FEEDING, LOCOMOTION AND RESPIRATION 23 



pair of legs for holding on to its victim. A more active predatory 

 mode of life has been adopted by Leptodora and Bythotrephes; in 

 these genera the limbs have lost the filtering mechanism altogether 

 and have become modified for grasping. 



The Notostraca feed on larger particles than most other 

 Branchiopoda. Moderate sized particles are passed backwards by 

 the tips of the beating limbs, and as the food travels backwards it 

 is gradually brought nearer to the body, so that when it reaches the 

 hind limbs it is down between their bases. The hind limb bases 



COMPOUND 

 £YE 



3RD TRUNK 



Fig. 18. Head of a male Artemia salina (Anostraca). The large 

 antennae are used to clasp the females. Note the forwardly 

 directed spines on the maxillae, and the way in which the labrum 

 overlaps the mandibles. Notice also the way in which the filter 

 setae form walls to the median space between the two rows of 

 limbs. 



break up the food to some extent — a feature reminiscent of the 

 Conchostraca, and it is then passed forwards by the spiny inward 

 projecting bases of the limbs. Each inward projection passes the 

 food to the limb in front, and so ultimately to the mouth. There 

 are no water currents of the type found in the Anostraca, and true 

 filtratory setae are absent. Large food masses are sometimes held 

 against the mouthparts by the front limbs and bitten into by the 

 spiny bases of these limbs and the first maxillae. In spite of the 



