Plate 9. Second-Stage Lobster. 



Figure 11. Right first antenna from inside and above, M=:48. In the sec- 

 ond-ptage lobsters the inner rami of the first pair of antennae have grown out from 

 the buds existing in the previous stage to half the lengths of the exopodites. The 

 latter have developed along the inner margin a line of olfactory setae. Slight 

 trace of segmentation is sometimes visible in both branches in this stage. The 

 position of the auditory sack is suggested in the basal joint. 



Figure 12. Right second antenna from above, M=:40. By this second 

 stage the endopodites of the second pair of antennae have grown out to more than 

 equal in length the broad, leaf-like exopodites and traces of segmentation are more 

 frequently visible. 



Figure 13. Right mandible from inside, M^80. The endopodite or palpus 

 is shown arising from the body of the mandible or propodite. The present 

 mandible was taken from a lobster which was about to moult, and the body of 

 the mandible is shown as it begins to draw away from the purely chitinous 

 covering. 



