A chai't of the Rugose corrals. — Sherzer, 
295 
DISTINGUISHING CHARACTERISTICS, 
RANGE. 
MAXIMUM. 
DISTRIBUTION. 
1. True vesicular structure. Incomplete tab- 
ula?. 2. Much shorter septa and weaker ves- 
icular structure. 
Devon., 
Carbon. 
Devon. 
Europe, 
America. 
Septa never reach center. Reticulate central 
structure instead of cells. 
Low. Car- 
bon. 
Low. Car- 
bon. 
Europe. 
Absence of outer wall. 
Carbon. 
Carbon. 
Europe. 
Centrally elevated tabula?. Calicinal boss is 
conical. Vertical plates more numerous and 
complete at center. 
Silur., 
Devon., 
Carbon. 
Carbon. 
Europe, 
America. 
1. More nearly central and heavier inner wall. 
Carinse. 2. Inner wall and shorter septa. 
Devon. 
Devon. 
America. 
Septal faces smooth; heavier vesicular devel- 
opment. See also Blothrophyllum, Diphy- 
phyllum and Acervularia. 
Silur., 
Devon., 
Carbon. 
Devon. 
Europe, 
America. 
Inner area is filled with a spongiose columel- 
lar structure containing vertical, radiating 
lamellae. 
Carbon. 
Carbon. 
Europe. 
The vertical plates of the central area are not 
so plainly developed. 
Low. Car- 
bon. 
Low. Car- 
bon. 
Europe. 
Median lamella extends across central area in- 
stead of half way. Eminence is low and 
rounded. 
Low. Car- 
bon. 
Low. Car- 
bon. 
Europe. 
Septa continue to the center; character of 
interseptal structure. 
Silur. 
Silur. 
Europe. 
1. Inner wall is marginal and weaker. No 
carinse. 2. Always compound. Inner wall, 
shorter septa, etc. 
Silur., 
Devon., 
Carbon. 
Devon. 
Europe, 
America. 
Absence of epitheca. Septa are but little de- 
veloped between the two walls. 
Devon. 
Devon. 
Europe. 
The fovea is replaced by a strong septum to 
which neighboring septa are pinnate. 
Silur., 
Devon. 
Silur. 
Europe, 
America. 
1. No inner wall, septa longer. 2. Presence of 
cai'inre, slighter development of vesicles. 
Silur., 
Devon. 
Devon. 
Europe, 
America. 
Deep fovea, septa very thick towards wall, ar- 
ranged in three cycla, strong costa?, no 
- epitheca. 
Cretace- 
ous. 
Cretac. 
Europe. 
1. Laterally compressed columella. Dense 
vesicular zone and line inosculating tabula'. 
2. Septa reach outer wall. 
Carbon. 
Carbon. 
Europe. 
1. Generally astneiform. Presence of colu- 
mella. 2. Always compound, weaker vesicu- 
lar development and stronger septa. 
Devon. y 
Carbon. 
Carbon. 
Europe, 
America. 
1. Outer wall is present. 2. Septa weak in 
outer area, vesicles large, sub-cylindrical col- 
umella formed of twisted plates. 
Silur., 
Carbon. 
Carbon. 
Europe, 
America. 
No columella, tour foveas in type, broad cen- 
tral area, strong radiciform processes. 
Silur. 
Silur. 
Europe, 
America. 
Well characterized tabula' at the center. 
J >evon. 
Devon. 
Europe, 
America. 
Tabulae at the center are obsolete or rudimen- 
tary. 
1 >evon„ 
Carbon. 
Europe, 
America. 
Silur. 
Silur. 
Europe. 
Calicinal boss not conical. Tabula; slightly 
concave upwards. Comparatively tew cen- 
tral, vertical, incomplete plates. 
Low. Car- 
bon. 
Low. Car- 
bon. 
Europe. 
1. 'J. No interna! wall. Septa reduced to 
mere stria' in periphery,. 2. No columella, 
less tabular development . 
Devon. 
1 le\oll. 
Europe. 
