NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
171 
Affinities . — In its small micrometric dimensions this species clearly differs 
from the others. It is rather close to Stamenocella inferaviculifera , whose opesium 
is often pyriform; it is distinguished from it by the very peculiar disposition of 
its cryptocyst, which is developed laterally and inferiorly to the opesium. 
Occurrence . — Lower Jacksonian (Moodys marl) : Jackson, Mississippi (com- 
mon). 
Cotypes. — Cat. No. 639-38, U.S.N.M. 
STAMENOCELLA MEDIA VICU LIFER A Canu and Bassler, 1917. 
Plate 31, figs. 1-5. 
1917. Stamenocella mediaviculifera Canu and Bassler, Synopsis of American Early 
Tertiary Cheilostome Bryozoa, Bulletin 9'6, United States National Museum, p. 22, 
pi. 3, fig. 1. 
Description . — The zoarium is bilamellar, with the two lamellae back to back 
and inseparable. The zooecia are very elongated, narrowed behind, distinct or 
indistinct; the mural rim is thin, salient, somewhat enlarged and attenuated, 
rounded, smooth. The opesium is elliptical or oval, entire; the gymnocyst is flat 
or somewhat convex and nearly as long as the opesium. The avicularium is salient 
and placed in the middle of the gymnocyst. The ovicell is rarely intact. 
Measurements . — Opesia 
ho=0A0 mm. 
fo=0.16 mm. 
Zooecia 
\Lz= 0.80 mm. 
1^=0.20-0.24 mm. 
Variations and affinities. — This species apparently lived in agitated waters. 
Although widely distributed, it is often very rare, and specimens are always more 
or less worn. In this condition the mural rim is worn away and invisible, the 
zooecia indistinct, and the avicularia absent or replaced by a concave cicatrix 
(fig. 2). We have never found the ovicell intact; it is always more or less broken, 
but its place is clearly visible on the gymnocyst, notably in the specimens from near 
Perry, Georgia (fig. 3). The avicularium is of the simple type without denticles 
or pivot. The dimensions in this species are much smaller than in S. grandis , and 
it is rarely as well preserved. On certain specimens from Rich Hill, Georgia, we 
have observed sometimes four punctations at the base of the gymnocyst. The rare 
specimens from the Yicksburgian are very mediocre in preservation and have the 
abraded aspect shown in figure 5. 
Occurrence. — Middle Jacksonian: Rich Hill, Crawford County, Georgia (very 
common ) ; 3£ miles south of Perry, Georgia (very common) ; 18 miles west of 
Wrightsville, Johnson County, Georgia (rare) ; 34 miles north of Grovania, Georgia 
(rare) ; 12 miles southeast of Marshallville, Georgia (rare) ; 17 miles northeast of 
Hawkinsville, Georgia (rare) ; one-half mile southeast of Georgia Ivaolin Company 
Mine, Twiggs County, Georgia (rare) ; Baldock, Barnwell County, South Carolina 
(rare) ; Wilmington, North Carolina (rare). 
Vicksburgian (Marianna limestone) : Salt Mountain, 5 miles south of Jackson, 
Mississippi (doubtful) ; near Claiborne, Monroe County, Alabama (doubtful). 
Cotypes.— Cat. Nos. 62581, 63939, 63940, U.S.N.M. 
