264 



CRUSTACEA. 



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

 to this series have been described from the Challenger material (Spence Bate, 

 No. 100). 



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

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

 limbs, but the third jiair of niaxillipedes has not yet developed. Oidy the first 



Fjo. 121.— Two larval stagps of ^erjrfste (after Claus). A, Protozoaea stage. B, Jcaiiihosoma 

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

 mj", second niaxillipede ; mf", tliird niaxillipede ; mz', tirst maxilla ; m.v", 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 Clai's (Fig. 121 A). 



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



