614 
BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 
CLITHRIDIATE GROUP. 
The orifice is oval. The frontal is a very thick olocyst perforated by some 
scattered avicularia. The ovicell is hyperstomial and lodged in the thickening of 
the olocyst. 
It would be convenient, perhaps, to make a special family for this group; but 
we are ignorant of the larva, and it is necessary to search first and find the analogous 
or closely related recent species. 
Some species have very little of cumulate zooecia. 
Genus ACANTHIONELLA Canu and Bassler, 1917. 
1917. Acantliionella Canu and Bassler, Synopsis of American Early Tertiary Clieilostome 
Bryozoa, Bulletin 96, United States National Museum, p. 72. 
The apertura is oval and bears a long lyrula. The frontal is a very thick 
olocyst, in which are lodged some avicularia. The ovicell is hyperstomial; it is 
lodged in the thickening of the 
frontal of the distal zooecia ; it 
opens into the peristomie. 
G enoty p e. — AcanthionelJ a 
( Escharifora ) typica Gabb and 
Horn, 1862. 
Range . — M aastrichtia n — 
Jacksonian. 
This genus differs from Klei- 
dionella in the presence of a 
lyrula and the rarity of cumu- 
late zooecia. 
ACANTHIONELLA OECIOPOROSA, new 
species. 
Plate 17, figs. 1-14. 
Description. — The zoarium 
is free, bilamellar, with fronds 
more or less rounded. The 
oriented zooecia are indistinct; the frontal is a very thick olocyst perforated 
by two to five small avicularia. The apertura (interior) is oval and garnished 
by a long proximal tyrula; the peristomice (exterior) is orbicular; the peristomie 
is very deep and contains sometimes an avicularium bearing the lyrula. The 
ovicell is buried in the distal zooecia; it opens into the peristomie; it bears a 
frontal area closed by a much branched spine. The young zooecia and the cumulate 
zooecia are distinct, elongated, gibbose. The interzooecial avicularia are rare, of 
the size of the zooecia, elliptical, and provided with a pivot. 
M easurements. — Apertura j ha= 0.10 mm. Zooecia f Lz= 0.35 mm. 
(interior) \la= 0.14 mm. (interior) lfe=0.26 mm. 
B >50 
Fig. 183 . — Cellepora ramalosa Busk, 1854. 
A. Zoarium, natural size. B. Zooecium, X 50. C. Portion 
of zoarium, X 25. (A-C after Busk, 1854.) 
