SHRIMPS, CRABS, AND BARNACLES 105 



by the opening of the intestine. You will see if you 

 compare the crab and the lobster (or the prawn, which 

 is very much like the lobster), that the crab has the 

 so-called head (really head and mid-body combined) 

 drawn out from side to side, so as to make it much 

 wider than it is long. And, moreover, the jointed tail or 



Fig. 9. — The larval or young form of Crustacea known 

 as "the Nauplius." This is the " Nauplius " of 

 a kind of Prawn. The three pairs of branched 

 limbs are well seen. Much magnified. 



hind-body seems at first sight to be absent in the crab. 

 But if you turn the crab (a dead one) on his back, you 

 will find that he has a complete tail, on the whole like 

 that of the lobster, but pointed and bent forwards, and 

 closely packed under the fused head and mid-body in a 

 groove, from which you can raise it and turn it back. 



We have not yet done with the various forms 



