NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
783 
Some branches (figs. 14, 15) are bevoncl all description on account of their great 
irregularity. The fascicles are quite salient (figs. 7, 8, 14), but they are fragile 
and break easily (fig. 16). 
The fascicles are quite distant from the median crest ; also on the longitudinal 
sections there are no zooecia with the apertura visible (fig. 22). In order to see the 
apertura of the zooecia it is necessary to make a meridian section by the prolonged 
abrasion of the frontal (fig. 23). 
The miscroscopic structure of the zooecial walls (fig. 24) is rather difficult to 
comprehend. 
Affinities. — This species is quite odd and easy to determine; it is impossible to 
confuse it with the others. One can not determine the isolated branches, for the 
reader can believe in the existence of many species of which intermediate stages 
appear in large numbers of specimens. 
The comparison with the French species has been made specimen with speci- 
men and the identification is absolutely certain. 
0 ccurrence. — Vicksburgian (Marianna limestone) : Salt Mountain, 5 miles 
south of Jackson, Alabama (common) ; near Claiborne, Monroe County, Alabama 
(common) ; Murder Creek, east of Castlebury, Conecuh County, Alabama (very 
common) ; west bank Conecuh River, Escambia County, Alabama (very com- 
mon) ; Escambia County, Alabama (deep well) (rare). 
Vicksburgian (Byram marl) : One-fourth mile west of Woodwards, Wayne 
County, Mississippi (common). 
Geological distribution. — Auversian of Biarritz (Canu). 
Plesiotypes. — Cat. Nos. 65441-65445, U.S.N.M. 
IDMONEA GRANDIORA, new species. 
Plate 162, figs. 1-3. 
Description. — The zoarium is free, linear, fixed by an expanded base, com- 
pressed. The fascicles are somewhat salient, close together, arranged alternately 
on each side of the median line and formed of three equal zooecia. The tubes 
are invisible ; the peristome is thin ; the apertura is large. 
Diameter of the zooecia 0.20 mm. 
Distance between the fascicles 0.20-0.22 mm. 
Measurements.- width of the fasoioIes 0.115-0.18 mm. 
Width of the zoarium 0.60 mm. 
Affinities . — Only the three specimens figured have been found. They are of 
interest merely on account of their great apertura and because this species exists in 
the strata of Vicentin where Canu has recently discovered it. 
Occum'ence . — Vicksburgian (Marianna limestone) : One mile north of Monroe- 
ville, Alabama (rare). 
Geological distribution . — Priabonian of the Vicentin. 
Holotype. — Cat. No. 65472, U.S.N.M. 
