NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
251 
It differs from Lunularia ovata in its much larger zooecial dimensions. 
This species has only been found in the single locality at Jackson, where it 
appears abundant in association with Lunularia fenestrata De Gregorio 1890. 
Occurrence. — Lower Jacksonian (Moodys marl) : Jackson, Mississippi (com- 
mon). 
Cotypes. — Cat. No. 63996, U.S.N.M. 
LUNULARIA TINTINABULA, new species. 
Plate 83, figs. 12-16. 
Description. — The zoarium is a Lunulites in the form of a little bell with 
hydrostatic zooecia. The zooecia are distinct, elongated, ogival; the mural rim is 
thin; the cryptocyst is quite concave, smooth, much shorter than the opesium. 
The opesium is oval, elongated, largely surrounded by a salient peristome. The 
vibracula are arranged in radial rows ; they are symmetrical, oval ; their opesium is 
narrowed laterally by two teeth; the anterior portion is much larger than the 
inferior portion. The hydrostatic zooecia bear a prominent thread, distal semi- 
lunar. On the inner side the radial rows are quite convex and garnished with large 
scattered pores. The zoarial surface is pelliculoid. 
Measurements. — Opesium 
Marginal zooecia 
/m=0.25 mm. 
lo~ 0.15 mm. 
As =0.35-0.40 mm. 
Zs=0.25-0.30 mm. 
, T ., , fAu=0.30mm. 
V uiracula 7 _ .. 
[Zv=0.12mm. 
Variations. -^-TYvq exterior surface of the zooecia is very fragile; it is easily 
detached. The zooecia then appear under another aspect. There is no crvptocyst; 
the peristome of the opesium does not exist. There are no condyles to the vibracula. 
These two aspects are quite visible on figure 14. An analogous phenomenon has 
been observed on Lunularia conica Busk, 1859, as Canu has noted it in 1916. 
Only the distal half of the opesial peristome exists on the hydrostatic zooecia. 
This is a very important character, but it is not constant. It is sometimes replaced 
by a furrow of the same form and limiting a long tongue as in Lunularia ligulata 
(%• 15 )- 
Affinities. — This species differs from Lunularia ligulata and from Lunularia 
fenestrata in which the opesium is also bordered by a peristome in its much larger 
micrometric dimensions (Lz= 0.35 mm. instead of 0.20 mm.). 
In its exterior aspect it much resembles Litnularia. jacksonensis ; it differs from 
it in its much more conical zoarium, in its hydrostatic zooecia provided with a semi- 
elliptical, distal thread, and in its inner side which is porous and not tuberous. 
It differs from Lunularia vicksburg ensis Conrad, 1847, in the disposition of 
its vibracula placed in all the interzooecial angles ; it is this feature which does not 
permit it to be classified in the Oligotresium group. 
Occurrence. — Vicksburgian (Byram marl) : One-fourth mile west of Wood- 
ward, Wayne County, Mississippi (very common). 
