2i8 STALK-EYED CRUSTACEA 



26. Pseudothelphusa affinis. 



Superior margin of front keeled. Cervical suture 

 arching forward in anterior half. Exognath reduced to 

 a stump, less than one-third the length of the third 

 joint of the external maxillipedes. No tubercle on outer 

 surface of hand at base of fingers. 



Cuba. 



27. Pseudothelphusa maxillipes. 



Superior margin of front keeled. No tubercle on outer 

 surface of hand at base of fingers. External maxillipedes 

 much wider than the buccal cavity, nearly covering the 

 jugal area, with exognath at least one-third the length of 

 the third joint. 



Mexico. 



28. Pseudothelphusa convexa. 



Superior margin of front keeled. No tubercle on 

 outer surface of hand at base of fingers. External 

 maxillipedes only a little wider than the buccal cavity, 

 with the exognath reaching distal third of third joint. 

 Carapace very convex longitudinally. Lateral margins 

 of fourth to sixth segments of abdomen of the male not 

 arcuate. 



Costa Rica, 



29. Pseudothelphusa richmondi. 



Carapace flattened or slightly convex longitudinally ; 

 cervical suture straight or nearly so; lateral margin armed 

 with rather large separated teeth, Superior margin of 

 front keeled. No tubercle on outer surface of hand at 

 base of fingers. External maxillipedes only a little wider 



