EXPLANATION OF PLATE XXVI. 



' v PORINA LABIATA (Gabb and Horn), p. 350 



1. Fragment of zoarium, natural size. 



2. The same much enlarged. 



3. Surface of zoarium much enlarged. 



4. View of ovicell, much enlarged. 



5. A longitudinal section, enlarged. 



6. A cross section, enlarged. 



(All figures after Gabb and Horn.) 

 Vinccntown limcsand. 



PORINA QUADRANGULARIS Gabb and Horn, p. 350 



7. Fragment of a zoarium possibly belonging to this species, 



(x6). . 



8. View of the type specimen. (After Gabb and Horn.) 



Vincentoivn limcsand; Vincentown, (154). 



LEPRAUA ASPERA ( Gabb and Horn ) , p. 352 



9. Much enlarged surface of zoarium. (After Gabb and 



Horn.) 



Vinccntown limcsand. 



MUCRONELLA MURALis (Gabb and Horn), p. 352 



10. Much enlarged surface of zoarium. (After Gabb and 



Horn.) 



Vincentown limcsand. 



PORINA CORONATA (Reuss) ? p. 351 



11. Fragment of zoarium, (x6). 



Vincentown limesand; V'mcentown, (154). 



MUCRONELLA TYPICA (Gabb and Horn), p. 353 



12. Fragment of zoarium, (x2). 



13. Fragment of zoarium, (*4). 



Vinccntown limesand; Vinccntown, (154). 



MUCRONELLA ASPERA Ulrich, p. 354 



14-15. Surface characters of two Eocene zoaria, (x2o). 

 (After Maryland Geological Survey.) 



MUCRONELLA PUMILA (Gabb and Horn), p. 355 



16. View of an encrusting zoarium upon a specimen of Onycho- 



cclla digitata, (x2). 



17. Much enlarged surface of zoarium. (After Gabb and 



Horn.) 



Vincentown limcsand; Vincentown, (154}. 



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