ART. 22. CYCL.OSTOMATOUS BRYOZOA CANU AND BASSLER. 55 



Affinities. — This genus is close to Osculipora in which the tubes 

 are also cylindrical, short and fasciculated; it differs from it in 

 the absence of nematopores and in the presence of an initial bundle 

 (central in the present case) with long tubes. 



Gregory's figure is not clear but it appears to us however to rep- 

 resent the habitual ovicell of the genera in the family Osculiporidae, 

 We have discovered a specimen preserving a fragmentary ovicell 

 which indicates this genus belongs to another family, possibly the 

 Diaperoeciidae. 



CYRTOPORA ELEGANS Hagenow, 1851. 



1909. Cyrtopo7-a elegans Gregory, Catalogue Fossil Bryozoa in British 

 Museum, Cretaceous, vol. 2, p. 53, tigs. IS, 19, 20, 21 (Bibliography 

 Geological distribution ) . 



Structure. — In transverse section, there are three larger tubes at 

 the center forming the central bundle. They are surrounded by 

 smaller tubes representing the base of short tubes and characterizing 

 the triparietal gemmation. In longitudinal section the tubes are 

 irregular, in general aspect cylindrical but slightly widened towards 

 their extremity. They are short and arranged around the central 

 bundle formed of three long tubes branching at divers heights to 

 engender new branches. Their gemmation is triparietal. 



The number of tubes in the central bundle does not appear to be 

 constant ; on Gregory's figures there is only one central tube. With 

 this difference they are identical with our specimens. 



OccuiTenee. — Cretaceous (Maastrichtian). Maastricht, Holland. 



Plesiotypes.— Cat. No. 98979, U.S.N.M. 



Genus PLETHOPORA Hagenow, 1851. 



1851. Plethopora Hagenow, Die Bryozoen der maastrichter Kreidebildung, 

 p. 45. 



The tubes are cylindrical, without peristome, with orbicular orifice, 

 grouped in salient bundles. The nematopores occur all around the 

 zoarium. 



Genotype. — Plethopora verrucosa Hagenow, 1851. Aptian- Maas- 

 trichtian. 



Affinit'ies. — Gregory, 1909, placed this genus in his family Zona- 

 tulidae. This is not natural as the structure of Plethopora is entirely 

 different from that of ZonatuTa which we have figured in the fam- 

 ily Ascosoeciidae. D'Orbigny, 1852, has correctly placed this genus 

 with Truncatula, Seniicytis^ etc. 



PLETHOPORA VERRUCOSA Hagenow. 1851. 



1851. Plethopora verrucosa Hagen'ow, Die Bryzoen der ]\Iaastrichter Kreide- 

 bildung, p. 45, pi. 5, fig. 10. 



20107— 22— Proc. N. M. vol. G] 35 



