232 



THE LIFE OF CRUSTACEA 



reproductive organs of the two sexes and a small 

 nerve ganglion representing the whole of the nervous 

 system. There is no mouth, no food-canal, and no 

 trace of appendages. Another Rhizocephalan, Pelto- 

 gaster, is not uncommonly found attached to the 



FIG. 75 FREE-SWIMMING STAGES OF Sacculina carcini. 

 ENLARGED. (After Delage ) 



A, Nauplius ; B, cypris stage. 



MUCH 



abdomen of Hermit Crabs. Although the nauplius 

 larva of Sacculina was described, and its resemblance 

 to that of the Cirripedia pointed out, as long ago as 

 1836, by that acute observer, J. Vaughan Thompson, 

 it is only recently that the full life-history has been 

 made known by the researches of Professor Delage 



