526 BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 



dietellae. " The distal wall has no expansion, partly separating the ovicell from 

 the zooecium; multiporous septulae; peristome present in the form of a lip-like 

 projection." (Levinsen. 1909.) 



Genotype. Cheilopora (Lepralia) sincera Smitt, 1867. 



Range. Aquia Recent. 



The genotype is unprovided with cardelles. We think that the species pro- 

 vided with cardelles and a different operculum might be introduced into a new genus. 



CHEILOPORA (?) LABIOSA Ulrich, 1901. 



Plate 2, figs. 1-3. 

 1001. LcfiraUa labiosa UI.RTCH, Maryland Geological Survey, Eocene, p. 220, pi. 60, figs. 10. 10. 



Description. "Zoarium forming thin crusts over shells and other foreign 

 bodies. Zooecia rhomboidal, hexagonal, or subovate arranged more or less irregu- 

 larly in curved series, five or six in 2 mm., often separated by a depressed line. 

 Front wall punctate, slightly convex, flat, or depressed, the last when the margin 

 on one or both sides is thickened and elevated. Aperture subquadrate or semi- 

 elliptical, sometimes contracted near the middle, always enclosed by a more or less 

 strongly thickened rim. Avicularia occur on the raised apertural border, usually 

 one to each zooecium, or two. as shown in the figures. Ooecia unknown." 



The figure published by Ulrich is somewhat theoretical; notably the area as 

 drawn is scarcely visible and only on a single zooecium of the type. We reproduce 

 two very frequent variations. None of the specimens examined bears ovicells; our 

 generic determination, made by analogy, necessarily remains somewhat doubtful. 



The zooecia are convex, elliptical, rather little distinct. The peristome is in- 

 complete in its proximal part; it bears laterally one or two very salient avicularia 

 of the more simple type. 



Occurrence. Lowest Eocene (Bryozoan bed at base of Aquia formation) : 

 Upper Marlboro, Maryland. 



Plesiotype.Cat. No. 63783, U.S.N.M. 



CHEILOPORA (?) ORBIFERA, new species. 



Plate 14, fig. 16. 



Description. The zoarium is unilamellar. The zooecia are distinct, a little 

 elongated, lozenge-shaped ; the frontal is somewhat convex and formed of a tremo- 

 cyst, each pore of which is surrounded by a special orbicular collar quite distinct 

 from the neighboring ones. The apertura is transverse, semielliptical ; the distal 

 half is surmounted by a peristomie with a border thin and sharp. The avicularium 

 is lateral, provided with a pivot; its beak is turned toward the bottom. 



fAa=0.10mm. . \Lz 0.80mm. 



Measurements. Apertura ' . .. Zooecia, ..,,, 



[Za=0.l7 mm. \h 0.6a mm. 



Affinities. In the form of its zooecia and in the nature of its frontal this species 

 very close to Cheilopora prelucidioidcs; it differs, however, in the length of its 



