180 ANIMAL ACTIVITIES. 
In a specimen which has been hardened in alcohol 
do you find vertebre ? Do you finda notochord? Do 
you find muscles like those in the fish? Notice the 
spirally coiled intestine. 
Hold the tail of a living tadpole under a compound 
microscope and observe the movement of the blood. 
Notice the corpuscles. 
Summary of Drawings. (a) Side view of tadpole. 
(4) Dorsal view of a young tadpole to show gills. 
(c) Sketch to show blood-vessels as seen under the 
microscope. 
The Frog Alive. How does the frog resemble the 
fish ? the tadpole? 
Do you find scales, hair, claws, or nails? 
Do you find tail or fins? How about legs? 
What is the frog’s mode of locomotion on land? in 
water ? 
How many divisions have the hind limbs? the fore 
limbs ? How do they compare with the limbs of the 
human body? Do the joints move in the same way as 
ours? Do you find arm, forearm, and wrist ? 
How many fingers? How many toes? Are fingers 
or toes webbed? Do you find a thumb ? 
How does the frog take its food? How does the 
tongue act? 
What movements are made in breathing? Are 
there any gills? How long can a frog live under 
water? 
Does the frog have the same senses and the same 
organs of sense as man ? 
Do you find ears? eyelids? Do you finda mem- 
brane covering the eye (nictitating membrane) ? 
Frog Hardened in Alcohol. Look in the mouth. 
Do you find any teeth? How many? Where are 
they ? 
What is the shape of the tongue? 
Do the nostrils connect with the mouth ? 
Does the ear-cavity connect with the mouth? 
