NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
293 
CRIBRILINA RATHBUNAE, new species. 
Plate 5, figs. 15-17. 
Description . — The zoarium incrusts other bryozoa. The zooecia are elongated, 
distinct, elliptical; the cribriform area is somewhat convex and formed of trans- 
verse costules; the lacunae are large and prominent, 1 to 2 to each pair of adjacent 
costules. The aperture is semilunar, transverse, bordered by a thin, smooth, im- 
prominent peristome. The two small oral avicularia are simple, peristomial, and 
without pivot. 
M easurements . — Aperture 
[ ha= 0.07 mm. 
[fa.— 0.10 mm. 
Zooecia 
j Lz= 0.35—0.45 mm. 
U.s=0.25 mm. 
Variations and affinities . — The lacunae are variable in number on each zooe- 
cium; their prominence is much lessened by fossilization. 
This species differs from Cribrilina verrucosa in its smaller zooecial dimen- 
sions and its less convex cribriform area. 
This interesting species is named in honor of Miss Mary J. Rathbun, of the 
United States National Museum, as a slight appreciation of her valuable work upon 
marine invertebrates. 
Occurrence. — Midwayan: Mabelvale. near Little Rock, Arkansas (very rare). 
Cotypes. — Cat. No. 63813, U.S.N.M. 
Genus PUELLINA Jullien, 1886. 
1886. Puellina Jullien, Les Costulidees, Bulletin Societe Zoologique France, vol. 11, p. 7. 
Bibliography (Anatomical). — 1902, Harmer, On the Morphology of the Cheilostomata, Quar- 
terly Journal of Microscopic Science, vol. 46. pp. 2. 293, 326, pi. 15, fig. 7. — 1903. Norman, 
Notes on the Natural History of Bast Finmark, Annals Magazine Natural History, ser. 7, 
vol. 12, p. 96, pi. 9, figs. 3, 4, 5. — 1909. Levinsen, Morphological and Systematic Studies on the 
Cheilostomatous Bryozoa, p. 159, pi. 9. fig. 12. 
The lacunae between the costules are very small ; the lumen, more or less visible, 
bears many pores, of which the first in the shield is larger than the others. The 
aperture is semicircular. The operculum is simple and entirely chitinous. The 
ovicell is hyperstomial and always closed by the operculum. Between the costular 
shields are papillae. The dietellae number at least three lateral pairs. 
Genotypes. — Puellina ( Cribrilina ) gattyae Busk, 1852, and Puellina ( Cribri- 
lina ) radiata Moll, 1803. 
Range. — Senonian-Recent. 
The papillae are short, tentaculiform evaginations. The first pair, near the 
aperture, is always the larger by far. They have been considered as true avicularia 
(Jullien) as sensorial vibracula (Smitt) or as simple appendages corresponding to 
the spines of the ancestrula (Harmer). Their place is almost invisible on the 
fossils. Levinsen limits this genus to species provided with an interzooecial 
avicularium. However, it would be difficult for us to classify our Puellina bispinosa 
and Puellina simulator in another genus. 
