CYCLOSTOMATOUS BEYOZOA CANU AND BASSLEB 



23 



enlaiged portion. The zonal lines are formed by vesicles which are 

 larger and have very thick walls; they become transformed some- 

 times into true partial basal lamellae. The new tubes arise from a 

 rootlike base and we can suppose that they cover tubes in which 

 the polypide is aborted or diseased and is not able to continue its 

 skeleton with enough of regularity. 



Affinities. — This species differs from Ceriopora angustipedis in its 

 more elongated zoarium, in the smaller diameter of its orifice, and in 

 the presence of false lamellae covering the zoarium. 



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

 Switzerland (common). 



Coty pes. —Cat. No. 69863, U.S.N.M. 



-j;gS[ffiSEE''«^^*'^SSi:». 



Fig T.— Ceriopora an^ustipedis,new species. Meridian section, X 16, entirely across a zoarium. Lower 

 Cretaceous (Valangian): Salnte-Croix, Switzerland 



CERIOPORA ANGUSTIPEDIS. new species 



Plate 22, figs. 15-17 



Description. — The zoarium is free, globular, with a narrow base, 

 somewhat broader than high, entire or apparently covered by lamel- 

 lae wholly enveloping it. The tubes have thickened walls; the aper- 

 tures are polygonal and arranged in quincunx. Zonal lines are 

 rare. 



Measurements. — Diameter of aperture, 0.12 mm.; maximum zo- 

 arial width, 9 mm.; maximum zoarial height, 8 mm. 



Structure. — In meridian section the tubes are cylindrical, with 

 very thick walls; these walls are very finely vesicular but never 

 moniliform; the diaphragms are concave and very irregularly placed. 

 Our sectioned specimen did not show zonal lines very clearly. It 

 is probable that the specimen shown, which exhibits at the base 

 three enveloping lamellae, would in sections show the zonal lines 

 transformed into basal lamellae, as in Ceriopora ovoidea. 



