Measurements.- 



NORTH AMERICAN EARLY TERTIARY BRYOZOA. 697 



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 0.16 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 quite 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 haiiiike, 

 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. 



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.C^. No. 65403, U.S.N.M. 



FILISPARSA LAXATA, ntw 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. 



Measurements.- 



Aleasuremen ts. 



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. 



