116 
BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 
smaller size of these last distinguish it from II. megavlcularia in which the avicu- 
laria are as large as the zooecia proper. 
Occurrence . — Middle Jacksonian (Castle Hayne limestone) : Wilmington, 
North Carolina (rare). 
Cotypes. — Cat. No. 63881, U.S.N.M. 
HINCKSINA MEGAVICULARIA Canu and Bassler, 1917. 
Plate 23, fig. 1. 
1917. Hincksina megavlcularia Canu and Bassler, Synopsis of American Early Tertiary 
Bryozoa, Bulletin 96, United States National Museum, p. 16, pi. 1, fig. 7. 
Description . — The zoarium incrusts other bryozoa. The zooecia are large, 
distinct, elongated, pyriform, and have a gymnocyst ; the mural rim is convex, 
salient, provided with 14 to 20 large, hollow spines. The opesium is terminal, 
elliptical, or somewhat pyriform, entire; the interzooecial avicularium is large, 
symmetrical, and has a gymnocyst; its opesium is constricted laterally, probably at 
the place where the pivot ought to be. 
Measurements.- 
. f/m=0.30-0.35 mm. 
-Opesial a25 mm . 
Zooecia 
Length of avicularia= 0.60-0.65 mm. 
|Zs=0.60-0.T0 mm. 
|fe=0.40 mm. 
Affinities .- — On account of its large avicularia this species differs considerably 
from Hincksina parv avicularia, but it approaches the recent II. pyrula Hincks, 
1881. It differs, nevertheless, in its larger number of spines; unfortunately we 
are unable to compare the ovicells. 
The specimen figured is very instructive. On a zooecium can be seen the 
coalescing of opposite spines, giving an aspect like the frontal of Menibraniporella. 
Many zooecia are regenerated; in one case a normal zooecium succeeds a normal 
zooecium and a double row of spines results; in another case an avicularium re- 
places a zooecium; in a third an avicularium again replaces a zooecium, but in a 
totally inverted position. 
Occurrence . — Middle Jacksonian (Castle Hayne limestone) : Wilmington, 
North Carolina (very rare). 
Holotype. — Cat. No. 62574, U.S.N.M. 
HINCKSINA COSTULIFERA, new species. 
Plate 23, figs. 2-5. 
Description . — The zoarium incrusts other bryozoa or creeps over algae. The 
zooecia are elongated, distinct, elliptical or pyriform with or without a gymno- 
cyst; the mural rim is convex, salient, ornamented with 13 to 15 areal spines and 
2 oral spines a little larger. The opesium is elliptical, entire. The endozooecial 
ovicell is a salient convexity. No interzooecial avicularia. The ancestrula is a 
small ordinary zooecium. 
“ ' ‘ " | Lz~- 
M easurements.- 
. \ho= 0.34-0.40 mm. 
-Opesia 7 n OA 
09=0.20 mm. 
Zooecia 
: 0.48-0.50 mm. 
17,3=0.28-0.32 mm. 
