406 
BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 
is concave. The ovicell is little salient. The avicularium replaces an areola ; it is 
elongated and inconstant. 
Measurements. — Zooecia 
| £2=0.65-0.70 nun. 
I 0.35-0.40 mm. 
Affinities. — The abnormal zooecia (fig. 10) are probably hydrostatic zooecia 
which are intended to buoy up the zoarium when the subtratum is very feeble. 
The apertures do not appear to be of equal size (fig. 8) ; but as it is very difficult 
in drawing under the camera lucida to discover their true plane, it is very probable 
that the great differences result from deformations due to perspective. 
This species differs from Bathosella aspera Ulrich, 1901, in its line of areolae 
and its free and not incrusting zoarium. 
It differs from Bathosella undata in the presence of a continuous' line of 
areolae around the zooecia and in its unilamellar and not bilamellar zoarium. 
Occurrence. — Midwayan (Clayton limestone) : Mabelvale, near Little Rock, 
Arkansas ( common ) . 
Iiolotype. — Cat. No. 63828, U.S.N.M. 
BATHOSELLA UNDATA, new species. 
Plate S, figs. 3, 4. 
Description. — The zoarium is free, bilamellar, the two lamellae, back to back, 
and inseparable. The fronds are undulated. The zooecia are indistinct, elongated ; 
the frontal is smooth, very little convex; it bears laterally 3 to 5 areolae. The aper- 
ture is very oblique and buried in the locella by a convex mucro and very finely 
denticulated. The ovicell is scarcely salient; it is deeply imbedded in the distal 
zooecia and it opens into the locella by a transverse slit. 
„ fZ.2=0.50-0.60 mm. 
M easurements. — Zooecia , . „ „ 
[£2=0.35 mm. 
Affinities.— This species much resembles Bathosella aspera Ulrich, 1901, when 
the latter is deprived of its avicularia with pivot. It differs from it in its bilamellar 
and not incrusting zoarium, in its much smaller and more buried ovicell, and in 
the absence of all frontal avicularia. 
Occurence . — Midwayan (Clayton limestone) : Mabelvale, near Little Rock, 
Arkansas (very rare) ; 1 mile west of Fort Gaines, Georgia (rare). 
Holotype. — Cat. No, 63827, U.S.N.M. 
Genus ROMANCHEINA Jullien, 1888. 
1888. Romancheina Jullien, Mission Scientifique du Cap Horn, vol. 6, Zoologie, Bryozoaires, 
p. 62. 
The aperture is oblique without lyrula, cardelles or rimule. The ovicell is 
imbedded in the distal zooecia. It opens above the aperture and below the frontal 
mucro in a locella. The frontal is a tremocyst with pores more or less large. The 
ovicell is much smaller than the zooecia; the mucro is wide and convex. The 
