22 Papers from the Marine Biological Laboratory at Tortugas. 



Ovary behind testes. 



45. Appendiculate 53 



Not appendiculate 46 



46. Testes behind acetabulum 47 



Testes in front of acetabulum, spinose Mesorchis urna 



47. Seminal vesicle in front of or dorsal to acetabulum 49 



Seininal vesicle behind acetabulum 48 



48. Vitelline glands with numerous lobes Macradcna pcrjecta 



Vitelline glands not lobed Opisthadena dimidia 



49. Ovary in front of vitelline glands 50 



Ovary behind vitelline glands Dictysarca virens 



50. Body without papillse 51 



Body with coarse papillae in mid-ventral region Theletrum fustlforme 



51. Vitelline glands not deeply lobed 52 



Vitelline glands with long clavate lobes Brachadena pyriformis 



52. Vitelline glands slightly lobed, body oval .Leitrodcra decora 



Left vitelline gland deeply, right slightly lobed Hysterolecitha rosea 



53. Vitellaria tubular 56 



Vitellaria not tubular 54 



54. Body smooth 55 



Body serrate Hemiurus merus 



55. Vitellaria moderately lobed Sterrhnrtis monticellii 



Vitellaria with about 7 long-clavate, slender lobes Sterrhuriis fiisiformis 



56. Body serrate 57 



Body wrinkled, not serrate, greatly elongated posteriorly.. .Dimirus rubeus 



57. Two dorsal eminences on neck Ectenurus virgula 



No eminence evident Immature distome near Ectenurus 



58. MoNOSTOMiD^ 59 



59. Anterior end somewhat triangular, a prominent muscular ridge separat- 



ing it from the rest of the body 60 



Body boat-shape Barisommn erubescens 



60. Linear oblong, posterior end truncate with 2 small, postero-lateral pits; 



intestinal rami with side projections Cricocephalus delitcscens 



Linear, strap-shape ; intestinal rami simple Him,asomum candidulutn 



