EARLY TEETIAEY CHEILOSTOME BRYOZOA. 65 



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Genus BRACEBRIDGIA MacGillivray, 1886. 



1886. Bracebridgio IMacGillivray, Description of new or little known 

 Polyzoa, Transactions Royal Society Victoria, p. 8. 



MacGillivray's original description is as follows : 



Zoarium bilaminate, erect. Apertura subcirciilar, straighter below, 

 with an internal denticle; peristome thickened, smooth, or with a 

 small apiciilate miicro ; frequently in the fossils, but rarely in recent 

 si^ecimens, a triangular avicularium immediately below the lower 

 lip ; lateral avicularia on the free edges of the zoarium. 



The gonoecia are larger than the usual zooecia. The frontal is par- 

 tially or totally covered by a pleuroc^'^st which is more or less con- 

 fluent with the subjacent olocyst. 



Genotype. — Bracehriclgia (Porella) emendata Waters. 1881. 



Range. — Jacksonian-Eecent. 



One new species from the INIiddle Jacksonian of Georgia and a 

 new variety of Bracehridgia polymorpha Reuss, 1864 occur in the 

 Lower Tertiary of the United States. 



Genus ADEONA (Lamouroux, 1816) Levinsen, 1909. 



1909. Adeona Levinsen (Lamouroux. 1S16). Morphological and Systematic 

 Studies on the Cheilostomatous Bryozoa, p. 283. 



The frontal is perforated by an ascopore opening into the com- 

 pensatrix. The operculum is semilunar. The goncecia are distinct 

 and larger than the ordinary zoacia. 



Genotype. — Adeona (Cellepora) herkeli Reuss, 1847. 



Genus ADEONELLA (Busk, 1884) Waters, 1888. 



1884. AdeoncUa Busk, Report Voyage Chalhuf/er. Zoology, vol. 10. pt. 30, 

 p. 183. 



Zoarium erect, very variously branched or lobate, attached by a 

 contracted base, or pedicle, often containing radical fibers and affixed 

 usually on a more or less flexible support (Busk). The zocecia with- 

 out such median ascopores; the proximal part of the secondary aper- 

 ture, which appears sooner or later, is transformed by a coalescence 

 of two calcareous processes into a pore, wliicli leads into the space 

 between the primary and secondary aperture. (Levinsen, Waters.) 



The peristomie is perforated by a spiramen. The aperture bears 

 a concave lower lip which is the opening of the compensatrix ; the 

 operculum is at the bottom of the peristomie and below the spiramen. 



Genotypes. — Adeonella polymorpha Busk, 1884, and Adeonella 

 (Eschara) polystomeUa Reuss, 1847. 



Range. — Jacksonian-Recent. 

 52091°— 17 ^5 



