NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
739 
When the ovicell is very thick the tubes appear displaced and more scattered. 
This is only an illusion provoked by the elongation of the tubes and their diver- 
gence; at their base they have the normal distance. (See Diaperoeda clava.) 
The tubes which traverse the ovicell are often closed by a finely porous, cal- 
careous lamella. 
D *36 
Fig. 239. — Anatomy of the Diaperoeciidae Canu, 1918. 
A, B. Diplosolen intricaria Smitt, 1871. A. Section through ovicell, X 25, containing a large 
number of small embryos. B. Section of lobe a of the same ovicell. (After Waters, 1900.) 
C-E. Diaperoeda intricaria Busk, 1875. C. Ovicelled zoarium, X 12 (o, oeciostome). After 
Harmer, 1915.) D. Transverse section through a zoarium, X 36, showing in the tubes a large 
number of minute rays with club-shaped heads, on which there are numerous tubercles. E. Bays 
included in the tubes, X 250. 
F. Diaperoeda rugosa, Waters, 1878. Longitudinal section through a zoarium, X 12. The 
most usual position for the calcareous plate which closes the tube would seem to be about the 
point where the zooecial tube rises free from the zoarium. (D-F after Waters, 1884.) 
G-K. Diaperoeda regularis MacGillivray, 1882. G. Transverse section, X 25, showing con- 
nection through tubes- divided by a disk. TI. Longitudinal decalcified section, X 25, showing 
thick membranous transverse wall. I. The thick membrane projects in the middle, but is not 
closed below, X 85. ts, tentacular sheath; at, tissue attached to the tentacular sheaths and to the 
zooecial wall. J. There is a thin tube (tb) arising from the transverse membrane, X 85. K. Ap- 
pearance of the diaphragm (dp) closing the tentacular sheath. (G-K, after Waters, 1905.) 
L. Diaperoeda pulcherrima Kirkpatrick, 1890. Many ovicells are reunited ; they form only 
one ovicell with many oeciostomes (o). (After Harmer, 1915.) 
