Finally, I want to acknowledge the very great help of my 
wife, Margaret Brooks Hickey, who spent 11 months at Patuxent Refuge 
checking records and punching IBM cards, and who later contributed 
so generously of her energy in editing the manuscript in its final 
stages. 
This manuscript was virtually completed on March 31, 199. 
Minor changes including cursory references to subsequent literature 
were made up to December 31, 1951. 
