NORTH AMERICAN EARLY TERTIARY BRYOZOA. 777 



Affinities. This species is easily confused with Id/niilronca maxttlaris Lons- 

 dale, 1845, in which the dorsal presents the same great development. It differs 

 from it in the complete absence of firmatopores which are visible either by abra- 

 sion, or in longitudinal sections. 



It differs from Idmonea tumida Smitt, I860, in the much less separation of 

 the fascicles (0.20 and not 0.50 mm.). 



Occurrence. Middle Jacksonian (Castle Hayne limestone) : Wilmington, 

 North Carolina (very common). 



Upper Jacksonian (Ocala limestone) : Alachua, Florida (rare) ; west bank 

 Sepulga River, Escambia County, Alabama (rare). 



Cotypes.Cat. No. 65352, U.S.N.M. 



IDMONEA GRALLATOR, new species. 



Plate 138, figs. 1-20. 



Description. The zoarium is small, filiform, linear, bifurcated, horizontal, 

 with oval transverse section which is a little higher than wide. The fascicles are 

 salient, little oblique, arranged alternately on each side of the median axis and 

 quite distant from it. They are formed by four or five zooecia. the last of which 

 is quite small. The tubes are visible, flat, separated by a salient thread. The 

 basal lamella is convex, flat, or somewhat concave; it is striated longitudinally 

 by the tubes and transversally by the convex zones of growth; it bears radicells 

 of consolidation. The ovicell is quite elongated between six or seven fascicles. 



Diameter of the tubes 0.12 mm. 



Distance between the fascicles 0.34-0.40 mm. 



Width of the fascicles 0.14 mm. 



Width of the zoarium 0.8 mm. 



Variations. The fascicles are quite salient and quite divergent from the 

 median crest (figs. 2, 3); abrasion lessens this character (fig. 6). The dorsal is 

 quite variable; it is flat on the young branches (fig. 8) ; but the older branches 

 are convex (fig. 9). 



The base of the zoarium is quite wide ; the branches are arranged horizontally 

 (fig. 19) ; the first bear radicells of consolidation, like small stilts (fig. 20) which 

 separate all the branches from the substratum. A section (fig. 15) taken through 

 these radicells shows that they are formed of ordinary zooecia curved as usual 

 and which were probably deprived of ordinary polypides. 



We are not certain that the ovicell shown in figure 12 really belongs to this 

 species; it is the only fragment found at this locality and the oeciostome is quite 

 clearly preserved on it. 



Affinities. The calcareous radicells are not rare. They have already bc<-n 

 noted by Smitt. 1872, in Idmonea milneana D'Orbigny, 1839, by Kirkpatrick. 1888, 

 in Idmonea radicata, and by Norman, 1909, in Idmonea pedata. 



This species differs from Idmonea pedata Norman in its less salient fascicles 

 and in having five zooecia (and not three) to a fascicle. 



Measurements. 



