50 



PROCEEDINGS OF THE NATIONAL MUSEUM 



y^G. 23. — Cea granulata, new species. A, B. 

 Longitudinal and transverse sections, X 16. 



peristomes, 0.40 mm.; diameter of orifice without facettes, 0.20- 

 0.24 mm.; diameter of zoarium, 3 mm. 



Structure. — The most frequent aspect is that of Figure 9; the ori- 

 fices are large and more or less transverse. The latter are sometimes 

 elongated (fig. 11). The tubes are occasionally visible below the 

 orifices, but they remain indistinct. As in all the Ceidae, the fa- 

 cettes are rarely preserved (fig. 13) ; 

 they are perforated by an orbicular 

 aperture. 



In longitudinal section the tubes 

 are club-shaped with walls thickened 

 at their extremity; the gemmation 

 is triparietal on a basal lamella. 



In transverse section the tubes are 

 polygonal, with thin waUs in the vi- 

 cinity of the basal lamella. They 

 have a center, rounded toward the 

 periphery by an internal secretion 



Lower Cretaceous (Aptian): Faringdon, "bccaUSC the polygOUal Walls are al- 

 England . ., , ' "^ "^ 



ways visible. 

 The ovicell is not known. 



Occurrence. — Lower Cretaceous (Aptian) : Faringdon, England 

 (common) . 



Coty pes. —Csit. No. 69899, U.S.N.M. 



Family DIAPEROECIIDAE Canu, 1918 



Genus DIAPEROECIA Canu, 1918 



DIAPEROECIA (7) SIMPLEX, new species 



Plate 4, fig. 16 



Description. — The zoarium is unilamellar; the noncellular face is 

 transversely striated. The tubes are quite salient, arranged in 

 quincunx; the orifices are orbicular; the peristomes are thick. The 

 ovicell is a limited sack, very convex, perforated by a normal tube; 

 the oeciostome is small, salient, placed at the middle of the ovicell. 



Measurements. — Diameter of aperture, 0.12 mm.; diameter of 

 peristome, 0.18 mm.; diameter of oeciostome, 0.10 mm. 



Affinities. — This species is not a typical Diaperoecia, but we have 

 classified it in this genus because of the median oeciostome. It ap- 

 pears intermediate between Diaperoecia and Tuhulipora, but more 

 specimens are necessary before the species can be classified without 

 doubt. 



Occurrence. — Lower Cretaceous (Aptian) : Faringdon, England. 



Holotype.— Cat. No. 69900, U.S.N.M. 



