NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
389 
disposed below the aperture. On the lower face, the zooecia are smooth, convex 
and ornamented with numerous small hydrostatic prickles. 
Measurements. — Aperture 
f ha= 0.23 mm. 
Ua=0.17 mm. 
Zooecia 
[Ts=0.75-0.85 mm. 
I lz=0. 65-0.80 mm. 
Affinities. — This is the species which has the most resemblance to the type 
of the genus HippomeneUa mucroneTliformis Waters, 1899. from Madeira as much 
in its frontal as in the form of its aperture. It differs from it in its much larger 
aperture (ha= 0.23 and not 0.16 mm.), in its avicularia of the same size, in the 
absence of a small oral mucro, and in its hydrostatic prickles. 
It differs clearly from the other species of HippomeneUa in the hexagonal form 
of the zooecia. 
The frontal is formed of a very thin pleurocvst (fig. 4), very distinct from the 
subjacent olocyst, from which it may be separated. 
Occurrence. — Vicksburgian (“Chimney rock” of Marianna limestone.) : One 
mile north of Monroeville, Alabama (very common). 
Cotypes. — Cat. No. 64278, U.S.N.M. 
Group 3. ZOARIUM INCRUSTING. 
HIPPOMENELLA PUNCTATA, new species. 
Plate 51, figs. 1-3. 
Description. — The zoarium incrusts shells and bryozoa, especially the Celle- 
pores. The zooecia are distinct, very elongated, fusiform, separated by a furrow; 
the frontal is convex, smooth in the middle, surrounded by a double row of small 
areolae and formed of an olocyst surmounted by a distinct pleurocyst. The aper- 
ture is elliptical, elongated, provided with two small cardelles placed very low; 
the peristome is thin and garnished with six distal spines. The ovicell is globular, 
salient, little imbedded in the distal zooecia, never closed by the operculum; the 
lateral areas almost disappear under a tremocyst, which has numerous small pores 
in quincunx. The avicularium is small, salient, triangular, placed eccentrically 
before the aperture; it is provided with a pivot and its beak is pointed downward. 
i,, . . \ , IAa=0.18-0.20 mm 
Measurements.- Aperture ’ Ua=0 15 mm . 
Zooecia 
\ Zs=0.80-0.90 mm. 
1 7^=0.35—0.45 mm. 
Affinities. — It is easy to understand in this species the deposit of the pleuro- 
cyst, the elements of which begin to be deposited around the areolae. The buds 
of the internal endocyst of which the areolae are the traces, reunite bv coalescence 
to form a superior endocyst and continue therefore to be able to secrete and deposit 
the pleurocyst. 
This species differs from HippomeneUa rotula in the presence of its spines, its 
ovicell with small pores and not with large costules, and its zoarium incrusting and 
not bilamellar. 
It differs from HippomeneUa radicata in its larger dimensions, its ovicell with 
pores more numerous and smaller, its unique avicularia and its zoarium incrusting 
and not unilamellar. 
