586 BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 
Genus HEMICYCLOPORA Norman, 1894. 
1894. Hemicyclopora Norman, A Month on the Trondhjem Fiord, Annals and Magazine 
Natural History, ser. 6, vol. 13, p. 124. 
The ovicell is recumbent. The apertura is provided with very low cardelles 
and formed of a large anter and of a small concave poster. The frontal is smooth 
and formed of an olocyst. Spines. 
Genotype. — Hemicyclopora ( Lepralia ) polita Hincks, 1880. 
Range. — Helvetian- — Recent. 
Another known recent species is Hemicyclopora ( Lepralia ) labiosa Jullien, 
1903. 
The only known fossil species is H emicyclopora obeliscus Manzoni, 1875. 
HEMICYCLOPORA PARAJUNCTA Canu and Bassler, 1917. 
Plate 74, tigs. 2, 3. 
1917. Hemicyclopora parajuncta Canu and Bassler, Synopsis of American Early Tertiary 
Cheilostome Bryozoa, Bulletin 96, United States National Museum, p. 69, pi. 6, fig. 6. 
Description. — The zoarium incrusts shells. The zooecia are distinct, some- 
what elongated, ogival ; the frontal is somewhat convex and absolutely smooth. 
The apertura is oblique, suborbicular ; the peristome bears 8 distal spines and a 
proximal small mucronoid lip. The ovicell is globular, very salient, smooth, very 
little joined to the distal zooecium ; it is recumbent, hyperstomial. 
Measurements . — Apertura 
/m=0.10 mm. 
Zfl.=0.09 mm. 
„ . 0.50-0. 55 mm. 
//ooccia 1 7 n ... n kk 
Us=0.40-0.55 mm. 
Affinities. — This species offers the exterior aspect of Perigastrella with very 
small areolae which generally appear smooth. 
It differs from Perigastrella depressa in the presence of the small labial 
mucro and in its ovicell almost completely detached from the distal zooecium. 
It differs from Perigastrella trapezoidea in the absence of areolae and in its 
much smaller ovicell more detached from the distal zooecium. 
Occurrence. — Middle Jacksonian: Near Lenuds Ferry, South Carolina (com- 
mon). 
Cotypes. — Cat. No. 62610, U.S.N.M. 
Genus MASTIGOPHORA Hincks, 1880. 
18S0. Mastigophora Hincks, British Marine Polyzoa, p. 278. 
The ovicell is small and recumbent. The apertura is semilunar; its proximal 
border is straight and bears a rimule elongated and rounded. The frontal is a 
tremocyst with small pores placed on an olocyst. Vibracula. 
Genotype. — Mastigophora hyndmanni Johnston, 1847, and Mastigophora 
(Flustra) dutertrei Savigny-Audouin, 1826. Lutetian— Recent. 
The fossil species of this genus are: 
Pachycraspedoum zitteli Koscliinskv, 1885. 
Pachycraspedoum lautum Ivoschinsky, 1885. 
