NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
449 
LEIOSELLA ROSTRIFERA Canu and Bassler, 1917. 
Plate 92, tigs. 11-17. 
1917. Leiosella rostrifera Canu and Bassler, Synopsis American Early Tertiary Cheilo- 
stonie Bryozoa, Bulletin 96, United States National Museum, p. 48, pi. 5, tig. 1. 
Description . — The zoarium is free, bilamellar; the fronds are narrow, flat, 
claviform, bifurcated. The zooecia are elongated, distinct, ovoid; the frontal is 
smooth, convex, formed by a thick olocyst. The peristomice is irregular; the 
rimule-spiramen is bordered laterally by the oral avicularium. The apertura is 
elongated, ovoid, very oblicpte. The oral avicularium is large, transverse, salient, 
with the beak strong and curved ; it is provided with a pivot and a large mandible, 
more or less spatulate. On the frontal, there are two small, elliptical avicularia 
with round mandible. 
Measurements . — Peristomice J ^ l ’ ( Inm * 
[tpe=0 . 25 mm. 
ZooeciaJZs=0.90-1.00 mm. 
(interior) 1/3 = 0.25-0.30 mm. 
Apertura f ha=0.11 mm. 
(interior) l/rt=0.10mm. 
Variations . — At the exterior the measurements are quite variable because of 
irregularity in calcification and the unequal development of the avicularium. The 
apertura is very oblique and elongated; in perspective in the interior (fig. 16) it 
appears transverse and elliptical. The oral avicularium on account of its great 
prominence is very fragile and easily broken (fig. 13) ; it is more or less lost in the 
thickness of the olocyst (figs. 14, 15). The small frontal avicularia are not always 
visible (fig. 15). 
Occurrence . — Vicksburgian (“Chimney rock” of Marianna limestone): One 
mile north of Monroeville, Alabama (very common). 
Vicksburgian (Red Bluff clay) : Seven and one-half miles southeast of Bladen 
Springs, Alabama (common). 
Cotypes. — Cat. No. 62597, U.S.N.M. 
LEIOSELLA GRANDISORA, new species. 
Plate 92, fig. IS. 
Description . — The zoarium is free, subcylindrical. The zooecia are indistinct, 
somewhat elongated ; the frontal is small, hardly convex, and is formed of a thick 
olocyst. The peristomice is very large, funnel-shaped, provided with a large 
rimule-spiramen, little distinct; the apertura is large, elongated, somewhat oval. 
The ovicell is large, prominent, transverse; the peristomice of the ovicelled zooecia 
is elliptical and transverse. In the peristomie there is a large thin, triangular 
avicularium. 
Measurements . — Peristomice f Ape =0.40-0.45 mm. 
(exterior) I lpe= 0.30 mm. 
J Lz= 0.70 mm. 
Zooecia 
1/3=0.40-0.45 
mm. 
Apertura | ha=0.S0 mm. 
(interior) [Za=0.25 mm. 
55899— 20— Bull. 106 29 
