576 REPTILES. 



part in the respiratory movements. In some lizards 

 (Chamseleon and Geckos) the lungs are prolonged in air- 

 sacs, suggesting those of Birds (Fig. 198). 



Excretory System. 



The paired kidneys lie in the extreme posterior region 

 of the abdominal cavity, and extend a little further back 

 than the level of the cloaca. Each is furnished with a very 

 short ureter. In the male the ureters unite with the vasa 

 deferentia; in the female they open separately into the 

 cloaca. Into the cloaca opens also a large thin-walled 

 " urinary bladder " ; this is a remnant of the fcetal allantois, 

 and has no functional connection with excretion. The 

 urine is semi-solid, and consists largely of uric acid. 





FIG. 198. Lung of Chamceleo vulgaris, showing 

 air sacs. (After WIEDERSHEIM.) 



Reproductive System. 



In the male the testes are two white oval bodies sus- 

 pended in a dorsal fold of mesentery. Along the inner 

 surface of each runs the epididymis, which receives the vasa 

 efferentia, and is continuous posteriorly with the vas 

 deferens. The two vasa deferentia, after receiving the 

 ureters, open by small papillae into the cloaca. In con- 

 nection with the cloaca there is a pair of eversible copulatory 

 organs. 



In the female the ovaries occupy a similar position to 

 that of the testes in the male. The oviducts open far for- 

 ward by wide ciliated funnels ; as they pass backward they 

 show a gradual increase in cross section, but there is no 

 line of demarcation between an oviducal and a uterine 

 portion. Posteriorly, the oviducts open into the cloaca. 



