305 
Zoecial apertures are small, separated completely by mesopores, and 
occur in diagonal and longitudinal rows; 10 zoecia in 2 mm. diagonally and 
7 in 2 mm. longitudinally. The vestibular walls of the zooecia and meso- 
pores are distinctly granular along the contact, forming an encircling dark 
band. The orifices of the zooecia lie at the base of sloping vestibules which 
are composed of homogenous tissue forming a ring about the opening. 
As shown in the longitudinal section the zooecial tubes are thin-walled 
in the primitive region and lie prostrate upward on the median lamina, 
then turning outward, opening into the vestibules acutely. The walls of 
the vestibules terminate almost perpendicularly at the periphery. A single 
diaphragm crosses many of the zooecial tubes usually shortly preceding the 
turn from the reclining position towards the vestibule. 
The mesopores are short, rising in the late primitive zone. True dia- 
phragms are absent, but in some thick irregularly arranged tabulae oceur. 
This species differs from Stictoporella cribrosa, in haying smaller fen- 
estrules, a granular band surrounding the apertures of the mesopores and 
zooecia, more numerous mesopores and diaphragms crossing the zooecia. 
The zoaria of the other species is so different from NS. cribilina that no other 
differentiating characters are necessary. 
Occurrence: Pierce limestone, Murfreesboro, Tennessee, and 1 mile 
north of McFadden Ford, Rutherford County, Tennessee. 
Holotype: 56162 U. S. Nat. Mus. 
Paratype: 238, 20, 21; 242-13. Indiana University. 
FIG. 1. 
Fig. 1.—A portion of the eastern part of the United States showing the probable 
boundary of the Early Stones River (Mosheim) Sea. 
