58 



MANUAL OF ELEMENTARY ZOOLOGY 



s. v 



high pressure in the carotid arch. Beyond the carotid 

 gland the artery runs forwards and upwards towards the 



head, where it di- 

 vides into an inter- 

 nal carotid, which 

 passes into the 

 skull and supplies 

 the brain, and an 

 external carotid, 

 which supplies the 

 orbit and roof of 

 the mouth. The 

 systemic arch 

 curvesupwardsand 

 backwards round 

 the oesophagus to 

 j oin its fellow i n the 

 middle line below 

 the backbone. On 

 its way it gives off 

 an oesophageal ar- 

 tery to the oesopha- 

 gus, an occipito- 

 •vertebral artery to 

 the head and back- 

 bone, and a large 

 subclavian artery 

 to the arm. Just 

 before joining its 

 fellow, the left sys- 



-A diagram 01 the venous system . ' , . ' 

 of the frog. temic arch g!Ves 

 a.ai., Anterior abdominal vein ; ir., brachial ; c.v., °" backwards the 

 cardiac (from wall of heart to anterior abdominal) ; large CCelidCO'ltlesen- 

 cut., cutaneous; d.L, dorsolumbar ; e.j., external , . . T^u" 

 jugular; /., femoral; h.p., hepatic portal; hep., *enc artery, 1 nlS 

 hepatic ; i.j., internal-jugular ; i.v.c, inferior vena divides into an 

 cava; inn., innominate; /., lingual; md., mandi- 

 bular;/!/., pelvic; >«/., pulmonary; r., renais; anterior mesenteric, 



r.p., renal portal ; sc, sciatic ; s.scp., subscapular ; *.-. hnwpl anrfl 



s.v., sinus venosus (seen through ventricle); s.v.c, u UUWcl and 



superior vena cava ; rc/., subclavian ; spm., right Spleen, and a 

 spermatic ; x., vessel joining sciatic to femoral. 7 - , . . 



cceliac, which sup- 

 plies the stomach after giving a hepatic branch to the liver. 

 The vessel formed by the junction of the systemic arches 



