NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
813 
even the recent ones, presents therefore much difficulty. • As the oeciostomes and 
the cancelli can only give constant characters, we have given a summary in figure 
256 of our knowledge of these important organs. On the fossils we have not yet 
discovered the complete oeeiostome and this absence of character much weakens 
the determinations. 
The first two zooecia issued from the ancestrula determines the direction of 
the tubes in a given section. We call them directrices and they are always of a 
smaller diameter than the other tubes. 
LXCHENOPORA BOLETIFORMIS Reuss, 1869. 
Plate 130, figs. 1-11. 
1869. ltadiopora boletiformis Reuss, Palaontologische Studien liber die iilteren Tertiar- 
seliichten der Alpen, Denkschriften der k. Akademie der Wissenschaften, Wien, 
vol. 29, p. 81, pi. 2S, fig. 7 (1) (not Tecticavea boletiformis D’Orbigny, 1854, nor 
Lichenopora boletiformis Waters, 1884.) 
Description. — The zoarium is free and reposes on the substratum only by a 
thin peduncle. It is formed of many lamellae superposed. Each lamella contains 
many confluent subcolonies. The basal lamella is thick and striated concentrically. 
The subcolonies are orbicular or elliptical with a large central area. The fascicles 
are little salient, short, biserial or triserial. The tubes are small and deprived of 
visor. The cancelli are larger than the tubes; they are polygonal and their walls 
are thin. 
I Diameter of the tubes 0.16 mm. 
Measurements.— Diameter of the cancelli 0.20 mm. 
Greatest dimension of the zoaria 1 cm. 
V aviations. — The fascicles become much attenuated and the zoaria have then 
much resemblance to Ceriopora (fig. 6). The zoarium has no fixed form, but 
a very convex ensemble is the most frequent. Each subcolony has no special basal 
lamella. The tubes are polygonal (figs. 7, 8) in the sections but they ai’e round 
in the broken portion. The spinules of the cancelli (fig. 8) are small, numerous, 
and arranged in longitudinal series. 
The median sections vary according to place where they are made. In a 
section (fig. 10) perpendicular to the fascicles the tubes are seen from the front. 
In section (fig. 11) practically within a fascicle the tubes appear in their length 
and parallel to each other. 
Affinities. — On account of its multiserial fascicles this species is very close to 
Lichenopora mediterranea Miehelin, 18-18, and to Lichenopora verrucosa Philippi, 
1813. It is distinguished from them by the greater micrometric and zoarial dimen- 
sions. 
Occurrence. — Middle Jacksonian: Wilmington, North Carolina (common): 
Eutaw Springs, South Carolina (very common) ; Baldock, Barnwell County, South 
Carolina (rare). 
Geological distribution. — Priabonian of the Yicentin (Reuss). 
Plesiotypes. — Cat, No. 65153, TJ.S.N.M. 
