NORTH AMERICAN LATER TERTIARY AND QUATERNARY BRYOZOA. 
67 
Genus LABIOPORA Levinsen, 1909. 
(For description, see Bulletin 106, U. S. National Museum, p. 258.) 
LABIOPORA MIOCENICA Canu and Bassler, 1919. 
Plate 6, fig. 1. 
1919. Labiopora mioceniea Canu and Bassler, Geology and Paleontology of the West Indies, 
Bryozoa, Publication of the Carnegie Institution of Washington, No. 291, p. 89, pi. 6, 
fig. 1. 
Description.— 1 The zoarium is unilamellar. The zooecia are elongate, distinct, 
rectangular; the mural rim is quite thin, round. The cryptocyst is little deep, 
flat, and formed of a tremocyst superposed on an olocyst perforated with corres¬ 
ponding pores. The opesium is tranverse, terminal or placed at the base of a funnel, 
formed by the much developed vestibular arch. The polypidian tube is visible, 
wide, median. 
Measurements .—Op esia- 
Ao = 0.10 mm. 
lo = 0.24-0.28 mm. 
Zooecia! 
X 2 = 0.50-0.64 mm. 
\lz = 0.32—0.34 mm. 
Affinities. —This new species differs from Labiopora crenulata Levinsen, 1909, 
in the wide form of the zooecia and in its transverse opesium. 
Occurrence. —Lower Miocene (Bowden horizon): Rio Gurabo, Santo Domingo 
(rare). 
Holotype. —Cat. No. 68488, U.S.N.M. 
CALPENSIIDAE, new family. 
No ovicell. The cryptocyst is perforated by one or two opesiules. 
We suppose that the ovicell is formed by an internal sac placed in the vicinity 
of the opercular region as in the genus Diplodidymia Reuss, 1869. The different 
genera which we classify here belong perhaps to distinct families; but as we are 
ignorant of the larva, it is preferable to group them provisionally under the same 
name. They may be classified in three groups. 
1. A single opesiule. Diplodidymia Reuss, 1869. 
2. Cryptocyst with spinous processes. Hemiseptella Levinsen, 1909; Cupu- 
laria Lamouroux, 1821. 
3. Complete cryptocyst. Calpensia Jullien, 1888; Verminaria Jullien, 18S8; 
Microporina Levinsen, 1909; Corynostylus Canu and Bassler, 1919. 
Genus DIPLODIDYMIA Reuss, 1869. 
1869. Diplodidymia Reuss, Zur fossilen Fauna der Oligocanschichten von Gaas, Sitzungsberichte 
der k. Akademie der Wissenschaften, Wien, vol. 59, Abth. 1, p. 469. 
The zoarium is articulated and radicelled. Each segment is formed of four 
rows of zooecia placed diagonally. No ovicell. Two very small pores are placed 
on each side before the apertura. The cryptocyst is perforated laterally by a long 
linear opesiule; it gives passage to the wide muscles attached to the ectocyst in a 
scelerity (= chitinous thickening). The avicularium is by the side of the apertura 
