NORTH .MUICIIK'AN EARLY TERTIARY BRYOZOA. 167 



entire. The nvirell 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. 



. (7(0=0.27-0.30 mm. . fZs=0.7'2 mm. 



Measurt ments. Opesia 7 /ooecia L 



r 7/j n.9?._n3fi mm \l.7 OSS mm 



1/0=0.23-0.30 mm. jfo=0.35 mm. 



Variations. 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 /.ooecia. 

 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 armsi? n<ith small swords. 



Whenever an interopesial avicularium does not surmoiyit the ovicell, it is 

 much smaller. 



Affiniti''.*. 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 avicularinm would place it in Ramphonotm 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 Callopora. 



Occurrence. Middle Jacksonian (Castle Hayne limestone): Wilmington. 

 North Carolina (rare). 



HoHoype.C&t.. 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 gynmocyst; the mural rim is thin, salient, 

 convex, ornamented with spines. The opesium is regular and similar in form to 

 the zpoecia. 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. 



i, Ao=0.30mm. . \Ls=0.oOmm. 



Measurements. Opesia, 1Knn Zooecia, 



?o=0.1o-0.20mm. [ls=0.30 mm. 



ir;,:*. 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 aailmf,/ in its small dimensions and in the 

 absence of the median opesial avicularium. 



It may be distinguished from Te<ifll<i (Membranipora) triminghamensis 

 Brydone, I'-'IO. by its smaller opesium and it- much smaller spines. 



