TYPES OF CONSTRUCTION. 83 



upper side of alimentary canal, the other spinal ; limbs 

 opposite nerves. Fishes, Amphibians, Reptiles, Birds, 

 Mammals, Man. 



II. In the Frontispiece the characteristic features of 

 biological types are represented. In the outline section 

 of each of the four types of higher animals the large 

 shaded spot shows the alimentary canal, the dark spot 

 the position of the heart, and the open rings the nervous 

 system. A diagram of the latter also accompanies each 

 of those types. 



