NORTH AMERICAN LATER TERTIARY AND QUATERNARY BRYOZOA. 
51 
frontal and characterized by the same calcareous lamellae. With our present 
poor state of knowledge of the larva we can not be absolutely certain that this 
single anatomical peculiarity is sufficient to characterize a family. We think, 
therefore, that it is preferable to group in a distinct section these species with 
concave frontal under the same name but placed under the authority of Waters. 
The Cretaceous forms figured by D’Orbigny and Hagenow have already been 
separated under tha name of Hagenowinella Canu, 1900. 
Jullien, who has studied and figured Mernbranipora gdleata Busk, 1852, has 
not classified it in his genus. 
Genus CHAPERIA (Waters, 1898) Levinsen, 1909 (second group). 
1909. Chaperia Levinsen, Morphological and Systematic Studies on the Cheilostomatous Bryozoa 
p. 115. 
The original description of this genus by Levinsen follows: 
The distal part of the zooecium is furnished internally with two lateral spaces open towards the 
frontal surface (sometimes coalesced to a single horseshoe shaped one), formed by two plates which 
project from the side walls and converge towards the distal wall. Each distal wall has two multiporous 
Fig. 4. —Genus Chaperia (Waters, 1898) Levinsen, 1909. 
Figs. A-D. Chaperia bilamellata Waters, 1898. A. Specimen, X25, from Port Elizabeth, South 
Africa, showing the principal variations of the avicularia, etc. B. Operculum of the orifice of the 
ovicell, X85. *C. Operculum of the aperture, X85. D. Mandible of the avicularium, X85. (Figs. A- 
D, after Waters, 1898.) 
Fig. E. Chaperia cervicornis Busk, 1852. Zooecia showing the operculum of the aperture and that 
of the ovicell in position (after Hincks, 1881). 
rosette plates [septular plates] and the distal half of each side wall a single one. Hyperstomial free 
ooecia with a completely calcified ectooecium [and a special operculum]. The zooecia, which may 
sometimes have a membraneous opercular valve, sometimes a chitinous compound operculum, are 
generally strongly provided with spines and have often a well-developed [concave] cryptocyst. Avicu¬ 
laria sometimes trumpet shaped, not always present. The colonies are generally incrusting. 
Type.—Chaperia bilamellata Waters, 1898. 
To this genus belong the following species: 
Chaperia ( Amphiblestrum ) cristata Busk, 1884. 
