EXPLANATION OF PLATE XXVI. 



Fig's 90 A and B. — Lasmonos fragilis (Raf.) 9, One— and-Two River, 

 vSt. Joseph. Fig. 90 B is the photograph of the animal in the left valve 

 showing the gravid marsupium. 



Fig's 90 C and D. — L. fragilis (Raf.) cf, Platte R., Agency Ford. 



Fig. 90 D. — A photograph of soft parts in left valve. 



Fig's. 91 A and B. — Lasmonos Simpsoni (Ferriss) 9, White R., Branson. 



Fig's 92. — A and B. — Proptera purpurata (Lamarck) a', White R., 

 Forsyth. 



Fig's 92 C and D. — Proptera purpurata (Lamarck) 9, White R., 

 Forsyth. 



Fig's 93 A and B. — Prop, capax (Green) 9, Miss. R., Hannibal. Fig. 

 93b sljows photograph of animal with gravid marsupinm. Note non-speciali- 

 zed post-ventral mantle margin. 



Fig's 94 A and B. — Prop, laeinssima (Lea) 9, Mud Lake, Kenmoor. 



Fig's 94 C and D. — Juveniles of laevissima, L. Contrary, St. Joseph. 



