ISO 



TIII-: /,/>///,' \-IIHIY .\rr.\it.\TUS. 



Fig. 246. 



.-weep through a third intercostal sac, it arrives nearer and nearer the la-t .lor.-al 

 \ertebni. In their dorsal portion, the prolongation- emanalin- from the cervical 



thus form two currents, 

 though these are constituted alt; i- 

 liately by the vertebra- and the small 

 air-sacs placed on their lateral a.-| 

 At the name time that tin s. 

 receive the air from the vertebra- pre- 

 ceding them, and transmit it to th.-<- 

 which follow, they communicate it to 

 all the Vertebral riiis. 



" In no order of birds do the a-rial 

 currents having the c.rvieal rent* 

 voirs communicate with tho.-e which 

 circulate in the cranium. Liquids 

 injected either by the ajiial jmrtion 

 of the vertebral canal or the luteral 

 prolongations of the neck, never enter 

 the bones of that cavity. Thinking 

 that the injection might perhaps 

 penetrate if passed in the opp -ite 

 direction, we have perforated the 

 bones of the cranium, and to tin- 

 aperture have adapted the extremity 

 of a steel syringe tilled with mercury ; 

 but the metal did not reach the a-rial 

 prolongations of the neck. From this 

 double experiment, we concluded 

 that the cranial bones have no com- 

 munication with the respiratory appa- 

 ratus." 



3. Anterior diaphragmatic reser- 

 voirs (Fig. 24b\ 8). "Placed !*- 

 tween the two diaphragms, they cor- 

 respond : in front, to the thoracic 

 reservoirs, against which they stand ; 

 behind, to the posterior diaphragm- 

 atic reservoirs; outwardly, to the 

 ribs and intercobtal muscles ; in- 

 wardly, to the thoraco-abdominal 

 diaphragm and oesophagus: below, 

 to tlie most distant part of the tho- 

 racic reservoir; above, to the pul- 

 monary diaphragm, which separate- 

 them from the corresponding lung. 

 These air-sacs communicate with tin- 

 lungs by a. circular opening, which 

 K originates from the gnat po-terior 

 diaphragmatic bronchus; there is 

 often a second opening of communi- 

 cation beyond the embouchure of the 

 trunk; this reservoir is the only i.m- 



voir. a, Membrane forming the anterior ilia- which receives air from the lung by 

 phragmatk- reservoir; /<, Membrane forming tin- a double orifice." 

 posterior ditto. 6, Section of the thoraco-ahilomi- .( /',,,./,,/, <liit/,lii-<itiiiuif!n reser- 

 nal diaphragm. d, Subpectoral prolongation of ri> ; r t (),'jg, l<\, -1). "'Oval-shaped 

 the thoracic reservoir; c, PerioardfauB ; /, J, like the preceding, and situated like 

 Liver; </, Gizzard; A, Intestines; in, Heart; tin-in in the interval \\hich separates 

 n, n, Section of the great pectoral muscle above t he two diaphragms, these air-sacs 

 its insertion into the humerus; o, Anterior are in contact, by their anterior part, 

 clavicle; p, Posterior clavicle of the right side w jth ^hu anterior diaphragmatic re- 

 cut and turned outwards. From M. Sapiwy's servoirs, with which they torm a ver- 

 work. + tical and transverse septum. f~ 



times this sejttum is can ied u little 

 more forward, and then the anterior reservoir is smaller; this is most fretjucnt in 



GENERAL VIEW OF THE AIR RESERVOIRS OP THE 

 DUCK, OPENED INFERIORLY ; ALSO THKIK Kl l.A- 

 TION8 WITH THE PRINCIPAL VISCERA 



TRUNK. 



OF 



