| OCR Text |
Show 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. A n oval roughness indicates the spot. It is at the angle formed by the pectoral ridge and the main part of the bone in the Gallinae, 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 Fig. 1. 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 Psittaci ends proximally in a point, peculiar to them. The Pteroclidee agree exactly with the Pigeons in all these points, and differ widely from all the Gallinae. In all important features the pelvis of the Pteroclidee differs with the Columbae from the Gallinae, a3 in having no strongly marked fossa on the inner surface of the ischium ; but in the slight development of the transverse processes of some of the sacral vertebrae it is peculiar. The general proportions of the muscles in the Pteroclidae are perfectly 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 Gallinee, 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. |
