25 1 



CRUSTACEA. 



fold covering the lateral parts of the posterior limb-rudiments. The 

 posterior end of the body, below the anal aperture which is now 

 becoming more distinct, is lengthened into two rounded f ureal 

 processes fringed with setae. Later ' Metanauplius stages show a 

 change in the third limb, which has entirely lost the form of 



! 



Pld. 117. -Three stages of development of Eitphausia (from Lang's Text-bool). A, Meta- 

 pltM (after Mktschnikoff). B, Calyptopis (after Claus). C, older Calyptopis (utter 

 Claus). 1 and "i, first and second antennae; 3, mandible ; It, 5, first and second maxillae ; 

 /, first pair of niaxillipedes ; ab, abdomen; (a^a^) first five abdominal segments; o 6 , 

 sixth pair of pleopoda ; an, anus ; fs, frontal sensory organ ; o, upper lip ; u, paragnatha ; 

 th, thoracic Mgraent*. 



a iwimming appendage and has developed into a masticatory blade 

 (mandible) with a greatly reduced palp. The shield-like fold has 

 now developed in the anterior region of the body, and thus 

 :<>unds the cephalic portion of the larva (rf. the later stages, 

 Fig. 117 B and C). In the posterior limbs, the first indication of 





