LIFE PLANS. 261 



still more remarkable. In the Jurassic slates of Solenhofen 

 in Bavaria, which have yielded specimens of Pterodactyls re- 

 taining the impression of the leathery wing, have been found, 

 also, remains of a bird which had a long vertebrated tail, like 

 a lizard, with a pair of quills standing out from each vertebra. 

 It had also, saurian teeth inserted in sockets. It had a true 

 bird-foot, except that the metacarpals were separate. This 

 wonderful compound of bird and reptile, after causing much 

 discussion, was finally assigned a place among birds and named 

 Ar-chce-op'-ter-yx or " old-flyer." Very recently, however, other 

 specimens have been found, and Carl Vogt of Geneva, after 

 careful examination, declares that the creature was a feathered 

 lizard, and not a bird. There are two conical teeth in the 

 upper jaw ; eight neck- vertebrae, with five pairs of ribs directed 

 backwards ; ten dorsal vertebrae without spiuous processes, and 

 supporting ribs without uncinate processes ; five sternal ribs 

 and very minute sternum. The fore-limb, he maintains, is 

 not a proper wing, and there are three digits resembling those 

 of a clawed lizard ; the feathers are attached to the side of 

 the arm, hand, body, legs, and tail. If the feathers had not 

 been preserved, no one would have thought this Old-flyer a 

 bird, or capable of flight. Now what can we say of a crea- 

 ture having the bird and reptile so mixed that the best judges 

 are unable to decide whether it is one or the other ? We can 

 pronounce it, at least, a comprehensive type, and receive it 

 as throwing some light on the method of organic history. 



The Cretaceous Age in America produced still other mon- 

 grel forms, which have been published to the world by Pro- 

 fessor Marsh. These seem to lean unmistakably toward the 

 side of birds; but they possessed saurian teeth, and are known 

 as O-dont-or'-ni-thes or ''Toothed-birds." There are two genera. 

 leh-thy-or'-nis or "Fish-bird," had strong wings, bi-concave (fish- 

 like) vertebrae, and teeth inserted in sockets. Hes-per-or'-nis 

 or "Western-bird" had feeble wings, and teeth inserted in 

 grooves along the crests of the jaws. 



From such examples as have been cited, it will be under- 

 stood that the principle of comprehensive types results in 



