XVI 
SYNOPSIS OF GENERA. 
popes more or less numerous, sometimes surrounding the cell apertures. Inter¬ 
cellular space occupied by septate tubuli. 
Examples: Callopora perelegans, pi. xii, figs. 10-17; pi. xxiiiA, fig. 14. 
Callopora multiseriata, pi. xxv, figs. 6, 7; pi. xxvi, figs. 18, 19. 
Callotrypa, n. s. g. [Type, Callopora macropora, Hall.] 
Zoarium ramose, solid. Cells tubular, arising from the center of the branch, 
increasing by interstitial addition. Apertures oval or polygonal. Mesopores 
minute. Inter-cellular space solid or with small tubuli destitute of septa. 
Examples: Callopora. ( Callotrypa) macropora , pi. xi, figs. 25-29 ; pi. xxiii, figs. 
15-19. 
Callopora ( Callotrypa) unispina, pi. xi, figs. 35-37. 
Coelocaulis, n. s. g. [Type, Callopora venusta, Hall.] 
Zoarium similar to Callopora in general form and in the characters of the 
cell apertures and inter-cellular structure, but growing in hollow stems, lined 
with a concentrically wrinkled and finely striated epitheca. 
Examples: Callopora ( Cadocaulis ) venusta, pi. xii, figs. 20-24; pi. xxiiiA, figs. 
1-3, 4 ? 5. 
Callopora ( Cadocaulis ) aculeolata, pi. xxvi, figs. 16, 17. 
Lichenalia, Hall (Pal. N. Y., vol. ii, p. 171. 1852). 
[Type, Lichenalia concentrica, Hall.] 
Zoarium explanate or massive. Cells septate, arising from the epitheca; 
apertures circular or trilobate, sometimes operculate, often denticulate with 
the posterior portion of the peristome arched and elevated. Interapertural 
space smooth; intercellular space vesiculose, vesicles irregularly disposed or 
more regularly superimposed, giving the appearance of walled septate tubuli. 
Examples: Lichenalia ovata, pi. xxxii, figs. 1-8. 
Lichenalia lunata, pi. xxxi, figs. 1-9. 
Pileotrypa, s. g., Hall (Report of State Geologist for 1885, advance sheets. 
Expl. pi. 30. 1886). [Type, Lichenalia denticulata, Hall.] 
Zoarium, in its manner of growth and general character, similar to Lichenalia; 
but with the posterior portions of the peristomes strongly elevated, and arched 
with distinct denticulations in the aperture, which in the course of growth 
form two longitudinal striations along the interior of the cell wall. 
Examples: Lichenalia (. Pileotrypa ) denticulata, pi. xxvi, figs. 21, 22, 26; pi. 
xxx, figs. 12-20. 
Lichenalia (. Pileotrypa ) pyriformis, pi. xxxi, figs. 21-27. 
