PLATE XV. 



LiNGtTLA Thedpoedensis (page 111). 

 Figure 1. Side view of the type of this species. Twice the natural size. 



Stropiialosia productoides (page 112). 



[Referred to in the text in connection witli Productdla {Stro- 

 piialosia) truncata, Hall.] 

 Figure 2. View of a specimen of this species from the Athabasca River, 



sliewing the exterior of the ventral valve. 

 Figure 2a. Opposite side of the same specimen, shewing the exterior of the 

 dorsal valve and the hinge areas of both. 

 Both three times the natural size. 



Spiripera subdecussata (page 114). 



Figure :!. View of the type of this species, shewing the dorsal valve and the 



hinge area of the ventral. Natural size. 

 Figure 3a. A portion of the surface of the same, enlarged, to shew the finer 



details of the sculpture. 



Grammysia arcuata ? Var. (page 116). 



Figure 4. View of the cast of the interior of the left valve, referred to in the 

 text as having been collected by Mr. j. Pettit. 



Platyoeras quinquesinuatum (page 11*1). 



F'igure 5. Side view of a specimen of this species from Thedford. 



Similar view of another specimen from the same locality. 



