LIFE 



n cf 



Fig. 338. ORDOVICIAN GASTROPODS: a, Subuliles regularis U. and S.; 6, 

 Maclurea logani Salter; c, Lophospira hdicteres (Salter) ; d, Cyclomani bilix (Conrad) ; 

 e, Schizolopha texlilis Ulrich;/, Connltiria trcitlonaisis Hall; g, Hormoloma gracilis 

 (Hall); h, Eccyliomphalus trlangulus Whitfield; i, Hdicototna planulala Salter; j, 

 Cyrtnlilcs orndtus Conrad; k, Raphislomina lapicida (Salter); /, Protowarthia can- 

 cettata (Hall); m, Bcllcrophon clausus Ulrich; and o, Archinacetta cingulata Uhich. 



1 



Fig- 330- ORDOVICIAN PELECYPODS: a, Plerinca dcmissa (Conrad); 6, Bysso- 

 tychia radiata (Hall); c, Vannxcmia dixom ;/\/.v M. and \\'.. interior of right valve, 

 i hi- hin^i' and niusi ular im])ressions; d and c, Ctenodonta tiasuta (Hall);/, 

 Lyrodcsma din inndtii nsis Hall, interior of right valve, showing a primitive type of 

 hinge; g, Ctenodonta rccurva Ulrich; h, Ctenodonia pectunculoides Hall; i, Rhytimya 

 radiata Ulrich, exterior of right valve. 



