REPRODUCTIVE SYSTEM. 605 



the fcetal allantois, and has no functional connection with 

 excretion. The urine is semi-solid, and consists largely of 

 uric acid. 



Reproductive system. In the male the testes are two 

 white oval bodies suspended 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 connection with the cloaca there is a pair of eversible 

 copulatory organs, postero-lateral in position. 



In the female the ovaries occupy a similar position to 

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





FlG. 297. Lung of Chamceleo vulgaris, showing air-sacs. 

 After \Yiedersheirn. 



forward 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. 



The right reproductive organ tends to be larger and in front of the 

 left. In many of the males the Wolffian body is well developed. 

 Viviparous, or what is clumsily called ovo-viviparous, parturition is 

 well illustrated by Zootoca vivipara, Anguis fragilis, Seps, etc., but 

 most lay eggs with more or less calcareous shells. In Trachydosaitnis 

 and Cyclodus the embryo seems to absorb food from the wall of the 

 uterus. It is likely that Lacertilians existed in Permian ages, but their 

 remains are not numerous before the Tertiary strata. 



Many instructive illustrations of evolutionary change are afforded by 

 lizards. Thus there are numerous gradations in the reduction of the 

 limbs, from a decrease in the toes to entire absence of limbs. The 

 diverse forms of tongue and the varied positions of the teeth are also 

 connected by gradations. From the variations of the wall-lizard 



/ o 



(Lacerta muralis}, Eimer elaborated most of his theory of evolution. 



