6 p. : ill. ; 24 cm.Includes bibliographical references (p. 5-6)

Barber, Herbert Spencer, 1882-1950.

Hyman, Libbie Henrietta, 1888-1969.

Shoemaker, Clarence Raymond, 1874-

American Museum of Natural History Scientific Publications

A1MERICAN MUSEUMNOVITATESPUBLISHED BY THE AMERICAN MUSEUM OF NATURAL HISTORYCITY OF NEW YORK SEPTEMBER 4, 1953 NUMBER 1629North American Triclad Turbellaria. 14A New, Probably Exotic, DendrocoelidBY LIBBIE H. HYMAN1There was sent for identification by the United %States NationalMuseum a single specimen of a fresh-water planarian that had beencollected in the Shaw Lily Ponds, Washington, D. C., by H. S. Barberand C. R. Shoemaker, April 10, 1926. A cursory examination of thisspecimen showed at once that it is something foreign to the planarianfauna of the Americas. Sections have revealed that it is closely related tothe Eurasian genus Bdellocephala de Man, 1874. Doubtless the animalwas carried into the lily ponds with exotic plants. It has appeared tome desirable to erect a new genus for this and some other dendrocoelidsthat had been put into Bdellocephala by their authors.ORDER TRICLADIDA2FAMILY DENDROCOELIDAEGenus Rectocephala, new genusDEFINITION: Dendrocoelidae with an adhesive organ in the centerof the anterior margin; colored or white; eyes two or none; penispapilla lacking; ejaculatory duct enters large, expanded, weakly muscular1 Research Associate in Invertebrates, Department of Fishes and Aquatic Biology,the American Museum of Natural History.2 I decline to accept the classificatory scheme for the Turbellaria first proposed byMeixner (1938) and vigorously promulgated by Karling (1940) and Westblad (1948),according to which the Tricladida are reduced to a section of the Alloeocoela Seriata.While no one doubts that the triclads are descended from the seriate alloeocoels, thedifferences between these groups in external appearance and internal structure areconsiderable. On the same grounds one could insist that mammals be made a sectionunder reptiles. I also cannot accept some other features of the Meixner-Karling..Westblad scheme but will defer consideration of them to some other occasion.AMERICAN MUSEUM NOVITATESbut highly glandular chamber (presumably the penis bulb) continuousposteriorly with the reduced male antrum; common ovovitelline ductenters the roof of the male antrum, immediately anterior to the entranceof the bursal canal.TYPE SPECIES: Bdellocephala mediobuccalis Sabussova, 1929.Rectocephala exotica, new speciesFigures 1-4The specimen, represented whole in figure 1, is 14 mm. long, pre-served. The anterior margin appears straight, with a central cushionrepresenting an adhesive organ. No eyes could be seen in the clearedspecimen, but sections showed that a pair of eyes is present. The animalappeared to be of a uniform black coloration.The anterior part was cut off, and both parts were sectioned sagittally.1FIGS. 1, 2. Rectocephala exotica, new species.1. View of specimen before sectioning. 2. Sagittal sec-tion through the adhesive organ. Sutbsidiary number-ing: 1, adhesive organ; 2, pharynx; 3, mouth; 4, copu-latory bursa; 5, bursal canal; 6, penis bulb; 7, commongonopore; 8, eosinophilous surface layer of adhesiveorgan; 9, central tubular invagination; 10, bundles ofcircular fibers; 11, bounding network of muscle fibers.2 NO0. 1629HYMAN: A NEW DENDROCOELIDGood sections were obtained of the adhesive organ which is shown insagittal view in figure 2. As usual in the Dendrocoelidae, the organ isonly moderately developed. It has the histological structure typical ofsuch organs. The surface epidermis disappears as it approaches the organwhich consists externally of several shallow folds and a deeper medianfold, all clothed with an indefinite layer without exact cell boundariesbut filled with eosinophilous granules. Definite gland cells could not bediscerned. The organ is very muscular. Muscle bundles, running mostlytransversely, appear to either side of the central tubular invagination,and the organ is demarcated from the general parenchyma by a curvednetwork of muscle fibers from which fibers extend to the muscle layersof the body wall.The remainder of the general histology appeared to offer nothing ofparticular interest. The inner muscular layer of the pharynx plainlyshows the lattice intermingling of circular and longitudinal fibersdiagnostic of the Dendrocoelidae.The series of sections of the trunk revealed a fully developed copulatoryapparatus, of which a general sagittal view is given in figure 3. Thelocation of the apparatus with reference to the pharynx appears in figure1. The copulatory bursa is situat-ed as usual directly behind the pharynx,but the bursal canal is very elongated so that the copulatory apparatuslies farther behind the pharynx than is usually the case in fresh-waterplanarians. The ovaries were found in the sections but appear somewhatfar posterior to the anterior end. Testes could not be identified. Anabundance of yolk glands is present between the intestinal diverticula.A few sperm are present in the ejaculatory duct. Apparently the animalis protandrous and had passed the male condition.An enlarged sagittal view of the copulatory apparatus is shown infigure 4. The ejaculatory duct with a somewhat muscular wall entersthe anterior end of the main male chamber of the copulatory apparatusand projects for some distance into the lumen of the latter. There isno indication of a penis papilla. The nature of the main chamber of themale apparatus is puzzling, but it may best be interpreted as a penisbulb. It is a large oval body with a thin muscular investment of outerlongitudinal and inner circular fibers. The lining epithelium consistsof tall slender cells, taller ventrally than dorsally, and is thrown intomany folds. The bulbous free ends of the epithelial cells are packedwith granules of glandular secretion, apparently cyanophilous, at leastnot eosinophilous. The secretion is seemingly produced in the epithelialcells themselves, as there is no evidence of parenchymal gland cells open-ing into the penis bulb.At its posterior end the penis bulb narrows into a very short male1953 3AMERICAN MUSEUM NOVITATESantrum, lined by an ordinary, non-secretory epithelium and receivingthe common ovovitelline duct into its dorsal wall. The male antrum,after being joined by the termination of the bursal canal, exits belowby the common gonopore.'2~~~~~2415I 1"77< b~~713~~~,11~ ~ ~ ~ ~ 13FIGS. 3, 4. Rectocephala exotica, new species. 3. General sagittal view of thecopulatory apparatus. 4. Enlarged view of the terminal part of the copulatoryapparatus. Subsidiary numbering: 2, pharynx; 4, copulatory bursa; 5, bursalcanal; 6, penis bulb; 7, common gonopore; 12, ejaculatory duct; 13, commonovovitelline duct; 14, projection of ejaculatory duct into penis bulb; 15, musclelayer of penis bulb; 16, glandular lining of penis bulb; 17, male antrum; 18,widened part of bursal canal; 19, narrowed, glandular, muscular part of bursalcanal.4 NO0. 1629HYMAN: A NEW DENDROCOELIDThe copulatory bursa is the usual oval sac located directly behindthe pharynx. Its unusually long canal runs posteriorly above the maleapparatus, then curves ventrally and opens into the common antrumdirectly behind the ovovitelline duct. The bursal canal is lined by acuboidal epithelium, taller dorsally than ventrally, and has a goodmuscular investment of inner circular and outer longitudinal fibers,somewhat intermingled. At its curve the bursal canal widens consider-ably, and here the lining epithelium shows evidence of glandular functionby the presence of distal granules. The bursal canal then narrows again,and this tubular portion is highly secretory as well as more muscularthan the preceding parts of the canal.Rectocephala exotica is differentiated from other species of the genusby the excessively long bursal canal and the projection of the ejaculatoryduct into the anterior end of the penis bulb.It remains to differentiate Rectocephala from Bdellocephala. Thestructure of the type species of Bdellocephala, B. punctata (Pallas), 1774,has been well elucidated by Ude (1908). From his figure of the copula-tory apparatus, it can be seen that the sperm ducts enter a small, highlymuscular penis bulb provided with external glands and opening from theventral side into an extensive male antrum with much folded walls; adefinite penis papilla is wanting. Consequently Bdellocephala is charac-terized by the highly muscular, definitely delimited penis bulb withexternal glands, entering ventrally the expanded male antrum. InRectocephala the large, highly glandular but weakly muscular penis bulbwithout external glands is axially continuous with and poorly separatedfrom the greatly reduced male antrum. I consider that the followingspecies belong to Bdellocephala, in addition to punctata: angarensis(Gerstfeld), 1858; annandalei Ijima and Kaburaki, 1916; brunneaIjima and Kaburaki, 1916; and parva Sabussova, 1936. I would transferthe following to Rectocephala: baicalensis (Sabussov), 1903; kamtscha-tica (Sabussova), 1929; mediobuccalis (Sabussova), 1929; and schnei-deri (Komarek), 1930. Planaria grubiiformis Sabussova, 1929, alsoprobably belongs in Rectocephala, but the figures furnished by theauthor are not sufficiently detailed.The type specimen of Rectocephala exotica in the form of sections(10 slides) has been deposited in the United States National Museum(U.S.N.M. No. 24714).LITERATURE CITEDIJIMA, I., AND T. KABURAKI1916. Preliminary description of some Japanese triclads. Annot. Zool.Japonenses, vol. 9, pp. 153-171.51953AMERICAN MUSEUM NOVITATESKARLING, T. G.1940. Zur Morphologie und Systematik der Alloeocoela cumulata undRhabdocoela Lecithophora (Turbellaria). Acta Zool. Fennica, vol. 26,pp. 1-260.KOMAREK, J.1930. Eine blinde Bdellocephala (Tricladida) aus dem Harz. Zool. Anz.,vol. 87, pp. 327-332.MEIXNER, J.1938. Turbellaria (Strudelwiirmer). In Grimpe, G., and E. Wagler (eds.),Die Tierwelt der Nord- und Ostsee. Leipzig, Lieferung 33, Teil IVb,146 pp.SABUSSOV, H.1903. Tricladenstudien. IV. Erster vorlaufiger Bericht uber die von HerrnW. Garjajew im Baikalsee gesammelten Planarien. [In Russian withGerman summary.] Trudy Obshchestvo Estestvolspytatelel KazanUniversitet (Trans. Soc. Nat. Univ. Kazan), vol. 36, no. 6, 39 pp.SABUSSOVA, Z.1929. Die Turbellarien der Kamtschatka-Halbinsel nach den Sammlungender Rjabuschinsky-Expedition 1908-1909. Zool. Jahrb., Abt. Syst.,vol. 57, pp. 497-536.UDE, J.1908. Beitrage zur Anatomie und Histologie der Susswassertricladen. Zeit-schr. Wiss. Zool., vol. 89, pp. 308-370.WESTBLAD, E.1948. Studien iiber skandinavische Turbellaria Acoela. V. Arkiv. Zool.,vol. 41A, no. 7, 82 pp.6 NO. 1629

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