Plate 52. 



Figs. 1—1. lJiiii)i)(liiil(isi(i pctiolu^: l.iiiisd.ilc, 1S4," (p. :i'.C>). 



1. Portion of the large biUiinelliu' zoarium. natural size. 



2. Surface of the same speciuien, X 20. Tlie shape of the aijerlura, the tremocystal 



frontal and the absence of avicnlaria are to be noted. 

 S. lulericir of the zooecia, X 20. The frontal is a troninc.vst iil.icpil ujiou a very thin 

 oldcy.st. 



4. An example, X20, presersinu; sevt'ral iivifclliMl zodceia. A few aviruinria are also 



present. 

 Middle JacUsouiau: Eutaw Springs, South Carolina. 

 Cat. No. C4094, U.S.X.M. 

 Fios. 0-12. Hiiipodiplosia vespertiHo, new sijecies (p. 394). 



5. Four examples of the narrow bifoliate fronds, natural size. 



G. An example, X 20, exhibiting ovieelled zooecia. The ovicell is surrounded by 



areolae. 

 T. Longitudinal section, X 20. The tubules of the tremocyst and the large distal 



septula are visible. 

 S. Transverse section of zoarium, X 20. 

 9. View of the interior, X 20. The tubules of the tremocyst are visible through the 



olocyst. 



10. Schematic longitudinal section through an ovicell, X 20. 



np. aperture; Of, ovicell; //■, tremocyst; tti, tubules; ::, zooeeium. 



11. Lower part of a zoarium, X 20, with some closed zooecia. 



12. The upper portion of the same specimen, X 20, showing the normal development of 



zooecia. 

 Middle Jacl<sonian : Near Lenuds Ferry, South Carolina. 

 Cat. No. 64095, U.S.N.M. 

 Figs. 1.3-16. Hippodiplosia falcifera, new species (p. 395). 



13. Basal portion of the free bilamellar zoarium. natural size. 



14. Surface of the same specimen, X 20, exhibiting the usual asiieet of the species. 



15. A well-preserved fragment, X 20, in which the falciform avicnlaria are clearly 



discernible. 



16. Old zooecia, X 20. The outlines are indistinct and the avicularia are immersed. 

 Middle Jacksonian (Castle Hayne limestone) : Wilmington, North Carolina. 



Cat. No. 64096, U. S .N. M. 

 Figs. 17, IS. Iliinzeauiiui libriitii, new species (p. 42:31. (See also pi. 55, tigs. 1-6.) 



IT. Surface of the free, narrow bilamellar zoarium, X 20, exhibiting the smooth frontal 



and the two areola like pores. 

 IS. Vertical section, X 20, illustrating thickness of the olocyst. 

 lip. aperture; ol, olocyst; z, zooeeium. 

 Jliddle Jacksonian (Castle Hayne limestone) : Wilmington, North Carolina. 

 Cat. No. 64097, U.S.N.M. 

 Figs 19-21. Hipiio-citnoselUi (lixtoitn, new species (p. 390). 



19. Celluliferous side of the free, subcylindrical zoarium, X20. The peristome with 



peristomial aviculariuni, the convex, porous frontal and an ovieelled zooeeium are 

 to be noted. 



20. Frontal side of the same specimen, X 20. 



21. One of the two lateral sides of the same, X 20, showing three zooeciules. 



Middle Jacksonian : Eighteen miles west of Wrightsville, Georgia. 



Cat. No. 6409S, U.S.N.M. 



53 



