CRUSTACEA. 



399 



flagellum appears inveryyoung Zoaeeeon the innerside of the antennules 

 (fig. 223 At. /.). The posterior antenna? are without the flagellum, 



FIG. 223. THE APPENDAGES OF A CRAB ZOMA. 



At. I. first antenna; At. II. second antenna; mil. mandible (without a palp); mx. 1. 

 first maxilla ; mx. 2. second maxilla; mx. 3. third maxilla ; mxp. 1. first maxilliped; 

 mxp. 2. second maxilliped. 



ex. exopodite; en. endopodite. 



but are provided with a scale representing the exopodite (fig. 223 

 At. II. ex) and usually a spmous process. The flagellum is very early 

 developed and is represented in fig. 223, At. II. en. The mandibles (md) 

 are large but without a palp. The anterior maxillae (mx 1) have a 

 short two-jointed endopodite (palp) with a few hairs, and a basal 



FIG. 224. CRAB ZO^A AFTER THE THIRD PAIR OF MAXILLIPEDS AND THE THORACIC 

 AND ABDOMINAL APPENDAGES HAVE BECOME DEVELOPED. 



at 1 , antenna of first pair; at 2 , antenna of second pair; mx 1 . first maxilla; mx". 

 second maxilla; nay 1 , first maxilliped; m.rp*. second maxilliped ; inxp 3 . third max- 

 illiped ; nc. eye ; ht . heart. 



