PREFAGE. xi 



The geologist, too, is patiently learning the language of the 

 rocks and the drift, written long ages ago, which can alone be 

 interpreted by comparing fact with fact, each of which, when 

 well authenticated, is a new word in this new language, in 

 which Nature tells the story of what once was and the changes 

 she has wrought in bringing her works to their present state. 

 So must the lessons of all the sciences be studied before they 

 can meet the demand for knowledge made by the advancing 

 standard set up by the inquiring mind of this our day, which we 

 may well anticipate will be greatly elevated in the immediate 

 future. 



I hope that others may take up other divisions of the subject, 

 and treat them so thoroughly as to leave nothing to be desired, 

 till at last the whole subject will be so wrought in detail that 

 the generalizer will find in his hands abundant material for his 

 part of the work. His great want now is well attested facts. 

 These I have attempted to give without adornment, as to the 

 animals treated. In preparing my illustrations, I have tried to 

 make them true to nature, regardless of the question whether 

 they were ornamental pictures or not. In the full figures I have 

 as far as possible drawn from photographs, taken when the 

 animals were standing at ease, believing that in this way I could 

 give a truer idea of them than if they were made to assume 

 striking and unusual attitudes, which might be more attractive 

 to the eye. If my animals differ in position and appear less 

 elegant in form than the same animals are generally represented 

 in books and in paintings, I can only say that mine are as near 

 to nature as I could represent them, without any attempt to im- 

 prove upon nature, for so I thought I could be most truthful 

 and most instructive. 



I only claim to be an amateur naturalist, wanting that severe 

 and systematic study and discipline indispensable to the pro- 

 fessional scientist. The labor of my life has been devoted to 

 another field, while scientific studies have been my recreation. 

 If I have learned how to observe facts, and have clearly stated 



