THE UNIVERSITY OF ILLINOIS LIBRARY NATURAL HISTORY SURVEY 5705 ILL v.4cop.4 ^y^mS^BBS^I^^ Return this book on or before the Latest Date stamped below. A overdue charge is made on all books. U. of I. Library MAR 2 7 19 '9 11148-S ILLINOIS BIOLOGICAL MONOGRAPHS Vol. IV January, 191 8 No. 3 Editorial Committee Stephen Alfred Forbes William Trelease Henry Baldwin Ward Published under the Auspices of the Graduate School by THE University of Illinois Copyright, 1918 by the University of Illinols Distributed Decesiber 31, 1918 MORPHOLOGY AND BIOLOGY OF SOME TURBELLARIA FROM THE MISSISSIPPI BASIN WITH THREE PLATES BY RUTH HIGLEY Contributions from the Zoological Laboratory of the University of Illinois Under the Direction of Henry B. Ward, No. 112 THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OP DOCTOR OF PHILOSOPHY IN ZOOLOGY IN THE GRADUATE SCHOOL OF THE UNIVERSITY OF ILLINOIS 1917 TABLE OF CONTENTS Page Introduction 7 Technique 9 Methods of Study 10 Biology 12 Types of Localities 12 Reactions of Worms 17 Morphology 22 Family Planariidae 22 Planaria velata Stringer 1909 22 Planaria macidata Leidy 1847 23 Planaria truncata Leidy 1851 24 Family Catenulidae 25 Stenostoma leucops (Ant. Duges) 1828 26 Stenostoma tenuicauda von Graff 1911 30 Stenostoma giganteum nov. spec 30 Stenostoma glandiferum nov. spec 35 Family Microstomidae 37 Microstoma caudatum Leidy 1852 38 Macrostoma sensitivum Silliman 1884 39 Macrostoma album nov. spec 39 Family Prorhynchidae 42 Prorhynchus stagnalis M. Schultze 1851 43 Prorhynchus applanatus Kennel 1888 44 Family Dalyelliidae 45 Dalyellia dodgei von Graff 1911 46 Dalyellia alba nov. spec 47 Dalyellia megacepkala nov. spec 49 Family Typhloplanidae 50 Rhynchomeso stoma rostratum (Miiller) 1774 51 Strongylostoma rosaceum nov. spec 52 Epithelium 54 Muscular system 57 Parenchyma 58 Digestive System 59 Nervous System 60 Excretory System 62 Reproductive System 63 Development 64 Life Habits 69 Typhloplana viridata (Abildgaard) 1789 71 Mesostoma ehrenbergii (Focke) 1836 73 • ILLINOIS BIOLOGICAL MONOGRAPHS [200 Mesostoma angidare nov. spec 74 Mesostotna simplex nov. spec 77 Family Gyratricidae 78 Gyratrix hertnaphroditus Ehrenberg 1831 78 Conclusions and Summary 81 General discussion 81 Summary 84 Bibliography 85 Explanation of Plates 88 201] TURBELLARIA FROM THE MISSISSIPPI BASIN—HIGLEY INTRODUCTION Although commonly little known, the Turbellaria as a class present certain characters of morphology and Ufe-history which make them of especial interest. Furthermore, their biologic processes and Ufe habits in relation to other forms, shed some light upon general problems of common existence, A knowledge of any group of animals is of value from a phylogenetic standpoint and also in the explanation of the interdependence among various types. So a study of this group, which stands out as a connection between the very lowest phyla, the aberrant parasitic worms, and the more speciahzed higher types, makes possible an understanding of one of the steps in the evolution of the animal kingdom, namely the transition from radial to bilateral symmetry. The simplicity of anatomical structure and lack of conspicuous detail, thus especially important in a comparative way, also enable these forms to carry on an exis- tence almost unsuspected and generally entirely overlooked. The fact of their widespread distribution in both salt and fresh water passes, for the most part, unnoticed. While the fresh water Turbellaria of Europe have been recognized and care- fully studied for nearly one hundred and fifty years, the American species have received little attention. The earliest records for this country are those of Leidy. In 1848, he gave the first brief description of the now well-known and very common Planaria maculata. He also studied rather completely Phago- cata gracilis, distinguishing the fundamental points in which it differed from Planaria. Later (1852) he added several other species to the Ust. No otheir studies were reported until a paper by Silliman appeared in 1885. This was also descriptive and systematic in character. The first morphological work was that by Ott (1892) who made the common Stenostoma leucops O. Sch. the basis of a detailed histological study. Woodworth (1896, 1897) next pub- lished results of collections made from rather widely separated localities, viz., Massachusetts and Illinois. He named four new species and added full descriptions of twelve others. Since 1900 there have appeared a number of papers, a few descriptive, but by far the most the results of experimental work. Of the first type, the paper by von Graff (1911) is noteworthy. In this, he gives descriptions and notes of some seventy-five species. Several other writers have from time to time added a few forms, but this is all. On the other hand, the more common species have been used in a vast amount of experimental work. Child's work with the common flatworm has explained a large number of facts of far-reaching general biologic significance. Other investigations, some of them exhaustive, have dealt with the more primitive rhabdocoels as well as with planarians. Among the many writers along this line are Kepner (1911, 1915), Curtis (1905), and Pearl (1903). • 8 ILUNOIS BIOLOGICAL MONOGRAPHS [2Q2 Although in general the Turbellaria are free-living forms, a few cases have been reported in which they are parasitic on molluscs and it is in these species that a beginning has been made in the study of the embryology and life-history. Two writers, Linton (1910) and Stanley C. Ball (1916), have published such investigations of a species Mving on Modiolus. The Turbellaria of the central and western states are almost unknown. Woodworth (1897) and Stringer (1909, 1913) have pubUshed descriptions of five new species from Illinois and Nebraska. Eleven other forms, found also in the eastern states, have been reported from a few locahties in Illinois, Neb- raska, Michigan, and Wisconsin, but these are all. That some species, at least, are present in great numbers is evident from the various collections for experimental studies. The whole Mississippi valley region with its lakes and almost numberless ponds furnishes conditions in many respects ideal for such types, and their existence will sooner or later be demonstrated. In fact, both Planaria and Rhabdocoelida are of much more common occur- rence than is generally supposed and for several reasons are especially valuable for study. First, they are available as living reproducing animals thruout the year. Then, they are good for experimental work since they illustrate a some- what primitive phylum, one in which the body structure is very different from that commonly encountered. Well adapted to such studies by their simplicity and great vitaUty, they have come to be the classic specimens employed both for elementary experiment and for compHcated investigation. The free-Uving method of Hfe, together with the simple fimdamental anatomy, when compared with the specialized and much changed condition of the nearly related parasitic worms, shows clearly the variations possible and actually brought about by a different mode of life. As a whole, the group is of more than ordinary interest. Always considered of no importance economically, their possible relation to other forms has been overlooked, so that only by chance have their habits of parasitism and voracious feeding been discovered, and there is need of further investigation along this line. In the present paper is reported a brief study of a few forms foimd in small lakes and ponds in Ilhnois and Iowa. This work covers three phases: First, a summary and comparison of the types of habitat which deals with such en- vironmental factors as flora, whether algae or higher water plants, animal com- mimities, whether few or many, bottom, whether sandy or muddy, and also the general water conditions; second, a few of the biological aspects, this out- line comprising a study of the reactions to the various stimuli; third, a mor- phological description of eight new species and additional data concerning fifteen others. These descriptions embrace to some extent histological struc- ture as well as gross anatomy, and a nmnber of points regarding the distribu- tion and characteristic variations of well-known species. In the case of one form a brief resume of the embryological stages is also given. In the plates are included, toto drawings of all the species, besides separate sketches of iso- lated parts. 203] TURBELLARIA FROM THE MISSISSIPPI BASIN—HIGLEY 9 The work, which was carried on for the most part at the University of Ilhnois, was undertaken at the suggestion of Dr. Henry B. Ward. To him I wish to express my sincere gratitude and appreciation for special opportunities and for his great help and inspiration. I also had the opportunity to make collections and to study at the United States Biological Station at Fairport, Iowa, and my thanks are due to the director, Mr. A. F. Shira, and to Mr. H. L. Canfield, who aided me in every way possible. I am also indebted to Mr. R. L. Barney, of the United States Biological Station at Homer, Minnesota, for material sent me, and to Miss Elizabeth Bodfish, of the University of Illinois, for many specimens from Urbana locaUties. Through the kindness of Dr. Stephen A. Forbes, director of the Illinois State Laboratory of Natural History, I was able to learn something of the conditions along the Illinois river at Havana and at Cedar Lake, having at my command the facilities of the laboratory. I wish to express my deep appreciation of these privileges. TECamiQTJE Collections were made in three ways. Surfaces or open water was dipped up with a pail or jar, and as large amounts as possible carried back to the laboratory, partly for the purpose of ascertaining whether or not specimens were present, and partly for use in aquaria. Then with a long-handled dip net, masses of algae and water-weed were taken either from shallow places along the shore line, or from the surface out in deeper water where they float in great tangles, or from the bottom.