244 
BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 
Variations.^- The hydrostatic zooecia which surround the ancestrula are very 
variable. The small tongue, which partially obstructs the false opesium, is more 
or less developed; it becomes transformed into a median column and it is then 
bordered by four small symmetrical pores. It is evident that the lateral fissures 
are opesiules through which the parietal muscles pass. 
Affinities. — This species differs from Limularia verrucosa in its larger micro- 
metric dimensions and in its hydrostatic zooecia. which are not wartlike, but are 
ornamented with a small tongue. 
Although closer still to Lunularia radiata Lamarck 1816, it differs from it in 
its smaller micrometric measurements (Lz= 0.20 mm. instead of 0.36 mm.), and 
in its transverse, and not elongated zooecia, and in its hydrostatic zooecia furnished 
with a tongue. 
It belongs to the group Dimiclausa De Gregorio, 1890, for which we have as 
yet no constant characteristics. 
Occurrence. — Lower Jacksonian: 34 miles southeast of Shell Bluff post office, 
Georgia ( rare). 
Claibornian (Cook Mountain formation) : Moseleys Ferry, Caldwell County, 
Texas (very common). 
Lower Jacksonian (Moodys marl) : Jackson, Mississippi (abundant). 
Jacksonian (Zeuglodon zone) : Bluff on south side of Suck Creek, Clarke 
County, Mississippi. 
Vicksburgian (Red Bluff clay) : Red Bluff, Wayne County, Mississippi (rare). 
Cotypes. — Cat. No. 63846, U.S.N.M. 
1890. Dimiclausa fenestrata De Gregorio, Monographie de la Faune Eocenique de Alabama. 
Annnles de Geologie, et de Paleontologie, Livraisons 7, S, p. 249, pi.. 42, figs. 23-27. 
Description. — The zoarium is a small, convex, expanded Lunulites with the 
zooecia and vibracula in distinct, alternating radial rows. The zooecia are rec- 
tangular, somewhat transverse, distinct, ogival ; the mural rim is thick ; the crypto- 
cyst very small; the opesium large, elongated, elliptical. The ovicell is a large 
distal convexity. The ancestrular zooecia are hydrostatic and calcified with four 
opesiular openings like a window. The vibraculum is long, narrow, fusiform, deep, 
primoserial in the middle, but in distinct rows along the margins. The inner side 
is formed of large, radial, convex ribs with small pores far apart. A large, distal 
septula and two pairs of large, lateral septulae are present. 
Affinities and variations. — As we have not observed a polypidian convexity 
or an opesiule, we can not affirm that this species should be classed in the Coilostega ; 
but on account of its resemblance to Lunularia distans Lonsdale 1845, we must 
LUNULARIA FENESTRATA De Gregorio, 1890. 
Plate 37, figs. 10-13. 
M easurements. — Opesia 
/i,<9= 0.20 mm. 
7o=0.14mm. 
