PARASITIC COPEPODS — WILSON 579 



e'. Smaller respiratory area more mesial ; ribs of suction cups 2-seg- 

 mented, distal segment longer than basal, acuminate; anterior 

 peg on fourth male basipod spherical, posterior process acute. 



maculosus* (p. 570) 

 e*. Smaller respiratory area entirely mesial ; ribs of suction cups 6-seg- 

 mented, basal segment longest ; anterior peg on fourth male basipod 

 conical, posterior process narrowly rounded. 



diversus'' (p. 572) 



e*. Smaller respiratory area entirely mesial ; ribs of suction cups 3- or 



4-segmented, basal segment narrowest; anterior peg on fourth 



male basipod lingerlike, posterior process with heel and ajcute 



toe versicolor 



<f . Only 2 postantennal spines on each side ; ribs of suction sups made up 

 of 5 to 8 rods diminishing in length distally ; anterior peg of fourth 

 male basipod conical; posterior processes on both basipod segments, 



without heels mississippiensis 



<r. No postantennal spines; lobes of basal maxillary plate close together, 

 laminate and truncate, the distal one widest, the central one nar- 

 rowest; ribs of suction cups made up of 11 beadlike segments, the 



2 distal ones imperfect rotundus* (p. 564) 



&. No spine at base of first antenna. 



d'. Basal maxillary plate lobed or with slender blunt teeth ; no spine on 



ventral surface of first antenna, or at base of first or second antennae. 



e\ Basal maxillary plate with 2 to 4 lobes, usually 3 ; postmaxillary spines 



absent; anterior knob present on first antennae; ribs of suction 



cups made up of 7 to 9 short rods catostomi 



f ^ Basal maxillary plate with 3 blunt teeth; anterior knob on first an- 

 tennae rudimentary ; tip of flagellum biramose ; ribs of suction cups 

 made up of 2 long rods ; posterior lobe of fourth male basipod very 



large appendiculosus 



i'. Basal maxillary plate with very sharp teeth ; no spine at base of first 

 antenna ; ribs of suction cups made up of rods, 

 e \ Ribs of suction cups with 8 or 9 rods ; lateral hook of first antenna 

 short, not reaching tip of flagellum; abdomen nearly half as wide 



as carapace lepidostei 



e^ Ribs of suction cups with 12 to IS short rods; abdomen two-fifths of 

 carapace width with lateral projections at anterior corners in male ; 

 protuberances at distal end of first endopod segment of third and 



fourth legs in male nobilis 



&. Ribs of suction cups made up of a long basal and 5 or 6 short distal 

 rods ; first 3 thoracic segments with narrow dorsal pads on their 

 posterior margins ; abdomen one-fifth as wide as carapace ; no pro- 



tubei-ances on legs of male intectus* (p. 553) 



d*. Basal maxillary plate with short truncate lobes ; a knob on anterior mar- 

 gin and a spine on ventral surface of first antennae ; ribs of suction 

 cups with 12 to 13 segments, tapered but not imbricated. 



paulensis* (p. 572) 



'^ New name for maculosus Meehean, preoccupied. 



