Plate 27. Fourth-Stage Lobster. 



Figure 38, Right second antenna from below, M=18. See description of 

 figure 37. The eiidopodite is represented cut off. 



Figure 39. Right mandible seen from the inside and above, M^65. The 

 palpus has further developed since the third stage, and the toothed part of the 

 mandible has become hard through the absorption of lime salts from the water. 

 The same is true of other parts of the exoskeleton. 



