PLATE 29 

 Rensselaeria atlantica Clarke 



Page 112 



i, 2 Ventral and profile views of an internal cast 



3 Exterior surface of a ventral valve 



4 Enlargement of the surface 



5 Dorsal view of an entire specimen retaining the shell 



6 Interior view of the ventral valve 

 7, 8 Dorsal views of internal casts 



9, 10 Dorsal and ventral views of an internal cast showing details of 

 muscular and cardinal structure 



1 1 Internal cast of ventral valve 



12 A dorsal valve retaining the shell 



13-15 Three views of a finely preserved sculpture cast 



1 6 Internal cast of a large ventral valve 



17 Interior of a dorsal valve 



1 8 Cast of the umbonal portion of a dorsal valve, x 2 



Localities. Figures i, 2, 9-18, Presque Isle stream; 3-8, Edmunds 



Hill 



Rensselaeria nov. 



Page 115 



19 Sculpture cast of a ventral valve of subcircular form and finely marked 



surface 



Locality. Edmunds Hill 



224 



