48 NATURE-STUDY LESSONS. 



web stretched not too tightly over the 

 V-shaped notch or hole. Examine with 

 a microscope using the objective of low 

 power. Arteries, veins and capillaries will 

 be plainly visible. With a higher power 

 the corpuscles can also be distinctly seen. 

 ((5) How can you distinguish veins from arteries? 



(f) What is the nature of the capillaries ? 



{d) Draw the arteries, capillaries and veins and a 



corpuscle. 

 (e) Are the corpuscles all of the same form and 



color? 

 {/) Why do the corpuscles seem so much paler 



than the blood when seen with the naked 



eye? 



(g) If you have a compound microscope compare 



as to size, shape and markings, the red 

 blood-cells (corpuscles) of a trog with those 

 in the blood obtained by pricking your 

 finger. 



I. Its Structure. 

 The Head. 

 (i) TAe Mouth. 



21. {a) Observe the form and size of the mouth. 



(3) With the fingers or a small, smooth stick 

 open it and note the shape of the upper 

 and lower jaws. 



(2) The Teeth. 



22. {a) Examine the teeth. Draw the fingers over 



them. 

 (V) Where are they situated ? 



