No. 3-] THE OSTEOLOGY OF THE PIGEONS. 



499 



gains breadth by its spreading xiphoidal processes. Of these, 

 the larger and stouter pair are the external ones, which have 

 pointed free ends directed 

 backwards and inwards. 

 They spring from the mid- 

 dle of the side of the bone. 

 The internal xiphoidal 

 processes are considerably 

 shorter, far more slender, 

 and have transversely di- 

 lated ends, and they spring 

 from the hinder third of 

 the bone. Mid- 

 xiphoidal process is 

 of a quadrilateral out- 

 line, with its posterior- 

 external angles some- 

 w h a t produced. 

 These processes form 

 a pair of notches upon 

 either side of the ca- 

 rina ; the large ante- 

 ro-external pair are 

 widely open behind, 

 and for the rest sub- 

 elliptical in outline ; 

 while the small 

 postero-internal pair, 

 also of subelliptical 

 outline, are nearly 

 closed in behind. In 

 several particulars 

 the sternum reminds us of the galline pattern of the bone.^ 



1 Some instructive figures of the sterna of various pigeons appear in PI. XXIII 

 of A. and E. Newton's " Osteology of the Solitaire " {Pezophaps solitarius) in 

 the Phil. Trans. Royal Society of London, 1869, PP- 327-362. The outlines of 

 the sterna of the following species are given : Coluniba livia, Didunculus strigi- 

 rostris, Leucosarcia picata, Patagicettas caribbaa, Chamapelia trochila, Geopelia 

 striata, and Goura coronata. A sternum of Colutnba livia is given that has 



Fig. 2. Fig. 3. 



Fig. I. — Dorsal aspect of the pelvis of Engyptila albifrons ; 



adult ^ ; natural size. 

 Fig. 2. — Pectoral aspect of the sternum of the Passenger 



pigeon (Ectopisies 7nigratoria) ; natural size. 

 Fig. 3. — The same view of the sternum of the Mourning dove 



{Zenaidura macrottrd). These bones give a good idea of 



the form of the pelvis and the sterna as they occur among 



the ordinary pigeons generally. 



