214 
BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 
The operculum is a wholly chitinized simple one, not separable from the ectocvst. 
Multiporous septulae. The mural rim is distinct from the cryptocvst. 
Genotype. — V elumella ( Onychocella ) levinseni Canu and Bassler, 1917. 1 
The mural rim and the cryptocyst are formed from the same olocystal ele- 
ments; they are not distinct from each other, and their separation is purely super- 
ficial. The operculum is revealed by the two small lateral teeth of the opesium 
which indicates its axis of rotation. The small size of the opesiular indentations 
is indicative of very small parietal muscles. 
VELUMELLA LEVIGATA, new species. 
Plate 34, figs. 1-3. 
Description . — -The zoarium incrusts rocks. The zooecia are hexagonal, regular, 
with their mural rim confluent. The cryptocyst is deep, flat, smooth. ; the mural 
rim is thick, convex; the opesium is semilunar, transverse; the polypidian con- 
vexity is little apparent ; the opesiular openings are small and round. The onycho- 
cellarium is hexagonal like the zooecium ; its opesium is large, elongated, irregular, 
oval or elliptical. 
Measurements . — Opesium 
ho= 0.07-0.10 mm. 
lo= 0.10-0.12 mm. 
Zooecium 
\Lz= 0.35 mm. 
lfe=0.32 mm. 
Opesium of \ A<m=0.22-0.30 mm. 
onychocellariumlZ(?^?L=0.10 mm. 
Affinities . — This species differs from V elumella plicata in its transverse ope- 
sium, its smooth cryptocyst, and its round opesiular openings. 
O ccurrence . — Upper Jacksonian (Ocala limestone) : Alachua, Florida (rare) ; 
9 miles north of Ocala, Florida (rare) ; West bank of Sepulga River, Escambia 
County, Alabama (rare). 
Cotypes. — Cat. Nos. 63972-63974, U.S.N.M. 
VELUMELLA PLICATA, new species. 
Plate 34, fig. 4. 
Description . — The zoarium forms broad incrustations on shells. The zooecia 
are hexagonal, elongated, their mural rims confluent. The cryptocyst is deep, flat, 
finely granulated ; the polypidian convexity is salient and longitudinally wrinkled ; 
the opesium is semilunar, crenulated, elongated; the opesiular openings are small, 
oblique, linear. The onychocellariiun is larger than the zooecium; its opesium is 
iarge, median and oval. 
Measurements- 
. [7(0=0.10-0.12 mm. 
-Opesium | ?< , =a0fMU0mm ,, 
Opesium of j h on— 0.25-0.30 mm. 
onychocellariuml?o/m=0.18-0.20 mm. 
E..LA 
|fe=0.30 mm. 
1 This new name was proposed for the recent species figured as Onychocella species by Levinsen in his 
Morphological and Systematic Studies on the Cheilostomatous Bryozoa, 1909, pi. 22, figs. 3 a-d. 
