Helminth Fauna of the Dry Tortugas. 21 



Ovary in front of testes, vitellaria diffuse, more or less spinose. 



19. Neck not slender, esophagus very short Stephanochasmus casus 



Neck slender, esophagus about as long as pharynx . . .Stephanochasmus sentus 



20. Two testes 21 



One testis Hapladena varia 



2 1 . Body short oval, esophagus short or none, testes diagonal . Lcpocreadium trulla 

 Body linear oval, esophagus distinct, testes nearly tandem 



Lcpocreadium levenseni 



Ovary in front of testes, vitelline glands diffuse, body smooth (except in Pachy psoitis) . 



22. Testes two 25 



One testis 23 



23. Ventral sucker larger than oral, ova large 24 



Suckers about equal, ova moderate Deradena ovalis 



24. Ventral sucker nearly twice diameter of oral Deradena acuta 



Ventral sucker about 1.25 times oral Deradena obtusa 



25. Folds of uterus extend back of one or both testes 39 



Folds of uterus not back of testes, at least not behind both 26 



26. Head without appendages 29 



Head with appendages 27 



27. Intestinal rami not united at posterior end 28 



Intestinal rami united at posterior end Enenterum aurcum 



28. Head with short nodular papillae and ventral flap 



Immature distome related to Calycodes 

 Head and neck with tentacular lobes Theledera pectinata 



29. Seminal vesicle near anterior border of acetabulum 30 



Seminal vesicle behind acetabulum Lcchradena edentula 



30. Ova not filamented 33 



Ova filamented 31 



31. Vitelline glands extend into neck 32 



Vitelline glands behind acetabulum Helicometra torta 



32. Testes irregular Helicometra execta 



Testes usually 5 right and 4 left Helicometrina nimia 



23- Vitellaria extend into neck 3 5 



Vitellaria do not extend into neck 34 



34. Ventral sucker larger than oral Hamacreadium oscitans 



Ventral sucker smaller than oral Mcgasolena cstrix 



3 5 . Esophagus short 37 



Esophagus long 36 



36. Genital aperture median Hamacreadium consuetum 



Genital aperture not median Hamacreadium mutabile 



37. Testes diagonal, or nearly so 38 



Testes opposite, or nearly so, body broad Didymorchis latus 



38. Genital aperture median Hamacreadium gulella 



Genital aperture not median Lebouria crassigula 



39. Folds of uterus extend back of both testes 40 



Folds of uterus mainly between the separated testes, but not behind the 



posterior testis Orchidasma amphiorchis 



40. Intestinal rami without lateral projections 41 



Intestinal rami with lateral projections Pachy psoitis ovalis 



41. Intestinal rami long Mesolccitha linearis 



Intestinal rami short Cymatocarpus undulatus 



Ovary in front of testes, vitelline glands compact. 



42. Testes tandem 4 ^ 



Testes opposite 44 



43. Ovary in front of testes Diplangus paxillus 



Ovary beside testis Dichadcna acuta 



44. Genital aperture lateral Deretrema fusillus 



Genital aperture median, body subcircular in outline, neck linear 



Xystretrum papillosum 



