292 
The American Geologist. 
May, 1891 
FOVE.E. 
SEPTA. 
49. 
One is occasionally present. 
Short, alternating, fall considerably short of center. 
Secondaries quite marginal. 
50. 
One is present. 
Well developed, alternating. Do not extend to center. 
61. 
Lamellar and well developed towards center. But 
slightly or not at all prolonged into vesicular area. 
52. 
One, more or less distinct. 
Well developed, alternating. Primaries never ex- 
tend further than outer edge of central boss. 
53. 
A wide fovea is generally 
present. 
Well developed, alternate; with denticulate edges. 
Primaries join the two walls. Secondaries shorter. 
54. 
Not distinct but occasionally 
present. 
Well developed, radiate, equal or alternating. Pri- 
maries extend to center. Side faces and edges 
smooth. 
55. 
One, variable in size, but 
veil marked. 
Numerous, well developed, alternate. Primaries ex" 
tend to columellar wall. Thin in the outer area. 
56. 
One, well marked. 
Usually thin, alternating. Flexuous in outer area. 
Primaries extend only to outer margin of central 
area. 
57. 
One, well marked. 
Well developed, generally of two orders. Primaries 
always fall short of central area. Secondaries short 
or wanting. 
58. 
Present as a narrow groove. 
Meeting at the center and forming an elevated and 
columella like whorl. 
59. 
Obscure or obsolete. 
Radiate, alternate. Primaries seldom reach the cen. 
ter; secondaries generally enter the tabulate area. 
60. 
None indicated. 
Septa project but slightly outside of well marked in- 
ternal wall. Alternating, flexuous. 
61. 
None. 
Well developed, alternate. Regularly radiate in one- 
half of calyx, in other half pinnate to large princi- 
pal septum. 
62. 
One, more or less distinctly 
developed. 
Well developed, alternate, radiate. Primaries ex- 
tend to center or its immediate vicinity. Fre- 
quently flexuous. 
63. 
One, deep. 
Slightly exsert, closely set, very thick exteriorly. 
Not reaching center. Slightly granulated laterally. 
64. 
Occasionally one. 
Well developed but always fall short of columella. 
Thin and delicate in vesicular zone, but reaching 
wall. Alternating. 
65. 
One is sometimes incon- 
spicuously present. 
Radiate, alternate. Various in extent, sometimes 
reaching columella. Sides smooth, not denticulate. 
66. 
Obscure or none. 
Generally alternating. Rudimentary or obsolete in 
vesicular area. Primaries ordinarily do not reach 
columella. 
67. 
Four, although three are sel- 
dom distinct. 
Numerous, equal or alternating. Broad, with tent- 
shaped crest in calyx, at times sharp, seldom 
rounded. 
68. 
Obscure or none. 
Well developed, alternate. Poorly developed in ves- 
icular zone. More or less thickened about pit. 
Somewhat confluent in neighboring corallites. 
69. 
Rudimentary or obsolete. 
Alternate, primaries unite at the center. Secondaries 
terminate at rim of calicinal pit. 
70. 
Equal. 
71. 
One, well marked in cross 
section. 
Alternate. Primaries extend only to outer edge of 
central boss: secondaries sometimes scarcely ob- 
servable. 
72. 
None indicated. 
Numerous, very slender, confined to central area. 
Generally lost in the outer vesicular zone. 
