CLASS AMPHIBIA 487 



branch, the occipital (oc), supplying the jaws and nose, the 

 other, the vertebral (v), supplying the vertebral column, and a 

 subclavian artery (br), which is distributed to the shoulder, 

 body-wall, and arm. The dorsal aorta (d.ao) gives off the cceli- 

 aco-mesenteric artery (cce); this divides, forming the cceliac 

 (cos'), which supplies the stomach, pancreas, and liver, and the 

 anterior mesenteric (m), which is distributed to the intestine, 

 spleen, and cloaca. Posterior to the origin of the cceliaco- 

 mesenteric, the dorsal aorta gives off four to six urinogenital 

 arteries (re) which supply the kidneys (&), reproductive organs 

 (ts), and fat bodies. A small posterior mesenteric artery (m.i) 

 arises near the posterior end of the dorsal aorta and passes to 

 the rectum, and in the female to the uter.us. The dorsal aorta 

 finally divides into two common iliac arteries (c.il), which are 

 distributed to the ventral body- wall, the rectum, bladder, the 

 anterior part of the thigh (femoral artery, fm) , and other parts 

 of the hind limbs (sciatic artery, sc). 



The veins (Fig. 415) return blood to the heart. The blood 

 from the lungs is collected in the pulmonary veins (pul) and 

 poured into the left auricle (/. au) . The rest of the venous blood 

 is carried to the sinus venosus (s.v) by three large trunks, the 

 two anterior venae cavae (pr. cv) and the posterior vena cava. 

 The anterior venae cavae receive blood from the external jugulars 

 (ext. ju) which collect blood from the tongue, thyroid, and 

 neighboring parts, the innominates which collect blood from 

 the head by means of the internal jugulars (int. ju) and from 

 the shoulder by means of the subscapulars, and the subclavians 

 which collect blood from the fore limbs by means of the 

 brachial (br) and from the side of the body and head by means 

 of the musculocutaneous veins (ms. cu). The J^oste^or^vejn.a 

 cava receives blood from the liver (Ivr) by means of two hepatic 

 veins (hp), from the kidneys (kd) by means of four to six pairs 

 of renal veins (rri), and from the reproductive organs (ts) TSy 

 means of spermatic or ovarian veins. 



The veins which carry blood to the kidneys constitute the 



