420 
BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 
M. Zoarium decalcified, seen posteriorly, X 45. N. Anterior view of a zooecium containing 
only a young polypide, X 115. (M, N after Jullien, 1888.) 
O. Microporella flaljellaris Busk, 1852. Dietellae, from the basal surface. Besides the 
basal wall of the dietellae, the small triangular basal surface of the vibracular chamber is seen 
lowest down to the right on the four zooec-ia. On some zooecia the basal surface shows a sep- 
tula, and on others an opening corresponding with a septula in an opposite zooecium, X 40. 
(After Levinsen, 1909.) 
P-W. Opercula of Microporella. M ciliata Pallas, 1766, X 85. Q. M. malusi Audouin, 
1826, X 85. (P, Q after Waters, 187S. ) R. M. parvipora Waters, 1904, X 85. (After Waters, 
1906.) S. M. divaricata Canu, 1903, X 85. (After Waters, 1904.) T. M. flabelligera Levinsen, 
1909, X 85. U. M. decorata Reuss, 1847, X 100. V. M. marginata Krauss, 1837, X 100. W. M. 
flabellaris Busk, 1852, X 140. (T-W after Levinsen, 1909.) 
Levinsen, in 1909, did not recognize the different genera established by authors 
according to the form of the aperture. We have been able to adopt a number of 
these genera, employing the principle of the great variations in the function of 
calcification. 
Many species hitherto believed to belong to the Microporellae have been recog- 
nized to belong in reality to the Adeonidae. 
Microporella Hincks, 1877, Flustramorpha Busk, 1884, and Diporula Hincks, 
1879, are referred to this group, the general anatomy of which is illustrated in 
figure 123. A discussion of the group will be deferred until the publication of our 
monograph on the later Tertiary Bryozoa of North America. 
The genera of this section have some peculiar characters which do not permit 
of their classification in any of the large groups cited; but they appear really to 
belong to the same general family. The principal of these genera are : 
Ilouzeav/ina Pergens, 1889. 
Cyclicopora Hincks, 1884. 
Kyvnella Canu and Bassler, 1917. 
Cyclocolposa , new genus. 
. C ycloperiella , new genus. 
Aimulosia Jullien, 1888. 
Anartliropora Smitt. 
This last genus, devoid of ovicells, belongs perhaps to a distinct family. 
ca, cardiac region of the stomach ; 
caec, caecum of the stomach ; 
corn, cornieula; 
die, dietella ; 
est, stomach ; 
gt, tentacular sheath ; 
ir, irisoid ; 
mop, occlusor muscles of the operculum ; 
mrp, large retractor muscles of the polypide ; 
ov ovary ; 
pli, pharynx and esophagus ; 
pm, parietal muscles; 
r, intestine and rectum; 
t, tentacles. 
Group 5, DIVERS GENERA. 
