VIII 



AKTHKOPODA 



209 



the Calyptopis in having two pairs of maxillipedes developed, and a 

 rudiment of the third, and in having small rudiments of appendages 

 even on the thin posterior thoracic segments ; also in having a 

 median rostral and two postero-lateral spines on the carapace, and 

 in having long-stalked compound eyes. 



FIG. 156. Zouea of Penaeus, ventral view. (After Clans. ) 



1 ' 3 , first, second, and third maxillipedes ; pi, rudiments of pleopods (i.e. abdominal appendages) ; 

 r, rostrum ; th, rudiments of hinder appendages of thorax ; ur, uropods (last abdominal appcnda^c'*). 



The Zoaea of the shrimps and prawns (i.e. Caridea) agrees with 

 the Zoaea larva of the Penaeidea in possessing these spines on the 

 carapace, but it differs from them and agrees with the Zoaea of the 

 higher Decapoda in two respects ; (1) in having the exopodite of the 

 second antenna converted into a flat unjointed scale (squame), as in 

 the adult Decapod, (2) in having the endopodite of this appendage 

 much shortened so that this limb is no longer locomotor in function. 



VOL. i ? 



