NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
605 
of the two usually has a small projection from the base or columella” (Waters, 
1909). Spines. 16-18 tentacles. 
Genotype. — Holoporella (C ellepora) descostilsii Savigny-Auclouin, 1826. 
Range . — Claibornian — Recent. 
HOLOPORELLA ORBICULIFERA, new species. 
Plate 16, figs. 10-15. 
Description . — The zoarium is small, massive, convex, incrusting shells. The 
superficial zooecia are prominent, orbicular , separated; the frontal is smooth gar- 
nished with a very few areolae; it is terminated by a very fragile aviculiferous 
beak. The apertura is somewhat elongated, finely crenulated; the anter is semi- 
lunar and is separated from a concave poster by two small cardelles placed very 
low ; the peristome is very thin and bears two large spines. The ovicell is recum- 
bent, hyperstomial, transverse. The deep zooecia have a deep peristomie; they 
have neither spines nor avicularia. The incomplete zooecia are accompanied by a 
small elliptical or round avicularium with pivot. 
Measurements. — Apertura 
ha= 0.09 mm. 
la— 0.06 mm. 
Variations. — Usually the beak is broken and leaves a broad cicatrix on the 
frontal. The very small zoarium does not permit of good photography of the 
characters. The thin section shows some more or less large pores between the 
zooecia; they are irregular and do not appear to correspond to a definite organ. 
Some zooecia have a small, triangular upper chamber; this is the cavity of the 
aviculiferous beak (fig. 15). The walls are formed of scattered olocystal elements 
(fig. 11). _ 
Affinities. — In the smallness of the zoarium and in its zooecial aspect this 
species approaches somewhat Holoporella separata. It differs from it in its im- 
bedded zooecia without pedunculate avicularia. 
Occurrence. — Claibornian (Gosport sand) : Claiborne, Alabama (rare) ; 1 mile 
west of Rockville, Clarke County, Alabama (rare). 
Cotypes. — Cat. No. 63859, U.S.N.M. 
HOLOPORELLA FISSURATA, new species. 
Plate 76, figs. 1-6. 
Description . — The zoarium forms small, convex masses on shells or on the 
radicells of algae; on oysters it is surrounded by a large zone of oriented zooecia. 
The superficial zooecia are salient, round, erect; the frontal is smooth, surrounded 
by four to seven large areolae; it is terminated by a pointed mucro deforming the 
apertura and bearing an oral avicularium, rather large and with a bar. The aper- 
tura is semilunar ; the anter is large and the poster is concave ; the peristome is very 
thin and very little salient and bears two large, symmetrical spines. The ovicell 
is salient, transverse, recumbent; it opens by a very large opening above the aper- 
tura; it bears a long arched fissure. The oriented zooecia are marginal; they are 
