PLATE 25 



Centronella glansfagea Hall 



Page 163 



1-3 Views of an entirely characteristic specimen, x i^ 

 4 Internal cast of a part of conjoined valves showing the muscle scars of 

 the dorsal valve, x 2 

 Grande Grcve limestone ; division 2. Grande Greve 



Cryptonella (?) fausta Clarke 



Page 164 



5-7 Specimens showing the general characters of the shell 

 Grande Grcve liinestone ; division 2. Grande Greve 



Cryptonella (?) ellsi nov. 



Page 163 



8-10 Views of a specimen showing the sloping prominent ventral umbo 

 shoulders and broad pallial region, x i^ 

 Grande Greve limestone ; division 2. Grande Greve 



Rensselaeria ovoides Eaton var. gaspensis nov. 



{See plate 26) 

 Pages 164, 234 



1 1 A small ventral valve 



12 Profile of the ventral umbonal region with spondylium and supporting 



septum, x 2 



13 Enlarged view of the dorsal hinge showing the crural plates, x 3 



14 Sculpture cast of a small ventral valve with radial lines 



15 Dorsal view of small finely striate example 

 16, 17 Average adult examples 



18 Internal cast of a ventral valve 



19, 20 Other usual expressions of the shell 



21 A broadly oval, somewhat flattened specimen 



22 .An elongate and narrow mature individual 



302 



