Till-: PO8TSS10B AOltr.i. 537 



: >r. Thf Hr.-t, destined for tin- .-.mall inte.-tiin-, creeps above it, between the two 

 of the nierv-ntery, !>ii(l passes liai-kw itnl liy d'-cribing a curve which gives oil' t'r .m 

 its convexity that if, Mow, a irn.it number of hr.mcli.r-. analogous in their mode of 

 termination to th" ai t.-ries l the .-mall intestine in the Horse. The posterior l>raiu-h goes 

 to tli.- lar-e intestine. where it separates into two principal branches : cue \\hieli passes 

 t.i th'- eolon, and whose divisions cross to the right, from before to behind and from above 

 to below, the convolution! described by that viacus ; another which reaches thftea 

 ;ir\ ,.r;i>- of the cajcum, and anastomoses by an urch with the terminal extremity of the 

 parent-brunch .if the arteries supplying the small intestine. 



HI>*< tit' ri<- art'-ri/. Very short und narrow. 



//' ,-ii/, >/ riiHittc, and small testicitlar arteries. These do not differ in their essential 

 disposition from the analogous vessels in Solipe.ls. 



2. Posterior Aorta in the 1'lij. 





the exception of the mesniteric ve.^l-., who.*' distribution resembles that 

 already in-Heated fur Kuminunts. und with the exception, also, .if the middle sacral artery, 

 which will he alluded to when describing the internal iliac arteries, all the branches 

 given off by the posterior aorta comport themselves almost as in the Horse. 



3. Posterior Aorta in Carnirr>i. 



lu these animals, as well as in the Pig, the denomination of posterior aorta is not 

 justifiable, because the arteries of the head and thoracic limbs spring directly from the 



:irch. 

 The branches of the aorta are distinguished as parietal and visceral. 



A. PARIETAL BRANCHES. Beyond the fourth space, the intercostal arteries are fur- 

 ni.-hed by the aorta; the first is voluminous, and throws off gome considerable filaments 

 to the muscles of the withers. The first two lumbar arteries arise from the thoracie 

 portion of the aorta, because of the very backward insertion of the diaphragm ; the third 

 is detached between the two pillars of that partition. In the abdominal cavity, close to 

 the great mesenteric, the aorta gives off a branch that soon divides into two : one is 

 ilin^hrngmatic, and descends on the posterior face of that muscle ; the other reaches the 

 Hihlumh.ir region, passes over the psoas muscle, and traverses the abdominal wall in the 

 vicinity of the tiansverse processes of the lumbar vertebrae. We will t-peuk presently of 



- icral. 



B. VISCERAL BRANCHES. I have not found in the Dog any special bronchial arteries ; 

 but there are four or five cesophageal art' ,-,'< * that arise from different points of the 

 thoracic aorta; they descend into the mediastinum, to the right and left of the 



. to which they are distributed. They furnish branches that accompany the 

 bronchi and enter the lungs. 



The ctcliuc trunk is again divided into three branches, whose disposition is as follows : 

 The gastric, or stomachic coronary artery, does not divide into two branch* s (anterior and 

 as in Solijx-ds. Near its origin it furnishes a pancr. atic branch ; then 

 it exp.-nd.- its- It' in a great number of filaments that arc spread over the posterior face 

 aud great tulx-rosity of the stomach, or over its anterior face after crossing the small 

 curvature. 



The >/,!> nit- artery reaches the spleen ft the middle of its upper border. It gives on 



ijrse: 1, A splenic branch that enters the up|M r extremity of that organ; 2, The 



ni ntal. The hi/Kittc nrtrrij provides the principal hepatic vessel at the 



ii<>r tissure of the liver; it is then continued by the right gastro-omental artery. 



duodenum, the latter gives origin fc> the pjrlork MM the pancreatico-duodenal 



i .- : tlf latter is voluminous, is lodged in the substance of the pancreas, and 



mo--- liy its laat filaments with th. gr at mescnteric. 



The iir-nt in- f at- 1-;<- artery arises in the vicinity of the cooliac artery; it forms a cm ve 



whose convexity is backward, and ana.-tomoees by its extremity with tin- pancrcatico- 



diiodeii.il branch of the hepatic. From its convexity are d ta.-h.d .- v. ml n'lam.-nts 



(tilam--:iN to the Miiall inlestine). that form arches towards tin- smaller curvature of that 



. Behind, and ut a short distance from its origin, it given a branch to the caecum 



.ranches to the colon ; the hitter are sometimes large. 



,;// in- /./// commences near the termination of the aorta, and divide* into 

 two branches: one passing forward, and the other backward; they form the Iwmoirhoidul 

 vessels (aoe Fig. 209). 



id to not. with regnnl t !!.- r. uul and spermatic arteries. 



