HIGH SCHOOL ZOOLOGY. 



135 



humerus alone, but the whole skeleton gives the impression of a large 

 (living bird like a Grebe, living on fish, and swimming by msans of the 

 [lowfrfid feet. On the other hand, the genus Icihllnjornli was truly 

 oarinate, its anterior extremity being like that of an ordinary bird, ))ut 

 the rest of the skeleton presenting primitive features indicating reptilian 

 affinities, such as teeth arranged as in Plesperornis (except that they 

 were in sockets), and amphiccelous verte1)ra3 as in Archreopteryx. 

 Icthtliynrnis, therefore, occupies a middle position between Archajop- 

 teryx and the Carinata?. 



Fig. 96.— Feet of various Avian genera. 



a. wading type, Cicnm'a; b. perching, Txirdux ; o. rasorial, Phaxinntix ; d. raiitoii.il. 

 Faico ; e. adlicrent, Cupmhts ; b. cureoiial, Struthin ; g. scansoiial, Picux ; h. lo'^ate, 

 Podiceps ; i. loliate and scolloped, Fulica ; k. palmate, A nas ; 1. totipalmate, Phnetlion. 



16. When we come to the classification of the Carinate birds 

 we meet with gi-eat difficulties ; for although we recognise tliat 

 there are certain orders which, are lower than the other.s, yet 

 the adaptation to an aerial life has impressed a certain uniformity 



