342 MR. r. E. BEDDARD OX THE [Feb. 16, 



Visceral Branches of the Aorta. — Thei-e are a large number of 

 branches to the oesophagus and to the liver, which I do not 

 pai'ticulaiise. Between the posterior end of the liver and the 

 mesenteric artery there are in both specimens 6 branches of the 

 aorta, which I may term gastric arteries. Of these the last two 

 are the most imjoortant. As illusti'ative of the small range of 

 variation on the arterial system in individuals, I may mention 

 that the number of intercostal arteries arisiiig from the stretch 

 of aorta which bears the six gastric arteries was 13 in one 

 individual and 14 in the other. Immediately after the origin of 

 the superior mesenteric, which branches similarly in both speci- 

 mens, two intercostal portals arise from the parietes and join 

 the main portal trunk. In both specimens these vessels lie at 

 approximately the same distance from the oi'igin of the superior 

 mesenteric, and of the two the more posteiior is the larger. 



The next artery wliich arises is the single artery of the anterior 

 testis ; the posterior testis also has but a single artery. In both 

 cases the testicular artery is continued along the A'as deferens, 

 whei'e it receives a very slender branch from the aorta a little 

 way behind each testis. The vas deferens of tlae anterior testis at 

 any rate i-eceives a second slender branch fi-om the aorta, which 

 springs from that trunk some little way behind the point whence 

 is given off the anterior of the two arteries of the fat-body. 

 Moi-eover, this latter artery gives off a branch to the vas deferens 

 which joins the longitudinal artery running along that duct. A 

 similar branch arises from the second fat-body artery. The fat- 

 body is supjDlied by two special arteries ali-eady mentioned, and 

 anterioi'ly by a sti'ong branch of the superior mesenteric. They 

 form a longitudinal trunk running along the fat-body. 



There are two well-developed intestinal arteries aidsing pos- 

 teriorly, of which one, springing just in front of the joosterior 

 testicular artery and just below the second fat-body artery, may 

 be called the inferior mesenteric. 



Coluber catenifer. 



In this species the left aorta is the largei- of the two and con- 

 siderably the longei- ; it has therefore to f oUow a sinuous course 

 on its way to the junction with the right and smaller aorta. It 

 gives off' several slendei- branches to the oesophagus. The right 

 aorta gives off two intercostals before its junction with the left. 



The common aorta from its oi'igin up to the origin of the 

 superior mesenteric gives off" 17 intercostal arteries. They are 

 distributed as follows in relation to the princijaal alimentary 

 viscera : — In front of the liver there is 1 intercostal, 8 arise 

 along the course of the liver, and the remainder belong to the 

 stomachal region. Corresponding in some degree to these inter- 

 costal arteries are a seiies of accessory poi'tal veins which run 

 from the parietes to the liver directly and of parietal affluents of 

 the piincipal poi-tal tviiuk. As to the arteries, they penetrate the 



