From near the distal tip of the endopod (Fig. 6D, E) projects a tube-like 

 cannula, whilst the distal edge of the endopod itself gives rise to a 

 rounded lobe, the caudal process. This conformation of endopod tip is 

 unique to A. oommunis. It, and that for other North American species of 



Fig. 6. A. oommunis: A, first pleopod; B, second pleopod; C, dorsal 



surface of endopod of second pleopod; D,E, respectively dorsal and 



ventral surfaces of tip of endopod of second pleopod. (After Williams, 



1970). 



can.=cannula, c.p.=caudal process, v.g.=ventral groove. 



