NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
309 
is semilunar; the distal part is bordered by a very thin, incomplete peristome. 
There are one or two small, triangular, transverse, oral avicularia touching each 
other at their tips. 
Measurements . — Aperture { ^ ° 5*1^/ mm. 
Zooecia 
| Lz— 0.60 mm. 
lfe=0.30mm. 
Affinities.- — All of the zooecia are not provided with the characteristic collar 
which arises from the more or less complete union of the first three pairs of costules. 
The number of pairs of costules varies from 12 to 17. 
Only a few specimens have been found, none of which shows an ovicell. The 
quadriserial zoarium and the costules with lumen pores are the only reasons we 
have for classifying this species in C orbulipora, a genus which must be considered 
as inadequately described. 
Occurrence. — Middle Jacksonian (Castle Hayne limestone) : Wilmington, North 
Carolina (rare). 
Holotype. — Cat. No. 61035, U.S.N.M. 
Genus ACANTHOCELLA Canu and Bassler, 1917. 
1917. Acantliocella Canu and Bassler, Synopsis of American Early Tertiary Clieilostome 
Bryozoa, Bulletin 96, United States National Museum, p. 35. 
The costules bear a row of very prominent lumen pores and are separated 
by lacunae of greater or less size. The aperture is semilunar. The ovicell is 
hyperstomial and its orifice is not in contact with the operculum. 
Genotype. — Gribrilina tubulifera Hincks, 1881, from Australian seas. 
Range . — J a ekson i an-Eecent . 
ACANTHOCELLA ERINACEA Canu and Bassler, 1917. 
Plate 43, figs. 10-13. 
1917. Acantliocella erinacea Canu and Bassler, Synopsis of American Early Tertiary 
Bryozoa, Bulletin 96, United States National Museum, p. 36, pi. 4, fig. 1. 
Description. — The zoarium incrusts shells and bryozoa or creeps over algae. 
The zooecia are distinct, very slightly elongated, subcircular; the frontal is very 
convex; the costules are thick, separated by the lacunae and ornamented by three 
very prominent, hollow spines corresponding to the lumen pores. The aperture 
is semilunar with a straight proximal border; the peristome is distal and bears 
four large, hollow spines. The ovicell is hyperstomial, buried in the distal zooecia, 
globose, not closed by the operculum, ornamented with small, remote punctations. 
M easurements. — Aperture 
) 7m=0.09 mm. 
j la— 0.11-0.12 mm. 
Zooecia 
Lz= 0.75-0.80 mm. 
lz =0.50— 0 . 6 5 mm. 
Variations. — The sharp points which decorate this species give it the spinous 
aspect of a hedgehog. It is very variable in its micrometer dimensions and its 
gemmation ; the zooecia are oriented in the most unexpected and divergent manner. 
The costules are separated first by an initial slit (fig. 13) hidden and almost ver- 
