576 
BULLETIN" 106, UNITED STATES NATIONAL MUSEUM. 
Genus PERIGASTEELLA Canu and Bassler, 1917. 
1917. Perigastrella Cantj and Bassler, Synopsis of American Early Tertiary Cheilostome 
Bryozoa, Bulletin 96, United States National Museum, p. 68. 
The apertura is semicircular. The band of the operculum is on the border. 
The frontal is surrounded by one or two rows of small areolae ; it is formed of an 
olocyst supporting a smooth or finely granular pleurocyst. Spines. 
Genotype. — Perigastrella ( Lepralia ) labiata Boeck. 1861. 
Range. — Lutetian— Recent. 
The recent species are: 
Perigastrella ( Lepralia ) labiata Boeck, 1861. 
Perigastrella ( Lepralia ) contracta Waters, 1899. 
Ihe fossil species are: 
Perigastrella ( Mucronell-a ) semi- 
erect a, Koschinsky, 1885. 
Perigastrella ( Lepralia ) grotriani 
Stoliczka, 1862. 
PERIGASTRELLA ANSATA, new species. 
Plate 14, figs. 18, 19. 
Description. — The zoarium incrusts 
shells. The zooecia are distinct, short, 
little elongated; the frontal is con- 
vex and formed of an olocyst per- 
forated laterally by widely spaced 
areolae and surmounted by a finely 
granular pleurocyst. The apertura 
is formed of a large ogival anter and 
of a concave poster; the peristome 
is little salient, very thin, with an in- 
ferior lip salient or somewhat de- 
pressed on the frontal. The ovicell is small, recumbent, little salient and hyper - 
stomial. On the peristome itself there are sometimes two small, round avicularia. 
c *85 
Fig. 174.- 
-Genus Perigastrella Canu and Bassler, 1917 
A-E. Perigastrella contracta Waters, 1899. A. Zooe- 
cia, X 25. B, C. Operculum and apertura, X 85. 
(A-C after Waters, 1899.) D, E. Zooecia and apertura. 
(After Norman, 1909.) 
,, , . , \ha= 0.14^0.16 mm. r , • \Lz~0A0mm. 
Measurements. — Apertura , A , . Zooecia 7 n OA AO/l 
1 via— 0.12-0.14 mm. [lz= 0.30-0.34 mm. 
The form of the apertura, like the handle of a basket, is rather characteristic. 
Widely spaced areolae have not been observed in any other species. The olocyst 
and the detachable pleurocyst are clearly visible on figure 19. 
Occurrence. — Claibornian (Gosport sand) : One mile southwest of Rockville, 
Clarke County, Alabama (rare). 
Cotypes. — Cat. No. 63853, TJ.S.N.M. 
