NORTH AMERICAN EARLY TERTIARY BRYOZOA. 245 



provisionally place it in the same vicinity. It differs from L. d titans, however, 

 in its solid and not hollow zoarium and its smaller zooecia. 



From Lunularia vicksburgensis Conrad it may be distinguished by the arrange- 

 ment of its vibracula in all the interzooecial angles. 



Its closest affinities are with Lunularia ligulata from which it differs in its 

 larger zooecial dimensions and its hydrostatic zooecia. which are always perforated 

 by four rectangular pores which are really opesiules. 



We have seen some zoaria without hydrostatic zooecia. 



Occurrence. Lower Jacksonian (Moodys marl) : Jackson, Mississippi (com- 

 mon) . 



Plesiotype.Cat. No. 63994, U.S.N.M. 



LUNULARIA TUBIFERA, new species. 



Plate 37, figs. 14-18. 



Description. The zoarium is a Lunulites. small, irregular, little convex, with- 

 out fibrous base. The zooecia are hexagonal, somewhat elongated; the mural rim 

 is scarcely distinct from the cryptocyst, which is quite shallow. The opesium is 

 oval, very finely crenulated. The ancestrular zooecia are ordinary zooecia trans- 

 formed into radicular zooecia by total regeneration. The vibracula are small, 

 symmetrical, without lateral condyles, embedded deeply when they are in distinct 

 rows. On the inner side the zooecia are visible as hollow tubes, salient, closed or 

 wide open. 



Variations. Toward the center of the zoarium the vibracula are not in distinct 

 rows. They are scattered among the zooecia and are very large (fig. 15). 



The hydrostatic zooecia are radicular (fig. 15). We have observed (fig. 16) 

 that the ordinary zooecia may be transformed in radicular zooecia by total regen- 

 eration. These zooecial transformations through regeneration according to the 

 necessities of the zoarial life, demonstrate the vital unity of the zoarium and the 

 importance of its special hydrostatic system. 



On the inner face only the hydrostatic zooecia appear to be tubiferous. We 

 can not explain the reason for this absence of the basal zooecial wall. Evidently 

 the ectocyst covers all of the zoarium, but must be extremely fragile (fig. 18). 



Affinities. Lunularia tubifera is close to L. ovata, but differs from it in its 

 ancestrular zooecia, which are radicular, and in the complete absence of ribs on 

 the inner face. 



Occurrence. Middle Jacksonian : One-half mile southeast of Georgia Kaolin 

 Company mine, Twiggs County, Georgia (rare). 



Cotypes.G&i. No. 63995, U.S.N.M. 



LUNULARIA DISTANS Lonsdale, 1845. 



Plate 38, figs. 1-20. 



1845. Lunulites dislans LONSDALE, Account of twenty-six species of Folyparia obtained from 

 the Eocene Tertiary formation of North America, Quarterly Journal Geological 

 Society London, vol. 1, p. 531, fig. 



