Cumacea 



More than one pair of peraeopods in female 



with exopods 7. Fam. Paralampropidae 



Only the first pair of peraeopods in female 



with exopods 8. Fam. Platysympodidae 



Pleopods in male limited to two pairs — 10. 

 Pleopods in male fewer than two pairs — 18. 



, No separate telson 9. Fam. Leuconidae 



I 



Telson separate — 11. 



IUropods with three-jointed endopod — 12. 

 Uropods with fewer than three joints to the 

 endopod — 16. 



, Mandibles broad at the base 10. Fam. Diastyloididae 



12 



I 



Mandibles narrow at the base — 13. 



I Telson with only two apical spines 11. Fam. Diastylidae 



13 •! Telson with fewer or more than two apical 

 I spines — 14. 



j Telson small 12. Fam. Colurostylidae 



\ Telson large — 15. 



{Telson with no apical spines . . . 

 Telson with three apical spines . . 



f Uropods with two-jointed endopod 

 I Uropods with endopod simple — 17 



, Telson large with two apical spines 



\ Telson small with no apical spines 



I 



13. Fam. OxyurostyUdae 



14. Fam. Pseudodiastylidae 



15. Fam. Ekdiastylidae 



16. Fam. Holostylidae 



17. Fam. Pseudocumatidae 



18. Fam. Paraleuconidae 



Pleopods in male a single pair . 

 ^ Pleopods in male wanting — 10. 



f Mandibles broad at base 19. Fam. Hemileuconidae 



\ Mandibles not broad at base — 20. 



„^ f Telson separate — 21. 

 20 ' ^ 



I 



No separate telson — 23. 

 21 



I Apical spines of telson three or more .... 20. Fam. Lampropidae 

 \ Apical spines of telson fewer than three — 22. 



IUropods with three-jointed endopod .... 21. Fam. Dicidae 1^ 1 



Uropods with endopod two-jointed or simple, , 



telson medium 22. Fam. Gynodiastylidae 



(Only first two pairs of peraeopods in male 

 with exopods 23. Fam. Heteroleuconidae 



"^^ \ First four pairs of peraeopods in male with 

 ' exopods — ■ 24. 



f Mandibles with stout molar 24. Fam. Nannastacidae 



\ Mandibles with slender molar — 25. 



Second maxilla and first maxilliped normal. 



second maxilliped with apical joint peculiarly 



dentate 25. Fam. Procampylaspididae ' ' 



\ Second maxilla undivided, first maxilliped with 

 I reduced number of joints, second maxilli- 

 ' ped normal 26. Fam. Campylaspididae ^ ' 



