AST. 22. CYCLOSTOMATOUS BRYOZOA — CANU AND BASSLER. 129 



Cretaceous (Danian) ; Faxe and D'Annetorp, Denmark (Hennig), 

 F lesioty pes. —Cdimx collection and Cat. No. 68971, U.S.N.M. 



Genus RETEPORIDEA D'Orbigny, 1852. 



1852, Reteporidea d'Orkigny, Paleontologie Francaise, Terrain Cr6tacg, 

 vol. 5. 



The ovicell is a large inflation, quite convex, covering the entire 

 width of the zoarium. The tubes are C3dindrical, with peristome 

 and with axial gemmation by bifurcation at all heights. There are 

 divergent parietal mesopores on the anterior face and vacuoles 

 buried in a lamellar tissue on the posterior face. 



Genotype. — Reteporidea royana D'Orbigny, 1850. Cretaceous. 



Historical. — Gregory in 1899 suppressed this genus of D'Orbigny 

 because he identified it with Se^nicellarla and Laterocavea of the same 

 author and because he had adopted the genus Hemicellaria D'Or- 

 bigny, 1847, which D'Orbigny had later declared to be erroneous. We 

 could adopt the conclusions of Gregory only after the discovery of the 

 ovicell of hemicellaria and Laterocavea and the preparation of the 

 necessary sections. 



Our studies having been based on typical specimens of Retepori- 

 dea, we are obliged to recognize D'Orbigny's genus in its original 

 meaning. 



Affinities. — This genus differs from Ascosoecia in the presence of 

 vacuoles and in the great thickness of lamellar tissue over all the 

 zoarium. It differs from Parascosoecia in its cylindrical and non- 

 conical tubes. 



RETEPORIDEA ROYANA D'Orbigny, 1854. 



Plate 22, figs. 1-5. 



1854. Reteporidea royana d'Obbiqny, Paleontologie frangaise, Terrain 

 Cr6tac4, vol. 5, Bryozoaires, p. 937, pi. 608, figs. 1-5 ; pi. 772, figs. 17, 18. 

 1899. Hemicellaria royana Gkegoby, Catalogue Fossil Bryozoa in British 

 Museum, Cretaceous, p. 369 (Bibliography). 



Peristome 0.12 mm. 



Distance between peristomes .36 mm. 



Separation of peristomes in quin- 



Measuremcnts. — { cunx .36 mm. 



Diameter of branches .80 mm. 



Dimension of the fenestrae 



1. 00 by 0. 70-. 80 mm. 



Structure. — D'Orbigny's figures are absolutely exact. The tubes 

 are arranged on the. anterior face of the branches which is at the 

 same time the exterior face of the zoarium. The latter assumes the 

 form of a deep, conical cup whose interior was occupied by the non- 



