ARKIY FOR ZOOLOGI. 



BAND 1. 



On the homologies of the different pieces of 

 the compound rhamphotheca of birds. 



By 



Dr. EINAR LÖNNBERG. 



With 13 figures in the text. 



Communicated March 9:th by Hj. Théel and Cmt. Aurivillius. 



The bill of birds seems usually to be regarded as such 

 a thorough avian structure tbat it is not supposed to bave 

 any direct homologies among otber animals, and yet I think 

 and I sball endeavour to prove that it is only a modification 

 of certain common reptiiian structures. 



Tbe sbape of tbe bill bas, by earlier autbors, often been 

 used as an important cbaracteristic on wbicb tbe classifica- 

 tion conld be based. It became bowever, soon apparent tbat 

 tbis was going too far and tbe over-estimation was, as always 

 is tbe case, followed by an nnder-rating. Låter autbors seem 

 tberefore almost to disdain tbe classificatory value of charac- 

 teristics derived from tbe bill and tbink tbat they only can 

 be used for separating or uniting minor groups. Furbringer 

 in bis great work seems, for instance, to be led by such an 

 opinion. Tbis might account for tbe fact tbat there is still 

 so mucb to do and so many open questions concerning tbis 

 organ. 



It is well known that the horny sheath of the bill of 

 some birds consists of several pieces which are more or less 



Arkiv för zoologi. Band 1. 35 



