220 PALEOZOIC PALEONTOLOGY. 
FAVOSITES CORRUGATUS Nl. Sp. 
Plate XVII., Figs. 1-2. 
Deservption.—Corallum explanate, forming masses 15 to 20 cm. in 
width by 2 to 2.5 cm. in thickness. Corallites polygonal, usually 
hexagonal in cross-section, 1 to 1.5 mm. in diameter. Tabule nu- 
muerous, situated at distances of about one-half tube diameter apart. 
The sides of the corallites are transversely corrugated, the corruga- 
tions being strongest near the angles, so that in longitudinal section 
the sides of the corallites are wavy lines. Walls of the corallites per- 
forated by a single vertical row of mural pores. 
Remarks.—This species may be easily recognized by the conspicuous 
transverse corrugations of the corallite walls, in which respect it 
differs from any similar form. 
FAVOSITES PYRIFORME (Hall). 
Plate XVII., Figs. 3-5. 
1852. Astrocerinum pyriforme Hall, Pal. N. Y., vol. IL., p. 123, pl. 
34 A, figs. 1 a-e. 
Description.—Corallum pyriform or obconical in the smaller colo- 
mies, the point of attachment small, becoming subhemispherical in 
the larger colonies. 'The corallites are exceedingly irregular in size, 
the larger ones from 1.5 mm. to 2 mm. in diameter, being surrounded 
by smaller ones, which vary in size down to mere points, their size 
depending upon the proximity to their points of origin. The tabule 
are closely arranged, from three to five occupying a space equal to the 
tube diameter. The septa are represented by twelve vertical rows of 
spiniform processes, one or two in each row being situated in each 
intertabular space. The walls of the corallites are perforated by 
rather large, circular, mural pores, arranged in one or two vertical 
series. 
Remarks.—This species grows in colonies which vary in size up to 
100 mm. or more, and which become more and more hemispherical 
with age. It is the only species of the genus which has been recog- 
