PLATE 27 



Megalanteris ovalis Hall 



Page 167 



1-3 Three views of a selicified replacement showing the exterior 

 characters 



4 Interior of a ventral valve giving details of internal structure 



5 A silica replacement showing the structure of the brachidium 



6 Interior of a dorsal valve 

 Oriskany limestone. Glenerie, N. Y. 



Megalanteris thunei nov. 



(See plate 26) 

 Page 168 



7 Internal cast of the ventral valve 



8, 9 Parts of dorsal valves to show the structure of the hinge plate. 



8x2 

 10 Interior of the umbonal portion of the ventral valve 

 II, 12 Umbonal and profile views of conjoined valves enlarged to i ^^ 

 diameters to show the introversion of the margins 



13 Dorsal view of a specimen which like most of the others has lost its 



superficial radial lines 



14 Umbonal view of a specimen with very strongly inbent margins 



15 Dorsal view of a shell with fine radial surface lines 



Grande Grive limestone; divisions i and 2. Various localities along 



the shore of the Forillon 



306 



