422 
BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 
discovery. The avicularium develops on a lateral areola slipping under the frontal 
in the form of a triangle and developed longitudinally at the middle of this frontal 
(pi. 54, fig. 17). 
HOUZEAUINA ORNATA, new species. 
Plate 54, figs. 12-17. 
Description. — The zoarium is an Escliara the fronds of which reach frequently 
more than a centimeter. The zooecia are quite elongated, distinct, rectangular, 
separated by a salient thread ; the frontal is flat, smooth, ornamented laterally with 
numerous areolae often very large. The aperture is subcircular. The ovicell is 
buried in the distal zooecia, globular and salient and has a very fragile olocvstal 
frontal. The avicularium is median, somewhat salient, triangular, the beak turned 
toward the bottom and provided with a pivot. 
Measurements. — Aperture 
j Aa=0.18 mm. 
1^=0.14-0.16 
Aperture of [Aa=0.10 nun. 
ovicelled zooecia I7a=0.14 mm. 
Zooecia 
[ Zs= 0.80-0.90 mm. 
\lz= 0.24-0.30 mm. 
Variations. — -The dimensions of the aperture which we mention are the maxi- 
mum ; most of the time they vary around 0.12-0.14 mm. by 0.12 mm. The aper- 
ture of the ovicelled zooecia is transverse; nevertheless in looking at the base of the 
locella the zooecial aperture is perfectly visible with a greater height (0.12-0.18 mm. 
and not 0.10 mm.). If this aperture were closed by an ordinary operculum it would 
not be able to open exteriorly to allow the passage of the tentacles. It is this 
which makes us suppose that the ovicelled zooecia have a special operculum. The 
areolae are small (fig. 14) or large (fig. 13). 
The active formation of the pleurocyst gives to the zooecia a remarkable orna- 
mentation (fig. 16) impossible to describe. In the interior (fig. 17) we see a thick 
olocyst perforated laterally by some very small areolae, and the triangular cavity 
which is the lodging of the avicularium by which the mesenchymatous elements 
pass through one of the lateral areola. When the avicularium does not exist (fig. 
13) the areolae are larger. 
Affinities. — This is the American representative of H ouzeauina parallela 
Reuss, 1869. It differs from it in its orbicular orifice (and not semilunar) with- 
out a straight proximal border. 
It differs from II ouzeauina callosa in its smaller oral dimensions ((a =0.14, 
and not 0.18 mm.) in its larger areolae and the much larger frontal callosity. 
Occurrence.— Middle Jacksonian; Rich Hill, Crawford County, Georgia (com- 
mon) ; Baldock, Barnwell County, South Carolina (very common) ; 34 miles north 
of Grovania, Georgia (rare) ; 3! miles south of Perry, Georgia (rare) ; 18 miles 
west of Wrightsville, Georgia (common) ; Eutaw Springs, South Carolina (rare). 
Cotypes. — Cat. No. 64111, U.S.N.M. 
