78 



PRAWNS. SEA-LICE. 



r y 



Fig. 65. PAL^EMON or PRAWN. 



the antennae are very long, and the beak or rostrum is serrated, 

 and very projecting. The flesh is very delicate and esteemed to 

 be superior to that of shrimps. 



15. Those crusta'ceans which compose the orders of AM'PHI- 

 roDA (from the Greek, amphis, on both sides, and pous, foot) and 

 ISO'PODA (from the Greek, isos, equal, and pous, foot), do not, 

 like the decapods, bear their eyes on movable peduncles, nor do 

 they possess a carapace ; their head is 

 distinct, and the thorax is divided into 

 seven rings. The Am'phipods breathe 

 by vesicular appendages fixed under 

 the thorax, near the base of the legs ; 

 and the Is'opods, by means of mem- 

 branous lamellae, which terminate the 

 appendages attached to the abdomen. 



16. Among the Am'phipods are the 



Fig. 66,-TALiTRA. sea-lice Talitra (jig. 66) small ani- 



mals which often remain on shore after 



the fall of the tide, where they may be seen jumping with great 

 activity. 



Explanation of Fig. 65. The Prawn or Paloemon : as, first pair of 

 antenna ; ai, second or inferior pair of antennae ; I, the lamellar append- 

 age covering its base; r, the rostrum ; y, the eyes; pm, external foot- 

 jaws; p, first thoracic leg; pp, second thoracic leg; fp, false natatory 

 legs of the abdomen ; n, caudal fin. 



15. How are the orders of Am'phipoda and Iso'poda characterized ? 



16. What are sea-lice ? 



