NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
487 
illumination from below is preferable. The most usual aspects are those of the 
figures 7-10, 13. Finally the species which is quite vigorous in the lower Jack- 
sonian (Z.s=0.70-0.80 mm.) appears to become stunted in the middle and upper 
Jacksonian (£.3=0.54-0.60 mm.) (fig. 16). The zooecia are not always distinct 
(figs. 10, 16). 
In the interior (fig. 15) the tubules are well marked by the white circle which 
surrounds the small pores of the olocvst. Moreover, there is a short lyrula and two 
small cardelles (fig. 15). 
This species has been found in many localities of the Jacksonian, which fact 
occasions its name. 
Occurrence. — Lower Jacksonian (Moodys marl) : Jackson, Mississippi (very 
common). 
Middle Jacksonian: Wilmington, North Carolina (common); Baldock, Barn- 
well County, South Carolina (rare). 
Jacksonian (Zeuglodon zone) : South side of Suck Creek, Clarke County. Mis- 
sissippi (very rare) ; Shubuta, Mississippi (rare). 
Upper Jacksonian (Ocala limestone) : Alachua, Florida (rare). 
Cotypes. — Cat. Nos. 64147-64150, U.S.N.M. 
PORELLA PUNGENS, new species. 
Plate 62, fig. 14. 
Description. — The zoarium incrusts oysters. The zooecia are distinct; quite 
elongated, fusiform, separated by a deep furrow ; the frontal is convex, formed 
of a tremocyst, with four rows of large scattered pores. The apertura is hidden 
at the base of the peristomie by the median avicularium; the peristome is very 
thin and somewhat salient. The ovicell is large, globular, salient, formed of an 
area with numerous small pores surrounded by a smooth collar. The median 
avicularium is enormous, very salient; elevated obliquely at 45°; it covers in part 
the apertura and opens on its side. 
,, , t> • i • f£oe=0.08mm. 
Measurements . — leristonuce 7 
\lpe= 0.10 mm. 
Zooecia 
( £3=0.70-0.80 mm. 
1/2=0.26-0.30 mm. 
Affinities. — This species differs from the incrusting species, such as Porella 
granulosa , Porella irregularis , and Porella coronata , in its enormous and salient 
median avicularium. 
Its aspect is similar to Porella jacksonica, of which it is perhaps only the 
incrusting form. It differs from it nevertheless in its avicularium still more 
elevated and its salient ovicell, little imbedded in the distal zooecium. It differs 
from Lepralia monoceros Beuss, 1847, and Lepralia ceratomorplia Beuss, 1847, of 
the European Miocene, in the presence of tremopores and not of areolae. The 
zoarium appears to be bristling with sharp points. 
Occurrence. — Lower Jacksonian (Moodys marl) : Jackson, Mississippi (com- 
mon). 
Holotype . — Cat. No. 64143, U.S.N.M. 
