CYCLOSTOMATOUS BRYOZOA CANU AND BASSLER 



27 



Our section does not indicate the enveloping false lamellae, but 

 on certain specimens not sectioned these are quite visible. 



The zoarial form characterizes this species very well exteriorly. 



Occurrence. — Lower Cretaceous (Valangian) : Sainte-Croix (Vaud), 

 Switzerland (rare). 



Coty pes. —C&t. No. 69868, U.S.N.M. 



CERIOPORA LOBIFERA, new species 



Plate 23, figs. 11-17 



Description. — The z o a r i - 

 um is large, free, subcylin- 

 drical; it bears lateral lohes 

 more or less developed. The 

 zoarial surface sometimes ex- 

 hibits small tuberosities. 

 The tubes are thin; the aper- 

 tures are polygonal and very 

 irregular. 



Measurements. — Diameter 

 of aperture, 0.12 mm.; di- 

 ameter of zoarium, 10 mm. ; 

 length of large fragments, 

 25 mm. 



Structure. — The base is a 

 somewhat expanded disk (fig. 

 13) ; the inferior part (fig. 14) 

 shows the characteristic loz- 

 enge-shaped tubes recurved 

 at their extremity, radiating 

 around the ancestrula. In 

 thin sections the tubes are 

 cylindrical, recurved at their 

 extremity. The walls are 

 thin and formed of a single 

 row of small vesicles. The 

 zonal lines are widely sepa- 

 rated and formed by the thickening of parietal vesicles. The dia- 

 phragms are almost always placed on the zonal lines. The latter are 

 transformed into basal lamellae in the inferior part of the colonies. 



The arborescent form of this species clearly distinguishes it from 

 all other species from the same locality. 



Occurrence. — Lower Cretaceous (Valangian): Sainte-Croix (Vaud), 

 Switzerland (common). 



Coty pes. —Csit. No. 69869, U.S.N.M. 



Fig. 12. — Ceriopora lobifcra, new species. A meridian sec- 

 tion, X 16. The zonal lines are transformed sometimes 

 into basal lamellae. Lower Cretaceous (Valangian): 

 Sainte-Croix, Switzerland 



