r MORPHOLOGY AND BIOLOGY OF SOME TURBELLARIA FROM THE MISSISSIPPI BASIN WITH THREE PLATES THESIS S1IllMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY IN ZOOLOGY IN THE GRADUATE SCHOOL OF THE UNIVERSITY OF ILLINOIS 1917 BY RUTH HIGLEY A. B. Grinnell College, 1911 I ContributioD3 from the Zoological Labor&toty o[ the Univenlty of Dlinois under the direction ofHC!l1Y B. Ward, No. 112 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 velaJa Stringer 1909............................. 22 Planoria maculata Leidy 1847......................... 23 Planaria lrumata Leidy 1851........................... 24 Family Catenulidae ,,,,, 25 Stenostrmro lew;ops (Ant. Duges) 1828 .. 26 Slcnostrmro tenuuauaa von Graff 1911.. 30 Stenostrmro giganteum nov. spec .. 30 Reprinted from the Stcnostrmro glandi(erum nov. spec . 35 lllinois Biological Monographs Volume 4, number 2, pages 195-288 Family Microstomidae......... .. ... 37 without changes in text or Murostoma cauaatum Leidy 1852 . 38 illustrations Macrostrmro sensitirJUm Silliman 1884 . 39 Macrostrmro album nov. spec ... 39 Family Prorhynchidae , .. 42 Prorhynchus stagna/is M. Schultze 1851.. .. 43 Prorltymh'" applana/us Kennel 1888 , .. 44 Family Dalyelliidae........................................................ .. ... 45 DalyeJUa dodgei von Graff 1911... 46 Dalye1lia alba nov. spec . 47 DalyeUia megacephala nov. spec . 49 Family Typhloplanidae , 50 RhY'u;homesosloma rostratum (MUller) 1774 . 51 Strongylostrmro rosaceum nov. spec .. 52 Epithelium . 54 Muscular system , , ' .. 57 Parenchyma . 58 Digestive System. , . 59 Nervous System. , . 60 Excretory System __ __ __ . 62 Reproductive System __ , __ .. 63 Deve!opment.. ,., __ , .. 64 Life Habits ,.. __ , ,. 69 Typltloplana viritUzta (Abildgaard) 1789 .. 71 Mososloma ehrenbergii (Focke) 1836 .. 73 6 ILLINOIS BIOLOGICAL MONOGRAPHS [200 201] TURBELLARJA FROM THE MISSISSIPPI BASIN-HIGLEY 7 Mesoswma angulare nov. spec................................................................................ 74 Mesoswma simp~ nov. spec................................................................................. 77 Family Gyratricidae........................................................................................................ 78 INTRODUCTION Gyratri: heNnaphroditus Ehrenberg 1831._.......................................................... 78 Although commonly little known, the Turbellaria as a class present certain ConclUllions and Summary.......................................................................................... 81 Geneml discussion........ 81 characters of morphology and life-history which make them of especial interest. Summary............................................................................................................................ 84 Furthermore, their biologic processes and life habits in relation to other forms, shed some light upon general problems of common existence. A knowledge Bibliography 85 of any group of animals is of value from a phylogenetic standpoint and also Explanation of Plates _...... 88 in the explanation of the interdependence among various types. So a study 6f this group, which stands out as a connection between the very lowest phyla, the aberrant parasitic worms, and the more specialized 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, thusespecially 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 m(U'ulata. 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 list. No other 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 Dlinois. 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 addeda 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 [202 203J TURBELLARIA FROM THE MISSISSIPPI BASIN-HIGLEY 9 Although in general the Turbellaria are free-living forms, a few cases have The work, which was carried on for the most part at the University of beer; reported in which they are parasitic on molluscs and it is in these species illinois, was undertaken at the suggestion of Dr. Henry B. Ward. To him I that a beginning has been made in the study of the embryology and life-history. wish to express my sincere gratitude and appreciation for special opportunities Two writers, Linton (1910) and Stanley C. Ball (1916), have published such and for his great help and inspiration. investigations of a species living on Modiolus. I also had the opportunity to make collections and to study at the United The Turbellaria of the central and western states are almost unknown. States Biological Station at Fairport, Iowa, and my thanks are due to the Woodworth (1897) and Stringer (1909, 1913) have published descriptions of director, Mr. A. F. Shira, and to Mr. H. L. Canfield, who aided me in every five new species from illinois and Nebraska. Eleven other forms, found also way possible. I am also indebted to Mr. R. L. Barney, of the United States in the eastern states, have been reported from a few localities in illinois, Neb­ Biological Station at Homer, Minnesota, for material sent me, and to Miss raska, Michigan, and Wisconsin, but these are all. That some species, at Elizabeth Bodfish, of the University of illinois, for many specimens from least, are present in great numbers is evident from the various collections for Urbana localities. experimental studies. The whole Mississippi valley region with its lakes and Through the kindness of Dr. Stephen A. Forbes, director of the Illinois almost numberless ponds furnishes conditions in many respects ideal for such State Laboratory of Natural History, I was able to learn something of the types, and their existence will sooner or later be demonstrated. conditions along the Illinois river at Havana and at Cedar Lake, having at In fact, both Planaria and Rhabdocoelida are of much more common occur­ my command the facilities of the laboratory. I wish to express my deep rence than is generally supposed and for several reasons are especially valuable appreciation of these privileges. 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 TECHNIQUE what primitive phylum, one in which the body structure is very different from Collections were made in three ways. Surfaces or open water was dipped that commonly encountered.. Well adapted to such studies by their simplicity up with a pail or jar, and as large amounts as possible carried back to the and great vitality, they have come to be the classic specimens employed both laboratory, partly for the purpose of ascertaining whether or not specimens were for elementary experiment and for complicated investigation. The free-living present, and partly for use in aquaria. Then with a long-handled dip net, method of life, together with the simple fundamental anatomy, when compared masses of algae and water-weed were taken either from shallow places with the specialized and much changed condition of the nearly related parasitic along the shore line, or from the surface out in deeper water where they float worms, shows clearly the variations possible and actually brought about by a in great tangles, or from the bottom. In some cases a good deal of water was different mode of life. As a whole, the group is of more than ordinary interest.