74 LABORATORY WORK. 



beneath the head. Pick this apart with the needle. How 

 many pairs * of mouth-parts can you find? Counting all 

 the appendages of the head, how many segments should 

 there be in this region? 



Make a tabular statement as for the lobster or crayfish 

 (p. 70) and ascertain the number of somites. 



* The two of the hinder pair are united, but should be counted 

 as a pair. 



