TO THE MEMORY 



OF 



IGNATIUS D L L I !s^ G E R, 



THE FOUNDER OF EMBRYOLOGY, WHO FIRST TAUGHT ME HOW TO TRACE THE DEVELOPMENT OF ANIMALS; 



AND OF 



FllANCIS CALLEY GRAY, 



OF BOSTON, MY FRIEND AND ADVISER IN PLANNING THE PUBLICATION OF THIS WORK; 



JOSIAII QUINCY, JONATHAN PHILLIPS, NATHAN APPLETON, 



DAVID SEARS, THOMAS GRAVES GARY, 



WILLIAM STORY BULLARD, JOHN ELIOT THAYER, 



JOHN AMORY LOWELL, AND STEPHEN SALISBURY, 



WHO rXITED WITH HIM IN SECURING THE MEANS FOK ENGRAVING THE PLATES, AT A TIME WHEN IT AITEAIiED 

 DOUBTFUL WHETHER THE SUBSCRIl'TION WOULD COVER THE EXPENSE OF ITS PUBLICATION, 



THIS WORK 



IS INSCRI15KD WITH DEEP GRATITUDE 

 BT 



THE AUTHOR. 



