. Outlines of zoology. Zoology. 596 BIRDS. In the hind-limb the fibula is incomplete, and more or less united to the tibia ; the proximal tarsal bones are united to the distal end of the tibia (which is therefore called a tibio- tarsus), the others being united to the proximal end of three united metatarsals (which thus form a tarso - metatarsus). As in reptiles, the ankle-joint is therefore intertarsal. The maximum number of toes is four, of which the first is the hallux ; and if there be four, the metatarsal of the hallux is free from the other three fused metatarsals. In regard to the alime
. Outlines of zoology. Zoology. 596 BIRDS. In the hind-limb the fibula is incomplete, and more or less united to the tibia ; the proximal tarsal bones are united to the distal end of the tibia (which is therefore called a tibio- tarsus), the others being united to the proximal end of three united metatarsals (which thus form a tarso - metatarsus). As in reptiles, the ankle-joint is therefore intertarsal. The maximum number of toes is four, of which the first is the hallux ; and if there be four, the metatarsal of the hallux is free from the other three fused metatarsals. In regard to the alimentary system, the absence of teeth, the frequent occurrence of a crop and a gizzard, the usual shortness of the large intestine, the presence of a cloaca, may be noted. The heart is four-chambered ; the single ^pT aortic arch curves to the right side; only m __. the pulmonary artery rises from the right niatic section of ventricle; the two valves between the right young bird.—After auricle and the right ventricle are in part Gadow. muscular; the red blood corpuscles are "'UbraT' r°rdrib •' T.', oval and nucleated ; the blood temperature liver; p., gut; som. is from 2°-ia° F. higher than that of (dotted), somatic layer 7 J of mesobiast; spt. Mammals. ia°eredof mesobiast^ ^ne non-expansible lungs are fixed to ao., aorta; r., re- the dorsal wall of the thorax; the bron- Productive organ ;K., ^/fl/ ^^ gxpand in irregular branches in the lungs; the ends of some of these branches are continued into surrounding air-sacs ; these may be continued i?ito the bones, and end in minute air-spaces. The trachea has bony rings, a voiceless larynx at its upper end, and a syrinx or song-box {with vocal cords) at the origin of the bronchi. Expiration is the more active part of the respiratory process. The (metanephric) kidneys are three-lobed, and lie em- bedded in the pelvis ; the ureters open into the cloaca ; there is no bladder; the urine is semi-solid, and consists chiefly o
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Keywords: ., bookauthorth, bookcentury1800, bookdecade1890, booksubjectzoology
