Fig. 11. A. ocoidentalis . Variation in morphology of tip of 

 endopod of second pleopod. A-E, ventral views; F-H, dorsal 

 views. From Williams (1970). 



3(2) Pleopod 2 with neither mesial nor caudal processes developed, 

 only cannula projects distally from endopod tip (Figs 12D, 

 E, 13A-F) ; dorsal surface of distal end of endopod with 

 numerous minute comb-like structures (Fig. 12D) ; endopod 

 shape and proportion of segments as in Fig. 12C. Both rami 

 of uropod always flat, lanceolate and broad (Fig. 12F, G) : 



A . latiaaudatus 

 Caudal process of pleopod 2 always more or less developed, mesial 

 process either developed or not, cannula never only process 

 to project distally from endopod tip; dorsal surface of dis- 

 tal end of endopod usually lacking minute comb- like struc- 

 ture (if present, these extend on to caudal process); endo- 

 pod shape and proportions of segments more or less dissimilar 

 to drawings of Fig. 12C. Rami of uropod either flat, lance- 

 olate and broad or linear and narrow 4 



4(3) Mesial process of pleopod 2 scarcely or not present 5 



Mesial process of pleopod 2 present and well-developed 6 



5(4) Inner and outer basal apophyses of endopod of pleopod 2 distinct 

 (Fig. 6B, C) ; caudal process usually broadly rounded, cannula 

 long and narrow (Figs 6D, E, 14A-M) ; shape of endopod and 

 proportions of segments as in Fig. 68: A. communis 



Inner basal angle of endopod of pleopod 2 obtuse, sharply angled, 

 or produced into small, acutely pointed apophysis, outer basal 

 apophysis not distinct (Fig. 15C) ; caudal process often with 

 acutely pointed apex, cannula short and wide (Figs 15D, 16A- 

 H) ; shape of endopod and proportions of segments as in Fig. 

 15C: A. intermedius 



6(4) Cannula of pleopod 2 long and narrow or triangular 7 



Cannula of pleopod 2 relatively short and wide 9 



20 



