Bulletin - United States National Museum - Smithsonian Institution

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 improminent
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.