NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
799 
HORNERA RETERAMAE, new species. 
Plate 144, figs. 1-8. 
Description. — The zoarium is large, with reticulated branches , the fenestrae 
of which are elongated and fusiform. The tubes are invisible exteriorly ; they bear 
iwo vacuoles adjacent to the peristome and a single sulcus of little depth. The 
peristome is little salient and orbicular. The dorsal bears longitudinal sulci of 
little depth and very large vacuoles; the nervi are wide. 
Diameter of the peristome 0.12 mm. 
Diameter of the aperture 0.08 mm. 
Measurements . — t-,-, , , ,, ■ , „ 
Distance between the peristomes 0.50 mm. 
Separation of the peristomes 0.40-0.50 mm. 
Affinities. — This species is quite constant on the whole, and Ave liaise observed 
only the habitual alterations due to fossilization. It differs from Tlornera rete- 
poracea Milne-Edwards, 1838, in the special arrangement of the zoarial netivork 
deprived of trabeculae and in which the branches are all of the same size. 
It differs from Tlornera polyporoides in the absence of trabeculae and in the 
larger, zooecial dimensions. 
O ccurrence. — Middle Jacksonian (Castle Hayne limestone) : Wilmington, 
North Carolina (rare). 
Cotypes. — Cat. No. 65328, U.S.N.M. 
HORNERA POLYPOROIDES, new species. 
Plate 144, figs. 9-13. 
Description . — The zoarium is reticulate and formed of compressed branches 
joined by short and thin transverse trabeculae. The tubes are invisible exteriorly: 
they bear a single Avide longitudinal sulcus, at the base of Avhich are three, four, 
or five large vacuoles. The peristome is wide, little salient, orbicular. On the 
dorsal the nervi are narrow, the sulci wide and deep, and the vacuoles large. 
l Diameter of the peristome 0.10 mm. 
M easurements. — ■ Diameter of the aperture 0.06 mm. 
[ Distance between the peristomes 0.38-0.40 mm. 
V aviations. — The number of frontal vacuoles is quite variable according to 
the form of the branches. The dorsal vacuoles are often smaller when the sulci 
are more numerous (fig. 12). 
Affinities . — In its zoarium, this species resembles Tlornera reteporacea Milne- 
Edwards, 1838, but the American species differs in its more numerous frontal 
vacuoles, in its smaller dorsal vacuoles, and in the absence of tivo large triangular 
vacuoles adjacent to the peristome. 
It differs from Tlornera reteramae in its zoarium formed of branches joined 
by narrow trabeculae and in the very great irregularity of the fenestrae. 
Occurrence. — Lower Jacksonian (Moodys marl) : Jackson, Mississippi 
(common). 
