EXPLANATION. OF PLATE XIX. 



Fig's. 50 A and B. — Q. verrucosa (Raf.) cf , Grand R., Darlington. 



Fig's 50 C and D. — Young Q. verrucosa (Raf.) 9, White R., Hollister. 



Fig's 51 A and B. — Q. ywhilis (Conrad) 9, Marais des Cygnes R., 

 Rich Hill. 



Fig's 52 A and B. — Q. cylindirca (Say) 9, Black R., Williamsville. 



Fig's 53 A and B. — Q. metanevra (Raf.) a', Meramec R., Meramcc 

 Highlands. 



Fig's 54 A and B. — Rolundaria tnherculala 'Raf.) 9, Osage R., vSchell 

 City. 



Fig's 55 A and B. — R. grant/era (Lea) 9, Miss. R., LaGrange. 



