ACKNOWLEDGMENTS 



THE author is indebted to R. Pearl for Plate IV, to 

 J. W. Connaway for Plates V and VI, to P. F. Trow- 

 bridge for Plates VII, VIII, IX, XXI, XXII, and XXV, 

 to E. A. Trowbridge for Plate XVI, to M. Boyd for 

 Plate XVII, to L. Monsees for Plate XVIII upper, to 

 W. J. Spillman for Plate XVIII lower, to Hart et al. 

 for Plates XXIII and XXIV, to C. H. Eckles for 

 Plates XXVI, XXIX, and XXX, and to H. Hackedorn 

 for Plates XXXI and XXXII. 



Grateful acknowledgment is made to all these persons 

 for their valuable assistance. 



