SECT. XI 



DKYKLOPMKXT 



159 



it mav function both as directive and as visual or^an. 



^ o 



Indeed, there is no reason why we should not assume 

 this double function at least during larval life, so long 



c 



FIG. 37. Nauplius of A. cancriformis just hatched (Claus) from the side, showing 

 the unpaired " eye " in its passage from the ventral to the dorsal position. /, 

 large upper lip ; s, dorsal shield ; d, dorsal parapodium of the second antennae ; 

 c, sensory cirrus of the same. 



as the paired eyes are not developed, and the animal 

 is transparent. On the other hand, if it is a directive 

 body its disappearance in the higher Crustacea is 

 quite intelligible, especially in the Decapoda, which 



