. Outlines of zoology. of a ^ ^^ ?•cloaca, may be noted. The heart is four-chambered ; the singleaortic arch curves to the right side; onlythe pulmonary artery rises from the rightventricle ; the two valves between the rightauricle and the right ventricle are in part muscular; there isno renal portal system ; the red blood corpuscles are oval andnucleated; the blood temperature is from 2°-i4° F. higherthan that of Mammals. The non-expansible lungs are fixed to the dorsal wall ofthe thorax ; the bronchial tubes expand in irregular branchesin the lungs ; the ends of some of these branches are co
. Outlines of zoology. of a ^ ^^ ?•cloaca, may be noted. The heart is four-chambered ; the singleaortic arch curves to the right side; onlythe pulmonary artery rises from the rightventricle ; the two valves between the rightauricle and the right ventricle are in part muscular; there isno renal portal system ; the red blood corpuscles are oval andnucleated; the blood temperature is from 2°-i4° F. higherthan that of Mammals. The non-expansible lungs are fixed to the dorsal wall ofthe thorax ; the bronchial tubes expand in irregular branchesin the lungs ; the ends of some of these branches are continuedinto surrounding air-sacs; these may be continued into thebones, and end in minute air-spaces. The trachea has bonyrings, a larynx {without vocal chords) at its upper end, and a tebra;liver ; C, gut ; som.(dotted), somatic layerof mesoblast ; spL(dotted), splanchniclayer of mesoblast;ao., aorta; R., re-productive organ ; 652 BIRDS. syrinx or song-box {with vocal chords) at the origin of the rm-. FiG. 357.—A falcon. »««., Mandible; C, cere; N.^ nostril; £.€., ear covert; ,thumb wing ; _C., wing coverts ; £>., dorsal coverts; ^., second-aries ; P., primaries; /?., rectrices; A., ankle; Mt., tarso-mctatarsus; /., first toe. bronchi. Expiration is the more active part of the respiratoryprocess. GENERAL CHARACTERS OF BIRDS. 6S5 Tfie {rnetanephric) kidneys are three-lobed, and lie embeddedtn the pelvis; the ureters open into the cloaca; there is nobladder ; the urine is semi-solid, and consists chiefly of must be mainly got rid of by evaporation from thewalls of the air-sacs and air-passages. The testes lie beside the kidneys; the vasa deferentia run
Size: 1200px × 2082px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookidcu3192, booksubjectzoology
