62 COMAPRATIVE MORPHOLOGY OF VERTEBRATES 



In the cervical region the true ribs are usually greatly reduced, and are 

 lacking in the turtles. In many reptiles they clearly show their nature, being 

 short, bicipital and with their heads articulated to dia- and parapophyses (fig. 

 51). In the birds they may be recognized (fig. 59), their distal ends being bent 

 inward to protect the carotid arteries. In the mammals they form the distal 

 part of the 'transverse process* of human anatomy, the vertebrarterial canal 

 and the development revealing their true nature. 



Fig. 60. — Skeleton of trunk of common goose, Anser domesticus. c, cuneiform; ca, 

 carina; co, coracoid;/, furcula (clavicle) ;/e, femur; h, humerus; il, ilium; w, ischium; mc, 

 metacarpals; p, pubis; ph, phalanges; r, radius; s, scaphoid; sc, scapula; sr, sternal rib; 

 st, sternum; m, uncinate process; ul, ulna; vr, vertebral rib; 2, 3, 4, digits. 



The dorsal ribs are very short in amphibians, never extending 

 far from the backbone. They are bicipital in most forms, except the 

 anura where they form small projections on the ends of the trans- 

 verse processes. In the amphibia the vertebral artery is ventral 

 to the parapophysis. In all vertebrates with a sternum, the am- 

 phibia excepted, at least a part of the dorsal ribs reach that struc- 



