in the Decapod Crustacea. 



331 



appearance which we here reproduce (fig. III.). The whole 

 organ, without quite attaining the width which it presents in 

 the female sex, is nevertheless much wider than in the normal 



Fig. I. 



Fiff. II. 



3+4+5 



Fig, III. 



Fig. IV. 



Fig. V. 



Fiix. VI. 



Fig. VII. 



Figs. l.-III. Abdomen of Carcinns mrpnas. — I. Female. II. ]Male (nor- 

 m<il). III. Maleinfestedby 'S'«<"c«/(«a. IV. Male infested by ^/«^io??e. 



Figs. V.-VII. Abdomen of Portumis huhutus. — V. Male (normal). VI. 

 Female. \^II. Male infested by SaccuUna. 



males. The segments 3, 4, and 5 are still generally soldered 

 together or very slightly movable, but their outlines are well 

 marked and they seem to be quite distinct ; segment 3 doe? 



