NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
697 
M easurements.- 
FILISPARSA SIMULATOR, new species. 
Plate 159, figs. 19-28. 
Description . — The zoarium is formed of rectilinear branches much compressed 
and pluriserial. The tubes are distinct, arranged in irregular quincunx or in 
transverse or oblique rows ; they are terminated by a short upward bent peristomie ; 
the peristome is thin, orbicular or elliptical. The dorsal is transversally striated. 
Diameter of the peristome 0.1G mm. 
Distance between the peristomes 0.40 mm. 
Separation of the peristomes 0.50 mm. 
Width of the branches 1.00 mm. 
Variations. — The arrangement of the peristomes is cpiite variable, being some- 
times in quincunx, and occasionally in oblique rows, when the species simulates 
Idmonea. More often, they are grouped in transverse rows and the specimens 
resemble Filispersa typica Manzoni 1877 but F . simulator differs in its smaller 
micrometric dimensions (D=0.16 and not 0.20 mm.). 
Occurrence . — Vicksburgian (Marianna limestone) : One mile north of Monroe- 
ville. Alabama (very common). 
Cotypes. — Cat. No. 65410, U.S.N.M. 
FILISPARSA ATOMICULA, new species. 
Plate 157, figs. 25, 26. 
^Description. — The zoarium is very small and formed of rectilinear hairlike, 
triserial branches. The tubes are very small, distinct, wrinkled transversally, 
arranged in irregular quincunx, terminated by an upward bent peristomie; the 
peristome is thick and orbicular, salient. 
Diameter of the peristome 0.10 mm. 
Diameter of the apertura 0.07 mm. 
Measurements. — Distance between the peristomes 0.30-0.50 mm. 
Separation of the peristomes 0.30-0.36 mm. 
Width of the branches 0.30 mm. 
This is the smallest of the American species of Filisparsa and occurs very 
rarely. 
Occurrence.- — -Vicksburgian (Marianna limestone) : One mile north of Monroe- 
ville, Alabama (very rare). 
Holotype. — Cat. No. 65403, U.S.N.M. 
FILISPARSA LAXATA, new species. 
Plate 160, figs. 1-4 
Description . — The zoarium is formed of much compressed branches enlarged, 
at the bifurcations^ pluriserial. The tubes are distinct, cylindrical, finely striated 
transversally, arranged in regular quincunx, terminated by a peristomie upward 
bent and salient. The peristome is thin and orbicular. 
Diameter of the peristome 0.14—0.16 mm. 
Distance between the peristomes 0.70-1.00 mm. 
Separation of the peristomes 0.60 mm. 
Width of the branches at the bifurcations-- 1.20 mm. 
Measurements . — 
