AVES 



371 



the metacarpal bones separated. The fingers had the same number 

 of joints as in the lizards. The keel was only lightly developed. 

 Archeopteryx used its wings chiefly for planing rather th.B.n flying. 

 The Archeornis (Gr. ancient bird), slightly different from the Arche- 

 opteryx, was discovered in an almost perfect state of preservation 

 in 1877, "6^^ Eichstatt, Bavaria. It had an extremely long reptilian 

 tail with twenty-one joints, which was " Hke a telescope pulled out, 

 while the tails of the modern birds are like a closed telescope." 



Fig. 207. Left, Ichthyornis victor. Right, Hesperomis regalis. (From Daugherty. 



Courtesy of W. B. Saunders & Co.) 



Ichthyornithiformes. — Ichthyornis (Figure 207 A) had socketed 

 teeth, a keeled sternum and was a strong flyer and apparently a fish 

 eater. It was found in the Cretaceous of Kansas. It was small, 

 about the size of a pigeon. 



Hesperornithiformes. — Hespej-ornis (Figure 207 B) was a three- 

 foot, flightless diving bird, with grooved teeth, a keelless sternum 

 and strong paddle-like hind limbs. It was also found in the Creta- 

 ceous of Kansas. 



A Living, Connecting Type. — In the South American Hoactzin, 

 the adults are like certain pheasants, but differ in anatomical 

 characteristics. The breast bone is wider behind than in front; the 

 keel of the sternum is confined to the posterior part; the crop is 



