330 



CHAPTEE XIV. 



B. SAUEOPSIDA. 



I. Eeptilks. 



The Sauropsida are the Eeptiles and Birds, — the Reptilia and 

 Avea. Although there seems much difference between a snake 

 and a fowl, yet we can even in such extremes find some points 

 of resemblance. Much greater is this affinity to be seen when 

 we examine extinct forms of life ; for amongst these ancient 

 remains of the past life of the globe are found many transi- 

 tional forms between the snake and the bird. These two groups 

 are united together because the resemblances between them are 

 greater and more fundamental than those between either of 

 these groups and the Mammals on the one hand and the 

 Amphibia on the other. Satiropsida, like Mammals, never 

 breathe by means of gills at any period of their life. They 

 always have, as we shall see in the Embryology of the Fowl, a 

 distinct amnion and allantois in the embryo — two foetal mem- 

 branes also found in the Mammalia ; the red blood-corpuscles 

 are also always nucleated. In the skeleton we see many 

 characters common to both Birds and Eeptiles, especially the 

 presence of the quadrate bone and the single occipital condyle in 

 the skull. 



EBrTiLiA (Snakes, Lizards;, Sfc.) 



The Snakes are of little or no importance to us, as they are 

 not in any Avay directly connected with agriculture. J^everthe- 



