like the barbs of a feather. 
With Ptlodictya gladiola, Billings (Cat. Sil. Foss. of Anti- 
costi, p. 10), our species agrees in the shape of the frond; but 
it is proportionally twice as wide, whilst the cells are oval 
instead of being rectangular or oblong, and are disposed in 
decussating diagonals instead of in regular longitudinal lines 
as in the former. 
Lastly, Péilodictya sulcata, Billings (loc. cit. p. 385), whilst 
resembling P. falciformis in shape, is distinguished by the 
nearly square cells with intercellular sulci, and by the fact 
that the cells are arranged in longitudinal lines. 
Locality and Formation.—Not uncommon in the Cincinnati 
Group, near Cincinnati, Ohio. Collected by Mr. U. P. James. 
