52 BULLETIN DC, UNITED STATES NATIONAL MUSEUM. 



is semilunar, with a very concave proximal border; the peristomicc is 

 irregular, but it often contains a false rimule limited by the avicu- 

 larium. The ovicell is globular, little salient; it is formed of a large 

 circular area with small numerous pores, surrounded by an impromi- 

 nent smooth collar; it is embedded in the distal zocecia and opens 

 into the peristomie. The avicularium is peristomial, placed more or 

 less laterally ; the mandible moves in the peristomie. 



Oceurrcnce. — Middle Jacksonian: Wilmington, North Carolina 

 (common). 



Upper Jacksonian (Ocala limestone) : Old factory, one-half mile 

 above Bainbridge, Georgia (rare). 



Yicksburgian : Salt Mountain, 5 miles south of Jackson, Alabama 

 (ver}' rare). 



Type.— C^ii. Xo. 62600, U.S.N.M. 



Genus MUCRONELLA Ilincks, 1880. 

 1880. Mucronclln Hincks, British Marine Polyzoa, p. 3G0. 



The frontal is surrounded by areolae and covered by a pleurocyst, 

 costulate or granular. There is a lyrule, and often some cardelles, in 

 the peristomice inferiorly. 



Genotype. — Miicronella {Lepralia) pcachi Johnston, 1847. 



Range. — Jacksonian-Eecent. 



The limits of this genus were rigorously established in 1904 by 

 Waters. It differs from Smittina in the replacement of the avicu- 

 larium by a mucro ; that is to say, by an organ which we know to be 

 almost equivalent. Several new species are known in our American 

 Early Tertiary. 



Genus RHAMPHOSTOMELLA Lorenz, 1886. 



1886. RhamphostowcUa Lorenz, Bryozoen von Jan Mayen, Die Oester- 

 reichiscbe rohirstation, J;m Mayen, vol. 3, p. 11. 



The operculum closes the ovicell, which is hyperstomial ; it is thin 

 and delicate, but there is a raised circular ridge. There is a very 

 narrow lyrule before an asymmetrical sinus. The frontal is an 

 olocyst with costules. Before the orifice of the ovicell, and at the 

 same height, there is a very large avicularium, oblique, salient, and 

 placed eccentrically. Eighteen tentacles. The oral glands are much 

 developed. 



Genotype. — RhamphostomeUa costata Hincks, 1889. 



Range. — Priabonian-Recent. 



A new variety of Rkaniphostoinelln hrendolcnsis Waters, 1891, 

 and two new species occur in the American Eocene. 



