580 TRANS. OF THE ACAD. OF SCIENCE. 
Geological position and Locality.—Devonian, Falls of the 
Ohio. In the Collection of Dr. B. F. Shumard, 
Potyrora HALLIAnA, n. sp. 
Polyzoum a broad fan-shaped expansion, with apparently 
entire rigid longitudinal rays radiating from a central point, 
7 
wards the border. 
Dissepiments mostly alternate, small, depressed, often not 
much more than connecting points between the longitudinal 
rays; about one-fourth as long as the fenestrule, and some- 
what expanded at their junction with the longitudinal rays. 
Owing to their depression the spaces between the rays appear 
as long furrows, somewhat notched. : 
enestrules long, oval and narrow, being from twice to 
three times as long as broad. Two longitudinally in a space 
of two lines, three transversely. ; 
Chalices small, pore-like, juxtaposed in sinistral spiral lines 
upon the longitudinal rays; about four lines of alternate chal- 
ices and sometimes five, rarely three toward the base. In 
straight lines there are about four to each fenestrule, in zig- 
zag, eight to nine. 
omparisons.—Resembles P. Mexicana, but differs by the 
want of contraction and expansion above and below the bi- 
furcations, in the fewer number of chalices oo the borders 
PoLYPORA GRACILIS, n. sp. 
Polyzoum a long narrow net-work, proceeding from Pa 
pedicle, with longitudinal rays of nearly uniform size, oe a 
ing to branch much more frequently toward the margin 
hear the base. : the bi- 
ongitudinal rays round, dilating very slightly at late 
farcations, spaces between the bifurcations long, gee ial 
dichotomizations from two to five lines apart, but on pa 
rays nearly opposite. RB : . 
Diamingus very small, expanded at their junction ie 
the longitudinal rays, dividing them into a somewhat ireg™ 
lar net-work, . Ps 
