130 



GENERAL ORNITHOLOGY. 



Fig. 45. — Zygodactyle foot of a woodpeckci". Hiilutomus 

 pileatus, nat. size. 



Fig. 44. — Syn- 

 dactyle foot of king- 

 fisher, nat. size. 



one either ; seen in those perching birds which scarcely use their feet for progression, bat 

 simply for sitting motionless, (c) The zygodactyle or yoke-toed modification has been suffi- 

 ciently noted (fig. 45). It was formerly made much of, as a scansorial or dimhing type of foot, 

 and an absurd "order" 

 of birds has been called 

 Scansores. But many 

 of the zygodactyle birds 

 do not climb, as the 

 cuckoos; while the most 

 nimble and admit nf 

 climbers, such as the 

 nuthatches and creepers, 

 retain a typically pas- 

 serine foot. The "scan- 

 sorial " is simply one modification of the insessorial plan, and has little clas- 

 sifieatory significance, — no more than that attaching to the particular con- 

 dition of the insessorial foot (d) which results from elevation or versatility of 

 the hind toe, as in some Cypselidce and Caprimulgidce. This is an abnormality which has 

 received no special name ; it is generally associated with some little webbing of the anterior 



toes at base, which is a de- 

 parture from the true inses- 

 sorial plan, or with abnormal 

 reduction of the phalanges of 

 the third and fourth toes, as 

 expilained above (figs. 40, 41). 

 (e) The raptorial is another 

 modification of the insessorial 

 foot. It is advantageous to a 

 bird of prey to be able to 

 spread the toes as widely as 

 possible, that the talons may 

 seize the prey like a set of 

 Fig. 46. — Eaptorialfoot of a hawk, ^cciTJtferccwiJm, nat. size. grappling irons; and accord- 



ingly the toes are widely divergent from each other, the outer one in the owls and a few hawks 

 being quite versatile. In a foot of raptorial character, the toes are cleft profoundly, or, if united 



at base, it is liy movable 

 webbing; the claws are im- 

 mensely developed, and the 

 under-surfaoes of the toes are 

 scabrous or bulbous for greater 

 security of the object grasped. 

 Any hawk or owl or old-world 

 vulture exhibits the i-aptorial 

 insessorial foot (figs. 46, 47)- 

 2. The cursorial or graUato- 

 rial type. The gist nf this 

 plan lies in the decrease or 

 Fig. 47. — Kaiituiial foot of an owl, ^^uco.^a7nme«s, nat. size. entire loss of the e:rasping 



function, and in the elevation, reduction in length, or loss of the hind toe: the foot is a good 

 foot, but nothing of a hand. The columbine birds, which are partly ten-estrial. partly arboreal. 



