ART. 22. CYCLOSTOMATOUS BRYOZOA CANU AND BASSLER. 83 



attributed this discovery to Gregory, but the catalogue of the British 

 Museum in which his results appeared was not published until 1899. 



MELICERITITES GRACILIS Goldfuss, 1827. 



Plate 13, figs. 1-4. 



1827. Ceriopora gracilis Goldfuss, Petrefacta Germaniae, vol. 1, p. 35, pi. 10, 



fig. 11 a-c. 

 1899. Meliceritites gracilis Gkegoky, Catalogue of Cretaceous Bryozoa in 



the British Museum, vol. 1, p. 324, fig. 38 (not synonymy). 

 1912. Meliceritites gracilis Levinskn, Studies on the Cyclostomata oper- 



culata, Kgl. Danske Vidensk Selsk. Skrifter, ser. 7, vol. 10, p. 28, 



figs, a, 6. 



Not Michelin, 1845, Roemer, 1840, Reuss, 1872, Marsson, 1887, Per- 



gens, 1890, Canu, 1897, Hagenow, 1851, etc. 



f Jia=0.lO mm. 

 Aijertura I , „ . „ 

 ^ I ?a =0.18 mm. 



^, . , f A»=0.28-0.32 mm. 



Peristome { ^ a n < a r.o 



I Ip =0.24-0.28 mm. 



^ . fAo=0.18mm. 



Operculum J 

 ^ I /o =0.18 mm. 



^ . „ lZo=0.90mm. 



Measurejnents.- , Ovicell -^ ^^ ^^^^ ^^^ 



^ . ^ f /^oe=0.10mm. 



Oeciostome i _ „ ^^ 



I loe =0.22 mm. 



^ . I //»=0.08 mm. 



Oeciopore ^^^^o.lCmm. 



Facettes | 'V= 0.40-0.44 mm. 

 1 aceiies | ^^. ^q^^^qj^S mm. 



Structure. — The specimen figured by Goldfuss in 1827 was incom- 

 plete and worn and his poor illustration has occasioned many false 

 determinations. With better specimens derived from the same 

 locality (Essen, Germany), Gregory, in 1899, and Levinsen, in 1912, 

 have described the various characters of this species and given better 

 figures. We are able finally to complete their observations. 



The tubes are arranged in transverse rows. The peristomes are 

 thin, salient, elongated, triangular, adjacent at their base. The 

 aperture is little transverse, semicircular, concave at its proximal 

 margin ; it is placed at the bottom of a peristomie and its form does 

 not correspond to that of the peristome. The operculum is tri- 

 angular and coA^ers the aperture and the calcified portion of the distal 

 peristome. The facettes are lozenge shaped, finely punctate, and 

 half of their surface is occupied by the peristome; they are somewhat 

 convex and separated by little salient threads. 



In order to interpret the oral arrangement it is necessary to admit 

 that the expanded and recurved part of the tubes is elliptical in sec- 



