BRYOZOA. 167 
Escharopoa.] 
Genus ESCHAROPORA, Hall. 
Escharopora, HALL, 1847. Pal. N.:Y., vol. i, p. 72. 
Ptilodictya (part.), ULR1cH and many other authors. 
Zoaria bifoliate, simple or branching, pointed below, and articulating into 
a spreading base as in Ptilodictya. Zocecia arranged in regular diagonally intersect- 
ing series throughout. In the small species these rows extend in a continuous line 
across the fronds, but in the larger forms their course is interrupted at more or less 
regular intervals by the development of raised clusters of large cells. Apertures 
rounded, elliptical or subcircular, set into sloping areas; the latter generally of 
rhomboidal or hexagonal shape and sharply defined, in other cases longitudinally 
confluent, and connected by a narrow channel. 
Internal structure essentially as in Péilodictya, the differences chiefly due 
to the different zocecial arrangements. 
Type: E. recta Hall, Pal. N. Y., vol. i, p. 72 ; 1847. 
Better known examples are Ptilodictya falciformis Nicholson, Pal, Ohio, vol. ii, p. 
259, 1875, and P. pavonia d’Orbigny, Prodr, de Pal., vol. i, p. 22, 1850. 
CLASSIFICATION OF SPECIES. 
Section a; zoaria simple, without monticules. 
E. acuminata (James), Galena limestone, Iowa; Utica horizon of the Cincinnati group, Ohio and 
Kentucky. 
E. angularis, 0. sp., lower Trenton, Minnesota. 
E. falciformis (Nicholson), Cincinnati group, Ohio, Indiana, Kentucky. 
E. recta Hall, Trenton limestone, New York, Canada, ? Galena shales, Minnesota, 
E. subrecta (Ulrich) lower Trenton shales, Minnesota. 
Section 6; zoaria simple, with monticules. 
E. hilli (James, as figured by Ulrich), Cincinnati group, Kentucky. 
E. libana (Safford), Birdseye limestone, Kentucky, Tennessee. 
E. maculata (Ulrich), Cincinnati group, Ohio, Kentucky. 
E. pavonia (d’Orbigny), Cincinnati group, Ohio, Indiana, Kentucky. 
E. n. sp., Birdseye limestone, Tennessee. 
E. n. sp. (near pavonia), top of Trenton, Nashville, Tennessee. 
E. n. sp., Cincinnati group, Kentucky. 
Section c; zoaria branching. 
E. briareus (Ulrich), Birdseye limestone, Tennessee. 
E, confluens, n. sp., lower Trenton shales, Minnesota, Tennessee. 
E. ramosa (Ulrich), Birdseye limestone, Tennessee, Kentucky. 
E. n.sp., Utica horizon of the Cincinnati group, Kentucky. 
From the preceding classifications we learn that EHscharopora began in the 
“Birdseye” or earlier, and ceased apparently in the age of the Cincinnati group— 
strictly speaking, in che middle division of that formation. True Ptilodictya is first 
met with in the upper beds of that group of rocks, and continues with varying rep- 
resentation up into the Lower Devonian. 
