NEW GENUS AND NEW SPECIES OF TREMATODEWORMS OF THE FAMILY PLAGIORCHIIDAEBy John T. LuckerJunior Zoologist, Zoological Division, Bureau of Animal IndustryUnited States Department of Agriculture In 1927, while a student at the University of Washington, thewriter collected about 10 flukes from the intestines of frogs {Ranaprethsa) . Owing to the lack of adequate library facilities, a de-scription of these parasites, which are regarded as representing anew genus and new species of the family Plagiorchiidae, could notbe completed until the writer came to Washington, D. C. A surveyof the literature has now made it possible to complete the study ofthese trematodes and to determine their systematic position. Thewriter takes pleasure in acknowledging his indebtedness to his asso-ciates in the Zoological Division of the Bureau of Animal Industryfor helpful suggestions. The host determination was made by mem-bers of the staff of the Department of Zoology in the Universityof Washington. HAPLOMETRANA, new genusGeneric diagnosis.?Plagiorchiinae : Slender worms, flattened dor-soventrally, and bluntly rounded at both extremities. Esophaguslong and slender. Intestinal ceca long, extending from the bifurca-tion almost to the posterior extremity of the body. The moderatelylong, slender cirrus pouch extends posterior to the acetabulum andcurves about it anteriorly. A saclike seminal vesicle occupies ap-proximately the posterior half of the cirrus pouch, anterior to whichare the narrow prostate duct and the ejaculatory duct. The cirrusis protrusible.Ha'plometrana may be distinguished from other genera of thesubfamily Plagiorchiinae by the possession of a definite combinationof characters. The testes are tandem and in the median line. Theovary is approximately median in position, and a seminal receptacleis present. Neither the descending ramus nor the ascending ramusof the uterus passes between the testes. Both branches of the uterusare normally ventral to the testes, and the ascending ramus usuallyNo. 2885.?Proceedings U. S. National Museum, Vol. 79, Art. 19.59929?31 1 2 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 79passes under the A^entral surfaces of the ovary and seminal receptacle.The seminal receptacle is just posterior to the ovary and nearlymedian. The vitellaria are lateral, occur in unorganized chains offollicles, and extend from about the level of the acetabulum poster-iorly to a point about halfway between the posterior testis and theposterior end of the body.Tijye species.?Haplornetrana intestinalis, new species.HAPLOMETRANA INTESTINALIS, new speciesDescription.?Hap-loinetrana: Rather small, slender distomes, ofsomewhat variable length and width. Mature specimens are about5 mm. long and 0.48 mm. to 0.63 mm. in maximum width; thus, thelength is about eight to ten times the maximum widih. There isno constriction between the anterior and posterior portions of thebody (pi. 1, fig. 1). The cuticle is spinous, especially in theanterior region.The oral sucker is about 0.256 mm. to 0.32 mm. in diameter; itis larger than the acetabulum and subterminal in position. Theacetabulum is about 0.176 mm. to 0.24 mm. in diameter and is sit-uated in the anterior sixth of the body length. The suctorial diskof the acetabulum is continued dorsally as a cone-shaped mass ofmuscular tissue.The muscular pharynx is preceded by a short prepharynx. Theformer is 0.11 mm. to 0.14 mm. wide and 0.08 mm. to 0.10 mm. long,is nearly contiguous to the oral sucker, and is roughly one-half itssize. The esophagus is long and very slender. The intestinal cecaare lateral in position, extending posteriorly from the bifurcationto a point within a short distance from the posterior tip of thebody. In some specimens the ceca are of unequal length.Since it was impossible to study the specimens in the living state,the precise structure of the excretory system can not be described.One stained specimen shows paired saclike bladders extending an-teriorly beyond the intestinal bifurcation, similar to those describedby Looss for Haplometva cylrndrica. These branches of the Y reachnearly to the oral sucker. The excretory pore is terminal.The genital pore is anterior to the acetabulum and median, ornearly median, in position. The cirrus pouch is slender and curlsabout the suctorial disk of the acetabulum. (PL 1, fig. 2.) It is foundeither to the left or to the right of the disk. The testes are tandemand median; they occupy all, or nearly all, the intercecal space andin some specimens are partially superimposed upon the ceca laterally.Usually the testes are separated from each other by a distance some-what less than their diameter. The posterior margin of the pos-terior testis marks the approximate equator of the body. The diam-eter of the testes is about 0.32 mm. to 0.368 mm. In the specimens ABT. 19 NEW GENUS AND SPECIES OF TREMATODE?LUCKER din which the vas efferens may be traced anteriorly, the position ofthese ducts varies considerably. In one specimen the duct of theposterior testis passes anteriorly between the intestinal ceca andanterior testis on the left and turns transversely to the right justposterior to the transverse vitelline duct. On the right it joins thevas efferens from the anterior testis and from this point proceeds asthe vas deferens to the seminal vesicle. Shortly before the cirruspouch is reached a small sac or reservoir is formed. (PL 1, fig. 2.)The seminal vesicle is bulky and rather long, occupying the pos-terior half of the slender cirrus pouch. Anterior to it are the narrowprostate canal, the ejaculatory duct, and the protrusible cirrus. (PL1, fig. a.)The ovary is located immediately caudad to the posterior borderof the cirrus pouch, a short distance posterior to the acetabulum,and immediately anterior to the seminal receptacle. The diameterof the ovary is about 0.22 mm. to 0.24 mm.A rather large and definite seminal receptacle is present, anteriorto the anterior testis, from which it is separated by the transversevitelline duct, and immediately posterior to the ovar3\The uterus is extensive, filling the posterior half of the body. Itextends from the termination of the short oviduct posteriorly andventrally, under the ventral surfaces of the testes to the posterior tipof the body, and then returns anteriorly to the genital pore. Boththe descending and ascending portions are coiled transversely andare folded upon themselves. The coils of the uterus are slender,except perhaps posteriorly, where no definite form is discernible.It is to be noted that the uterus passes not between the testes butunder their ventral surfaces. The ascending ramus also passesventrall}' beneath the seminal receptacle, ovary, and cirrus i^ouch.The vitellaria are distinct follicles, disposed in lateral chains, andextend from near the posterior edge of the ovary to a point aboutone-fifth of the body length from the posterior tip of the body.There is no pattern or definite organization of the follicles. Thejuncture of the oviduct, the vitelline duct, and the duct of the sem-inal receptacle is variable in position, but usually these ducts unitein close proximity to the ovary and seminal receptacle. (PL 1, fig. -i.)Laurer's canal is present and communicates directly with the sem-inal receptacle. The yolk reservoir is variable in position but is lo-cated somewhere along the transverse vitelline duct and near themedian line.The fully formed eggs are brownish yellow and about 0.048 mm. to0.058 mm. long and 0.018 nmi. to 0.026 nun. wide. Those observedin the initial portion of the descending ramus are transparent andcolorless. 4 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 79Host.?Raim pretiosa.Location.?Intestine.Zoc?7?7.y.?United States (Bothell, Wash.)Type Ipedmen.?V.S.^M. Helm. Coll. No. 29903; paratypes,U.S'.N.M. Helm. Coll. No. 29904.SYSTEMATIC POSITION OF HAPLOMETKANA INTESTINALISThe family Plagiorchiidae Llihe, 1901, has been frequently sub-divided and revised by various parasitologists. The most recent re-vision, and one that is based upon extensive studies pertaining tomany of the genera concerned, is that of Travassos (1928). Hissix subfamilies represent a conciliation of his own studies and viewswith those of Baer (1924) and Poche (1926), and are as follows:Plagiorchiinae Pratt, 1902; Brachycoeliinae Looss, 1900; Saphae-drinae Baer, 1924; Reniferinae Pratt, 1902; Prosthogoniminae Llihe,1909; and Opisthogoniminae Travassos, 1928.Travassos evidently prefers to accept Pratt's (1902) diagnosis ofthe subfamily Plagiorchiinae rather than that of Looss (1899),which was accepted by Baer (1924). The former allows somewhatgreater latitude, and 22 genera are placed in this group by Travas-sos. Pratt's key was devised to include only North American forms ; however, from a study of it the following diagnosis may be given : Subfamily PLAGIORCHIINAE Pl-att, 1902Suhfamily diagnosis.?Plagiorchiidae: Hermaphroditic distomesin which the acetabulum is median and ventral. The ovarj^ isanterior to the testes. The uterus usually extends posterior to thetestes and usually reaches the posterior end of the body. The intes-tinal ceca are long, extending more than one-half the body length.The ovary is usually located immediately behind the acetabulum orbeside it. The genital pore is near the acetabulum or in front ofit. There are no papillae or projections surrounding the oral aper-ture. The intestinal ceca usually do not reach the posterior end ofthe body. The cuticle is usually spiny. The excretory canal orbladder is usually Y shaped. A cirrus sac is present. The esophagusis long or lacking. The cirrus pouch extends posteriorly to, or be-yond, the acetabulum. The extent of the vitellaria is variable. Theposition of the testes with relation to each other is variable.With reference to the characters of the Plagiorchiinae, agreementseems to be general upon one point, namely, that the subfamilydisplays the typical anatomy of the family. The remaining sub-families possess more or less distinct, divergent characters.The writer has reviewed descriptions and illustrations pertainingto the 22 genera credited to the subfamily Plagiorchiinae by Travas-sos, particularly with reference to the 9 genera comprising the "A" AKT. 19 NEW GENUS AND SPECIES OF TEEMATODE LUCKER 5group, which most typically represent it, in the opinion of Travassos.Of all these genera, Haplometra as defined by Odhner, is mostclosely related to the proposed new genus HapJometraiia: on thebasis of the existing generic conceptions within the subfamily, thecreation of a new genus for the new species from Rana pretiosa isjustified and necessary.The fact that some of the genera of Plagiorchiinae are extremelyclosely related morphologically is generally recognized. The char-acters that distinguish the earlier genera, especially those of Looss,Liihe, and Odhner, should, it is believed, be accepted for the pres-ent as a guide, at least until the need for an adequate revision of thegroup is fulfilled.The writer believes that the validity of the proposed new genusHaplometrana depends only upon the demonstration of its distinc-tion from Haplometra; for, as will be shown, the latter genus shareswith Haploinetrana^ to a degree, certain characters that distinguishboth from all other genera of the subfamily.According to Odhner (1911), Looss concluded that the tandemposition of the testes in Haplometra cyUndnca Looss was to be re-garded as an abnormality, and the oblique position stands in hisgeneric diagnosis. Looss also states that the uterus passes betweenthe testes. On the basis of observations upon some 30 specimens ofHaplometra cylindrical Odhner (1911) maintains that the tandemposition of the testes must be regarded as normal for this genus,and he points out emphatically that the uterus does not pass betweenthe testes but under them. That Odhner's observations are correctis supported by a recent publication of Travassos (1930), who de-scribes specific variations of Haplometra cylirhdrica. Odhner regardsHaplometra as related to, and derived from, Lepoderma (synonym ofPlagiorchis). He concludes that the modifications that Haplometraexhibits follow as a natural result of its topography. He thereforeregards these features, which must be admitted as atypical for thesubfamily, as comprising a basis entirely adequate for the validityof the genus.In Haplometrana intestinalis^ owing to the still greater diameterof the testes as compared with the body width, a tandem and medianposition of the testes becomes the only possibility. As a result ofthis morphological feature, the passage of the uterus between thetestes is rendered a physical impossibility. Dorsoventral passageof the uterus between the testes is a theoretical possibility but hasnot been observed. The new generic concei^tion is based essentiallyupon these facts.If Odhner's emended concept of the genus Haplometra is accepted,Haplometrana is distinguished from Haplometra principally by thepossession of a definite seminal receptacle. Moreover, in Haplo- 6 PROCEEDINGS OF THE NATIONAL MUSEUM vol.79metrana the vitellaria do not extend anterior to the acetabulum.The uterus is transversely coiled and narrow. The intestinal cecado not extend to the posterior tip of the body. If the originaldiagnosis of Looss (1899) is accepted, the distinction between thetwo genera is even more marked.The genus Opisthiocjlijfhe Looss also exhibits an aberrant mor-phology, in that the uterus does not pass between the testes. In thisgenus, however, the uterus is confined to the space between theacetabulum and the middle of the anterior testis. The testes areusually oblique but may be tandem, and they are usually locatedwell back in the posterior portion of the body. Typically, thecirrus pouch is entirely, or mostly, anterior to the acetabulum. Thevitellaria extend to the posterior tip of the body.Concerning the separation of the testes by the uterus in the genusMediorima NicoU, 1914:, no definite statement can be made, since thisgenus is inadequately described. Travassos includes it in thePlagiorchiinae. Sumwait (1926) expresses the opinion that theestablishment of the genus Mediorima seems unnecessai-y. Mediorimaappears to be so closely related to Zeugorchis Stafford, 1905, andLechrioTckis Stafford, 1905, both of which belong to the subfamilyReniferinae Pratt, 1902, that its inclusion in the Plagiorchiinae ap-pears dubious. BIBLIOGRAPHYBaee, Jean G.1924. Description of a new genus of Lepodermatidae (Trematoda) witha systematic essay on the family, rarasitology, vol. 16, no. 1, pp.22-31, iigs. 1-2, Jan.BlIALERAO, G. D.1926. On the trematode parasites of a water-snake, Troi>uJo)wtus pi-icator.Parasitology, vol. 18, no. 1, pp. 4r-13, figs. 1-2, Jan.1926. On the treniarodes of the digestive tract of a common Indian frog,Rana tigr'rna, with a description of Centrinntus peniudelphi n. g.,n. sp. Parasitology, vol. 18, no. 2, pp. 154-159, figs. 1-lA, June.CORT, W. W.1919. A new distome from Rana aurora. Univ. California Publ. Zool., vol.19, no. 8. pp. 283-298, tigs. 1-5, Nov. 15.Looss, A.1894. Die Distomen xmserer Fische und Frosclie. Neue Untersuchungeniiber Bau und Entwickelung des Distonjonkorpers. 296 pp., 9 pis.,192 figs. Stuttgart. (Biblioth. zool., Heft 16.)1899. Weitere Beitriige zur Kcuutniss der Trematoden-Fauua Aegyptens,zugleich Yersuch eiuer natiirliehen Gliederung des Genus Dis-toDiiirn Retzius. Zool. Jahrb., Alit. f. Syst., vol 12, nos. 5-6, pp.521-784, figs, a-b, pis. 24-32, figs. 1-90, Dec. 28.19U2. Ueber neue und hekannte Treniatnden aus Seeschildkroten. NebstEnuterungen zur Systematik und Nomenclatur. Zool, Jahrb.,Al.t. f. Syst., vol. 16, nos. 3-6, pp. 441-894, figs. A-B, pis. 21-32,figs. 1-lSl, Nov. 24. ART. 19 NEW GENUS AND SPECIES OF TREMATODE?LUCKER 7LuHE, Max.1909. Parasitische Plattwiirmer. 1 : Treniatodes. Siisswasserfauna Deutscli-lands (Brauer). Heft 17, 217 pp., 188 figs.Mehra, H. R., and Negi, P. S.1926. On a new trematode TreinlorcJiis ranarum nov. gen., nov. spec, fromthe common Indian frog Rana tigrina. Parasitology, vol. IS, no. 2,pp. 168-181, figs. 1-9, June.NicoLL, William.1911. On three new trematodes from reptiles. Proc. Zool. Soc. London,.1911, pp. 677-686, pis. 27-28, figs. 1-10, Sept.1912. On two new trematode parasites fruni the Indian cobra. Proc. Zool..Soc. London, 1912, pp. 851-856, fig. 122, Dec.1914. The trematode parasites of North Queensland. 1. Parasitology,vol. 6, no. 4, pp. 333-350, pis. 23-24, figs. 1-9, Jan. 31.1914. Trematode parasites from animals dying in the Zoological Society'sgardens during 1911-1912. Proc. Zool. Soc. London, 1914, pp.139-154, pis. 1-4, figs. 1-11, Mar.1926. A reference list of the trematode parasites of British amphibia.Parasitology, vol. 18, no. 1, pp. 14-20, Jan. 22.Odhner, Teodob.1911. Notdostafrikanische Trematoden, grosstenteils vom Weissen Nil (vonder schwedisclien zoologischen Expedition gesammelt). 166 pp., 14figs., 6 pis. Uppsala. (Results of the Swedish Zoological Expeditionto Egypt and the White Nile, 1901, under the direction of L. A.Jjigerskiold, pt. 4.)PocHE, Franz.1926. Das System der Plotoduria. Arch. f. Naturg., Abt. A, vol. 91, no. 2,pp. 1-240, figs. 1-5, pis. 1-3, figs. 1-95, Jan. ; no. 3, pp. 241-458,figs. 7-16, pis. 4-7, figs. 96-126, Mar.Pratt, H. S.1902. Synopses of North American invertebrates. 12. The trematodes.Part 2. The Aspidocotylea and the Malacocotylea, or di geneticforms. Amer. Nat., vol. 36. pp. 887-910, Nov. ; pp. 953-379, 8 pis.,figs. 1-30, Dec.StTMM'ALT, Margaret.1926. Trematode infestation of the snakes of San Juan Island, PugetSound. Washington Univ. Studies, sci. ser., vol. 13, no. 2, pp.73-101, pis. 1-4, figs. 1-10.Travassos, Lauro.1928. Fauna helminthologica de Matta Grosso (Trematodeos, I parte).Mem. Inst. Oswaldo Cruz, vol. 21, no. 2, pp. 309-341, pis. 42-54;French version, pp. 343-372.1930. Pesquizas helminthologicas realisadas em Hamburgo. I. GeneroHapiomctra Looss, 1S99 (Trematoda: Plagiorchiidae). Mem. Inst.Oswaldo Cruz, vol. 23, no. 4, pp. 163-108, pis. 27-37, figs. 1-30,Apr.1930. Pesyuizas helminthologicas realisadas em Hamburgo. IV. Notassobre o genero OpistJiiogJyphe Looss, 1899 e generos proximos.Mem. Inst. Oswaldo Cruz, vol. 24, no. 1, pp. 1-17, pis. 1-7, figs. 1-29,Aug.Ward, H. B., and Whipple, G. C.1918. Fresh-water biology. 1,111 pp., 1,547 figs. New York. EXPLANATION OF PLATE 1Figure 1. Camera lucida drawing of ventral view of a stained speciuTen : o. s.,Oral sucker ; ph., pharynx ; oe., esopliagus ; a., acetabulum ; c. p.,cirrus pouch ; ov., ovary ; s. r. seminal receptacle ; s. g., shell gland ;t., testis ; v. f., vitelline follicle ; L, intestine ; ut., uterus ; e. p.,excretory pore.2. Normal position of the cirrus pouch and end ducts of the reproductivesystem.3. Cirrus pouch showing the cirrus protruding from the genital pore.4. Diagrammatic representation of the relationships of the femalereproductive organs : ov., ovary ; o. d., oviduct ; s., seminal recep-tacle ; L. c, Laurer's canal ; v. d., transverse vitelline duct ; s. g.,shell gland.8 U. S. GOVERNMENT PRINTING OFFICE: 1931 U. S. NATIONAL MUSEUM PROCEEDl NGS. VOL. 79, ART. 1 9 PLl HAPLOMETRANA INTESTI N ALIS. NEW GENUS. NEW SPECIESFOR EXPLANATION OF PLATE SEE PAGE 8