1874.] 



ANATOMY OF THE COLUMBA. 



255 



the proximal end of this ridge, or into a prolongation of it. In the 

 Columbae, Psittaci, and Alcidae this is not the case ; for in them it 

 has quite an independent place of insertion into the general surface 

 of the head of the bone at some distance from the pectoral ridge. 

 An oval roughness indicates the spot. It is at the angle formed by 

 the pectoral ridge and the main part of the bone in the Gallinse, but 

 nearer the other side of the bone in the Columbae. A glance at the 

 bone itself or the accompanying drawing of it (fig. 1) will explain 

 the point more than any amount of description. It will also be 



Heads of right humerus of: — a. Pterocles arenarius ; b. Gallus bankiva ; 

 c. Columba livia. 



found that the pectoral ridge in the Columbae and some of the Psit- 

 taci ends proximally in a point, peculiar to them. The Pteroclidse 

 agree exactly with the Pigeons in all these points, and differ widely 

 from all the Gallinse. 



In all important features the pelvis of the Pteroclidae differs with 

 the Columbae from the Gallinse, as in having no strongly marked 

 fossa on the inner surface of the ischium ; but in the slight deve- 

 lopment of the transverse processes of some of the sacral vertebrae 

 it is peculiar. 



The general proportions of the muscles in the Pteroclidae are per- 

 fectly Columbine. The pectoral muscles are similarly disposed, and 

 the crop rests on the proximal surface of the great pectoral in a 

 similar manner. In the leg the same resemblance maintains. Among 

 muscles the ambiens, the femoro-caudal (A), the accessory femoro- 

 caudal (B), the semitendinosus (X), and the accessory semitendinosus 

 (Y) are all present in Columbae and in Gallinae, which prevents any 

 difference in myological formula* from assisting in distinguishing 

 them. In the obturator internus muscle a well-marked contrast 

 between the Pigeons and Fowls is observed, which also shows that 

 Pterocles is one of the former. In Columba and the whole suborder 

 this muscle is small, narrow, and elliptical ; but in Gallus and all its 



♦SeeP.Z.S. 1874, p. 111. 



