PLATE LXXXIT. 



(Figures 1-K, 10-13, 18, 22, 23, 2.'j, 2(i Ijy G. IJ. Simpson ; 7, n liy E. IOmmiin.s ; s, :i, 14-17, l!i-:i, -.'7 38 liv U. I'. Win 1 1 iki.k. 



Genus CCELOSPIRA. Hall. 



Page l:iO. 

 CcELOSPIRA HEMISPHERICA, SoWOlliy. 



Figs. 1, 2. Exteriors of two pedicle-valves ; showing the contour, character of pli(^ation and concentric 



strise. 

 Figs. 3, 4. Exteriors of brachial valves. 



Clinton group. Western New Yrn-k. 



CcELOSPIRA PLICATULA, Hull. 



See Plate 52. 



Fig. f). The interior of a portion of the bi-achial valve ; showing the divided hinge-plate and median 

 ridge. X 2. 



Clinton group. Wayne county. New York. 



Genus ATRYPINA, gen. nov. 



Page IBl. 



Atrypina Clintoni, sp. IIOV. 



See Plate 53. 



Fig. 6. The exterior of a pedicle-valve. X 2, 



Clinton group. Fi'om a boulder : Western, New York. 



Genus ANABAIA, Clarke. 



Page Ul. 



Anabala. Paraia, Claikf. 



Fig. 7. An internal cast of the brachial valve ; showing the impression of the cardinal process and the 

 marginal elevation of the median fold. 



Middle Silurian. liio TroiiMtris. Brazil. 



Genus VITULINA, Hall. 



Page l.is. 

 VlTULINA PUSTULOSA, Hull. 



Fig. 8. The exterior of a pedicle-valve of an average sjiecimen. 

 Fig. 9. The exterior of a brachial valve. 



Fig. 10. Ventral side of an internal cast; showing the impressions of the teeth, adilui-tor and diiluctor 

 muscles. X 2. 



Hamilton shales. Western New York- 

 Fig. 11. Ventral view of a preparation ; .showing three volutions of the spiral cone whicli is directed towai'it 

 the lateral margin of the shell. 



Hamilton shales. Alden, New York. 

 Figs. 12, 13. Interiors of brachial valves ; showing the cardinal process and low crural plates. 



Mid<lle Devonian. Erere, Brazil. 



