COMPARISONS. 



With two columns, one for Grasshopper, the other for 

 Crayfish (and Sow-bug), answer the following questions: 



(1) Is the body made up of a series of segments? 



(2) Do any of the segments have jointed appendages? 



(3) Do you find more than one pair of appendages on 

 one segment? 



(4) Are the hard parts (skeleton) external or internal? 



(5) Do the jaws work in a longitudinal or in a transverse 

 plane? 



(6) Can the jaws be compared to the other appendages 

 of the body? 



(7) Is the heart above or below the alimentary canal? 



(8) Is the brain above or below the oesophagus? 



(9) Where is the largest part of the nervous system? 



(10) How are the two parts of the nervous system con- 

 nected? 



(11) Is there any relationship between nerve-enlarge- 

 ments (ganglia) and the external segments of the body? 



Read the whole section (pp. 215 to 272) upon the Arthro- 

 poda. 



If there be sufficient time the following insects may be studied. 

 This will be valuable to the student who is especially interested 

 in entomology. 



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