EXPLANATION OF PLATE XXIII. 



HETEROPORA PARVICELLA (Gabb and Horn) , P- 3 2 7 



1-2. Views of two fragments of zoaria, (x3). 



Vincentown lime sand; Vincentown, (154)- 



RETELEA OVAUS Gabb and Horn, P- 3 2 8 



3. View of a fragment of a zoarium, natural size. 



4. View of a celluliferous surface, much enlarged. (Both fig- 



ures after Gabb and Horn.) 

 Vincentown limesand. 



FLUSTRELLA ? CAPISTRATA Gabb and Horn, P- 3 2 9 



5. View of a fragment of a zoarium, much enlarged. 



6. View of the basal expansion, much enlarged, described as 



Membranipora abortiva by Gabb and Horn. (Both fig- 

 ures after Gabb and Horn). 

 Vincentown limcsand. 



ONYCHOCELLA DIGITATA (Morton), . . . ., - P- 33o 



7-10. Views of four fragments of zoaria, (x2). 



Vincentown limcsand; Vincentown, (154). 



BIFLUSTRA TORTA Gabb arid Horn, p. 331 



11-12. Views of two fragments of zoaria, (x3). 



Vincentown limesand; Vincentown, (154)- 



BIFLUSTRA DISJUNCTA Gabb and Horn * p. 333 



13. View of the celluliferous surface of a zoarium much en- 



larged. (After Gabb and Horn.) 

 Vincentown limesand. 



AMPHEBLESTRUM HETEROPORA (Gabb and Horn), p. 333 



14. Surface of zoarium, much enlarged. (After Gabb and 



Horn.) ' 



Vincentown limesand. 



15. Surface of a zoarium from the Eocene, (x2o). (After Mary- 



land Geological Survey.) 



16. View of a single zoecium more highly magnified. (After 



Maryland Geological Survey.) 



MEMBRANIPORA PLEBIA Gabb and Horn, P- 334 



17. Surface of zoarium much enlarged. (After Gabb and Horn.) 

 Vincentown limesand. 



MEMBRANIPORA ANNULOIDEA Ulrich and Bassler n. sp., p. 335 



18. Surface of the zoarium, (x24). 



Vincentown limesand; Vincentown, (154}. 



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