New Investigations into the Distribution of the Vocal Muscles. 



Deppe, Richard Schomburgk, and v. Winterfeld, the African by Krebs and Peters ; many 

 were obtained by purchase, and have been for a long time collected for this purpose ; 

 for perfect and undissected animals, preserved in spirit, are of much more value for the 

 progress of science than anatomical preparations of separate parts. 



I was enabled from this material to investigate the typical differences in the 

 structure of the larynx of the Passerines, and to settle the matter, of which I gave a full 

 account in the Monatsbericht of the Academy in June, 1845; but it was not sufficient 

 for me to be able to draw from them all those conclusions on the subject of the 

 Classification of Birds, which could be gained from these anatomical facts. 



Since that time the number of birds which I have examined has greatly increased. 

 Of several collections, the materials with which my friend Professor Eschrieht most 

 kindly supplied me were exceedingly useful in increasing my knowledge as to the 

 distribution of the observed forms of the larynx in America, and in aiding me to draw 

 conclusions as to their classification. I gave an account of my work to the Academy, 

 in an Appendix to my earlier paper. (See the Monatsbericht of the Academy for May, 

 1846.) I have lately received a great addition to my material from the collection 

 of Indian Birds in spirit, made by Dr. Philippi in Tenasserim. I must also thank 

 Herren Stannius of Rostock and Focke of Bremen for their assistance. It was necessary 

 for the object of the work that the systematic position of the animals to be dissected, not 

 only as regards their species, but also subgenera and synonymy, should be perfectly 

 certain. The author has not dared to rely on his own ornithological knowledge and 

 studies, but an experienced ornithologist of the department, Herr Cabanis, Assistant 

 in the Zoological Museum, from whom we may expect the description of the new birds 

 obtained by Richard Schomburgk in his travels, has compared the spirit specimens with 

 the dried birds in the Zoological Collection, and has named them. 



Table of the Genera and Species examined , possessincj a Muscular Organ of Voice. 

 (The Species examined by the Author are marked with an asterisk.) 



