NORTH AMERICAN EARLY TERTIARY BRYOZOA. 



259 



either side connected with the lateral wall by a vertical calcareous lamina; multi- 

 porous septulae. 



Genotype. Lablopora wenulata Levinsen, 1909. 



Genus CRATEROPORA Levinsen, 1909. 



1909. Crateropora LEVINSEN, Morphological and systematic studies on the Cheilostomatous 

 Bryozoa, p. 171. 



No ovicell; distinct raised margins; frontal wall of polypide-tube not quad- 

 rangular and not surrounded by projecting flanges. Polypide-tube not bilabiate, 

 with an expanded distal margin, not connected with the lateral walls by vertical cal- 

 careous laminae; uniporous septulae. (Levinsen, 1909.) 



Genotype. Crateropora falcata Levinsen. 1909. 



Aspidostoiiia flammulum Canu. 1908, of the Pata- 

 gonian of Argentina may perhaps belong to this genus, 

 although it bears ovicells. 



Family STEGANOPORELLIDAE Levinsen, 1909. 



Bibliography (Anatomical). 1900. HARSIER, A revision of the 

 genus Stegauoporella, Quarterly Journal Microscopical Science, 

 vol. 43, pp. 225-295, pi. 12, 13. 1902. HARMEE, On the Mor- 

 phology of the Cheilostomata, Quarterly Journal of Microscopi- 

 cal Science, p. 317, pi. IS, figs. 64, 65, 66. 1909. LEVINSEN, 

 Morphological and systematic studies on the Cheilostomatous 

 Bryozoa, p. 167, pi. 6, figs. 2-7. 1913. WATERS, Bryozoa from 

 Zanzibar, Proceedings of the Zoological Society of London, p. 

 498, pi. 72, figs. 12-20. 



The zooecium is divided into two chambers. The 

 proximal chamber contains the polypide and the ovaries ; 

 it is terminated by an ascending tube, the polypide 

 tube, in which the tentacles are lodged when the polypide is retracted. The upper 

 chamber contains the parietal and opercular muscles. The retractor muscles of the 

 polypide are attached in one of the lower angles of the zooecium, which causes the 

 general assymetry of the zooecium. No ovicells, no avicularia. Generally two 

 forms of zooecia : a and B. The two opesiules are generally not separated from 

 the aperture of the zooecium. The operculum. which is sometimes bounded by a 

 chitinous sclerite proximally. sometimes continued immediately into the frontal 

 membrane, is, as a rule, very large, and then suspended by strong hinge-teeth. 



The structure in this family is remarkable and of great interest. The figures 

 that are reproduced permit the reader to easily comprehend its details, despite the 

 complexity of the terminology. The two known genera are Steganoporella Smitt. 

 1873, and Siphonoporetta Hincks 1880. 



FIG. 70. Genus Crateropofc 



Levinsen, 1909. 

 Crateropora falcata Levin- 

 sen, 1909. Zooecia, X23. (Af- 

 ter Levinsen, 1909). 



Genus STEGANOPORELLA Smitt, 1873. 



SMITT, Floridan Bryozoa, Kongl. Svenska 



Vetinskaps-Akadeniiens 



1873. Steganoporella 



Handlingar. vol. 11, No. 4, p. 15. 



The whole of the calcined part of the frontal area lying proximally to the 

 aperture is a depressed cryptocyst; the aperture of the zooecium is surrounded 



