vi PREFACE. 



Leyden ; Dr. Strahl, of Berlin ; Professor Owen and Dr. Gray, of the 

 British Museum ; and Professor AUman, of Edinburgh, To my friend, 

 Mr. Alex. Agassiz, I wish esj)ecially to make my acknowledgments for 

 the tedious labor of correcting the proofs, which he has cheerfully 

 undertaken during my unavoidable absence. Professor Agassiz has, 

 in the kindest manner, superintended the work. 



THEODORE LYMAN. 



Cambridge, Mass., October, 1864. 



