68 
8. No conical spicules behind, cloacal aperture; caudal lobes cylindrical; male. 
Gordins plaiycephcdus Montgomery 
Conical spicules behind cloacal aperature 9 
9. Caudal lobes short, thick, nearly conical; male. 
Gordius densareolatus Montgomery 
Caudal lobes nearly cylindrical; male Gordius longareolatus Montgomery 
Chordodes male. 
10. Cuticular areoles longer than high; on or between them are small circular 
pits; male Chordodes occidentalis Montgomery 
Cuticular areolae higher than long 11 
11. Spines on summits of the highest arioles (papillae); male. 
Chordodes puerilis Montgomery 
No spines on summits of the highest papillae; male. 
Chordodes morgani Montgomery 
Chordodes and Gordius females. 
12. Caudal end not noticeably enlarged Gordius (females), 13 
Caudal end swollen, somewhat knob-shaped, slightly constricted off. 
C/?ordod^s (females), 19 
Gordius females. 
13. Elevated cuticular areoles on entire surface of body 14 
IVithout elevated cuticular areolae on entire surface 17 
14. With paired dark stripes in median lines; females Gordius leidyi 'Slonigomery 
No dark stripes in median lines 15 
15. Areoles elongated in long axis, and well separated from one another; female. 
Gordius longareolatus Montgomery 
Areoles not elongated in long axis of body 16 
16. Areoles closely apposed, tending to produce longitudinal ridges; female. 
Gordius lineatus Leidy 
Areoles more or less confluent, tending to produce transverse rows; head usually 
cylindrical; female : Gordius densareolatus Montgomery 
Areoles usually separated, interareolar groups of fine hairs, head usually flat- 
tened; female Gordius j^ledycephcdus Montgomery 
17. Cuticular areoles only at ends of body; female. 
Gordius aquaticus difficiUs Montgomery 
Cuticular areoles entirely absent 18 
18. Cuticle marked with white spots; female Gordius aquaticus lArm^eus 
Cuticle without white spots; female , . Gordius aquaticus rohustus Leidy 
Chordodes females. 
19. Cuticular areoles longer than high; on or between them circular pits; female. 
Chordodes occidentalis Montgomery 
Cuticular areoles higher than long; female 20 
20. Spines on summits of highest areoles; female Chordodes q)uerilis'SlontgomQvy 
No spines on summits of highest areoles; female. 
Chordodes morgani Monticelli 
