BRYOZOA. a PAll 
Spatiopora fowensis,] 
never exceeds 1mm. Diaphragms are wanting in most of the tubes, but here and 
there the sections pass through one or several adjoining tubes having one diaphragm 
about midway up and sometimes another at the month. 
This is an interesting and easily recognized species. Of associated parasitic 
forms only two need be compared; one, Stromatotrypa ovalis of this work, has oval 
and much larger zocecia; the other is a rare and as yet undetermined form with 
circular and smaller zocecia, numerous mesopores, and more uneven zoarium. S. 
labeculosa differs from both in the greater size and distinctness of its maculie, and in 
the slight obliquity of its zocecial apertures. The macule will distinguish the species 
at once from all the other species of the genus. 
Formation and locality.—In the middle third of the Trenton shales at Minneapolis and St. Paul. 
Mus. Reg. No. 5026. 
° SPATIOPORA IOWENSIS, ”. Sp. 
(Not figured.) 
Zoarium spread as an exceedingly thin crust over the cones of Orthoceras sociale 
Hall. Monticules wanting, but unusually distinct clusters of large cells are dis- 
tributed over the surface at intervals of about 5mm., measuring from center to 
center. Zocecia larger than in other species of the genus, their walls thin, the 
apertures nearly or quite direct, angular, often of hexagonal or rhombic shapes, with 
three of those in the clusters in 2 mm. and an average of nine of those in the spaces 
between the clustersin 3mm. Mesopores wanting except in the clusters mentioned 
where a few may be wedged in among the large cells. Many of the angles of junc- 
tion between the apertures are raised into sometimes small, at other times large, 
acanthopore-like prominences. 
In the dark shales at Graf, Iowa, this bryozoan is preserved as a thin gladiolus 
leaf-like film, the Orthoceras grown upon being compressed to such a degree that its 
original presence may not be suspected. 
This species is in every respect a true Spatiopora. The affinities are nearer 
S. maculosa Ulrich, of the Cincinnati rocks, than to any of the others, and it is with 
that species that I first thought to place it. On comparison however S. owensis 
proved to have larger zocecia, with eight to ten where the Ohio species has eleven or 
twelve. 
Formation and locality Maquoketa shales of the Hudson River group at Graf, Iowa, 
Mus. Reg. Nos. 7586, 7587. 
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