NORTH AMERICAN HATER TERTIARY AND QUATERNARY BRYOZOA. 
71 
HEMISEPTELLA GKANDICELLA Canu and Bassler, 1919. 
Plate 5, fig. 12. 
1919. Hemiseptella grandicella Canu and Bassler, Geology and Paleontology of the West Indies, Bry- 
ozoa, Publications of the Carnegie Institution of Washington, No. 291, p. 84, pi. 5, fig. 11. 
Description. —The zoarium incrusts shells. The zooecia are large, elongate, 
ogival, distinct, separated by a furrow of little depth; the mural rim is narrow, little 
salient, round, finely granulated; the cryptocyst is large, flat, granulated; the ope- 
sium is elongated, elliptical, irregular and nonsymmetrical in the proximal portion. 
,, , ~ 7io = 0.40 mm. 
Measurements. —Opesia 7 . _ 
r (o = 0.25 mm. 
Zooecia 1 
Lz = 0.65-0.70 mm. 
?2 = 0.35 mm. 
Affinities. —The group of inferior opesiular spines was certainly dissymmetrical; 
trace of the lateral spines is scarcely visible on our specimens. 
This species differs from Hemiseptella denticulata Smitt, 1872, in the absence of 
nodosities in the interzooecial angles and in the nontrifoliate opesium. It differs 
from Hemiseptella tenuis Desor, 1848, in the larger micrometric measurements and 
in the more fragile and less numerous spines. 
Occurrence. —Lower Miocene (Bowden marl): Bowden, Jamaica (rare). 
Holotype. —Cat. No. 68490, U.S.N.M. 
HEMISEPTELLA FILIMARGO, new species. 
Plate 10, fig. 9. 
Description. —The zoarium incrusts shells. The zooecia are distinct, separated 
by a very thin salient thread, elongated, subhexagonal; the mural rim is very thin, 
filiform, salient; the cryptocyst is large, flat, shallow. The opesium is semielliptical, 
transverse, with an irregular proximal border, two large lateral spicules and many 
spicules placed inferiorily. 
,, , „ [7io = 0.12-0.18 mm. r , . \Lz = 0.40-0.50 mm. 
^ [ lo = 0.15-0.20 mm. [ (2 = 0.25-0.30 mm. 
Variations.—' The micrometric measurements are very irregular. Interzooecial 
tubercles are sometimes present. On our single specimen the spicules are badly 
preserved. The extreme thinness of the mural rim well characterizes this species. 
Cases of regenerated zooecia have been observed. 
Occurrence. —Miocene (Yorktown formation): York River, Virginia (very 
rare). 
Holotype. —Cat. No. 68491, U.S.N.M. 
HEMISEPTELLA TUBEROSA, new species. 
t 
Plate 46, fig. 10. 
Description. —The zoarium incrusts shells. The zooecia are distinct, elongated, 
rectangular, ornamented with large interzooecial tubercles ; the mural rim is thick, 
rounded, granulated; the cryptocyst is much reduced, deep, granulated. The 
opesium is elongated, elliptical, with an irregular proximal border. 
Measurements. —Opesia 
7io = 0.25 mm. 
. To = 0.15 mm. 
Zooecia 
[1,2 = 0.35 mm. 
Iz = 0.25 mm. 
Variations. —On our type specimen there are very few spicules visible, 
micrometric measurements are very- irregular. 
The 
