Several species of hemiurid trematodes belonging to two subfamilies, Dinurinae Looss, 1907, and Stomachicolinae Yamaguti, 1958, are represented in a collection of helminths of Formosan vertebrates. Erilepturus formosae sp. n. (from Alectis indica) and Lecithocladium bulbolabrum sp. n. (from Rastralliger kanagurta) are described and discussed. Stomachicola muraenesocis Yamaguti, 1934, is reported again from the type host, Muraenesox cinereus. Keys to the species of Erilepturus and Lecithocladium are included. The present paper is based upon a study of trematodes collected by the third author from marine fishes while a member of the Parasitology Department of Naval Medical Research Unit No. 2, Taipei, Taiwan. This paper is part of an extensive project concerned with a study of host-parasite and zoogeographic relationships of helminths of vertebrates taken on Taiwan (Formosa) and its offshore islands. Since Looss' (1907) extensive analysis of the family Hemiuridae Liihe, 1901, a large number of subgroups have been added to it. The high degree of diversity exhibited by these various groups has resulted in state of taxonomic confusion. Yamaguti (1958), for example, recognized no fewer than 19 subfamilies containing 58 genera. Many of these subfamilies are monogeneric, monotypic, or both, and may be unwarranted. Presently, however, the family seems distinct in two major respects: (1) the vitelline follicles are compacted into masses which may be unlobed, Received for publication 14 May 1965. * This study, Project Number MR.005.09.01031.02, Bureau of Medicine and Surgery, Navy Department, was supported in part by funding under Public Law 480, Section 104(c), and in part by Public Health Service Research Grant AI-05123, from the NIAID. The opinions and assertions contained herein are those of the authors and are not to be construed as official or reflecting the views of the Navy Department or the Naval Service at large. t From a dissertation submitted in partial fulfillment of the requirements for the Master of Arts degree. t Present address: Microbiology Department, Southwest Research Foundation, San Antonio, Texas. lobed to varying degrees, or tubular, and (2) the uterus joins the male duct proximal to the genital pore, forming an hermaphroditic duct. A cirrus and cirrus pouch are absent. Characters which are too variable to be useful as family criteria are: (1) cuticular plications, (2) ecsoma (tail appendage), (3) sinus sac, (4) degree of lobation of the vitellaria, and (5) the nature of the terminal genitalia. These characters, however, are used extensively by various authors in distinguishing subfamilies and genera. The subfamily Dinurinae Looss, 1907, is one of the larger taxa of the family, characterized primarily by a long, tubular, sometimes sinuous, pars prostatica. Other genera which do not fully fit within Looss' (1907) original diagnosis (i.e., plicated cuticle, oral sucker with a large, characteristic lip, and vitellaria consisting of long, filiform tubules) have been variously added to or removed from the subfamily. Three species of hosts examined in this study (Alectis indica, Rastralliger kanagurta, and Muraenesox cinereus) were each found to be infected with a different species of hemiurid parasite. Two of these helminth species belong to the genera Erilepturus and Lecithocladium (subfamily Dinurinae) and are described below as new. The third is reported as a previously described representative of Stomachicola (subfamily Stomachicolinae Yamaguti, 1958). Keys to the species of Erilepturus and Lecithocladium are presented. MATERIALS AND METHODS Standard techniques were used to remove the trematodes from the host. The parasites were killed by quick immersion in hot water and were then transferred to stender dishes with FAA for fixation.