NORTH AMERICAN EARLY TERTIARY BRYOZOA. 695 



Occurrence. Middle Jacksonian: Wilmington, North Carolina (very com- 

 mon; near Lenuds Ferry, South Carolina (common); Eutaw Springs South 

 Carolina ( common "1 . 



Vicksburgian (Marianna limestone) : Salt Mountain, 5 miles south of Jackson, 

 Alabama (very rare). 



Cotypes. Cat. No. 65327, U.S.N.M. 



FILISPAKSA BIN1, new species. 



Plate 159, figs. 1-7 



Description. The zoarium is formed of filiform, sinuous, dichotomous, very 

 little compressed branches, whose dorsal is very finely striated transversally. The 

 tubes are distinct, convex, much elongated, arranged alternately in pairs on each 

 side of the longitudinal axis, terminated by a narrowed peristomie, bent upward 

 and salient ; the peristome is thin and orbicular. 



Diameter of the peristome 0.12 mm. 



Measuremcn is. 



Distance between the peristomes 1.20-1.60 mm. 



Diameter of the tubes 0.18-0.20 mm. 



Width of the branches . 0.38 mm. 



Affinities.- -The tubes which form each pair have their peristomes close together 

 but not adjoining; they do not therefore form lines as in Idinonea bialternata 

 Gregory, 1893. The present species differs from FiUsparsa fallax not only in this 

 very important character, but also in its smaller peristomial diameter (0.12 and 

 not 0.16 mm.). 



Occurrence. Vicksburgian (Bed Bluff clay) : Seven and one-half miles south- 

 west of Bladen Springs, Alabama (rare). 



Vicksburgian (Marianna limestone) : One mile north Monroeville, Alabama 

 (rare). 



Cotypes. Cat. Nos. 65406, 65407, U.S.N.M. 



FILISPAKSA GRACILIS, new species. 



Plate 159, figs. 8-11. 



Description. The zoarium is formed of slender, rectilinear branches bifurcated 

 at a very acute angle, compressed, formed of three longitudinal rows of tubes. 

 The tubes are distinct, cylindrical, hardly curved at their extremity, finely striated 

 transversally and irregularly placed; the peristome is thin, orbicular or elliptical. 



Diameter of the peristome 0.16 (0.14-0.18 mm.). 



Measurements. 



Distance between the peristomes 0.60-0.80 mm. 



Width of the branches 0.40 mm. 



Affinities. This species differs from Filisparsa bini in its rectilinear, not 

 sinuous, branches and in its shorter peristomial distance (0.80 and not 1.20 mm.). 

 In the number of longitudinal rows, its affinities are chiefly with Filisparsa fallax; 



