118 



AMPHIBIANS 



nerve to nose 

 Olfactory Lobe 



- Cerebrum 



nerve 



to 



eye 



Thalamencephalic^ 

 Medulla ■-•- 



y 



Optic Lobe 



Cerebellum 



"--Nerve to ear 



■ ..4th Ventricle 



. nerve to arm 



kidney (Figure 116). Each spermary is yellow in color. 

 The sperms escape through the kidney. In the female 

 frog ovaries, sometimes filled with eggs, are easily seen. 

 A long, closely coiled pair of oviducts (6'vi-dukts) opens 

 in front near the forward end of the stomach and in 

 the back into the cloaca. The eggs break through the 



wall of the ovary and 

 enter the oviducts. As 

 the eggs pass down 

 through the oviducts, 

 they are coated with a 

 jelly-like covering that 

 swells in the water. 

 This jelly covering pro- 

 tects the eggs. 



Nervous Syste?n. — The 

 nervous system of the 

 frog is more highly de- 

 veloped than that of the 

 earthworm. It consists 

 of a central part enclosed 

 in the backbone and cra- 

 nium (braincase). This 

 central nervous system 

 in all vertebrates is al- 

 ways found above the 



Figure 1 1 7. - Central Nervous System digestive tube, and is di- 



op Prop 



vided into the brain and 

 the spinal cord, from which numerous nerves arise and 

 extend to all parts of the body. 



The parts of the brain are the same as in man and 

 much easier to study. Beginning at the front (anterior) 

 end of the brain the parts are as follows (1) : small 

 olfactory (61-fak'to-ry) lobes, which are not sharply marked 



nerve 

 to leg 



