EXPLANATION OF PLATES. 

 Plate 1. 



Memhraniporina hertjamini, new species (page 11). 

 Fig. 1. Surface of tlie incrusting zoaiium X 20, showing the elliptical zooecia 

 and the incomplete small canal. 

 Upper Jacksonian, Rich Hill, Crawford County, Georgia. 

 Cat. No. 62569, U. S. N. M. 



Adenifcra inarmata, new species (page 12). 

 2. The usual aspect of the zooecia, X 20. 



Middle Jacksonian near Lenuds Ferry, South Carolina. 

 Cat. No. 62570, U. S. N. M. 



Otionella perforata, new species (page 13). 



3. Poi-tion of the upper surface of an incomplete discoidal zoarium, X 20. 



4. The inner side of a fragment, X 20. 

 Claiborniau, Claiborne, Alabama. 



Cat. No. 62571, U. S. N. M. 



TihraccUhia capillaria, new si^ecies (page 14). 



5. The type-specimen, X 20, 



Claiborniau, Moseley's Ferry, Caldwell County, Texas. 

 Cat. No. 62572, U. S. N. M. 



Hincksina jacksoiiira. new species (page 15). 



6. Surface of the bilamellar zoarium, X 20; with interzooecial avicularia 



little developed. 

 Middle Jacksonian. Rich Hill, Crawford County, Georgia. 

 Cat. No. 62573, U. S. N. M. 



ninclcftina uicfjaikiihiria, new species (page 16). 

 7. Portion of a zoarium, X 20, illustrating especially the coalescing of 

 opposite spines and the occurrence of large avicularia. 

 Middle Jacksonian, Wilmington, North Carolina. 

 Cat. No. 62574, U. S. N. M. 



I'LATE 2. 



Offiralina eximipora, new species (page 17). 

 Fig. 1, Portion of a zoarim, X 20, showing several ovicelled zooecia. 

 Middle Jacksonian, Rich Hill, Crawford County, Georgia. 

 Cat. No. 62575, U. S. N. M. 



Memhrendoccium pyri forme, new species (page 17). 



2. Surface of a specimen. X 20, exhibiting the characteristic pyriform 



opesium. 

 Lower Jacksonian, Jackson. Mississippi. 

 Cat. No. 62576, U. S. N. M. 



Periporosella taut ilia, new species (page 19). 



3. Exterior of a zoarium, with ovicells, X 20. 



4. An example with the surface abraded to show the dietellae, X 20. 

 Middle Jacksonian, Wilmington, North Carolina. 



Cat. No. 62577, U. S. N. M. 



77 



