NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
167 
entire. The ovicell is hyperstomial, never closed by the opercular valve, globose, 
smooth, ornamented with a small frontal linear callosity. The median avicularium 
is salient and transverse. The interopesial avicularia are long, very thin, and 
pointed. 
,, . r\ ' ^0=0.27-0.30 mm. 
Measurements . — Opesia , „„„ n „„ 
1 \lo= 0.23-0.30 mm. 
Zooecia 
Lz— 0.72 mm. 
lz— 0.35 mm. 
V aviations . — The interzooecial avicularium is always placed exactly in the 
axis of the proximal zooecium with which it appears in immediate relation. On 
the figured specimen an avicularium may be seen developed on the distal zooecia. 
There are only two pairs of symmetrical spines on the ovicelled zooecia. The 
ovicell is formed of two calcareous lamellae. The external lamella (ectooecium of 
Levinsen) covers the lower lamella almost entirely and leaves only a thin linear 
portion of it visible. The presence of large avicularia gives the zoarinm the aspect 
of being armed with small swords. 
Whenever an interopesial avicularium does not surmount the ovicell, it is 
much smaller. 
Affinities . — The close connection of the ovicell with the distal avicularium 
renders it necessary to class this species in Tegella Levinsen, 1909, and its pedicel- 
lated avicularium would place it in Ramphonotus Norman, 1894. Such con- 
tradictions are inevitable when characters of adaptation like the avicularium are 
employed in classification. It is easy to avoid this by giving the genera broader 
limits precisely as Levinsen has done with the genus C allop ora. 
Occurrence . — Middle Jacksonian (Castle Havne limestone) : Wilmington, 
North Carolina (rare). 
Holtoype. — Cat. No. 63936, U.S.N.M. 
TEGELLA NICKLESI, new species. 
Plate 30, figs. 9, 10. 
The zoarium incrusts pebbles. The zooecia are elongated, distinct, elliptical 
or oval, and provided with a very small gymnocyst; the mural rim is thin, salient, 
convex, ornamented with spines. The opesium is regular and similar in form to 
the zooecia. The ovicell is hyperstomial, never closed by the opercular valve, 
small, convex. It is surmounted by an elliptical, elongated avicularium placed 
exactly in the axis itself of the proximal zooecium. 
Measurements . — Opesia 
Ae>=0.30 mm. 
lo— 0.15—0.20 mm. 
Zooecia 
fZs=0.50mm. 
ife=0.30 mm. 
Affinities . — In the vicinity of the ancestrula the zooecia are smaller and lack 
the distal avicularium ; here also their mural rim bears larger spines. 
The species differs from Tegella aculeata in its small dimensions and in the 
absence of the median opesial avicularium. 
It may be distinguished from Tegella ( Membranipora ) triminghamensis 
Brydone, 1910, by its smaller opesium and its much smaller spines. 
