NORTH AMERICAN EARLY TERTIARY BRYOZOA. G67 



Occurrence- Vicksburgian (Marianna limestone) : Salt Mountain, 5 miles 

 south of Jackson, Alabama (rare). 



Cotypes.Czt. No. 65378, U.S.N.M. 



PROBOSCINA CLAVATIRAMOSA. new species. 



Plate 153, figs. 1, 2. 



Description. The-zoarium inc rusts shells in multiserial claviform branches. 

 The tubes are scarcely distinct, cylindrical, arranged in quincunx 0.3G mm. apart. 

 The peristome is thin, salient, orbicular. 



Maximum width of zoarium _ 1.00 mm. 



Measurements 



Length of tube-- - 0.40 



mm. 

 Diameter of peristome 0.10 mm. 



Affinities -This species differs from Proboscina conve.ni.ens in its claviform 

 branches, much narrowed at their base, and in the much more scattered arrange- 

 ment of the peristomes. 



Occurrence. Vicksburgian (Marianna limestone) : Salt Mountain, 5 miles 

 south of Jackson, Alabama (rare) ; near Claiborne, Monroe County, Alabama 

 (rare). 



Holotype.Czi. No. 65379, U.S.N.M. 



PROBOSCINA LATOBREVIS. new species. 



Date 118, figs. 10-12. 



Description- The zoarium is biserial and incrusts shells and orbitoid forami- 

 nifera in short and undulated branches. The tubes are distinct, wide and short, 

 punctate, arranged alternately. The peristome is thin, salient orbicular, oblique. 

 The branches commence with a very large zooecium. 



Maximum width of zoarium 0.70-0.80 mm. 



Length of tube 0.60-0.80 mm. 



Diameter of peristome 0.22-0.30 mm. 



Variations. The tubes in the vicinity of the ancestrula have no constant mi- 

 crometric measurements; the peristome increases gradually from 0.11 to 0.22 mm.; 

 the length of the tubes grows from 0.50 to 0.70 mm. Sometimes the branches are 

 triserial ; when two zooecia are adjacent their peristomes remain free. 



The phenomenon of rejuvenation is rather rare. Here the branches commence 

 indeed in a single zooecium, but it is enormous when the ancestrula is very small. 



Occurrence. Upper Jacksonian (Ocala limestone) : Old Factory about 1^ 

 miles above Bainbridge, Georgia (rare). 



Vicksburgian (Marianna limestone) : Near Claiborne, Monroe County, Ala- 

 bama (rare). 



s.CAt. Nos. 65291, 65292, U.S.N.M. 



Measurements. 



