COMPARATIVE ANATOMY. 



Circulation. The temperature of the blood exceeds that of 

 any other vertebrates, ranging on an average from 100 to 109 

 or 110. In sea-birds, as the gull, the temperature is lower 

 thaii that of other birds, varying from 100 to 105. In Un- 

 common fowl it range* from 107 to 1 10. In the swallow it 

 is said to be as high an 111} . The blood-corpuscles are for 

 the most part red, and nucleated. 



In-art is double, each one presiding over a separata 

 system ; tho right one ovi-r tho pulmonary, the loft one over 



VI. 



enlargements whrs the oarres emanate to be distributed to the 

 extremities. 



The Sfctefcn.The skull of Mid* is mad* up of a number of 

 bones, separate in the young bird, bat which, speedily growing, 

 become inseparably blended together in the adult The jaws, 

 as already mentioned, are elongated, and both an movable. The 

 lower one is connected to the cranial bones bj the interven- 

 tion of a second one called the tympanic or quadrate boo* 

 The skull is connected to the vertebral column by means of a 



I. BEAKS or (a) SHRIKE, (b) CROW, AND (c) JABIRU. II. TONGCTKS or (a) SKIPS, (b) FIELDFARE, (o) Goosx, AJTU (i) KtvanSRn. HI. Dtors- 

 TIVE CANAL OF COMMON FOWL. IV. GASTRIC GLANDS IN (a) EAOLE, (6) PIQBON, (c) SWAN, (d) KHIA, AHD () OSTRICH. V. DIAGRAM 

 or LOBULE or BIRD'S LUNG VI. FEMALE ORGANS or FOWL AT BREEDING SEASON (OWEN). VII. a. INFERIOR LARTHX or BOOK. Vll.b. 

 VERTICAL SECTION OF INFERIOR LARYNX OF BOOK. VIII. HEAD or WOODPECKER (MILNE-EDWARDS). 



Befs. to NOB. in Figs. III. 1, gullet ; 2, crop ; 3, proveutriculus ; 4, gizzard ; 5, small intestine ; 6, caoa; 7, large intestine; 8, 8, uietsts 

 9, 9, oviducts ; 10, cloaca; 11, process for attachment of yolk-bag. V. a a, subdivisions of bronchus ; b b. smaller subJirisiona. VI. 1, ova, 

 or yolks ; 2, vascular membrane of calyx ; 3, zone, or stigma ; 4, empty calyx ; r>. iuf undibulum ; 6, 6, oviduct ; 7, oblique ridgwe of lining 

 membrane of oviduct ; 8, shell-forming dilatation ; 9, egg exposed ; 10, villi, containing follicle* concerned in the secretion of shell ; 11, con- 

 volutions of oviduct ; 12, cloaca. Vll.a, 1, trachea ; 2, drum formed by the lower end of trachea ; 3. middle ossicle ; 4, first ring of the 

 bronchi; 5, bronchi ; 6, proper muscles of the larynx ; 7, depressor muscles of the trachoa. VII. b. 1, inferior portion of the trachea 

 divided as regards the half ; 2, semi-lunar membrane ; 3, osseous cross-bearer ; 4, little rim formed by internal lip of the right glottis ; 5, 

 inner surface of right bronchus, formed by a tympaniform membraue ; o, portion of the cavity of the right bronchus exposed by a i 

 of part of this membrane. VIII. 1, hyoid apparatus ; 2, tongue. 





the general or systemic Tlio main object of the right system 

 is to remove from the blood carbonic acid, which results from 

 the waste-tissue products, and replace it with oxygen. 



Nervous System. The brain of birds mates some little 

 advance towards the mammalian character. The cerebral 

 hemispheres are increased in size, and possess traces of con- 

 volutions. The ganglia which preside over the sense of taate 

 are small. The optic lobes are large, as might be anticipated 

 from the keen sense of sight and the complete power of adapta- 

 tion of it, at all distances, which birds possess. The cerebellum 

 and spinal cord are both of large size. The latter presents 



single condyle. The vertebras vary in number, the cenleal 

 ranging from ten to twenty. Tho dorsal, lumbar, and sacral 

 vertebra are generally found fused together and immovable. 

 The ooocygeal, which support the toil, are movable. The 

 sternum, or breast-bone, is large and expanded, and has pro- 

 jecting in tho median lino a keel-like ridge, to increase the sor 

 faoe of attachment of the large elevator and depressor muscles 

 of the wing. It has connected with it two bones ; one small, 

 the f urculum or clavicle ; the other Urge and strong, the 

 coracoid bone. The bitter acts as a powerful fulcrum to the 

 wing, as well as a point of attachment to muscles. The 



