PLATE XXVIII. 



PAGE. 



Fig. 1. ZEACBINUS COXANUS 302 



Anterior view of the body, arms and tentacula, and a portion of the column, 

 natural size. 



Tig. 2. POTEBIOCRIVUS ASPERATUS 280 



Posterior view of the body, arms and tentacula, and a portion of the 

 column, natural size. 



Fig. 3. ZEACBINUS KEOKUK 303 



Anterior view of body and arms, natural size. 



Tig. 4. POTEBIOCEINUS OlTERENSIS 283 



Side view of a crushed specimen, and a part of the pentagonal column. 



Fig. 5. CYATHOCBINUS PAKVIBRACHIATUS 309 



Anterior view of the body, arms, and a part of the column, natural size. 



Fig. 6. POTEBIOCRINUS LATIDACTYLUS 275 



Bide view of the body, a part of the arm?, and upper portion of the column, 

 natural size. 



Fig. 7. RHODOCBINUS COXANUS 305 



Posterior view, natural size. 



Fig. 8. POTEKIOCBINUS BUBKETI 270 



Anterior view of body and arms. 

 8 a. Posterior view of another individual showing the ventral tube and column. 



Fig. 9. POTEBIOCBINUS PENICILLIFOBMIS 276 



Posterior view of a nearly perfect individual, natural size. 

 Fig. 10. POTEBIOCBINUS NAUVOOENSIS 282 



Side, view of a crushed specimen, natural size. 

 Fig. 11. POTEBIOCBINUS TENTACULATUS 277 



Posterior view, natural size. 

 Fig. 12. POTEBIOCBINUS ABACHN^FOEMIS 281 



Posterior view of the body and a portion of one of the arms, natural size. 

 Fig. 13. POTEBIOCEINUS TENUIDACTYLUS 271 



Anterior view of the body and a part of the arms, natural size. 

 Fig. 14. EBETMOCBINUS VAESOVIENSIS 306 



Side view of the body with arms complete, and a part of the column, natu- 

 ral size. 



Fig. 15. POTEBIOCBINCJS VABSOVIENSIS 290 



Side view of the body and a part of the arms and column, natural size. 

 Fig. 16. POTEBIOCBINUS VALIDUS 287 



Anterior view of the body and a part of the arms and column, natural size. 

 Fig. 17. POTEBIOCEINUS ILLINOIENSIS 289 



Posterior view of the body and part of the arms, natural size. 



