264 



CRUSTACEA. 



the Protozoaea stage of this genus. More recently, many larval forms belonging 

 to this series have been described from the Challenger material (Si'ENCE BATE, 

 No. 100). 



The youngest Protozoaea of Sergestcs is only known from a drawing by 

 WiLLEMOES-SuHM (No. 100, p. 354). It possesses the seven anterior pairs of 

 limbs, but the third pair of maxillipedes has not yet developed. Only the first 



B 



Fio. 121. Two larval stages of Sergestes (after CLAUS). A, Protozoaea stage. B, Acantfiosoma 

 stage, seen from the dorsal side, a', first antenna ; a", second antenna ; mf, first maxillipede ; 

 mj", second maxillipede; mf", third maxillipede ; mx', first maxilla ; mx", second maxilla ; 

 ol, upper lip ; sd, shell-gland. 



rudiments of the paired eyes can be made out. Within the alimentary canal a 

 large amount of yolk remains, and this no doubt allows the larva to leave the 

 egg at this stage. In all other respects the larva drawn by WILLEMOES-SUHM 

 agrees with the youngest stage described by GLAUS (Fig. 121 A}. 



This latter (Fig. 121 A) can be compared in all its essentials with the later 



