NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
787 
Fig. 253. — Idmidronea, new genus. 
A-L. Idmidronea ( Idmonea ) coronopus Defrance, 1822. A. Zoaria, natural size, from 
various localities in the Lutetian of France. B. Zoarium, X 6, with layer of firmatopores form- 
ing many columns (on rocks). C. Specimen, X 6, with a small basal plate of firmatopores (in- 
crusting shells), bearing a branch without firmatopores. D. A concave base of firmatopores, X 6, 
attached to an alga. E. A large base, X 12, without firmatopores. The ancestrular zooecium is 
visible. F. A small base, X 12, without firmatopores. The ancestrular zooecium is visible. 
G. The same specimen, X 25, showing absence of firmatopores. H. An example, X 6, showing 
that the layer of firmatopores is separable. I. Specimen, X 12, showing that there are 
many layers of firmatopores. J. The firmatopores occur at the bottom of sulci, X 12. K. Longi- 
tudinal section in a thick zoarium through the axis of the fascicles, X 25. The basal lamella 
(BB) is visible. The firmatopores are the cylindrical tubes growing on the basal lamella but 
directed toward the base while the polypidian tubes are ascending. L. Longitudinal section, 
X 25, in the thick zoarium taken between the fascicles and in the axis of a bifurcation. The 
basal lamella (BB) is visible. M. Thin section in the base of a zoarium, X 25. 
