NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
793 
vex, elongated, elliptical, symmetrical, suspended on the lateral edge of the zoarium ; 
the oeciostome is terminal, very large, transverse, fastened to a small isolated tube, 
and separated from the fascicles. 
-Diameter of the peristome 0.10 nun. 
Distance between the fascicles 0.30 mm. 
Width of the fascicles 0.12 mm. 
Width of the branches 2.00 mm. 
M easurem en ts.- 
Variations . — The lamellar fascicles are often oblique 
(fig. 3) ; the sixth tube, which composes them and which 
is placed in the vicinity of the lateral edge, is often isolated. 
The ovicell is always placed laterally (fig. 1) ; its posi- 
tion is hardly disarranged at the bifurcations (fig. 2), even 
though this takes place at a very acute angle. It is remark- 
able that the oeciostome should be joined to a tube, but this 
tube does not belong to a fascicle, for it is always 
isolated. 
The variation of the nature of the ovicells in species with 
the Idmonea form of growth is very great. This is a proof 
of the poor method followed even to this day by the natural- 
ists is the classification of the cyclostomatous bryozoa. 
Idmonea unrestricted is only a zoarial form common to a 
great many families. 
Occurrence . — W ilcoxian (Bashi, formation) : Woods 
Bluff, Alabama (common). 
Cotypes. — Cat. No. 65261, TJ.S.N.M. 
Genus PROSTHENOECIA Canu, 1918. 
Fig. 255. — Genus Prosthe- 
noecia ) Canu, 1918. 
Two ovieelled zoaria of 
Prosthenoecia ( Reptotubig - 
era) lateralis, D’Orbigny, 
1852, from the Lutetian of 
France . 
1918. Prosthenoecia Canu, Les ovicelles des bryozoaires cyclostomes, Bulletin Societe 
gdologique de France, ser. 4, vol. 16, p. 327. 
The ovicell is placed on the celluliferous face; the oeciostome is large and trans- 
verse. 
Genotype.— Prosthenoecia ( Reptotubigera ) lateralis D'Orbigny, 1852. 
Lutetian. 
Family HORNERIDAE Gregory, 1899. 
Anatomical bibliography. — 1888. Waters, On some Ovicells of Cyclostomatous Bryozoa, Journal 
Linnean Society, London, Zoology, vol. 20, p. 275, pt. 14, figs. 1, 3, 4, 7. — 1903. Waters, Bryozoa 
from Franz-Joseph Land, pt. 2, Journal Linnean Society, London, Zoology, vol. 29, p. 168, pi. 
20, figs. 1-6. — 1904. Waters, Expedition antarctic Beige, Bryozoa, p. 93, pi. 9, fig. 1. — 1911. 
Hennig, Le conglomerat pleistocene a Pecten de l’ile de Cockburn, Wissenshaftliclie ergebnisse 
der schwedischen sudpolar expedition, vol. 3, p. 37, pi. 5, figs. 8-11. — -1914. Waters, Marine 
Fauna British East Africa and Zanzibar Bryozoa, Cyclostomata, Proceedings Zoological 
Society, London, p. 836. 
The ovicell is symmetrical, sacciform, subglobular. The oeciostome is lateral 
and opens on the frontal. The zoarial walls are lamellose and squamous. They are 
traversed by vacuoles. 
