x PREFACE. 



never thought of, especially as even the part already published contained certain errors and 

 required first of all to be remodelled. These errors he carefully noted in an interleaved copy, 

 and thus materially facilitated my revision of them. In this way two more years passed away, 

 and with them all inclination to proceed with the work he had so vigorously commenced. The 

 man who appeared still to have plenty of time for mature consideration was at the end of his 

 activity. In the midst of his endeavours to procure fresh materials for the completion of his 

 task, death surprised him. Thus were solved at once all the doubts that still prevailed in his 

 mind, almost exclusively and constantly occupied with scientific meditations. His last thoughts 

 were in accordance with this state of mind : he fervently regretted his indecision, and looked 

 upon all the labour of his life as lost ! 



But that this should not be the case, were my first thoughts when I came to Halle in his 

 place. Well acquainted with the rich treasures which his manuscripts contained, it was my most 

 important business to search through and make myself familiar with them. I succeeded beyond 

 expectation ; although Nitzsch himself, when dying, had doubted whether it were possible that 

 another person could introduce his work to the world. On examination, I quickly saw that an 

 abundance of materials existed for the completion of the Pterylography, if it were resolved 

 to limit it to what Nitzsch had investigated ; but that, on the contrary, the anatomical portion of 

 his works, although very rich in details, was far too imperfect to allow a uniform whole to be 

 prepared from it ; and, finally, that his studies of the Epizoa, as Nitzsch called all parasitic 

 insects, certainly presented matter enough for a very copious, if not perfect, representation of 

 that group of animals. Thus it appeared certain that the Pterylography must be undertaken 

 first. I therefore began to work it up in the manner traced out for me by Nitzsch in the Latin 

 text of the general part and in the finished copper-plates ; but thought it desirable, both for 

 facility of description and for the sake of more general diffusion, to adopt German in place of 

 Latin for the expression of the results. 



In this form the complete work is now presented to the friends of science, in the hope that 

 its rich and almost unknown contents may astonish all zoologists, keep permanently alive the 

 memory of its author, and also procure for its editor a favorable judgment. May it assist in 

 the attainment of the chief object of its author, namely, a better insight into the true natural 

 differences of the structure of birds, which is apparently so uniform. But may it also induce 

 ornithologists to give to their future systematic investigations an extension and depth, without 

 which, least of all in this department of Zoology, can the final problem be solved, as, indeed, has 

 been shown, as it seems to me, by the one-sided, and for this very reason unsuccessful, attempts 

 which have hitherto been made with this object. 



H. BURMEISTER. 

 HALLE ; 20th May, 1840. 



