ART. 22. CYCLOSTOMATOUS BRYOZOA CANU AND BASSLER. 73 



oHolen raviulosus Lonsdale, 1850. The ovicell not being placed on the 

 branches as in H omoeosolen^ we believe that D'Orbigny's genus ought 

 to be maintained. The discovery of ncAV material alone will enable 

 us to establish its reality. 



SUPERCYTIS DIGITATA D'Orbigny, 1854. 



Plate 27, figs. 1-4. 



1854. Supercytis digitata d'Oebigny, Paleontologie frangaise, Tt-rraiu 

 Cretace, vol. 5, p. 1061, pi. 79S, figs. &-9. 

 The specific characters of this interesting form are brought out 

 above in the generic description. 



Occurrence. — Cretaceous (Coniacian) : Fecamp, etc., France. 



Genus UNICYTIS D'Orbigny, 1854. 



1854. Unicytis d'Oebigny, Paleontologie frangaise, Terrain Cretace, vol, 

 5, p. 1047. 



The ovicell is placed on the lateral face between two pinnules. 

 The tubes are cylindrical, long, oriented without peristome, with 

 dorsal gemmation, and ramified in the pinnules. All the pinnules 

 are placed on the median axis of the frontal; they are composed of 

 alternate bundles. The zoarium is surrounded on three sides by a 

 thick calcareous epitheca formed of nematopores with very thick 

 walls. 



Genotype. — Unicytis falcata D'Orbigny, 1854. Coniacian-Cam- 

 panian. 



Structure. — In its general structure this genus is very close to 

 Truncatula Hagenow, 1851, which is also provided with dorsal 

 nematopores. It differs from it in its cylindrical and nonexpanded 

 tubes and in its pinnules formed of two alternate bundles. 



The apertures of the tubes are at the extremity of the pinnules. 

 The triangular zoarium is surrounded by a dense layer of nemato- 

 pores with thick walls, with orifices transverse and much smaller 

 than the apertures. 



UNICYTIS FALCATA D'Orbigny, 1854. 



Plate 27, figs. 5-11. 



1854. Unicytis falcata d'Oebigny, Paleontologie frangaise. Terrain Cretac6, 

 vol. 5, p. 1048, pi. 794, figs. 8-12. (Geographic distribution.) 

 Structure. — In transverse section the tubes are nearly of the same 

 size ; they are therefore cylindrical ; they are somewhat smaller 

 toward the dorsal; their gemmation is therefore dorsal. The 

 zoarium is almost surrounded by a very thick epitheca, in which the 

 perforations of the nematopores are visible with difficulty. 



