168 
BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 
The specific name is in honor of Mr. John M. Nickles, of the United States 
Geological Survey, whose work upon American Paleozoic bryozoa is well known. 
Occurrence . — Middle Jacksonian: Eutaw Springs, South Carolina (very rare). 
Cotypes. — Cat. No. 63935, U.S.N.M. 
Genus STAMENOCELLA Canu and Bassler, 1917. 
1917. Stamenocella Canu and Bassler, Synopsis of American Early Tertiary Cheilostome 
Bryozoa, Bulletin 96, United States National Museum, p. 21. 
Ovicell hyperstomial not closed by the opercular valve. No dietellae. Gvm- 
nocyst long and flat, supporting a small sessile, salient avicularium. 
Genotype. — Stamenocella mediaviculif era Canu and Bassler, 1917. 
Range. — Senonian-Vicksburgian. 
The genus which is nearest to this type of structure is Bactrellaria Marsson, 
1887, in which the zooecia are identical, but are disposed on a single side of a 
triserial zoarium. The two genera undoubtedly belong to the same family. 
The genus Bugularia Levinsen, 1909, the type of which is the recent Oarhasea 
dissimilis Busk, 1896, appears very similar. Nevertheless its zooecia are disposed 
on only one side of the zoarium, the basal edge of its distal wall is angular and the 
ovicell is free. Levinsen has classed his genus Bugularia in the Bicellariidae , but 
his family is not an entirely natural one, as it contains three genera. Bugula. 
Eucratea , and Bicellaria , which have absolutely distinct larvae. It also contains 
Chaperia , in which the anatomical characters are quite different from Bugida. 
In Stamenocella the gymnocyst supports the ovicell which is extremely fragile, 
and also the avicularium. The ovicell of the proximal zooecia forces the avicu- 
larium of the distal zooecia near to their opesia. 
There may be classed in this genus — 
Stamenocella ( Biflustra ) fenestrella D’Orbigny, 1852. 
Stamenocella ( Flustrella ) convexa D’Orbigny, 1852. 
Stamenocella ( Eschara ) cuvieri Yon Hagenow, 1851. 
The genus also probably includes the Cretaceous group of Rhynchotella Canu, 
which, however, presents some divergent characters. The name Rhynchotella can 
not be admitted in nomenclature because it was proposed by Canu as a simple 
artificial grouping to facilitate the determination of species. 
STAMENOCELLA CYLINDRICA, new species. 
Plate 1, fig. 15. 
D escription.- — The zoarium is free, cylindrical , formed of 6 longitudinal rows 
of zooecia. The zooecia are long, distinct, a little narrowed behind ; the mural rim 
is salient, wide, convex, smooth ; the gymnocyst is flat, as long as half of the zooecium 
and bears 2 to 4 proximal punctations. The opesium is elliptical or oval. 
Measurements . — Opesia 
ho— 0.22-0.25 mm. 
lo= 0.10 mm. 
Zooecia 
\Lz= 0.70-0.72 mm. 
172=0.25 mm. 
Affinities . — Only the figured specimen has been found, which permits no serious 
study. It contains a calcified zooecium. It is possible, indeed, that the zoarium 
