VEINS OF BEPTILES. 503 



kidney of its own side. It inclines to the outer border of the 

 gland, and divides into two branches, which ramify in the renal 

 tissue. The vein of the sjenital glands and conduits, and a vein 

 from the lumbo-dorsal segments, also enter and ramify in the 

 kidneys. The blood of this ' reni-portal ' system is collected into 

 a sinus at the inner border of each gland, and is conveyed 

 by the vein, k, into the postcaval trunk, v. The iimbilical vein 

 ascends along the ventral aspect of the abdomen, attached to the 

 mid-line of the muscular walls of the cavity : as it approaches 

 the liver it sends branches which penetrate directly the hepatic 

 tissue, and a branch which receives the veins of the intestines, 

 sj)leen, and stomach ; but, before completing the portal system, L, 

 it sends a small vein directly to the postcaval, near the auricle. 

 The hepatic vein, I, joins the postcaval trunk, v. The blood 

 from the head and fore-limbs is collected into a right and left 

 jugular and axillary trunk, which unite to form a precaval vein, 

 o, on each side. The postcaval vein, in the Perennibranchs, after 

 receiving the renal veins, is suspended by a duplicature of peri- 

 toneum to the back of the abdomen, the fold being continued 

 from the vein to the mesentery : it enters a groove or canal in the 

 liver, and receives the hepatic veins and the left precaval, before 

 terminating in the auricular sinus. There are a few valves in 

 the venous trunks of Batrachia ; but their chief characteristic is 

 the presence of ' striped fibre ' in the muscular coat.' This is 

 associated with the faculty of rhytlnuical pulsation in the post- 

 caval, axillary, and iliac trunks, independently of the pulsations 

 of the heart. ^ The abdominal venous trunks traverse wide lymph- 

 reservoirs ; and their exterior is here and there roughened by 

 little vascular loops, floating in the lymph, but communicating 

 exclusively with the mother-vein.^ 



In Oplddia the cutaneous veins of the trunk and intercostal 

 veins communicate with a large abdominal vein which runs along 

 the under part of the abdominal walls, and answers to the umbi- 

 lical vein in Batrachia. The caudal vein bifurcates on entering 

 the abdomen, each division after receiving blood from the genital 

 ducts and contiguous intestine, attaches itself to the kidney, and 

 ramifies upon its several overlapping lolies : the efferent renal 

 veins unite to form a trunk, which, on emerging from the innci- 

 and fore-part of the kidney, joins its fellow to form the postcaval 

 vein. The veins of tlie intestinal canal, genital glands, and fatty 

 appendages, which have not contributed to the reni-portal system, 

 unite with those of the pancreas and spleen to form the hepato- 



