Plate 100. 



Figs. 1-11. Adconcllopsis cyclops, new .species (p. 070). 



1. A complfle zonrinm, mitunil size, recoiistnirli'il t'l-mii fragments. 

 Yicksburgian (Mnriann;i iiniestone) : Murder Cro«:k, east or" Castleburv, Alaljaiiia. 



Cat. No. 64320, U.S.N.M. 



2. Surface of mature zoarium, X 20, with lar.ue cribriform area and beginning of 



tlcvelopnient of total area. 



3. Branch of young zoarium, X 20, showing the long marginal zooecia without distal 



or median aviculari.-i. 



4. Portion of a well-preserved fragment, X 20. Tlie marginal zooecia are long and have 



a small cribriform area while the median zooecia are shorter and have a larger area. 



5. Transverse fractm-e of branch, X 20. 



G. Surface, X 20, of a very young zoarium showing beginning of development of total 

 area and large areolar pores. 



7. Basal portion of a zoarium, X 20. At the base itself the apertures are closed and 



only the avieularia and areolae are present. 



8. A mature specimen, X 20, with total area in process of development. 



9. An old zoarium, X 20, in which the total area is well developed ami its peristome Is 



greatly thickened. 



10. Surface of specimen, X 20, with avicularium only visible at base of total area. 



11. A fragment, X 20, with total area developed, but avieularia and cribriform area still 



plainly visible. 

 Vicksburgian (Glendou member of Marianna limestone) : West bank of Conecuh 

 Itiver, Escambia Countv, Alabama. 

 Cat. No. 64321, U.S.N.Jl. 

 Figs. 12-17. Perigastrclla costifera, new species (p. 5S4). 



12. A complete zoarium, X 20, incrusting a cyclostome bryozoan. Th(> apertura is visible 



at the bottom of the poristomie and the zooecia are smooth. 



13. Zooecia, X 20, exhibiting areolae. 



14. Another zoarium, X 20, with interareolar costules and long peristomie well developed. 



15. Zooecia with ovieell, X 20, the latter being broken. 



16. Portion of a zoarium, X 20, exhibiting the ancestrula and alsi;i with some zooecia 



seen in profile. 



17. Zooecia, X 20, showing the small ancestrula. 



Vicksburgian (Glendon member of Marianna limestone) : West bank of Conecuh 

 River, Escambia County, Alabama. 

 Cat. No. 64322, U.S.N.M. 

 Pigs. 18-21. Pcrigastrella plana, new species (p. 583). 



IS. Surface of the incrusting zoarium, X 20. This specimen shows the old condition in 

 which the well developed pleurocyst appears as a collar about the zooecia. The 

 ovieell is seen to be composed of two layers, the upper one being a pleurocyst. 

 Vicksburgian (Marianna limestone) : Salt Jlountain, 5 miles south of Jackson, Ala- 

 bama. 



Cat. No. 64323, U.S.N.M. 



19. Another old zoarium, X 20, with ovicelled zooecia and pleurocyst well developed. 



20. A young zoarium in the vicinity of the ancestrula. 



Vicksburgian (Glendon member of Marianna limestone) : West bank of Conecuh 

 River, Escambia Countv. Alabama. 

 Cat. No. 64324, U.S.N.M. 



21. Another young zoai-ium, X 20, well preserved and .showing the complete peristome, 



spines, and areolae. 

 Vicksburgian (Byram marl) : Byram, Mississippi. 

 Cat. No. 64325, U.S.N.M. 

 Fig. 22. Costazzia antiqua, new species (p. 604). 



Surface of the poorly presen-ed type-specimen, X 20. The ovieell with its flat area 



and bordering pores Is to be noted. 

 Vicksburgian (Glendon member of Marianna limestone) : West bank of Conecuh 

 River, Escambia Countv, Alabama. 

 Cat. No. 64326. U.S.N.M. 



101 



