: cr ; CO i Lo i f^ CD o PROTOZOOTvOGY (^rd Edition) PROTOZOOLOGY By RICHARD R. KUDO, D.Sc. Professor of Zoology The University of Illinois Urbana, Illinois With three hundred and thirty-six illustrations CHARLES C THOMAS • PUBLISHER 301-327 EAST LAWRENCE AVENUE SPRINGFIELD • ILLINOIS 1946 Published by Charles C Thomas 301-327 East Lawrence Avenue, Springfield, Illinois Published simultaneously in Canada by The Ryerson Press, Toronto All rights in this book are reserved. No part may be repro- duced in any form w^hatsoever without permission in writing from the publisher, except by a reviewer who wishes to quote extremely brief passages in connection with a critical review. Reproduction in whole or in part in digests, in condensations of the literature, in lectures, or in films; or by multigraphing, lithoprinting, or by any other processes or devices, is reserved by the publisher. For information, address Charles C Thomas. Copyright, 19^6, by Charles C Thomas First Edition, January 1931 Second Edition, September 1939 Third Edition, January 1946 Printed in the United States of America 'The revelations of the Microscope are perhaps not excelled in importance by those of the telescope. While exciting our curiosity, our ivonder and admiration, they have proved of infinite service in advancing our knowledge of things around us." Leidy Preface to the third edition IN REVISING Protozoology for the second time, the author has maintained the original aim of the work for setting forth "in- troductory information on the common and representative genera of all groups of both free-living and parasitic Protozoa," and en- deavored to limit its expansion to minimum. Errors, typograph- ical and otherwise, which had appeared in the last edition have been corrected. In this he is much indebted to his former students, both graduates and undergraduates, who untiringly detected them and suggested improvement of many passages for clearer presentation. The criticisms offered by the reviewers of the second edition have also been considered. Published papers that had been overlooked before and those that have appeared in the last six years have been consulted and referred to in the present edition. Chapters 4 to 6 were largely rewritten and enlarged in the light of recent works. Alterations and additions have been made in all other chapters. Two new chapters have been added; they are chapter 7 (Major groups and phylogeny of Protozoa) and chapter 45 (Collection, cultivation, and observation of Protozoa). Since there is now a greater demand of the information on Proto- zoa that parasitize man than in the past, they have been more thoroughly treated in the present edition. The author continues to believe in the importance of adequate illustrations in this sort of work. Sixty-nine new figures have been added; of these forty-seven have been newly prepared or rearranged from former figures, while twenty-two have been taken from his Manual of human Protozoa (1944). The author once more expresses his indebtedness to numerous authors of published papers for the materials which have been in- corporated in the work. He is under special obligation to Doctor Harold Kirby, University of California; Doctor Reginald D. Man- well, Syracuse University; Doctor Tracy M. Sonneborn, Indiana University; Doctor David H. Wenrich, University of Pennsylvania; and Doctor Lorande L. Woodruff, Yale University, for their kind advices, sincere criticisms and suggestions. He further wishes to thank Mr. Charles C Thomas for the interest and care with which the present edition has been put in print. Richard R. Kudo Urbana, Illinois October, 1945 Preface to the second edition THE present work is similar in its primary aim to that of its predecessor, Handbook of Protozoology (1931), in presenting "introductory information on the common and representative genera of all groups of both free-living and parasitic Protozoa," to advanced undergraduate and graduate students in zoology in colleges and universities. With the expansion of courses in protozoology at the University of Illinois and elsewhere, it seemed advisable to incorpor- ate more material for lecture and discussion, in addition to the en- largement of the taxonomic section. The change of the text-contents has, therefore, been so extensive that a new title, Protozoologij , is now given. Chapters 1 to 6 deal with introduction, ecology, morphology, physiology, reproduction, and variation and heredity, of Proto- zoa. Each subject-matter has been considered in the light of more recent investigations as fully as the space permitted. Selection of material from so great a number of references has been a very diffi- cult task. If any important papers have been omitted, it was en- tirely through over-sight on the part of the author. The taxonomic portion (Chapters 7 to 43) has also been com- pletely rewritten and enlarged. Numerous genera and species, both old and new, have been added ; synonymy of genera and species has as far as possible been brought down to date; new taxonomic ar- rangement of major and minor subdivisions in each class has resulted in numerous changes. The class Ciliata has completely been reclassi- fied, following Kahl's admirable work on free-living ciliates (1930- 1935) ; however, unlike the latter, all parasitic ciliates have also been considered in the present work. The author continues to believe that good illustrations are in- dispensable in this kind of work, since they are far more easily comprehended than lengthy descriptions. Therefore, many old illustrations have been replaced by more suitable ones and numerous new illustrations have further been added. All illustrations were especially prepared for this work and in the case of those which have been redrawn from illustrations found in published papers, the indebtedness of the author is indicated by mentioning the names of the investigators from whose works the illustrations were taken. In order to increase the reference value, all figures are accompanied by scales of magnification which are uniformly somewhat greater than those of Handbook of Protozoology, since the microscope now used in the class-room has been improved upon in recent years. X PREFACE The list of references appended to the end of each chapter has been enlarged and is meant to aid those who wish to obtain fuller information than that which is given in this volume. Since com- prehensive monographs on various groups of Protozoa are widelj^ scattered and ordinarily not easily accessible, the author has en- deavored to provide for each group as complete an information as possible for general reference purpose within the limited space, and hopes that the present work has reference value for teachers of biology, field workers in pure and applied biological sciences, veterinarians, physicians, public health workers, laboratory tech- nicians, and others. The author is under obligation to numerous writers for their valuable contributions which have been incorporated in the text. Special thanks are due Professor L. R. Cleveland, Harvard Uni- versity; Professor R. P. Hall, New York University; Professor H. Kirby, Jr., University of California; Professor L. E. Noland, Uni- versity of Wisconsin; Professor H. J. Van Cleave, University of Illinois; Professor D. H. Wenrich, University of Pennsylvania; and Professor L. L. Woodruff, Yale University, for their valued criti- cisms and suggestions. The author further wishes to express his appreciation to Mr. Charles C Thomas, for his patient and kind cooperation which has aided greatly in the completion and appear- ance of the present work. R.R.K. Urbana, Illinois, U.S.A. July, 1939 CONTENTS Preface vii Part I: General biology 3 CHAPTER 1 Introduction 5 Relationship of protozoology to other fields of biological science, p. 6; the history of protozool- ogy, p. 10. 2 Ecology 17 The free-living Protozoa, p. 17; the parasitic Protozoa, p. 24. 3 Morphology 33 The nucleus, p. 34; the cytosome, p. 38; loco- motor organellae, p. 41; fibrillar structures, p. 52; protective or supportive organellae, p. 61; hold-fast organellae, p. 65; the parabasal appa- ratus, p. 66; the blepharoplast, p. 67; the Golgi apparatus, p. 68; the chondriosomes, p. 70; the contractile and other vacuoles, p. 73; the chro- matophore and associated organellae, p. 78. 4 Physiology 84 Nutrition, p. 84; the reserve food matter, p. 98; respiration, p. 101; excretion and secretion, p. 103; movements, p. 106; irritability, p. 113. 5 Reproduction 122 Nuclear division, p. 122; cytosomic division, p. 143; colony formation, p. 145; asexual repro- duction, p. 147; sexual reproduction and life- cycles, p. 149; regeneration, p. 170. 6 Variation and heredity 176 Part II: Taxonomy and special biology 191 CHAPTER 7 Major groups and phylogeny of Protozoa 193 8 Phylum Protozoa 198 Subphylum 1 Plasmodroma 198 Class 1 Mastigophora 198 Subclass 1 Phytomastigina 200 Order 1 Chrysomonadina 200 XI 59941 CONTENTS 9 Order 2 Cryptomonadina 213 10 Order 3 Phytomonadina 217 11 Order 4 Euglenoidina 232 Order 5 Chloromonadina 243 12 Order 6 Dinoflagellata 245 13 Subclass 2 Zoomastigina 263 Order 1 Rhizomastigina 263 14 Order 2 Protomonadina 268 15 Order 3 Polymastigina 293 16 Order 4 Hypermastigina 318 17 Class 2 Sarcodina 328 Subclass 1 Rhizopoda 329 Order 1 Proteomyxa 329 18 Order 2 Mycetozoa 335 19 Order 3 Amoebina 343 20 Order 4 Testacea 374 21 Order 5 Foraminifera 394 22 Subclass 2 Actinopoda 406 Order 1 Heliozoa 406 23 Order 2 Radiolaria 417 24 Class 3 Sporozoa 427 Subclass 1 Telosporidia 427 Order 1 Gregarinida 428 25 Order 2 Coccidia 464 26 Order 3 Haemosporidia 484 27 Subclass 2 Acnidosporidia 507 Order 1 Sarcosporidia 507 Order 2 Haplosporidia 510 28 Subclass 3 Cnidosporidia 515" Order 1 Myxosporidia 515 Order 2 Actinomyxidia 531 29 Order 3 Microsporidia 535 Order 4 Helicosporidia 542 30 Subphylum 2 Ciliophora 545 Class 1 Ciliata 545 Subclass 1 Protociliata 547 31 Subclass 2 Euciliata 551 Order 1 Holotricha 551 Suborder 1 Astomata 552 32 Suborder 2 Gymnostomata 560 Tribe 1 Prostomata 560 33 Tribe 2 Pleurostomata 580 CONTENTS xiii Tribe 3 Hypostomata 585 34 Suborder 3 Trichostomata 593 35 Suborder 4 Hymenostomata 608 36 Suborder 5 Thigmotricha 623 37 Suborder 6 Apostomea 630 38 Order 2 Spirotricha 636 Suborder 1 Heterotricha 636 39 Suborder 2 Oligotricha 652 40 Suborder 3 Ctenostomata 665 41 Suborder 4 Hypotricha 668 42 Order 3 Chonotricha 681 43 Order 4 Peritricha 683 44 Class Suctoria 695 45 Collection, cultivation, and observation of Protozoa 710 Author and subject index 731 PROTOZOOLOGY PROTOZOOLOGY PART I: GENERAL BIOLOGY Chapter 1 Introduction PROTOZOA are unicellular animals. The body of a protozoan is morphologically a single cell and manifests all characteristics common to the living thing. The various activities which make up the phenomena of life are carried on by parts within the body or cell. These parts are comparable with the organs of a metazoan which are composed of a large number of cells grouped into tissues and are called organellae or cell-organs. Thus one sees that the one-celled protozoan is a complete organism somewhat unlike the cell of a metazoan, each of which is dependent upon other cells and cannot live independently. From this viewpoint, certain students of proto- zoology maintain that the Protozoa are non-cellular, and not uni- cellular, organisms. Dobell (1911) for example, pointed out that the term "cell" is employed to designate (1) the whole protozoan body, (2) a part of a metazoan organism, and (3) a potential whole organ- ism (a fertilized egg) which consequently resulted in a confused state of knowledge regarding living things, and, therefore, proposed to define a cell as a mass of protoplasm composing part of an organ- ism, and further considered that the protozoan is a non-cellular but complete organism, differently organized as compared with cellular organisms, the Metazoa and Metaphyta. The great majority of protozoologists, however, continue to consider the Protozoa as uni- cellular animals. Through the processes of organic evolution, they have undergone cytological differentiation and the Metazoa histo- logical differentiation. In being unicellular, the Protozoa and the Protophyta are alike. The majority of the Protozoa are quite clearly distinguishable from the majority of the Protophyta on the basis of nuclear condition, method of nutrition, direction of division-plane, etc. While numerous Protophyta appear to possess scattered nuclear material or none at all, the Protozoa contain at least one nucleus. It is generally con- sidered that the binary fission of the Protozoa and of the Protophyta is longitudinal and transverse, respectively. A great majority of Ciliata, however, multiply by transverse division. In general the nutrition of Protozoa is holozoic and of Protophyta, holophytic; but there are large numbers of Protozoa which nourish themselves by holophytic method. Thus an absolute and clean-cut separation of the two groups of unicellular organisms is not possible. Haeckel 6 PROTOZOOLOGY coined the name Protista to include these organisms in a single group, but this is not generally adopted, since it includes undoubted animals and plants, thus creating an equal amount of confusion between it and the animal or the plant. Calkins (1933) excluded chromatophore-bearing Mastigophora from his treatment of Pro- tozoa, thus placing organisms similar in every way, except the presence or absence of chromatophores, in two different groups. This intermingling of characteristics between the two groups of microorganisms shows clearly their close interrelationship and sug- gests strongly their common ancestry. Although the majority of Protozoa are solitary and the body is composed of a single cell, there are several forms in which the organism is made up of more than one cell. These forms, which are called colonial Protozoa (p. 145), are well represented by the mem- bers of Phytomastigina, in which the individuals are either joined by cytoplasmic threads or embedded in a common matrix. These cells are alike both in structure and in function, although in a few forms there may be a differentiation of the individuals into repro- ductive and vegetative cells. Unlike the cells in a metazoan which form tissues, these vegetative cells of colonial Protozoa are not de- pendent upon other cells; therefore, they do not form any tissue. The reproductive cells produce zygotes through sexual fusion, which subsequently undergo repeated division and may produce a stage comparable with the blastula stage of a metazoan, but never reach- ing the gastrula stage. Thus colonial Protozoa are only cell-aggre- gates without histological differentiation and may thus be distin- guished from the Metazoa. Between 15,000 and 20,000 species of Protozoa are known to man. From comparatively simple forms such as Amoeba, up to highly complicated organisms as represented by numerous ciliates, the Protozoa vary exceedingly in their body organization, morphological characteristics, behavior, habitat, etc., which necessitates a tax- onomic arrangement for proper consideration as set forth in detail in chapters 8 to 44. Relationship of protozoology to other fields of biological science A brief consideration of the relationship of Protozoology to other fields of biology and its possible applications may not be out of place here. Since the Protozoa are single-celled animals manifesting the characteristics common to all living things, they have been studied by numerous investigators with a view to dis- INTRODUCTION 7 covering the nature and mechanism of various phenomena, the sum-total of which is known collectively as life. Though the in- vestigators generally have been disappointed in the results, in- asmuch as the assumed simplicity of unicellular organisms has proved to be offset by the complexity of their cell-structure, never- theless any discussion of biological principles today must take into account the information obtained from studies of Protozoa. It is now commonly recognized that adequate information on various types of Protozoa is a prerequisite to a thorough comprehension of biology and to proper application of biological principles. Practically all students agree in assuming that the higher types of animals have been derived from organisms which existed in the remote past and which probably were somewhat similar to the Protozoa of the present day. Since there is no sharp distinction between the Protozoa and the Protophyta or between the Protozoa and the Metazoa, and since there are intermediate forms between the major classes of the Protozoa themselves, progress in proto- zoology contributes toward the advancement of our knowledge on the probable steps by which living things in general evolved. Geneticists have undertaken studies on heredity and variation among Protozoa. "Unicellular animals," wrote Jennings (1909), "present all the problems of heredity and variation in miniature. The struggle for existence in a fauna of untold thousands showing as much variety of form and function as any higher group, works itself out, with ultimate survival of the fittest, in a few days under our eyes, in a finger bowl. For studying heredity and variation we get a generation a day, and we may keep unlimited numbers of pedigreed stock in a watch glass that can be placed under the micro- scope." Morphological variations are encountered commonly in all forms. Whether variation is due to germinal or environmental condi- tions, is often difficult to determine. The recent discovery of the mating types in Paramecium aurelia (Sonneborn; Kimbell) and in P. bursaria (Jennings) will probably assist in bringing to light many genetic problems of Protozoa which have remained obscure in the past. Parasitic Protozoa are limited to one or more specific hosts. Through studies of the forms belonging to one and the same genus or species, the phylogenetic relation among the host animals may be established or verified. The mosquitoes belonging to the genera Culex and Anopheles, for instance, are known to transmit avian and human Plasmodium respectively. They are further infected by specific microsporidian parasites. For instance, Thelohania 8 PROTOZOOLOGY has been found widely only in many species of anopheline mosqui- toes; T. opacita has, on the other hand, been found exclusively in culicine mosquitoes, although the larvae of the species belonging to these two genera live frequently in the same body of water. By ob- serving certain intestinal Protozoa in some monkeys, Hegner ob- tained evidence on the probable phylogenetic relationship between them and other higher mammals. The relation of various Protozoa of the wood-roach to those of the termite, as revealed by Cleveland and his associates, gives further proof that the Blattidae and the Isoptera are of the common origin. Study of a particular group of parasitic Protozoa and their hosts may throw light on the geographic condition of the earth in the remote past. The members of the genus Zelleriella are usually found in the colon of the frogs belonging to the family Leptodactylidae. Through an extensive study of these amphibians from South Amer- ica and Australia, Metcalf found that the species of Zelleriella occur- ring in the frogs of the two continents are almost identical. He finds it more difficult to conceive of convergent or parallel evolution of both the hosts and the parasites, than to assume that there once existed between Patagonia and Australia a land connection over which frogs, containing Zelleriella, migrated. Experimental studies of large Protozoa have thrown light on the relation between the nucleus and the cytoplasm, and have furnished a basis for an understanding of regeneration in animals. In Protozoa we find various types of nuclear divisions ranging from a simple amitotic division to a complex process comparable in every detail with the typical metazoan mitosis. A part of our knowledge in cytology is based upon studies of Protozoa. Through the efforts of various investigators in the past fifty years, it has now become known that numerous parasitic Protozoa occur in man (Kudo, 1944). Entamoeba histolytica, Balantidium coli, and three species of Plasmodium, all of which are pathogenic to man, are widely distributed throughout the world. In certain restricted areas are found other pathogenic forms, such as Trypanosoma and Leishmania. Since all parasitic Protozoa presumably have originated in free-living forms and since our knowledge of the morphology, physiology, and reproduction of the parasitic forms has largely been obtained in conjunction with the studies of the free-living organ- isms, a general knowledge of the entire phylum is necessary to under- stand the parasitic forms. Recent studies have further revealed that almost all domestic animals are hosts to numerous parasitic Protozoa, many of which INTRODUCTION 9 are responsible for serious infectious diseases. Many of the forms found in domestic animals are morphologically indistinguishable from those occurring in man. Balantidium coli is now generally considered as a parasite of swine, and man is its secondary host. Knowledge of protozoan parasites is useful to medical practitioners, just as it is essential to veterinarians inasmuch as certain diseases in animals, such as Texas fever, dourine, nagana, blackhead, coccidio- sis, etc., are caused by protozoans. Sanitary betterment and improvement are fundamental re- quirements in the modern civilized world. One of man's necessities is safe drinking water. The majority of Protozoa live freely in various bodies of water and some of them are responsible, if present in suffi- ciently large numbers, for giving certain odors to the waters of reservoirs or ponds (p. 100). But these Protozoa which are occasion- ally harmful are relatively small in number compared with those which are beneficial to man. It is generally understood that bacteria live on various waste materials present in polluted water, but that upon reaching a certain population, they would cease to multiply and would allow the excess organic substances to undergo decompo- sition. Numerous holozoic Protozoa, however, feed on the bacteria and prevent them from reaching the saturation population. Protozoa thus seem to help indirectly in the purification of the water. Protozo- ology therefore must be considered as part of modern sanitary science. Young fish feed extensively on small aquatic organisms, such as larvae of insects, small crustaceans, annelids, etc., all of which de- pend largely upon Protozoa and Protophyta as sources of food sup- ply. Thus the fish are indirectly dependent upon Protozoa as food material. On the other hand, there are numbers of Protozoa which live at the expense of fish. The Myxosporidia are almost exclusively parasites of fish and sometimes cause death to large numbers of com- mercially important fishes. Success in fish-culture, therefore, requires among other things a thorough knowledge of Protozoa. Since Russel and Hutchinson suggested some thirty years ago that Protozoa are probably a cause of limitation of the numbers, and therefore the activities of bacteria in the soil and thus tend to de- crease the amount of nitrogen which is given to the soil by the nitrifying bacteria, several investigators have brought out the fact that in the soils of temperate climates Protozoa are present com- monly and active throughout the year. The exact relation between specific protozoans and bacteria in the soil is a matter which still awaits future investigations, although numerous experiments and 10 PROTOZOOLOGY observations have already been made. All soil investigators should be acquainted with the biology and taxonomy of free-living pro- tozoans. It is a matter of common knowledge that the silkworm and the honey bee suffer from protozoan infection known as microsporidiosis. Sericulture in southern Europe suffered great damages in the middle of the nineteenth century because of the "pebrine" disease, caused by the microsporidian, Nosema hombycis. During the first decade of the present century, another microsporidian, Nosema apis, was found to infect a large number of honey bees. Methods of control have been developed and put into practice so that these micro- sporidian infections are at present not serious, even though they still occur. On the other hand, other Microsporidia are now known to in- fect certain insects, such as mosquitoes and lepidopterous pests, which, when heavily infected, die sooner or later. Methods of de- struction of these insects by means of chemicals are more and more used, but attention should also be given to utilization of the parasitic Protozoa and Protophyta for this purpose. While the majority of Protozoa lack permanent skeletal structures and their fossil forms are unknown, there are at least two large groups in the Sarcodina which possess conspicuous shells and which are found as fossils. They are Foraminifera and Radiolaria. From early palaeozoic era down to the present day, the carbonate of lime which makes up the skeletons of numerous Foraminifera has been left embedded in various rock strata. Although there is no dis- tinctive foraminiferan fauna characteristic of a given geologic pe- riod, there are certain peculiarities of fossil Foraminifera which dis- tinguish one formation from the other. From this fact one can un- derstand that knowledge of foraminiferous rocks is highly useful in checking up logs in well drilling. The skeletons of the Radiolaria are the main constituent of the ooze of littoral and deep-sea regions. They have been found abundantly in siliceous rocks of the palaeozoic and the mesozoic eras, and are also identified with the clays and other formations of the miocene period. Thus knowledge of these two orders of Sarcodina, at least, is essential for the student of geology and paleontology. The history of protozoology Aside from a comparatively small number of large forms. Protozoa are unobservable with the naked eye, so that we can easily under- stand why they were unknown prior to the invention of the micro- scope. Antony van Leeuwenhoek (1632-1723) is commonly recog- INTRODUCTION 11 nized as the father of protozoology. Grinding lenses himself, Leeuwenhoek made more than four hundred simple microscopes, in- cluding one which, it is said, had a magnification of 270 times (Harting). Among the many things he discovered were various Pro- tozoa. According to Dobell (1932), Leeuwenhoek saw in 1674 for the first time free-living Protozoa in fresh water. Among them, he observed bodies "green in the middle, and before and behind white," which Dobell interprets were Euglena. Between 1674 and 1716 he observed numerous microscopic organisms which he communicated to the Royal Society of London and which, as Dobell considered, were Vorticella, Stylonychia, Carchesium, Volvox, Haematococcus, Coleps, Kerona, Anthophysis, Elphidium, Polytoma, etc. According to Dobell, Huygens gave in 1678 "unmistakable descriptions of Chilodon(ella), Paramecium, Astasia and Vorticella, all found in in- fusions." Colpoda was seen by Bonanni (1691) and Harris (1696) rediscov- ered Euglena. In 1718 there appeared the first treatise on micro- scopic organisms, particularly of Protozoa, by Joblot who empha- sized the non-existence of abiogenesis by using boiled hay-infusions in which no Infusoria developed without exposure to the atmosphere. This experiment confirmed that of Redi who, some forty years be- fore, had made his well-known experiments by excluding flies from meat. Joblot illustrated, according to Woodruff (1937), Paramecium, the slipper animalcule, with the first identifiable figure. Trembley (1745) studied division in some ciliates, including probably Para- mecium, which generic name was coined by Hill in 1752. Noctiluca w^as first described by Baker (1753). Rosel von Rosenhoff (1755) observed an organism, possibly either Pelomyxa carolineyisis Wilson (Chaos chaos Linnaeus (Schaeffer, 1926)) or a mycetozoan (Mast and Johnson, 1931), which he called "der kleine Proteus," and also Vorticella, Stentor, and Volvox. Wris- berg (1764) coined the term "Infusoria" (Dujardin; Woodruff). By using the juice of geranium, Ellis (1770) caused the extrusion of the 'fins' (trichocysts) in Paramecium. Eichhorn (1783) observed the heliozoan, Actinosphaerium, which now bears his name. O. F. Miiller described Ceratium a little later and published two works on the In- fusoria (1773, 1786). Although he included unavoidably some Meta- zoa and Protophyta in his monographs, some of his descriptions and figures of Ciliata were so well done that they are of value even at the present time. At the beginning of the nineteenth century the cylcosis in Para- mecium was brought to light by Gruithuisen. Goldfuss (1817) coined 12 PROTOZOOLOGY the term Protozoa, including in it the coelenterates. Ten years later there appeared d'Orbigny's systematic study of the Foramini- fera, which he considered "microscopical cephalopods." In 1828 Ehrenberg began publishing his observations on Protozoa and in 1838 he summarized his contributions in Die Infusionsthierchen als Vollkommene Organismen, in which he diagnosed genera and species so well that many of them still hold good. Ehrenberg excluded Rota- toria and Cere aria from Infusoria. Through the studies of Ehrenberg the number of known Protozoa increased greatly; he, however, pro- posed the term "Polygastricha," under which he placed Mastigo- phora, Rhizopoda, Ciliata, Suctoria, desmids, etc., since he believed that the food vacuoles present in them were stomachs. This hypothe- sis became immediately the center of controversy, which incidentally, together with the then-propounded cell theory and improvements in microscopy, stimulated researches on Protozoa. Dujardin (1835) took pains in studying the protoplasm of various Protozoa and found it alike in all. He named it sarcode. In 1841 he published an extensive monograph of various Protozoa which came under his observations. The term Rhizopoda was coined by this investigator. The commonly used term protoplasm was coined by Purkinje in 1840. The Protozoa was given a distinct definition by Siebold in 1845, as follows: "Die Thiere, in welchen die verschied- enen Systeme der Organe nicht scharf ausgeschieden sind, und deren unregelmassige Form und einfache Organization sich auf eine Zelle reduzieren lassen." Siebold subdivided Protozoa into Infusoria and Rhizopoda. The sharp differentiation of Protozoa as a group cer- tainly inspired numerous microscopists. As a result, various stu- dents brought forward several group names, such as Radiolaria (J. Muller, 1858), Ciliata (Perty, 1852), Flagellata (Cohn, 1853), Suctoria (Claparede and Lachmann, 1858), Heliozoa, Protista (Haeckel, 1862, 1866), Mastigophora (Diesing, 1865), etc. Of Suc- toria, Stein failed to see the real nature (1849), but his two mono- graphs on Ciliata and Mastigophora (1854, 1859-1883) contain con- cise descriptions and excellent illustrations of numerous species. Haeckel (1873), who went a step further than Siebold by distinguish- ing between Protozoa and Metazoa, devoted ten years to his study of Radiolaria, especially those of the Challenger collection, and de- scribed in his celebrated monographs more than 4000 species. In 1879 the first comprehensive monograph on the Protozoa of North America was put forward by Leidy under the title of Fresh- water Rhizopods of North America, which showed the wide distribu- tion of many known forms of Europe and revealed a number of new INTRODUCTION 13 and interesting forms. This work was followed by Stokes' The Fresh- water Infusoria of the United States, which appeared in 1888. Butschli (1880-1889) established Sarcodina and made an excellent contribution to the taxonomy of the then-known species of Protozoa, which is still considered as one of the most important works on gen- eral protozoology. The painstaking researches by Maupas, on the conjugation of ciliates, corrected erroneous interpretation of the phenomenon observed by Balbiani some thirty years before and gave impetus to a renewed cytological study of Protozoa. The variety in form and structure of the protozoan nuclei became the subject of in- tensive studies by several cytologists. Weismann (1881) put into words the immortality of the Protozoa. Schaudinn contributed much toward the cytological and developmental studies of Protozoa. In the first year of the present century, Calkins in the United States and Doflein in Germany wrote modern textbooks on protozo- ology dealing with the biology as well as the taxonomy. Calkins initiated the so-called isolation pedigree culture of ciliates in order to study the physiology of conjugation and other phenomena connected with the life-history of the ciliates. Recently application of bacteria- free culture technique to certain free-living flagellates and ciliates has brought to light hitherto unknown facts regarding nutritional re- quirements of these organisms. Today the Protozoa are more and more intensively and exten- sively studied from both the biological and the parasitological sides, and important contributions appear continuously. Since all parasitic Protozoa appear to have originated in free-living forms, the com- prehension of the morphology, physiology, and development of the latter group is obviously fundamentally important for a thorough understanding of the former group. Compared with the advancement of our knowledge on free-living Protozoa, that on parasitic forms has been very slow. This is to be ex- pected, of course, since the vast majority of them are so minute that the discovery of their presence has been made possible only through improvements in the microscope and in technique. Here again Leeuwenhoek seems to have been the first to observe a parasitic protozoan, for he observed, according to Dobell, in the fall of 1674, the oocysts of the coccidian, Eimeria stiedae, in the con- tents of the gall bladder of an old rabbit; in 1681, Giardia intestinalis in his own diarrhceic stools; and in 1683, Opalina and Nyctotherus in the gut contents of frogs. The oral Trichomonas of man was ob- served by O. F. Miiller (1773) who named it Cercaria tenax (Dobell, 1939). There is no record of anyone having seen Protozoa living in 14 PROTOZOOLOGY other organisms, until 1828, when Dufour's account of the gregarine from the intestine of coleopterous insects appeared. Some ten years later. Hake rediscovered the oocysts of Eimeria stiedae. A flagellate was observed in the blood of salmon by Valentin in 1841, and the frog trypanosome was discovered by Gluge and Gruby (1842), the latter author creating the genus Trypanosoma for it. The gregarines were a little later given attention by Siebold (1839), KoUiker (1848) and Stein (1848). The year 1849 marks the first rec- ord of an amoeba being found in man, for Gros then observed Enta- moeba gingivalis in the human mouth. Five years later, Davaine found in the stools of cholera patients two flagellates (Trichomonas and Chilomastix). Kloss in 1855 observed the coccidian, Klossia heli- cina, in the excretory organ of Helix ; and Eimer (1870) made an ex- tensive study of Coccidia occurring in various animals. Balantidium coll was discovered by Malmsten in 1857. Lewis in 1870 observed Entamoeba coli in India, and Losch in 1875 found Entamoeba histo- lytica in Russia. At the beginning of the last century, an epidemic disease, pebrine, of the silkworm appeared in Italy and France, and a number of biologists became engaged in its investigation. Foremost of all, Pasteur (1870) made an extensive report on the nature of the causative organism, now known as Nosema bombycis, and also on the method of control and prevention. Perhaps this is the first scientific study of a parasitic protozoan to result in an effective practical method of control of its infection. Lewis observed in 1878 an organism which is since known as Trypanosoma lewisi in the blood of rats. In 1879 Leuckart created the group "Sporozoa," including in it the gregarines and coccidians. Other groups under Sporozoa were soon definitely designated. They are Myxosporidia (Biitschli, 1881), Microsporidia and Sarcosporidia (Balbiani, 1882). Parasitic protozoology received a far-reaching stimulus when Laveran,(1880) discovered the malarial parasite in the human blood. Smith and Kilbourne (1893) demonstrated that the Babesia of the Texas fever of cattle in the southern United States was transmitted by the cattle tick from host to host, and thus brought to light for the first time the close relationship which exists between an arthropod and a parasitic protozoan. Two years later, Bruce discovered Try- panosoma brucei in the blood of horses and cattle suffering from "nagana" disease in Africa, and in the following year he showed by experiments that the tsetse fly transmits the trypanosome from host to host. Studies of malarial diseases continued and several important contributions appeared. Golgi (1886, 1889) studied the schizogony INTRODUCTION 15 and its relation to the occurrence of fever and was able to distinguish two types of fever. MacCallum (1897-1898) found in the United States the union of a microgamete and a macrogamete of Haemopro- teus of birds. Almost at the same time, Schaudinn and Siedlecki (1897) showed that anisogamy results in the production of zygotes in Coccidia. The latter author published later further observations on the life-cycle of Coccidia (1898, 1899). Ross (1898) showed how Plasmodium relictum (P. praecox) was carried by Culex fatigans and described its life-cycle. Since that time several investigators have brought to light important observations concerning the biology and development of malarial organisms and their relation to man. In the present centur}'^, Forde and Button (1901) observed that the sleeping sickness in equatorial Africa was due to an infection by Trypanosoma gambiense. In 1903 Leishman and Donovan recognized Leishmania of "kala-azar." Artificial cultivation of bacteria had contributed toward a very rapid advancement in bacteriology, and it was natural, as the num- ber of known parasitic Protozoa rapidly increased, that attempts to cultivate them in vitro should be made. Musgrave and Clegg (1904) cultivated, on bouillon-agar, small free-living amoebae from old faecal matter. In 1905 Novy and McNeal cultivated successfully the trypanosome of birds in blood-agar medium, which remained free from bacterial contamination and in which the organisms underwent multiplication. Almost all species of Trypanosoma and Leishmania have since been cultivated in a similar manner. This serves for de- tection of a mild infection and also identification of the species in- volved. It was found, further, that the changes which these organ- isms underwent in the culture media were imitative of those that took place in the invertebrate host, thus contributing toward the life-cycle studies of them, Bass (1911), and Bass and Johns (1912) demonstrated that Plas- modium of man could be cultivated in vitro for a few generations. During and since the World War I, it became known that numerous intestinal Protozoa of man are widely present throughout the tropi- cal, subtropical and temperate zones. Taxonomic, morphological and developmental studies on these forms have therefore appeared in an enormous number. Cutler (1918) seems to have succeeded in cultivating Entamoeba histolytica, though his experiment was not repeated by others. Barrett and Yarborough (1921) cultivated Balantidium coli and Boeck (1921) cultivated Chilomastix mesnili. Boeck and Drbohlav (1925) succeeded in cultivating Entamoeba histolytica, and their work was repeated and improved upon by sev- 16 PROTOZOOLOGY eral investigators. While the cultivation has not yet thrown much light on this and similar amoebae, it has revealed certain evidences that there is no sexual reproduction in these amoebae. References BtJTSCHLi, O. 1887-1889 Bronn's Klassen und Ordnungen des Thier-reichs. Vol. 1, Part 3. Calkins, G. N. 1933 The biology of the Protozoa. 2 ed. Philadelphia. Cole, F. J. 1926 The history of protozoology . London. DoBELL, C. 1911 The principles of protistology. Arch. f. Protis- tenk., Vol. 23. 1932 Antony van Leeuivenhoek and his "little animals.'' New York. 1939 The common flagellate of the human mouth, Tri- chomonas tenax (O.F.M.): its discovery and its nomenclature. Parasitology, Vol. 31. DoFLEiN, F. and E. Reichenow. 1929 Lehrhuch der Protozoen- kunde. 5 ed. Jena. DujARDiN, F. 1841 Histoire natiirelle des Zoophytes. Paris. Kudo, R. R. 1944 Manual of Human Protozoa. Springfield, Illinois. Nordenskiold, E. 1928 The history of biology. New York. Woodruff, L. L. 1937 Louis Joblot and the Protozoa. Sci. Monthly, Vol. 94. 1939 Some pioneers in microscopy, with special reference to protozoology. Tr. N. Y. Acad. Sci., Ser. 2, Vol. 1. Chapter 2 Ecology WITH regard to their habitats, the Protozoa may into free-living forms and those Hving on or in other organisms. Mastigophora, Sarcodina, Cihata, and Suctoria include both free- living and parasitic Protozoa, but Sporozoa are exclusively parasi- tic. The free-living Protozoa The vegetative or trophic stages of free-living Protozoa have been found in every type of fresh and salt water, soil and decaying or- ganic matter. Even in the circumpolar regions or at extremely high altitudes, certain protozoa occur at times in fairly large numbers. The factors, which influence their distribution in a given body of wa- ter, are temperature, light, chemical composition, acidity, kind and amount of food, and degree of adaptability of the individual proto- zoans to various environmental changes. Their early appearance as living organisms, their adaptability to various habitats, and their capacity to remain viable in encysted condition, probably account for the wide distribution of the Protozoa throughout the world. The common free-living amoebae, numerous testaceans and others, to mention a few, of fresh waters, have been observed in innumerable places of the world. Temperature. The majority of Protozoa are able to live only within a small range of temperature variation, although in the en- cysted state they can withstand a far greater temperature fluctua- tion. The lower limit of the temperature is marked by the freezing of the protoplasm, and the upper limit by the destructive chemical change within the body protoplasm. The temperature toleration seems to vary among different species of Protozoa; and even in the same species under different conditions. For example, Chalkley (1930) placed Paramecium caudatum in 4 culture media (balanced saline, saline with potassium excess, saline with calcium excess, and saline with sodium excess), all with pH from 5.8 or 6 to 8.4 or 8.6, at 40°C. for 2-16 minutes and found that (1) the resistance varies with the hydrogen-ion concentration, maxima appearing in the alkaline and acid ranges, and a minimum at or near about 7.0; (2) in a bal- anced saline, and in saline with an excess of sodium or potassium, the alkaline maximum is the higher, while in saline with an excess of calcium, the acid maximum is the higher; (3) in general^ acidity de- creases and alkalinity increases resistance; and (4) between pH 6.6 17 18 PROTOZOOLOGY and 7.6, excess of potassium decreases resistance and excess of cal- cium increases resistance. Glaser and Coria (1933) cultivated Para- mecium caudatum on dead yeast free from living organisms at 20-28°C. (optimum 25°C.) and noted that at 30°C. the organisms were killed. Doudoroff (1936), on the other hand, found that in P. multimicronucleatum its resistance to raised temperature was low in the presence of food, but rose to a maximum when the food was exhausted, and there was no appreciable difference in the resistance between single and conjugating individuals. The thermal waters of hot springs have been known to contain liv- ing organisms including Protozoa. Glaser and Coria obtained from the thermal springs of Virginia, several species of Mastigophora, Ciliata, and an amoeba which were living in the water, the tempera- ture of which was 34-36°C., but did not notice any protozoan in the water which showed 39-41°C. Uyemura and his co-workers made a series of studies on Protozoa living in various thermal waters of Ja- pan, and reported that many species lived at unexpectedly high temperatures. Some of the Protozoa observed and the temperatures of the water in which they were found are as follows: Amoeba sp., Vahlkampfia Umax, A. radiosa, 30-51°C.; Amoeba verrucosa, Chilo- donella sp., Lionotus fasciola, Paraynecium caudatum, 36-40°C.; Oxytricha fallax, 30-56°C. Under experimental conditions, it has been shown repeatedly that many protozoans become accustomed to a very high temperature if the change be made gradually. Dallinger (1887) showed a long time ago that Tetramitus rostratus and two other species of flagellates became gradually acclimatized up to 70°C. in several years. In na- ture, however, the thermal death point of most of the free-living Protozoa appears to lie between 36° and 40°C. and the optimum temperature, between 16° and 25°C. On the other hand, the low temperature seems to be less detri- mental to Protozoa than the higher one. Many protozoans have been found to live in water under ice, and several haematochrome- bearing Phytomastigina undergo vigorous multiplication on snow in high altitudes, producing the so-called "red snow." Klebs (1893) sub- jected the trophozoites of Euglena to repeated freezing without ap- parent injury and Jahn (1933) found no harmful effect when Euglena cultures were kept without freezing at — 0.2°C. for one hour, but when kept at — 4°C. for one hour the majority were killed. Gaylord (1908) exposed Trypanosoma gambiense to liquid air for 20 minutes without apparent injury, but the organisms were killed after 40 min- utes' immersion. ECOLOGY 19 Kiihn (1864) observed that Amoeba and Actinophrys suffered no ill effects when kept at 0°C. for several hours as long as the culture medium did not freeze, but were killed when the latter froze. Molisch (1897) likewise noticed that Amoeba dies as soon as the ice forms in its interior or immediate vicinity. Chambers and Hale (1932) dem- onstrated that internal freezing could be induced in an amoeba by inserting an ice-tipped pipette at — 0.6°C., the ice spreading in the form of fine featherly crystals from the point touched by the pipette. They found that the internal freezing kills the amoebae, although if the ice is prevented from forming, a temperature as low as — 5°C. brings about no visible damage to the organism. At 0°C., Deschiens (1934) found the trophozoites of Entamoeba histolytica remained alive, though immobile, for 56 hours, but were destroyed in a short time when the medium froze at — 5°C. According to Greeley, when Stentor coeruleus was slowly sub- jected to low temperatures, the cilia kept on beating at 0°C. for 1-3 hours, then cilia and gullet were absorbed, the ectoplasm was thrown off, and the body became spherical. When the temperature was raised, this spherical body is said to have undergone a reverse proc- ess and resumed its normal activity. If the lowering of temperature is rapid and the medium becomes solidly frozen, Stentor perishes. Efimoff (1924) observed that Paramecium multiplied once in about 13 days at 0°C., withstood freezing at — 1°C. for 30 minutes, but died when kept for 50-60 minutes at the same temperature. He further stated that Paramecium caudatum, Colpidium colpoda, and Spiro- stomum amhiguum, perished in less than 30 minutes, when ex- posed below — 4°C., and that quick and short cooling (not lower than — 9°C.) produced no injury, but if it is prolonged, Paramecium be- came spherical and swollen to- 4-5 times normal size, while Colpid- ium and Spirostomum shrunk. Wolfson (1935) studied Paramecium sp. in gradually descending subzero-temperature, and observed that as the temperature decreases the organism often swims backward, its bodily movements cease at — 14.2°C., but the cilia continue to beat for some time. While Paramecium recover completely from a momentary exposure to — 16°C., long cooling at this temperature brings about degeneration. When the water in which the organisms are kept freezes, no survival was noted. Plasmodium knowlesi and P. inui in the blood of Macacus rhesus remain viable, according to Coggeshall (1939), for as long as 70 days at — 76°C., if frozen and thawed rapidly. Light. In the Phytomastigina which include chromatophore-bear- ing flagellates, the sun light is essential to photosynthesis (p. 92). The 20 PROTOZOOLOGY sun light further plays an important role in those protozoans which are dependent upon chromatophore-possessing organisms as chief source of food supply. Hence the light is another factor concerned with the distribution of free-living protozoans in the water. Chemical composition of water. The chemical nature of the water is another important factor which influences the very existence of Protozoa in a given body of water. Protozoa differ from one another in morphological as well as physiological characteristics. Individual protozoan species requires a certain chemical composition of the wa- ter in which it can be cultivated under experimental conditions, al- though this may be more or less variable among different forms (Needham et al., 1937). In their "biological analysis of water" Kolkwitz and Marsson (1908, 1909) distinguished four types of habitats for many aquatic plant, and a few animal, organisms, which were based upon the kind and amount of inorganic and organic matter and amount of oxygen present in the water: namely, katharobic, oligosaprobic, mesosapro- bic, and polysaprobic. Katharobic protozoans are those which live in mountain springs, brooks, or ponds, the water of which is rich in oxygen, but free from organic matter. Oligosaprobic forms are those that inhabit waters which are rich in mineral matter, but in which no purification processes are taking place. Many Phytomastigina, various testaceans and many ciliates, such as Frontonia, Lacrymaria, Oxytricha, Stylonychia, Vorticella, etc. inhabit such waters. Meso- saprobic protozoans live in waters in which active oxidation and de- composition of organic matter are taking place. The majority of freshwater protozoans belong to this group: namely, numerous Phytomastigina, Heliozoa, Zoomastigina, and all orders of Ciliata. Finally polysaprobic forms are capable of living in waters which, because of dominance of reduction and cleavage processes of organic matter, contain at most a very small amount of oxygen and are rich in carbonic acid gas and nitrogenous decomposition products. The black bottom slime contains usually an abundance of ferrous sul- phide and other sulphurous substances. Lauterborn (1901) called this sapropelic. Examples of polysaprobic protozoans are Pelomyxa palustris, Euglypha alveolata, Pamphagus armatus, Mastigamoeba, Trepomo7ias agilis, Hexamita inflata, Rhynchomonas nasuta, Hetero- nema acus, Bodo, Cercomonas, Dactylochlamys, Ctenostomata, etc. The so-called "sewage organisms" abound in such habitat (Lackey). Certain free-living Protozoa which inhabit waters rich in decom- posing organic matter are frequently found in the faecal matter of various animals. Their cysts either pass through the alimentary ECOLOGY 21 canal of the animal unharmed or are introduced after the faeces are voided, and undergo development and multiplication in the faecal infusion. Such forms are collectively called coprozoic Protozoa. The coprozoic protozoans grow easily in suspension of old faecal matter which are rich in decomposed organic matter and thus show a strik- ingly strong capacity of adapting themselves to conditions different from those of the water in which they normally live. Some of the Protozoa which have been referred to as coprozoic and which are mentioned in the present work are, as follows: Scytomonas pusilla, Rhynchomonas nasuta, Cercomonas longicauda, C. crassicauda, Tre- yomonas agilis, Dimastig amoeba gruheri, Acanthamoeba hyalina, Chlamydophrys stercorea and Tillina magna. As a rule, the presence of sodium chloride in the sea water prevents the occurrence of the large number of fresh-water inhabitants. Cer- tain species, however, have been known to live in both fresh and brackish or salt water. Among the species mentioned in the present work, the following species have been reported to occur in both fresh and salt waters: Mastigophora: Amphidinium lacustris, Cerat- ium hirundinella; Sarcodina: Lieberkuhnia wagneri; Ciliata: Meso- dinium pulex, Prorodon discolor, Lacrymaria olor, Amphileptus claparedei, Lionotus fasciola, Nassula aurea, Trochilioides recta, Chilodonella cucullulus, Trimyema compressum, Paramecium cal- kinsi, Colpidium campylum, Platynematum sociale, Cinetochilum margaritaceum, Pleuronema coronatum, Caenomorpha medusula, Spirostomum minus, S. teres, Climacostomum virens, and Thuricola follicidata; Snctoria: Metacineta mystacina, Endosphaera engelmanni. It seems probable that many other protozoans are able to live in both fresh and salt water, judging from the observations such as that made by Finley (1930) who subjected some fifty species of freshwater Protozoa of Wisconsin to various concentrations of sea water, either by direct transfer or by gradual addition of the sea water. He found that Bodo uncinatus, Uronema marina, Pleuron- ema jaculans and Colpoda aspera are able to live and reproduce even when directly transferred to sea water, that Amoeba verrucosa, Euglena, Phacus, Monas, Cyclidium, Euplotes, Lionotus, Para- mecium, Styl onychia, etc., tolerate only a low salinity when directly transferred, but, if the salinity is gradually increased, they live in 100 per cent sea water, and that Arcella, Cyphoderia, Aspidisca, Ble- pharisma, Colpoda cucullus, Halteria, etc. could not tolerate 10 per cent sea water even when the change was gradual. Finley noted no morphological changes in the experimental protozoans which might be attributed to the presence of the salt in the water, except Amoeba 22 PROTOZOOLOGY verrucosa, in which certain structural and physiological changes were observed as follows: as the salinity increased, the pulsation of the contractile vacuole became slower. The body activity continued up to 44 per cent sea water and the vacuole pulsated only once in 40 minutes, and after systole, it did not reappear for 10-15 minutes. The organism became less active above this concentration and in 84 per cent sea water the vacuole disappeared, but there was still a tendency to form the characteristic ridges, even in 91 per cent sea water, in which the organism was less fan-shaped and the cytoplasm seemed to be more viscous. Yocom (1934) found that Eiiplotes pa- tella was able to live normally and multiply up to 66 per cent of sea water; above that concentration no division was noticed, though the organism lived for a few da3^s in up to 100 per cent salt water, and Paramecium caudatum and Spirostomum ambiguum were less adaptive to salt water, rarely living in 60 per cent sea water. Frisch (1935) found that no freshwater Protozoa lived above 40 per cent sea water and that Paramecium caudatum and P. multimicronucle- atum died in 33-52 per cent sea water. Hardin (1942) reports that Oikomonas termo will grow when transferred directly to a glycerol- peptone culture medium, in up to 45 per cent sea water, and cultures contaminated with bacteria and growing in a dilute glycerol-peptone medium will grow in 100 per cent sea water. Hydrogen-ion concentration. Closely related to the chemical com- position is the hydrogen-ion concentration (pH) of the water which influences the distribution of Protozoa. The hydrogen-ion concentra- tion of freshwater bodies vary a great deal between highly acid bog waters in which various testaceans may frequently be present, to highly alkaline water in which such forms as Acanthocystis, Hyalo- bryon, etc., occur. In standing deep fresh water, the bottom region is often acid because of the decomposing organic matter, while the surface water is less acid or slightly alkaline due to the photosyn- thesis of green plants which utilize carbon dioxide. In some cases different pH may bring about morphological differences. For exam- ple, in bacteria-free cultures of Paramecium hursaria in a tryptone medium, Loefer (1938) found that at pH 7.6-8.0 the length averaged 86 or 87m, but at 6.0-6.3 the length was about 129^. The greatest variation took place at pH 4.6 in which no growth occurred. The shortest animals at the acid and alkaline extremes of growth, were the widest, while the narrowest forms (about 44ju wide) were found in culture at pH 5.7-7.4. Several workers have made observations on the pll range of the water or medium in which certain proto- zoans live, grow, and multiply, which data are collected in Table 1. ECOLOGY 23 Table 1. — Protozoa and hydrogen-ion concentration pH range of Protozoa medium in which Optimum Observers growth occurs range A. In bacteria-free cultures Euglena gracilis 3.5-9.0 — Dusi 3.0-7.7 6.7 Alexander 3.9-9.9 6.6 Jahn E. deses 6.5-8.0 7.0 Dusi 5.3-8.0 7.0 Hall E. pisciformis 6.0-8.0 6.5-7.5 Dusi 5.4-7.5 6.8 Hall Chilomonas Paramecium 4.8-8.0 6.8 Mast and Pace 4.1-8.4 4.9;7.0 Loefer Chlorogoniiim euchlorum 4.8-8.7 7.1-7.5 Loefer C. elongatum 4.8-8.7 7.1-7.5 Loefer C. teragamum 4.2-8.6 6.7-8.3 Loefer Colpidium campylum — 5.4 Kidder Glaucoma scintillans — 5.6-6.8 Kidder G. ficaria 4.0-9.5 5.1;6.7 Johnson Tetrahymena geleii — 5.6-8.0 Kidder T. vorax — 6.2-7.6 Kidder Paramecirim bursaria 5.3-8.0 6.7-6.8 Loefer B. In cultures containing bacteria Carteria ohtusa — 3.5-4.5 Wermel Acanthocystis aculeata 7.4 or above 8.1 Stern Paramecium caudatum 5.3-8.2 7.0 Darby 6.0-9.5 7.0 Morea P. aurelia 5.7-7.8 6.7 Morea 5.9-8.2 5.9-7.7 Phelps P. mullimicronucleatum 4.8-8.3 7.0 Jones P. sp. 7.8-8.0 Saunders 7.0-8.5 7.8-8.0 Pruthi Colpidium sp. 6.0-8.5 — Pruthi Colpoda cucullus 5.5-9.5 6.5;7.5 Morea Holophyra sp. 6.5-7.4 — Pruthi Plagiopyla sp. 6.9-7.5 — Pruthi Amphileptus sp. 6.8-7.5 7.1-7.3 Pruthi Spirostomum amhiguum 6.8-7.5 7.4 Saunders S. sp. 6.5-8.0 7.5 Morea Stentor coeruleus 7.8-8.0 — Hetherington Blepharisma undulans — 6.5 Moore Gastrostyla sp. 6.0-8.5 — Pruthi Stylonychia pustidata 6.0-8.0 6.7;8.0 Darby Seemingly various Protozoa require a definite pH value in order to carry on maximum metabolic activities. As a matter of fact, 24 PROTOZOOLOGY Pringsheim, Hall, Loefer, Johnson, and others, found that sodium acetate may increase or decrease the growth rate of various Phyto- mastigina subject to the hydrogen-ion concentration of the culture media. Food. The kind and amount of food available in a given body of water also controls the distribution of Protozoa. The food is ordinarily one of the deciding factors of the number of Protozoa in a natural habitat. Species of Paramecium and many other holo- zoic protozoans cannot live in waters in which bacteria or minute protozoans do not occur. If other conditions are favorable, then the greater the number of food bacteria, the greater the number of these protozoans. Didinium nasutum feeds almost exclusively on Para- mecium, hence it cannot live in the absence of the latter ciliate. As a rule, euryphagous protozoans are widely distributed and stenophagous forms are limited in their distribution. Some protozoans inhabit soil of various types and localities. Un- der ordinary circumstances, they occur near the surface, their maxi- mum abundance being found at a depth of about 10-12 cm. (Sandon, 1927). It is said that a very few protozoans occur in the subsoil. Here also one notices a very wide geographical distribution of ap- parently one and the same species. For example, Sandon found Amoeba proteus in samples of soil collected from Greenland, Tristan da Cunha, Gough Island, England, Mauritius, Africa, India, and Argentina. This amoeba is known to occur in various parts of North America, Europe, Japan, and Australia. The majority of Testacea inhabit moist soil in abundance. Sandon observed Trinema enchelys in the soils of Spitzbergen, Greenland, England, Japan, Australia, St. Helena, Barbados, Mauritius, Africa, and Argentina. The parasitic Protozoa ' Some Protozoa belonging to all groups live on or in other organ- isms. The Sporozoa are made up exclusively of parasites. The rela- tionships between the host and the protozoan differ in various ways, which make the basis for distinguishing the associations into three types as follows: commensalism, symbiosis, and parasitism. Commensalism is an association in which an organism, the com- mensal, is benefited, while the host is neither injured nor benefited. Depending upon the location of the commensal in the host body, the term ectocommensalism or endocommensalism is used. Ecto- commensalism is often represented by Protozoa which may attach themselves to any aquatic animals that inhabit the same body of water, as shown by various species of Chonotricha, Peritricha, and ECOLOGY 25 Suctoria. In other cases, there is a definite relationship between the commensal and the host. For example, Kerona polyporum is found on various species of Hydra, and many ciliates placed in Thigmo- tricha (p. 623) are inseparably associated with certain species of the mussels. Endocommensalism is often difficult to distinguish from endo- parasitism, since the effect of the presence of a commensal upon the host cannot be easily understood. On the whole, the protozoans which live in the lumen of the alimentar}^ canal may be looked upon as endocommensals. These protozoans undoubtedly use part of the food material which could be used by the host, but they do not in- vade the host tissue. As examples of endocommensals may be men- tioned: Endamoeha hlattae, Lophomonas blattarum, L. striata, Nyciotherus ovalis, etc., of the cockroach; Entamoeba coli, lodamoeba biitschlii, Endolimax nana, Dientamoeba fragilis, Chilomasiix mes- nili, etc., of the human intestine; numerous species of Protociliata of Anura, etc. Because of the difficulties mentioned above, the term parasitic Protozoa, in its broad sense, includes the commenals also. Symbiosis on the other hand is an association of two species of organisms, which is of mutual benefit. The cryptomonads belonging to Chrysidella ("Zooxanthellae") containing yellow or brown chrom- atophores, which live in Foraminifera and Radiolaria, and certain algae belonging to Chlorella ("Zoochlorellae") containing green chromatophores, which occur in some freshwater protozoans, such as Paramecium bursaria, Stentor amethystinus, etc., are looked upon as holding symbiotic relationship with the respective protozoan host. Several species of the highly interesting Hypermastigina, which are present commonly and abundantly in various species of termites and the woodroach Cryptocercus, have been demonstrated by Cleveland to digest the cellulose material which makes up the bulk of wood- chips the host animals take in and to transform it into glycogenous substances that are used partly by the host insects. If deprived of these flagellates by being subjected to oxygen under pressure or to a high temperature, the termites die, even though the intestine is filled with wood-chips. If removed from the gut of the termite, the flagellates die. Thus the association here may be said to be an abso- lute symbiosis. Parasitism is an association in which one organism (the parasite) lives at the expense of the other (the host). Here also ectoparasitism and endoparasitism occur, although the former is not commonly found. Hydramoeba hydroxena (p. 370) feeds on the body cells of Hydra which, according to Reynolds and Looper, die on an average 26 PROTOZOOLOGY in 6.8 days as a result of the infection and the amoebae disappear in from 4 to 10 days if removed from a host Hydrsi. Costia necatrix (p. 297) often occurs in an enormous number, attached to various freshwater fishes especially in an aquarium, by piercing through the epidermal cells and appears to disturb the normal functions of the host tissue. Ichthyophthirius muUifiliis (p. 568), another ectoparasite of freshwater fishes, goes further by completely burying themselves in the epidermis and feeds on the host's tissue cells and, not infre- quently, contributes toward the cause of the death of the host fishes. The endoparasites absorb by osmosis the vital body fluid, feed on the host cells or cell-fragments by pseudopodia or cytostome, or enter the host tissues or cells themselves, living on the cj^oplasm or in some cases on the nucleus. Consequently they bring about abnor- mal or pathological conditions upon the host which often succumbs to the infection. Endoparasitic Protozoa of man are Entamoeba histolytica, Balantidium coli, species of Plasmodium and Leishmania, Trypanosoma gamhiense, etc. The Sporozoa, as was stated before, are without exception coelozoic, histozoic, or cytozoic parasites. Because of their modes of living, the endoparasitic Protozoa cause certain morphological changes in the cells, tissues, or organs of the host. The active growth of Entamoeba histolytica in the glands of the colon of the victim, produces slightly raised nodules first which de- velop into abscesses and the ulcers formed by the rupture of ab- scesses, may reach 2 cm. or more in diameter, completely destroying the tissues of the colon wall. Similar pathological changes are also noticed in the case of infection by Balantidium coli. In Leishmania donovani, the victim shows an increase in number of the large macro- phages and mononuclears and also an extreme enlargement of the spleen. Trypanosoma cruzi brings about the degeneration of the in- fected host cells and an abundance of leucocytes in the infected tissues, followed by an increase of fibrous tissue. T. gambiense, the causative organism of African sleeping sickness, causes enlargement of lymphatic glands and spleen, followed by changes in meninges and an increase of cerebro-spinal fluid. Its most characteristic changes are the thickening of the arterial coat and the round-celled infiltration around the blood vessels of the central nervous system. Brand's (1938) summary of the carbohydrate metabolism of the pathogenic trj^panosomes tends to show that the sugar is only par- tially oxidized in the presence of oxygen and that the carbohydrate metabolism of the infected host is disturbed, as shown mainly by the unbalanced condition of the blood sugar, by lowering of the glycogen reserves, and by reduced ability to build glycogen from ECOLOGY 27 sugar. Malarial infection is invariably accompanied by an enormous enlargement of the spleen ("spleen index"); the blood becomes watery; the erythrocytes decrease in number; the leucocytes, sub- normal; but mononuclear cells increase in number; pigment granules which are set free in the blood plasma at the time of merozoite- liberation are engulfed by leucocytes; and enlarged spleen contains large amount of pigments which are lodged in leucocytes and endo- thelial cells. In Plasmodium falciparum, the blood capillaries of brain, spleen and other viscera may completely be blocked by in- fected erythrocytes. pfiKppillTf Fig. 1. Histological changes in host fish caused by myxosporidian in- fection, X1920 (Kudo), a, portion of a cyst of Myxobolus intestinalis, sur- rounded by peri-intestinal muscle of the black crappie; b, part of a cyst of Thelohanellus notatus, enveloped by the connective tissue of the blunt- nosed minnow. In Myxosporidia which are either histozoic or coelozoic parasites of fishes, the tissue cells that are in direct contact with highly en- larging parasites, undergo various morphological changes. For exam- ple, the circular muscle fibers of the small intestine of Pomoxis sparoides, which surround Myxobolus intestinalis, a myxosporidian, become modified a great deal and turn about 90° from the original direction, due undoubtedly to the stimulation exercised by the myxosporidian parasite (Fig. 1, a). In the case of another myxo- sporidian, Thelohanellus notatus, the connective tissue cells of the host fish surrounding the protozoan body, transform themselves into 28 PROTOZOOLOGY "epithelial cells" (Fig. 1, h), a state comparable to the formation of the ciliated epithelium from a layer of fibroblasts lining a cyst formed around a piece of ovary inplanted into the adductor muscle of Pecten as observed by Drew (1911). Practically all Microsporidia are cytozoic, and the infected cells become hypertrophied enormously, producing in one genus the so- called Glugea cysts (Fig. 257). In many cases, the hypertrophy of the nucleus of the infected cell is far more conspicuous than that of the cytoplasm (Fig. 255). Information concerning toxic substances produced by parasitic Protozoa is meager. Sarcosporidia appear to produce a certain toxic substance which, when injected into the blood vessel, is highly toxic to experimental animals. This was named sarcocystine (Laveran and Mesnil) or sarcosporidio toxin (Teichmann and Braun). For the great majority of parasitic Protozoa, there exists a de- finite host-parasite relationship and animals other than the specific hosts possess a natural immunity against an infection by a particular parasitic protozoan. Immunity involved in diseases caused by Pro- tozoa has been most intensively studied on haemozoic forms, es- pecially Plasmodium and Trypanosoma, since they are the causative organisms of important diseases. Development of these organisms in hosts depends on various factors such as the species and strains of the parasites, the species and strains of vectors, and immunity of the host. Boyd and co-workers showed that reinoculation of persons who have recovered from an infection with Plasmodium vivax or P. falciparum with the same strain of the parasites, will not result in a second clinical attack, because of the development of homologous immunity, but with a different strain of the same species or different species, a definite clinical attack occurs, thus there being no hetero- logous tolerance. The homologous immunity was found to continue for at least three years and in one case for about seven years in P. vivax, and for at least four months in P. falciparum after apparent eradication of the infection. In the case of leishmaniasis, recovery from a natural or induced infection apparently develops a lasting immunity against reinfection with the same species of Leishmania. It has been shown that in infections with avian, monkey and hu- man Plasmodium or Trypanosoma lewisi, a considerable number of the parasites are destroyed during the developmental phase of the infection and that after a variable length of time, resistance to the parasites often develops in the host, as the parasites disappear from the peripheral blood and symptoms subside, though the host still harbors the organisms. In malarious countries, the adults and chil- ECOLOGY 29 dren show usually a low and a high rate of malaria infection respect- ively, but the latter frequently do not show symptoms of infection, even though the parasites are detectable in the blood. Apparently repeated infection produces tolerance which can keep, as long as the host remains healthy, the parasites under control. There seems to be also racial difference in the degree of immunity against Plasmodium and Trypanosoma, as shown by James, Milam and Kusch, etc. As to the mechanism of immunity, the destruction of the parasites by phagocytosis of the endothelial cells of the spleen, bone marrow and liver and continued regenerative process to replace the de- stroyed blood cells, are the two important phases in the cellular de- fense mechanism. Besides, there are indications that humoral de- fense mechanism through the production of antibodies is in active operation in infections by Plasmodium knowlesi (Coggeshall and Kumm, Eaton, etc.) and trypanosomes (Taliaferro), With regard to the origin of parasitic Protozoa, it is generally agreed among biologists that the parasite in general evolved from the free-living form. The protozoan association with other organ- isms was begun when various protozoans which lived attached to, or by crawling on, submerged objects happened to transfer them- selves to various invertebrates which occur in the same water. These Protozoa benefit by change in location as the host animal moves about, and thus enlarging the opportunity to obtain a con- tinued supply of food material. Such ectocommensals are found abundantly; for example, the peritrichous ciliates attached to the body and appendages of various aquatic animals such as larval in- sects and microcrustaceans. Ectocommensalism may next lead to ectoparasitism as in the case of Costia or Hydramoeba, and then again instead of confining themselves to the body surface, the Pro- tozoa may bore into the body wall from outside and actually acquire the habit of feeding on tissue cells of the attached animals as in the case of Ichthyophthirius. The next step in the evolution of parasitism must have been reached when Protozoa, accidentally or passively, were taken into the digestive system of the Metazoa. Such a sudden change in habitat appears to be fatal to most protozoans. But certain others possess extraordinary capacity to adapt themselves to an entirely different environment. For example, Dobell (1918) observed in the tadpole gut, a typical free-living limax amoeba, with characteristic nucleus, contractile vacuoles, etc., which was found in numbers in the water containing the faecal matter of the tadpole. Glaucoma pyriformis (Tetrahymena geleii), a free-living ciliate, was found to 30 PROTOZOOLOGY occur in the body cavity of the larvae of Theohaldia annulata (after MacArthur) and in the larvae of Chironomus -plumosus (after Treil- lard and Lwoff). Lwoff successfully inoculated this ciliate into the larvae of Galleria mellonella which died later from the infection. Recently Janda and Jirovec (1937) injected bacteria-free culture of this ciliate into annelids, molluscs, crustaceans, insects, fishes, and amphibians, and found that only insects — all of 14 species (both larvae and adults) — became infected by this ciliate. In a few days after injection the haemocoele became filled with the ciliates. Of various organs, the ciliates were most abundantly found in the adipose tissue. The organisms were much larger than those present in the original culture. The insects, into which the ciliates were in- jected, died from' the infection in a few days. The course of develop- ment of the ciliate within an experimental insect depended not only on the amount of the culture injected, but also on the temperature. At 1-4°C. the development was much slower than at 26°C.; but if an infected insect was kept at 32-36°C. for 0.5-3 hours, the ciliates were apparently killed and the insect continued to live. When Glaucoma taken from Dixippus morosus were placed in ordinary water, they continued to live and underwent multiplication. The ciliate showed a remarkable power of withstanding the artificial digestion; namely, at 18°C. they lived 4 days in artificial gastric juice with pH 4.2; 2-3 days in a juice with pH 3.6; and a few hours in a juice with pH 1.0. Cleveland (1928) observed Tritrichomonas fecalis in faeces of a single human subject for three years which grew well in faeces diluted with tap water, in hay infusions with or with- out free-living protozoans or in tap water with tissues at —3° to 37°C., and which, when fed per os, was able to live indefinitely in the gut of frogs and tadpoles. Reynolds (1936) found that Colpoda steini, a free-living ciliate of fresh water, occurs naturally in the intestine and other viscera of the land slug, Agriolimax agrestis, the slug forms being much larger than the free-living individuals. It may be further speculated that Vahlkampfia, Hydramoeba, Schizamoeba, and Endamoeba, are the different stages of the course the intestinal amoebae might have taken during their evolution. Obviously endocommensalism in the alimentary canal was the initial phase of endoparasitism. When these endocommensals began to consume an excessive amount of food or to feed on the tissue cells of the host gut, they became the true endoparasites. Destroying or penetrating through the intestinal wall, they became first established in the body or organ cavities and then invaded tissues, cells or even nuclei, thus developing into pathogenic Protozoa. The endoparasites ECOLOGY 31 developing in invertebrates which feed upon the blood of vertebrates as source of food supply, will have opportunities to establish them- selves in the higher animals. References Calkins, G. N. and F. M. Summers (editors). 1941 Protozoa in biological research. New York. Chalkley, H. W. 1930 Resistance of Paramecium to heat as af- fected by changes in hydrogen-ion concentration and in inor- ganic salt balance in surrounding medium. U. S. Publ. Health. Rep., Vol. 45. Cleveland, L. R. 1926 Symbiosis among animals with special reference to termites and their intestinal flagellates. Quart. Rev. Biol., Vol. 1. 1928 Tritrichomonas fecalis nov. sp. of man; its ability to grow and multiply indefinitely in faeces diluted with tap water and in frogs and tadpoles. Amer. Jour. Hyg., Vol. 8. Dallinger, W. H. 1887 The president's address. Jour. Roy. Micr. Soc. for 1887. DoBELL, C. 1918 Are Entamoeba histolytica and Entamoeba ranarum the same species? Parasitology, Vol. 10. DouDOROFF, M. 1936 Studies in thermal death in Paramecium. Jour. Exp. Zool., Vol. 72. Efimoff, W. W. 1924 Ueber Ausfrieren und Ueberkaltung der Protozoen. Arch. f. Protistenk., Vol. 49. Finley, H. E. 1930 Toleration of freshwater Protozoa to increased salinity. Ecology, Vol. 11. Glaser, R. W. and ISF. A. Coria. 1933 The culture of Paramecium caudatum free from living microorganisms. Jour. Parasit. Vol. 20. Janda, V. and 0. Jirovec 1937 Ueber kiinstlich hervorgerufenen Parasitismus eines f reilebenden Ciliaten Glaucoma piriformis und Infektionsversuche mit Euglena gracilis und Spirochaeta hiflexa. Mem. soc. zool tehee, de Prague, Vol. 5. Kidder, G. W. 1941 Growth studies on cihates. VII. Biol. Bull., Vol. 80. Kolkwitz, R. and M. Marsson 1909 Oekologie der tierischen Saprobien. Intern. Rev. Ges. Hydrobiol. u. Hydrogr., Vol. 2. Kudo, R. R. 1929 Histozoic Myxosporidia found in freshwater fishes of Illinois, U.S.A. Arch. f. Protistenk., Vol. 65. Lackey, J. B. 1925 The fauna of Imhof tanks. Bull. New Jersey Agr. Exp. Stat., No. 417. Lauterborn, R. 1901 Die "sapropelische" Lebewelt. Zool. Anz., Vol. 24. Needhum, J. G., P. S. Galtsoff, F. E. Lutz and P. S. Welch. 1937 Culture methods for invertebrate animals. Ithaca, N.Y. Noland, L. E. 1925 Factors influencing the distribution of fresh- water ciliates. Ecology, Vol. 6. 32 PROTOZOOLOGY Reynolds, B. D. 1936 Colpoda steini, a facultative parasite of the land slug, Agriolimax agrestis. Jour. Parasit., Vol. 22. and J. B. Looper 1928 Infection experiments with Hydra- moeha hydroxena nov. gen. Ibid., Vol. 15. Sandon, H. 1927 The composition and distribution of the protozoan fauna of the soil. Edinburgh. Taliaferro, W. H. 1926 Host resistance and types of infections in trypanosomiasis and malaria. Quart. Rev. Biol., Vol. 1. VON Brand, T. 1938 The metabolism of pathogenic trypanosomes and the carbohydrate metabolism of their hosts. Ibid., Vol. 13. Wenyon, C. M. 1926 Protozoology. 2 vols. London and New York. WoLFSON, C. 1935 Observations on Paramecium during exposure to sub-zero temperatures. Ecology, Vol. 16. YocoM, H. B. 1934 Observations on the experimental adaptation of certain freshwater ciliates to sea water. Biol. Bull., Vol. 67. Chapter 3 Morphology PROTOZOA range in size from ultramicroscopic to macroscopic, though they are on the whole minute microscopic animals. The parasitic forms, especially cytozoic parasites, are often extremely small, while free-living protozoans are usually of much larger dimen- sions. Noctiluca, Foraminifera, Radiolaria, many ciliates such as Stentor, Bursaria, etc., represent larger forms. Colonial proto- zoans such as Carchesium, Zoothamnium, Ophrj^dium, etc., are even greater than the solitary forms. On the other hand, Plasmodium, Leishmania, and microsporidian spores may be mentioned as exam- ples of the smallest forms. The unit of measurement employed in protozoology is, as in general microscopy, 1 micron (ju) which is equal to 0.001 mm. The body form of Protozoa is even more varied, and because of its extreme plasticity it frequently does not remain constant. Fur- thermore the form and size of a given species may vary according to the kind and amount of food as is discussed elsewhere (p. 94). From a small simple spheroidal mass up to large highly complex forms, all possible body forms occur. Although the great majority are without symmetry, there are some which possess a definite symmetry. Thus bilateral symmetry is noted in all members of Diplomonadina (p. 311); radial symmetry in Gonium, Cyclonexis, etc.; and universal symmetry, in certain Heliozoa, Volvox, etc. The fundamental component of the protozoan body is the pro- toplasm which is without exception differentiated into the nucleus and the cytosome. Haeckel's monera are now considered as non- existent, since improved microscopic technique has failed in recent years to reveal any anucleated protozoans. The nucleus and the cyto- some are inseparably important to the well-being of a protozoan, as has been shown by numerous investigators since Verworn's pioneer work. In all cases, successful regeneration of the body is accomplished only by the nucleus-bearing portions and enucleate parts degenerate sooner or later. On the other hand, when the nucleus is taken out of a protozoan, both the nucleus and cytosome degenerate, which indi- cates their intimate association in carrying on the activities of the body. It appears certain that the nucleus controls the assimilative phase of metabclism which takes place in the cytosome in normal animals, while the cytosome is capable of carrying on the catabolic 33 34 PROTOZOOLOGY phase of the metabolism. Aside from the importance as the control- ling center of metabolism, evidences point to the conclusion that the nucleus contains the genes or hereditary factors which characterize each species of protozoans from generation to generation, as in the cells of multicellular animals and plants. The nucleus Because of a great variety of the body form and organization, the protozoan nuclei are of various forms, sizes and structures. At one extreme there is a small nucleus and, at the other, a large voluminous one and, between these extremes, is found almost every conceivable variety of form and structure. The majority of Protozoa contain a single nucleus, though many may possess two or more throughout the greater part of their life-cycle. In several species, each individual possesses two similar nuclei, as in Diplomonadina, Protoopalina and Zelleriella. In Euciliata and Suctoria, two dissimilar nuclei, a macronucleus and a micronucleus, are typically present. The macro- nucleus is always larger than the micronucleus, and controls the trophic activities of the organism, while the micronucleus is con- cerned with the reproductive activity. Certain Protozoa possess numerous nuclei of similar structure, as for example, in Pelomyxa, Mycetozoa, Actinosphaerium, Opalina, Cepedea, Myxosporidia, Microsporidia, etc. The essential components of the protozoan nucleus are the nuclear membrane, chromatin, plastin and nucleoplasm. Their interrela- tionship varies sometimes from one developmental stage to an- other, and vastly among different species. Structurally, they fall in general into one of the two types: vesicular and compact. The vesicular nucleus (Fig. 2, a) consists of a nuclear membrane which is sometimes very delicate but distinct, nucleoplasm and chromatin. Besides there is an intranuclear body which is, as a rule, more or less spherical and which appears to be of different make-ups as judged by its staining reactions among different nuclei. It may be composed of chromatin, of plastin, or of a mixture of both. The first type is sometimes called karyosome and the second, nucleolus or plasmosome. Absolute distinction between these two terms cannot be made as they are based upon the difference in affinity to nuclear stains which cannot be standardized and hence do not give uni- formly the same result. Following Minchm and others, the term endosome is advocated here to designate one or more conspicuous bodies other than the chromatin granules, present within the nuclear membrane. MORPHOLOGY 35 When viewed in life, the nucleoplasm is ordinarily homogeneous and structureless. But, upon fixation, there appear invariably plastin strands or networks which seem to connect the endosome and the nuclear membrane. Some investigators hold that these strands or networks exist naturally in life, but due to the similarity of refractive indices of the strands and of the nucleoplasm, they are not visible and that, when fixed, they become readily recognizable because of a change in these indices. In some nuclei, however, certain strands have been observed in life, as for example in the nucleus of the species of Barbulanympha (Fig. 152, c), according to Cleveland and his associates (1934). Others maintain that the achromatic structures prominent in fixed vesicular nuclei are mere artifacts brought about Nuclear membrane Endosome Achromatic strand Chromatin granules a b Fig. 2. a, vesicular nucleus; b, compact nucleus (diagrams). by fixation and do not exist in life and that the nucleoplasm is a homogeneous liquid matrix of the nucleus. The chromatin substance is ordinarily present as small granules although at times they may be in block forms. Precise knowledge of chromatin is still lacking. At present the determination of the chromatin depends upon the following tests: (1) artificial digestion which does not destroy this substance, while non-chromatinic parts of the nucleus are completely dissolved; (2) acidified methyl green which stains the chromatin bright green; (3) 10 per cent sodium chloride solution which dissolves, or causes swelling of, chromatin granules, while nuclear membrane and achromatic sub- stances remain unattacked; and (4) in the fixed condition Feulgen's nucleal reaction. The vesicular nucleus is most commonly present in various orders of the Sarcodina and Mastigophora. The compact nucleus (Fig. 2, b), on the other hand, contains a large amount of chromatin substance and a comparatively small amount of nucleoplasm, and is thus massive. The macronucleus of the Cihophora is almost always of this kind. The variety of forms of the compact nuclei is indeed remarkable. It may be spherical, ovate, cylindrical, club-shaped, band-form, moniliform, horseshoe- form, filamentous, or dendritic. The nuclear membrane is always 36 PROTOZOOLOGY distinct, and the chromatin substance is usually of spheroidal form, varying in size among different species and often even in the same nucleus. In the majority of species, the chromatin granules are small and compact, though in some forms, such as Nydotherus ovalis (Fig. 3), they may reach 20^ or more in diameter in some individuals. Fig. 3. Parts of four macronuclei of Nydotherus ovalis, showing chromatin spherules of different sizes, X650 (Kudo). and while the smaller chromatin granules seem to be solid, larger forms contain alveoli of different sizes in which smaller chromatin granules are suspended (Kudo, 1936). There is no sharp demarcation between the vesicular and compact nuclei, since there are numerous nuclei the structures of which are intermediate between the two. Moreover what appears to be a vesicular nucleus in life, may approach a compact nucleus when fixed and stained as in the case of Euglenoidina. Several experimental observations show that the number, size, and structure of the endo- MORPHOLOGY 37 some in the vesicular nucleus, and the amount and arrangement of the chromatin in the compact nucleus, vary according to the physio- logical state of the whole organism. The macronucleus may be divided into two or more parts with or without connections among them and in Dileptus anser into more than 200 small nuclei, each of which is "composed of a plastin core and a chromatin cortex" (Cal- kins; Hayes). In general, the chromatin granules or spherules fill the intra- nuclear space compactly, in which one or more endosomes may occur. In many nuclei these chromatin granules appear to be sus- pended freely, while in others a reticulum appears to make the background. The chromatin of compact nuclei gives a strong posi- tive Feulgen's nucleal reaction. The macronuclear and micronuclear chromatin substances respond differently to Feulgen's nucleal re- action or to the so-called nuclear stains, as judged by the difference in the intensity or tone of color. In Paramecium caudatum, P. aurelia, Chilodonella, Nyctotherus ovalis, etc., the macronuclear chromatin is colored more deeply than the micronuclear chromatin, while in Colpoda, Urostyla, Euplotes, Stylonychia, and others, the reverse seems to be the case, which may support the validity of the assumption by Heidenhain that the two types of the nuclei of Euciliata and Suctoria are made up of different chromatin sub- stances— idiochromatin in the micronucleus and trophochromatin in the macronucleus — and in other classes of Protozoa, the two kinds of chromatin are present together in a single nucleus. Chromidia. Since the detection of chromatin had solely depended on its affinity to certain nuclear stains, several investigators found extranuclear chromatin granules in many protozoans. Finding such granules in the cytosome of Actinosphaeriu7n eichhorni, Arcella vul- garis, and others, Hertwig (1902) called them chromidia, and main- tained that under certain circumstances, such as lack of food ma- terial, the nuclei disappear and the chromatin granules become scat- tered throughout the cytosome. In the case of Arcella vulgaris, the two nuclei break down completely to produce a chromidial-net which later reforms into smaller secondary nuclei. It has, however, been found by Belar that the lack of food caused the encystment rather than chromidia-formation in Actinosphaerium and, according to Reichenow, Jollos observed that in Arcella the nuclei persisted, but were thickly covered by chromidial-net which could be cleared away by artificial digestion to reveal the two nuclei. In Difflugia, the chromidial-net is vacuolated or alveolated in the fall and in each alveolus appear glycogen granules which seem to serve as reserve 38 PROTOZOOLOGY food material for the reproduction that takes place during that season (Zuelzer), and the chromidia occurring in Actinosphaerium appear to be of a combination of a carbohydrate and a protein (Rumjantzew and Wermel). Apparently the widely distributed volutin (p. 101), and many inclusions or cytozoic parasites, such as Sphaerita, which occur occasionally in different Sarcodina, have in some cases been called chromidia. Bj^ using Feulgen's nucleal reac- tion, Reichenow (1928) obtained a diffused violet-stained zone in Chlamydomonas and held them to be dissolved volutin. Calkins (1933) found the chromidia of Arcella vulgaris negative to the nucleal reaction, but by omitting acid-hydrolysis and treating with fuchsin- sulphurous acid for 8-14 hours, the chromidia and the secondary nuclei were found to show a typical positive reaction and believed that the chromidia were chromatin. Thus at present the real nature of chromidia is still not clearly known, although many protozoolo- gists are inclined to think that the substance is not chromatinic, but, in some way, is connected with the metabolism of the protozoan. The cytosome The extranuclear part of the protozoan body is the cytosome. It is composed of the cytoplasm, a colloidal system, which may be homogenous, granulated, vacuolated, reticulated, or fibrillar in optical texture, aud is almost always colorless. The chromatophore- bearing Protozoa are variously colored, and those with symbiotic algae or cryptomonads are also greenish or brownish in color. Fur- thermore, pigment or crystals which are produced in the body, may give protozoans various colorations. In several forms pigments are diffused throughout the cytoplasm. For example, many dinoflagel- lates are beautifully colored, which, according to Kofoid and Swezy, is due to a thorough diffusion of pigment in the cytoplasm. Stentor coeruleus is ordinarily blue-colored, the pigment stentorin (Lankester) is lodged as granules between the surface striae; and rose- or purple- coloration of several species of Blepharisma appears to be due to a special pigment, zoopurpurin (Arcichovskij) which is said to be lodged in the ectoplasmic granules often called protrichocysts (p. 65). The development of zoopurpurin is definitely correlated with the sun-light, as shown by Giese. Deeply pink specimens will lose color completely in a few hours when exposed to strong sun-light and the recoloration takes place in darkness very slowly. The extent and nature of the cytosomic differentiation differ greatly among various groups. In the majority of Protozoa, the cytoplasm is differentiated into the ectoplasm and the endoplasm. MORPHOLOGY 39 The ectoplasm is the cortical zone which is hyaline and homogene- ous. In the Ciliophora, it is a permanent and distinct part of the body and contains several organellae; in the Sarcodina and the Sporozoa, it is more or less a temporarily differentiated zone and hence varies greatly at different times and, in the Mastigophora, it seems to be more or less permanent. The endoplasm is more voluminous and fluid. It is granulated or alveolated and contains various organellae. While the alveolated cytoplasm is normal in forms such as the members of Heliozoa and Radiolaria, in other cases the alveolation of normally granulated or vacuolated cytoplasm indicates invariably the degeneration of the protozoan body. In Amoeba and other Sarcodina, the "hyaline cap" and "layer" (Mast) make up the ectoplasm, and the "plasmasol" and "plamagel" (Mast) compose the endoplasm (Fig. 44). In numerous Sarcodina and certain Mastigophora, the body surface is naked and not protected by any form-giving organella. According to the observations by Kite, Rowland, and others, the surface layer is not only elastic, but solid, and therefore the name plasma-membrane may be applied to it. Such forms are capable of undergoing amoeboid movement by formation of pseudopodia and by continuous change of form due to the movement of the cytoplasm which is more fluid. However, the majority of Protozoa possess a characteristic and constant body form due to the development of a special envelope, the pellicle. In Amoeba striata and A. verrucosa, there is a distinct pellicle. The same is true with some flagellates, such as certain species of Euglena, Peranema, and Astasia, in which it is elastic and expansible so that the organisms show a great deal of plasticity. The pellicle of a ciliate is much thicker and more definite, and often variously ridged or sculptured. In many, linear furrows and ridges run longitudinally, obliquely, or spirally; and, in others, the ridges are combined with hexagonal or rectangular depressed areas. Still in others, such as Coleps, elevated platelets are arranged paral- lel to the longitudinal axis of the bodJ^ In certain peritrichous ciliates, such as Vorticella monilata, Carchesiiim granulatum, etc., the pellicle may possess nodular thickenings arranged in more or less parallel rows at right angles to the body axis. While the pellicle always covers the protozoan body closely, there are other kinds of protective envelopes produced by Protozoa which may cover the body rather loosely. These are the shell, test, lorica or envelope. The shell of various Phytomastigina is usually made up of cellulose, a carbohydrate, which is widely distributed 40 PROTOZOOLOGY in the plant kingdom. It may be composed of a single or several layers, and may possess ridges or markings of various patterns on it. In addition to the shell, gelatinous substance may in many forms be produced to surround the shelled body or in the members of Volvo- cidae to form the matrix of the entire colony in which the individuals are embedded. In the dinoflagellates, the shell is highly developed and often composed of numerous plates which are variously sculp- tured. In other Protozoa, the shell is made up of chitin or pseudo-chitin (tectin). Common examples are found in the testaceans; for example, in Arcella and allied forms, the shell is made up of chitinous material constructed in particular ways which characterize the different gen- era. Newly formed shell is colorless, but older ones become brownish, because of the presence of iron oxide. Difflugia and related genera form shells by gluing together small sand-grains, diatom-shells, debris, etc., with chitinous or pseudochitinous substances which they secrete. Many foraminiferans seem to possess a remarkable selective power in the use of foreign materials, for the construction of their shells. According to Cushman, Psammosphaera fusca uses sand- grains of uniform color but of different sizes, while P. parva uses grains of more or less uniform size but adds, as a rule, a single large acerose sponge spicule which is built into the test and which extends out both ways considerably. Cushman thinks that this is not acci- dental, since the specimens without the spicules are few and those with a short or broken spicules are not found. P. howmanni, on the other hand, uses only mica flakes which are found in a comparatively small amount, and P. rustica uses acerose sponge spicules for the framework of the shell, skilfully fitting smaller broken pieces into polygonal areas. Other foraminiferans combine chitinous secretion with calcium carbonate and produce beautifully complicated shells (Fig. 4) with one or numerous pores. In the Coccolithidae, variously shaped platelets of calcium carbonate ornament the shell. The silica is present in the shells of various Protozoa. In Euglypha and related testaceans, siliceous scales or platelets are produced in the endoplasm and compose a new shell at the time of fission or of encystment together with the chitinous secretion. In many helio- zoans, siliceous substance forms spicules, platelets, or combination of both which are embedded in the mucilaginous envelope that surrounds the body and, in some cases, a special clathrate shell com- posed of silica, is to be found. In some Radiolaria, isolated siliceous spicules occur as in Heliozoa, while in others the lateral development of the spines results in production of highly complex and the most MORPHOLOGY 41 beautiful shells with various ornamentations or incorporation of foreign materials. Many pelagic radiolarians possess numerous con- spicuous radiating spines in connection with the skeleton, which ap- parently aid the organisms in maintaining their existence in the open sea. Fig. 4. Diagram of the shell of Fetieroplis pertusus, X about 35 (Carpenter), ep, external pore; s, septum; sc, stolon canal. Certain Protomonadina possess a funnel-like collar in the flagel- lated end and in some in addition a chitinous lorica surrounds the body. The lorica found in the Ciliophora is mostly composed of chitinous substance alone, especially in Peritricha, although others produce a house made up of gelatinous secretion containing foreign materials as in Stentor (p. 645). In the Tintinnidae, the loricae are either solely chitinous in numerous marine forms not mentioned in the present work or composed of sand-grains or coccoliths ce- mented together by chitinous secretion, which are found in fresh- water forms. Locomotor organellae Closely associated with the body surface are the organellae of locomotion : pseudopodia, flagella, and cilia. These organellae are not confined to Protozoa alone and occur in various cells of Metazoa. All protoplasmic masses are capable of movement which may result in change of their forms. Pseudopodia. A pseudopodium is a temporary projection of part of the cytoplasm of those protozoans which do not possess a definite pellicle. Pseudopodia are therefore a characteristic organella of 42 PROTOZOOLOGY Sarcodina, though many Mastigophora and certain Sporozoa, which lack a pellicle, are also able to produce them. According to their form and structure, four kinds of pseudopodia are distinguished. 1). Lobopodium is formed by an extension of the ectoplasm, accompanied by a flow of endoplasm as is commonly found in Amoeba proteus (Figs. 44; 161). It is finger- or tongue-like, sometimes branched, and its distal end is typically rounded. It is quickly formed and equally quickly retracted. In many cases, there are many pseudopodia formed from the entire body surface, in which the largest one will counteract the smaller ones and the organism will move in one direction; while in others, there may be a single pseudopodium formed, as in Amoeba striata, A. guttula, Vahlkampfia Umax, Pelomyxa caroUnensis, etc., in which case it is a broadly tongue-like extension of the body in one direction and the progressive movement of the organisms is comparatively rapid. The lobopodia may occasionally be conical in general shape, as in Amoeba spumosa. Although ordinarily the formation of lobopodia is by a general flow of the cytoplasm, in some it is sudden and "eruptive," as in End- amoeba blattae or Entamoeba histolytica in which the flow of the endo- plasm presses against the inner zone of the ectoplasm and the ac- cumulated pressure finally causes breaks through the zone, resulting in a sudden extension of the endoplasmic flow at that point. 2). Filopodium is a more or less filamentous projection com- posed almost exclusively of the ectoplasm. It may be sometimes branched, but the branches do not anastomose. Many testaceans, such as Lecythium, Boderia, Plagiophrys, Pamphagus, Euglypha, etc., form this type of pseudopodia. The pseudopodia of Amoeba radiosa may be considered as approaching this type rather than the lobopodia. 3). Rhizopodium is also filamentous, but branching and anastomosing. It is found in numerous Foraminifera, such as Elphidium, Peneroplis (Fig. 5), etc., and in certain testaceans, such as Lieberkiihnia, Myxotheca, etc. The abundantly branching and anastomosing rhizopodia often produce a large network which serve almost exclusively for capturing prey. 4). Axopodium is, unlike the other three types, a more or less semi-permanent structure and composed of axial rod and cytoplas- mic envelope. Axopodia are found in many Heliozoa, such as Actino- phrys, Actinosphaerium, Camptonema, Sphaerastrum, and Acan- thocystis. The axial rod, which is composed of fibrils (Doflein; Roskin), arises from the central body or the nucleus located in the approximate center of the body, from each of the nuclei in multi- MORPHOLOGY 43 nucleate forms, or from the zone between the ectoplasm and endo- plasm (Fig. 6). Although semipermanent in structure, the axial rod is easily absorbed and reformed. In the genera of Heliozoa, not . \ M 1 A ." 'K I'' ' '7' r- Fig. 5. Pseudopodia of Elphidiuni strigilata, X about 50 (Schulze from Kiihn). mentioned above and in numerous radiolarians, the radiating fila- mentous pseudopodia are so extremely delicate that it is difficult to determine whether an axial rod exists in each or not, although they resemble axopodia in general appearance. There is no sharp demarcation between the four types of pseudo- 44 PROTOZOOLOGY podia, as there are transitional pseudopodia between any two of them. For example, the pseudopodia formed by Arcella, Lesquer- eusia, Hyalosphaenia, etc., resemble more lobopodia than filopodia, though composed of the ectoplasm only. The pseudopodia of Actino- monas, Elaeorhanis, Clathrulina, etc., may be looked upon as transitional between rhizopodia and axopodia. Fig. 6. Portion of Adinosphaerium eichhorni, X800 (Kiihn), ar, axial rod; cv, contractile vacuole; ec, ectoplasm; en, endoplasm; n, nucleus. While the pseudopodia formed by an individual are usually of characteristic form and appearance, they may show an entirely different appearance under different circumstances. According to the often-quoted experiment of Verworn, a limax amoeba changed into a radiosa amoeba upon addition of potassium hydrate to the water (Fig. 7). Mast has recently shown that when Amoeba proteus or A. duhia was transferred from a salt medium into pure water, the amoeba produced radiating pseudopodia, and when transferred back to a salt medium, it changed into monopodial form, which change, he was inclined to attribute to the difference in the water contents of the amoeba. In some cases during and after certain in- ternal changes, an amoeba may show conspicuous differences in pseudopodia (Neresheimer). As was stated before, pseudopodia occur widely in forms which are placed under classes other than Sarcodina during a part of their life-cycle. Care, therefore, should be exer- MORPHOLOGY 45 cised in using them for taxonomic consideration of the Protozoa. Flagella. The flagellum is a filamentous extension of the cyto- plasm and is ordinarily extremely fine and highly vibratile, so that it is difficult to recognize it in life under the microscope with a moderate magnification. It is most clearly observed over a darkfield condenser. Lugol's solution (p. 721) stains it, though the organ- ism is killed. In a number of species, the flagellum, however, can be seen in life as a long filament, as for example in Peranema. As a rule, the number of flagella present in a single individual is small, varying from one to eight, but in Hypermastigina there are numerous fla- 5^®ID Fig forms dition of KOH solution to the water 7. Form-change in a limax-amoeba (Verworn). a, b, contracted c, individual showing typical form; d-f, radiosa-forms, after ad- gella. A flagellum appears to be composed of at least two parts (Fig. 8, a, b). An elastic axial filament takes its origin in the basal granule. Surrounding this filament there is a sheath of contractile cytoplasm which varies in thickness alternately on the opposite sides of the filament. The flagellum ordinarily tapers toward its distal end where the axial filament is said to be frequently exposed. Vlk (1938) found, besides the kind mentioned above which he called the whip-flagellum, another form named by him ciliary flagel- lum. The latter is said to be uniformly thick, but possesses dense ciliary projections which are arranged on it in one or two spiral rows 46 PROTOZOOLOGY b Fig. S. Diagrams of flagella. a, flagellum of Euglena (Biitschli) ; b, flagel- lum of Trachelomonas (Plenge); c, ciliary flagellum w'ith one row of cilia; d, a ciliary flagellum with two rows of cilia; e, whip-flagella of Polytoma uvella; f, ciliary flagellum of Urceolus cyclostomus; g, the flagella of Monas socialis (Vlk). (Fig. 8, c, d). The whip-flagellum occurs in Chlamydomonas, Poly- toma uvella (e), Cercomonas crassicaiida, Trepomonas rotans, T. agilis, Hexamita inflata, Urophagus rostratus, etc.; the ciliary MORPHOLOGY 47 flagellum, in Mallomonas, Chromulina, Trachelomonas, Urceolus (/), Phaciis, Euglena, Astasia, Distigma, etc.; and both kinds in Synura, Uroglena, Dinobryon, Monas (g), etc. (Vik). The flagellum is most frequently inserted near the anterior end of the body and directed forward, its movement pulling the organ- ism forward. Combined with this, there may be a trailing flagellum which is directed posteriorly and serves to steer the course of move- ment or to push the body forward to a certain extent. In a compara- tively small number of flagellates, the flagellum is inserted near the Flagellum Undulating membrane Nucleus Anterior flagellum Basal granule Blepharoplast Rhizoplast Nucleus Parabasal body Basal granule m Blepharoplast f^7^ Posterior flagellum Fig. 9. Diagrams of two flagellates, showing their structures (Kiihn). a, Trypanosoma brucei; b, Proteromonas lacertae. posterior end of the body and would push the body forward by its vibration. Lankester coined the terms tractella and pulsella for pulling and pushing flagella respectively. In certain parasitic Mastigophora, such as Trypanosoma (Fig. 9, a). Trichomonas, etc., there is a very delicate membrane extending out from the side of the body, a flagellum bordering its outer margin. When this membrane vibrates, it shows a characteristic undulating movement, as will easily be seen in Trypanosoma rotatorium of the frog, and is called the undulating membrane. In many of the dino- flagellates, the transverse flagellum seems to be similarly constructed (Kofoid and Swezy) (Fig. 107, d,f). Cilia. The cilia are the organella of locomotion found in the Cilio- phora. They aid in the ingestion of food and serve often as a tactile organella. The cilia are fine and more or less short processes of ecto- plasm and occur in large numbers in the majority of the Holotricha. 48 PROTOZOOLOGY They may be uniformly long, as in Protociliata, or may be of differ- ent lengths, being Ipnger at the extremities, on certain areas, in peristome or in circumoral areas. Ordinarily the cilia are arranged in longitudinal, oblique, or spiral rows, being inserted either on the ridges or in the furrows. Again the cilia may be confined to certain parts or zones of the body. Fig. 10. Diagrams of cilia (Klein), a, Coleps; b, Cyclidium glaucoma; c, Colpidi'uni colpoda. af, axial filament; bg, basal granule; cf, circular fibril; cs, cross-striation; sg, secondary granule. Each cilium originates in a basal granule situated in the deeper part of the ectoplasm and, in a few species, a cilium is found to be made up of an elastic axial filament arising from the basal granule, and the contractile sheath. Gelei observed in flagella and cilia, lipoid substance in granular or rod-like forms which differed even among different individuals of the same species; and Klein found in many cilia of Colpidium colpoda, an argentophilous substance in granular form much resembling the lipoid structure of Gelei and called them "cross-striation" of the contractile component (Fig. 10). MORPHOLOGY 49 Cirrus fiber Ectoplasmic granules Basal plate of the cirrus Basal granules of component cilia Undulating membrane Fig. 11. a, five anal cirri of Ewplotes eurystomus (Taylor); b, schematic ventral view of Stylonychia to show the distribution of the cirri. 50 PROTOZOOLOGY The cilia are often present more densely in a certain area than in other parts of body and, consequently, such an area stands out conspicuously, and is sometimes referred to as a ciliary field. If this area is in the form of a zone, it may be called a ciliary zone. Some authors use pectinellae for short longitudinal rows or transverse bands of close-set cilia. In a number of forms, such as Coleps, Sten- tor, etc., there occur, mingled among the vibratile cilia, immobile stiff cilia which are apparently solely tactile in function. cpg Fig. 12. Diagrams of cirrus and membranella of Euplotes eurystomus, X1450 (Taylor), a, an anal cirrus in side view; b, a membranella; bg, basal granule; cpg, coagulated protoplasmic granules; cr, ciliary root; fp, fiber plate. In the Hypotricha, the cilia are largely replaced by cirri, although in some species both may occur. A cirrus is composed of a number of cilia arranged in 2 to 3 rows that fused into one structure com- pletely (Figs. 11, 12), which was demonstrated by Taylor. Klein also showed by desiccation that each marginal cirrus of Stylonychia was composed of 7 to 8 cilia. In some instances, the distal portion of a cirrus may show two or more branches. The cirri are confined to the ventral surface in Hypotricha, and called frontal, ventral, anal, caudal, and marginal cirri, according to their location (Fig. 11). Un- like the cilia, the cirri may move in any direction so that the organ- isms bearing them, show various types of locomotion. Oxytricha, MORPHOLOGY 51 Stylonychia, etc., walk on f rentals, ventrals, and anals, while swim- ming movement by other species is of different types. In all euciliates except Holotricha, there are adoral membranellae. A membranella is composed of a double ciliary lamella, fused com- pletely into a plate (Fig. 12). A number of these membranellae occur on a margin of the peristome, forming the adoral zone of membranel- lae, which serves for bringing the food particles to the cytostome. The frontal portion of the zone, the so-called frontal membrane appears to serve for locomotion and Kahl considers that it is prob- ably made up of three lamellae. The oral membranes which are often found in Holotricha and Heterotricha, are transparent thin mem- branous structures composed of one or two rows of cilia, which are i^^ n jHOl' Fig. 13. Diagrams showing the possible development of a suctorian tentacle from a cytostome and cytopharynx of a ciliate (Collin). more or less strongly fused. The membranes, located in the lower end of the peristome, are sometimes called perioral membranes, and those in the cytopharynx, undulating membranes. In Suctoria, cilia are present only during the developmental stages, and, as the organisms become mature, tentacles develop in their stead. The tentacles are concerned with food-capturing, and are either prehensile or usually suctorial. In some instances the tentacles are tubular and this type is interpreted by Collin as possibly derived from a cytostome and cytopharynx of the ciliate (Fig. 13). Although the vast majority of Protozoa possess only one of the three organellae of locomotion mentioned above, a few may possess pseudopodia in one phase and flagella in another phase during their life-cycle. Among many examples, may be mentioned Dimastig- amoebidae (Fig. 160), Tetramitus rostratus (Fig. 134), etc. Further- more, there are some protozoans which possess two types of organ- ellae at the same time. Flagellum or flagella and pseudopodia occur 62 PROTOZOOLOGY in many Phytomastigina and Rhizomastigina, and a flagellum and cilia are present in Ileonema (Fig. 273, b, c). In the cytosome of Protozoa there occur various organellae, each of which will be considered briefly here. Fibrillar structures One of the fundamental characteristics of the protoplasm is its contractility. If a fully expanded Amoeba proteus is subjected to a mc i*^:*/ ^^- bg 1 1® - f 1 ; z -i;VVt'; \ = E \ f:! glS Fig. 14. Myonemes in Stentor coeruleus (Schroder), a, cross-section of ectoplasm; b, surface view of three myonemes; c, two isolated myonemes; bg, basal granules; cl, cilium; gis, granules between striae; m, myonemes; mc, myoneme canal. mechanical pressure, it retracts its pseudopodia and contracts into a more or less spherical form. In this response there is no special or- ganella, and the whole body reacts. But in certain other Protozoa, there are special organellae of contraction. Many Ciliophora are able to contract instantaneously when subjected to mechanical pressure, as will easily be noticed by following the movement of Stentor, Spirostomum, Trachelocerca, Vorticella, etc., under a dissecting microscope. The earliest observer of the contractile elements of MORPHOLOGY 53 Protozoa appears to be Lieberkiihn (1857) who noted the "muscle fibers" in the ectoplasm of Stentor which were later named myonemes (Haeckel) or neurophanes (Neresheimer). The myonemes of Stentor have been studied by several in- vestigators. According to Schroder (1906), there is a canal between each two longitudinal striae and in it occurs a long banded myoneme which measures in cross-section 3-7m high by about l/x wide and which appears cross-striated (Fig. 14). Roskin (1923) considers that, oe " 0^^< Fig. 15. a, b, fibrillar structures of the stalk of Zoothamnium (Kolt- zoff); c, m}''onemes in Gregarina (Schneider), ef, elastic fiber; ie, inner envelope; k, kinoplasm; oe, outer envelope; t, thecoplasm. the myoneme is a homogeneous cytoplasm (kinoplasm) and the wall of the canal is highly elastic and counteracts the contraction of the myonemes. All observers agree that the myoneme is a highly con- tractile organella. Many stalked peritrichous ciliates have well-developed myonemes not only in the body proper, but also in the stalk. Koltzoff 's studies show that the stalk is a pseudochitinous tube, enclosing an inner tube filled with granulated thecoplasm, which surrounds a central 54 PROTOZOOLOGY rod, composed of kinoplasm, on the surface of which are arranged skeletal fibrils (Fig. 15). The contraction of the stalk is brought about by the action of kinoplasm and walls, while elastic rods will lead to extension of the stalk. Myonemes present in the ciliates aid in the contraction of body, but those which occur in many Gre- garinida aid apparently in locomotion, being arranged longitudi- nally, transversely and probably spirally (Fig. 15,c). In certain Radio- laria, such as Acanthometron elasticum (Fig. 195, c), etc., each axial spine is connected with 10-30 myonemes (mj^ophrisks) originating in the body surface. When these myonemes contract, the body vol- ume is increased, thus in this case functioning as a hj^drostatic organella. In Isotricha prostoma and I. intestinalis, Schuberg (1888) observed that the nucleus is suspended by ectoplasmic fibrils and called the apparatus karyophore. In some forms these fibrils are replaced by ectoplasmic membranes as in Nydotherus ovalis (Zuluta; Kudo), ten Kate (1927) studied fibrillar systems in Opalina, Nyctotherus, Ichthyophthirius, Didinium, and Balantidium, and found that there are numerous fibrils, each of which originates in a basal granule of a cilium and takes a transverse or oblique course through the endoplasm, ending in a basal granule located on the other side of the body. He further noted that the cytopharynx and nucleus are also connected with these fibrils, ten Kate suggested morphonemes for them, since he believed that the majority were form-retaining fibrils. The well-coordinated movement of cilia in the ciliate has long been recognized, but it was Sharp (1914) who definitely showed that this ciliary coordination is made possible by a certain fibrillar system which he discovered in Epidinium (Diplodinium) ecaudatum (Fig. 16). Sharp recognized in this ciliate a complicated fibrillar system connecting all the motor organellae of the cytostomal region, and thinking that it was "probably nervous in function," as its size, ar- rangement and location did not suggest supporting or contractile function, he gave the name neuromotor apparatus to the whole system. This apparatus consists of a central motor mass, the motorium (which is stained red with Zenker fixation and modified Mallory's connective tissue staining), located in the ectoplasm just above the base of the left skeletal area, from which definite strands radiate: namely, one to the roots of the dorsal membranellae (a dorsal motor strand) ; one to the roots of the adoral membranellae (a ventral motor strand); one to the cytopharynx (a circum-oeso- phageal ring and oesophageal fibers); and several strands into the MORPHOLOGY 55 Fig. 16. A composite drawing from three median sagittal sections of Epidinium ecaudatum, fixed in Zenker and stained with Mallory's connec- tive tissue stain, X1200 (Sharp), am, adoral membranellae; c, cytostome; cp, cytopharynx; cpg, cytopyge; cpr, circumpharyngeal ring; dd, dorsal disk; dm, dorsal membrane; ec, ectoplasm; en, endoplasm; m, motorium; DC, oral cilia; od, oral disk; oef, oesophageal fibers; of, opercular fibers J p, pelhcle; prs, pharyngeal retractor strands; si, skeletal laminae; vs, ven- tral skeletal area. 56 PROTOZOOLOGY ectoplasm of the operculum (opercular fibers). A similar apparatus has since been observed in many other ciliates: Euplotes CYocom; Taylor), Balantiduum (McDonald), Paramecium (Rees; Brown; Lund), Tintinnopsis (Campbell), Boveria (Pickard), Dileptus (Visscher), Chlamydodon (MacDougall), Entorhipidium and Le- chriopyla (Lynch), Eupoterion (MacLennan and Connell), Metopus (Lucas), Troglodytella (Robertson), Oxytricha (Lund), Ancistruma and Conchophthirus (Kidder), etc. Fig. 17. Diagrams showing the neuromotor apparatus of Euplotes pa- tella (Taylor), a, diagrammatic dorsal view of the entire apparatus, X1600; b, dissected portion of disintegrating membranella fiber plates attached to the membranella fiber; c, a dissociated fiber plate of a frontal cirrus with its attached fibers, X1450. acf, anal cirrus fiber; afp, anal fiber plate; eg, small and large ectoplasmic granules; m, motorium; mf, mem- branella fiber; mfp, membranella fiber plate. Euplotes patella, a common free-living hypotrichous ciliate, has been known for nearly 50 years to possess definite fibrils connecting the anal cirri with the anterior part of the body. Engelmann sug- gested that their function was more or less nervelike, while others maintained that they were supporting or contracting in function. Yocom (1918) traced the fibrils to the motorium, a very small bilobed body (about 8/i by 2^) located close to the right anterior corner of the triangular cytostome (Fig. 17, a). Joining with its left end are five long fibers from the anal cirri which converge and appear to unite with the motorium as a single strand. From the right end of the motorium extends the membranella-fiber anteriorly and then to left MORPHOLOGY 57 along the proximal border of the oral lip and the bases of all mem- branellae. Yocom further noticed that within the lip there is a latticework structure whose bases very closely approximate the cyto- stomal fiber. Taylor (1920) recognized two additional groups of fibrils in the same organism: (1) membranella fiber plates, each of which is contiguous with a membranella basal plate, and is attached at one end to the membranella fiber; (2) dissociated fiber plates con- tiguous with the basal plates of the frontal, ventral and marginal cirri, to each of which are attached the dissociated fibers (c). By means of microdissection needles, Tajdor demonstrated that these fibers have nothing to do with the maintenance of the body form, since there results no deformity when Euplotes is cut fully two- thirds its width, thus cutting the fibers, and that when the motorium is destroyed or its attached fibers are cut, there is no coordination in the movements of the adoral membranellae and anal cirri. A striking feature common to all neuromotor systems, is that there seems to be a central motorium from which radiate fibers to different ciliary structures and that, at the bases of such motor or- ganellae, are found the basal granules or plates to which the "nerve" fibers from the motorium are attached. Independent of the studies on the neuromotor system of American investigators, Klein (1926) introduced the silver-impregnation method which had first been used by Golgi in 1873 to demonstrate various fibrillar structures of metazoan cells, to Protozoa in order to demonstrate the cortical fibers present in ciliates, by dry-fixation and impregnating with silver nitrate. Klein (1926) subjected the ciliates of numerous genera and species to this method, and observed that there was a fibrillar system in the ectoplasm at the level of the basal granules which could not be demonstrated by other methods. Klein (1927) named the fibers silver lines and the whole complex, the silverline system, which vary among different species (Fig. 18). Gelei, Chatton and Lwoff, Jirovec, Lynch, Jacobson, Kidder, Lund, and others, applied the silver-impregnation method to many other ciliates and confirmed Klein's observations. Chatton and Lwoff (1935) found in Apostomea, the system remains even after the embryonic cilia have entirely disappeared and considered it in- fraciliature. The question whether the neuromotor apparatus and the silver- line system are independent structures or different aspects of the same structure has been raised frequently. Turner (1933) found that in Euplotes patella (E. eurystomus) the silverline system is a regular latticework on the dorsal surface and a more irregular network on 58 PROTOZOOLOGY the ventral surface. These lines are associated with rows of rosettes from which bristles extend. These bristles are held to be sensory in function and the network, a sensory conductor system, which is connected with the neuromotor system. Turner maintains that the neuromotor apparatus in Euplotes patella is augmented by a distinct but connected external network of sensory fibrils. He however finds no motorium in this protozoan. Lund (1933) also made a comparative study of the two systems in Paramecium multimicronucleatum, and observed that the silverline system of this ciliate consists of two parts. One portion is made up Fig. 18. The silverline system of Ancistruma imjlili, XlOOO (Kidder), a, ventral view; b, dorsal view. of a series of closely-set polygons, usually hexagons, but flattened into rhomboids or other quadrilaterals in the regions of the cyto- stome, cytopyge, and suture. This system of lines stains if the or- ganisms are well dried. Usually the lines appear solid, but fre- quently they are interrupted to appear double at the vertices of the polygons which Klein called "indirectly connected" (pellicular) conductile system. In the middle of the anterior and posterior sides of the hexagons is found one granule or a cluster of 2-4 granules. MORPHOLOGY 59 which marks the outer end of the trichocyst. The second part which Klein called "directly connected" (subpellicular) conductile system consists essentially of the longitudinal lines connecting all basal granules in a longitudinal row of hexagons and of delicate transverse fibrils connecting granules of adjacent rows especially in the cyto- stomal region CFig. 19). Fig. 19. Diagram of the cortical region of Paramecium mtdtimicromi- cleatum, showing various organellas, X7300 (Lund), bg, basal granule; c, cilia; et, tip of trichocyst; If, longitudinal fibril; p, pellicle; t, trichocyst; tf, transverse fibril. By using Sharp's technique, Lund found the neuromotor system of Paramecium multimicronucleatum constructed as follows: The subpellicular portion of the system is the longitudinal fibrils which connect the basal granules. In the cytostomal region, the fibrils of right and left sides curve inward forming complete circuits (the circular cytosomal fibrils) (Fig. 20). The postoral suture is separated at the point where the cytopyge is situated. Usually 40-50 fibrils radiate outward from the cytostome (the radial cytostomal fibrils). The pharyngeal portion is more complex and consists of (1) the oesophageal network, (2) the motorium and associated fibrils, (3) penniculus which is composed of 8 rows of basal granules, thus form- ing a heavy band of cilia in the cytopharynx, (4) oesophageal process, (5) paraoesophageal fibrils, (6) posterior neuromotor chain, and (7) postoesophageal fibrils. Lund concludes that the so-called silverline 60 PROTOZOOLOGY Fig. 20. The neuromotor system of Paramecium multimicromicleatum (Lund), a, oral network; b, motorium, X1670. aep, anterior end of pen- niculus; c, cytopyge; ccf, circular cytostomal fibril; cof, circular oesopha- geal fibril; cpf, circular pharyngeal fibril; ef, endoplasmic fibrils; Ibf, longitudinal body fibril; lof, longitudinal oesophageal fibrils; Ipf, longi- tudinal pharyngeal fibril; m, motorium; oo, opening of oesophagus; op, oesophageal process; paf, paraoesophageal fibrils; pep, posterior end of penniculus; pnc, posterior neuromotor chain; pof, postoesophageal fibrils; rcf, radial cytostomal fibril; s, suture. MORPHOLOGY 61 system includes three structures: namely, the peculiarly ridged pellicle; trichocysts which have no fibrillar connections among them or with fibrils, hence not conductile; and the subpellicular sys- tem, the last of which is that part of the neuromotor system that concerns with the body cilia, ten Kate (1927) suggested that senso- motor apparatus is a better term than the neuromotor apparatus. Protective or supportive organellae The external structures as found among various Protozoa which serve for body protection, have already been considered (p. 39). Here certain internal structures will be discussed. The greater part of the shell of Foraminifera is to be looked upon as endoskeleton and thus supportive in function. In Radiolaria, there is a mem- branous structure, the central capsule, which divides the body into a central region and a peripheral zone. The intracapsular portion contains the nucleus or nuclei, and is the seat of reproductive proc- esses, and thus the capsule is to be considered as a protective or- ganella. The endoskeletal structures of Radiolaria vary in chemical composition and forms, and are arranged with a remarkable regular- ity (pp. 418-425). In some of the astomatous euciliates, there are certain structures which seem to serve for attaching the body to the host's organ, but which seem to be supportive to a certain extent also. The peculiar organella /wrcwZa, observed by Lynch in Lechriopyla (p. 597) is said to be concerned with either the neuromotor system or protection. The members of the family Ophryoscolecidae (p. 654), which are common commensals in the stomach of ruminants, have conspicuous endoskeletal plates which arise in the oral region and extend posteri- orly. Dogiel (1923) believed that the skeletal plates of Cycloposthium and Ophryoscolecidae are made up of hemicellulose, "ophryoscole- cin," which was also observed by Strelkow (1929). MacLennan found that the skeletal plates of Polyplastron multivesiculatum were composed of small, roughly prismatic blocks of paraglycogen, each possessing a central granule. In certain Polymastigina and Hypermastigina, there occurs a flexible structure known as the axostyle, which varies from a fila- mentous structure as in several Trichomonas, to a very conspicuous rod-like structure occurring in Parajoenia, Gigantomonas, etc. The anterior end of the axostyle is very close to the anterior tip of the body, and it extends lengthwise through the cytoplasm, ending near the posterior end or extending beyond the body surface. In other cases, the axostyle is replaced by a bundle of axostylar filaments 62 PROTOZOOLOGY which have connections with the fiagella as seen in certain Hyper- mastigina such as Lophomonas. In trichomonad flagellates there is often present along the line of attachment of the undulating membrane, a rod-like structure which has been known as costa (Kunstler) and which, according to Kirby's extensive study, appears to be most highly developed in Pseudo- trypanosoma and Trichomonas. The staining reaction indicates that its chemical composition is different from that of fiagella, blepharo- plast, parabasal body, or chromatin. Fig. 21. a, trichites in Spathidium spathula, X300 (Woodruff and Spencer); b, trichites in Pseudoprorodon fardus, X400 (Roux). In the gymnostomatous ciliates, the cytopharynx is often sur- rounded by rod-like bodies, and the entire apparatus is often called oral or pharyngeal basket, which is considered as supportive in function. The rod-like bodies appear in most cases to be trichites which may have been derived from the trichocysts, but which do not explode as do the latter. For example, in Chilodonella cucuUulus the oral basket is composed of 12 trichites which are so completely fused in part that the lower portion appears as a smooth tube and in Pseudoprorodon farctus (Fig. 21, h) much longer trichites form the basket, with reserve structures scattered throughout the cytoplasm (Engelmann). In Spathidium spathida (Fig. 21, a), trichites are imbedded like a paling in the thickened rim of the anterior end. They are also distributed throughout the endoplasm and, according to Woodruff and Spencer, ''some of these are apparently newly formed and being transported to the oral region, while others may well be MORPHOLOGY 63 thr •i ;: J) extr W%s^ t > trb trg trb rt Fig. 22. a, b, cortical region of Frontonia leucas, with embedded and extruded trichocysts (Tonniges); c, d, embedded and discharged tricho- cysts of Dileptiis anser, X4200 (Hayes); e, two extruded trichocysts of Paramecium caudatum, X1530 (original), ci, cilium; ec, ectoplasm; en, en- doplasm; extr, extruded trichocyst; p, pellicle; rt, root of trichocyst; th", thread of trichocyst; tr, trichocyst; trb, bulb of trichocyst; trg, trichocyst granule. 64 PROTOZOOLOGY trichites which have been torn away during the process of prey in- gestion." Whether the numerous 12-20/i long needle-like endoskele- tal structures which Kahl observed in Remanella (p. 584) are modi- fied trichites or not, is not known. In numerous ciliates, there is another ectoplasmic organella, the trichocyst, which is much shorter, though somewhat similar in general form. As seen in a Paramecium, the refractile fusiform trichocysts are embedded in the ectoplasm and arranged regularly at right angles to the body surface, while in forms, such as Cyclo- gramma they are situated obliquely (Fig. 278, c). In Frontonia leucas (Fig. 22), Tonniges found that the trichocysts originate in the chromatinic endosomes of the macronucleus and development takes place during their migration to the ectoplasm; on the other hand, Brodsky believes that the trichocysts are composed of col- loidal excretory substances and are first formed in the vicinity of the macronucleus, becoming fully formed during the course of their migration toward the periphery of the body. In species of Prorodon, Kriiger recently observed that the rod-like trichocysts of these ciliates are composed of a cylindrical sac containing a long filament which is arranged in a manner somewhat similar to the polar capsule of cnidosporidian spores. The end facing the body surface is fila- mentous and connected with the pellicle. The extrusion of the trichocysts is easily induced by means of mechanical pressure or chemical (acid or alkaline) stimulation, though the mechanism of extrusion is not well understood in all forms. Brodsky maintains that the fundamental force is not the mechanical pressure, but that under the influence of certain stimuli the expansion of the colloidal substances results in the extrusion of the trichocysts through the pellicle. The fully extruded tricho- cysts are needle-like in general form. The trichocysts of Frontonia leucas are about 6m long, but when extruded, measure 50-60m in length, and those of Paramecium caudatum may reach 40m in length. Dileptus anser feeds on various ciliates through the cytostome, located at the base of the proboscis, which possesses a band of long trichocysts on its ventral side. When food organisms come in contact with the ventral side of the proboscis, they give a violent jerk, and remain motionless. Visscher saw no formed elements discharged from the trichocysts, and, therefore, considered that these tricho- cysts contained a toxic fluid and named them toxicytes. Recently Hayes found that the exploded trichocysts (Fig. 22) could be dis- tinctly seen and suggested that these trichocysts themselves may be toxic. MORPHOLOGY 65 Although the trichocyst was first discovered by Elhs (1769) and so named by Allman (1855), nothing concrete is yet known as to their function. Ordinarily the trichocysts are considered as a de- fensive organella as in the case of the oft-quoted example Parame- cium, but, as Mast demonstrated, the extruded trichocysts of this ciliate do not have any effect upon Didinium other than forming a viscid mass about the former to hamper the latter. Penard con- siders that some trichocysts may be secretory organellae to produce material for loricae or envelope, with which view Kahl concurs, as granular to rod-shaped trichocysts occur in Metopus, Amphileptus, etc. Klein has called these ectoplasmic granules protrichocysts, and in Prorodon, Kriiger observed, besides typical tubular trichocysts, torpedo-like forms to which he applied the same name. To this group may belong the trichocysts recognized by Kidder in Con- chophthirus mijtili. The trichocysts present in certain Cryptomonad- ina (Chilomonas and Cyathomonas) are probably homologous with the protrichocysts. The pigments, which give a beautiful coloration to certain ciliates such as Stentor and Blepharisma, are said to be lodged in the protrichocysts. Hold-fast organellae In the Mastigophora, Ciliophora, and a few Sarcodina, there are forms which possess a stalk supporting the body or the lorica. With the stalk the organism is attached to a solid surface. In some cases, as in Anthophysis, Maryna, etc., the dendritic stalks are made up of gelatinous substances rich in iron, which gives to them a reddish brown color. In parasitic Protozoa, there are special or- ganellae developed for attachment. Many genera of cephaline gregarines are provided with an epimerite of different structures (Figs, 208-210), by which the organisms are able to attach them- selves to the gut epithelium of the host. In Astomata, such as Into- shellina, Maupasella, Lachmannella, etc., simple or complex pro- trusible chitinous structures are often present in the anterior region; or a certain area of the body may be concave and serves for ad- hesion to the host, as in Rhizocaryum, Perezella, etc.; or, again, there may be a distinctive sucker-like organella near the anterior extremity of the body, as in Haptophyra, Steinella, etc. A sucker is also present on the antero-ventral part of Giardia intestinalis. In the Myxosporidia and Actinomyxidia, there appear, during the development of spore, 1-4 special cells which develop into polar capsules, each, when fully formed, enclosing a more or less long spirally coiled delicate thread, the polar filament (Fig. 259). 66 PROTOZOOLOGY The polar filament is considered as a temporary anchoring organella of the spore at the time of its germination after it gained entrance into the alimentary canal of a suitable host. In the Microsporidia, the filament may or may not be enclosed within a capsule. The ne- matocysts (Fig. 110, h) of certain dinoflagellates belonging to Nema- toidium and Polykrikos, are almost identical in structure with those Fig. 23. Parabasal apparatus in: a, Lojihomonas blattarum (Kudo); b, Metadevescovina debilis; c, Devescovina sp. (KirbjO- af, axostylar fila- ments; bl, blepharoplasts; f, food particles; fl, flagella;n, nucleus; pa, para- basal apparatus. found in the coelenterates. They are distributed through the cyto- plasm, and various developmental stages were noticed by Chatton, and Kofoid and Swezy, which indicates that they are characteristic structures of these dinoflagellates and not foreign in origin as had been held by some. The function of the nematocysts in these proto- zoans is not understood. The parabasal apparatus In the cytosome of many parasitic flagellates, there is frequently present a conspicuous structure known as the parabasal apparatus (Janicki), consisting of the parabasal body and often thread (Cleve- land), which latter may be absent in some cases. This structure MORPHOLOGY 67 varies greatly among different genera and species in appearance, structure and position within the body. It is usually connected with the blepharoplast and located very close to the nucleus, though not directly connected with it. It may be single, double, or multiple, and may be pyriform, straight or curved rod-like, bandform, spirally coiled or collar-like (Fig. 23). Kofoid and Swezy considered that the parabasal body is derived from the nuclear chromatin, varies in size according to the metabolic demands of the organism, and is a "kinetic reservoir." On the other hand, Duboscq and Grasse main- tain that this body is the Golgi apparatus, since (1) acetic acid destroys both the parabasal body and the Golgi apparatus; (2) both are demonstrable with the same technique; (3) the parabasal body is made up of chromophile and chromophobe parts as is the Golgi apparatus; and (4) there is a strong evidence that the parabasal body is secretory in function. According to Kirby, who has made an extensive study of this organella, the parabasal body could be stained with Delafield's haematoxylin or Mallory's triple stain after fixation with acetic acid-containing fixatives and the body does not show any evidence to indicate that it is a secretory organella. More- over the parabasal body is discarded or absorbed at the time of divi- sion of the body and two new ones are formed. The parabasal body of Lophomonas hlattarum to which the name was originally applied, is discarded when the organism divides and two new ones are reformed from the centriole or blepharoplast (Fig. 62), and its function appears to be supportive. Possibly not all so- called parabasal bodies are homologous or analogous. A fuller com- prehension of the structure and function of the organella rests on further investigations. The blepharoplast In the Mastigophora or in other groups in which flagellate stages occur, the flagellum ends internally in a basal granule, which, in turn, is sometimes connected by a much larger bod}^ This latter organella has been called the blepharoplast. In many instances they appear to be combined in one. The blepharoplast is further connected by a fibril, the rhizoplast, with the nucleus (Fig. 24). The blepharoplast and centriole are considered synonymous by Minchin, Cleveland, and others, since they give rise to the kinetic organella. Woodcock and Minchin held, on the other hand, that the blepharoplast was a nucleus holding a special relation with loco- motor organellae, and called it kinetonucleus. In recent years it has become known that the blepharoplast of many flagellates re- 68 PROTOZOOLOGY spends positively to Feulgen's nucleal reaction which may indicate the presence of thymonucleic acid or chromatin in this structure. The Golgi apparatus With the discovery of a wide distribution of the so-called Golgi apparatus in metazoan cells, a number of protozoologists also re- tm Fig. 24. Flagellar attachment in Euglenoidina (Hall and Jahn"). a, Euglena deses, X2025; b, E. actis, X750; c, E. spirogyra, X720; d, Menoiclium incurvum, X1550. ported a homologous structure from many protozoans. It seems im- possible at present to indicate just exactly what the Golgi appara- tus is, since the so-called Golgi techniques, the important ones of which are based upon the assumption that the Golgi material is MORPHOLOGY 69 osmiophile and argentophile, and possesses a strong affinity to neutral red, are not specific and the results obtained by using the same method often vary a great deal. Some of the examples of the Golgi apparatus reported from Protozoa are summarized in Table 2, It appears thus that the Golgi bodies occurring in Protozoa are small osmiophilic granules or larger spherules which are composed of osmiophile cortical and osmiophobe central substances. Fre- 93.0 o Fig. 25. The Golgi bodies in Amoeba yroteus (Brown). quently the cortical layer is of unequal thickness, and, therefore, crescentic forms appear. Ringform apparatus was noted in Chilo- donella and Dogielella by Nassonov and network-like forms were ob- served by Brown in Pyrsonympha and Dinenympha. The Golgi ap- paratus of Protozoa as well as of Metazoa, appears to be composed of a lipoidal material in combination with protein substance. In line with the suggestion made for the metazoan cell, the Golgi apparatus of Protozoa is considered as having something to do with secretion or excretion. Nassonov considers that osmiophilic lipoidal substance, which he observed in the vicinity of the walls of the contractile vacuole and its collecting canals in many ciliates and flagellates, is homologous with the metazoan Golgi apparatus and secretes the fluid waste material into the vacuole from which it is excreted to the exterior. According to Brown, there is no blackening by osmic impregnation of the contractile vacuole in Amoeba proteus, 70 PROTOZOOLOGY but fusion of minute vacuoles associated with crescentic Golgi bodies produces the vacuole. Duboscq and Grasse who hold that the parabasal body is the Golgi apparatus, maintain that this body is a source of energy which is utilized by the motor organellae. Joyet-Lavergne pointed out that Table 2. — Golgi apparatus in Protozoa Protozoa Golgi apparatus Observers Monocystis, Gregarina Spheres, rings, crescents Hirschler Endamoeha blattae Spheres, rings, crescents Hirschler Adelea Crescents, beaded grains King and Gatenby Entamoeba gingivalis Rings, crescents to network Causey Vorticella, Lionotus, The membrane of contrac- Nassonov Paramecium, Dogiel- tile vacuole and collecting ella, Nassula, Chilo- canals monas, Chilodonella Holomastigotes, Pyr- Parabasal bodies Dubocsq and sonympha, etc. Grass6 Aggregata, gregarines Crescents, rings Joyet-Lavergne Euglenoidina Stigma Grass6 Chilomonas Granules, vacuoles Hall Peranema Rings, globules, granules Hall Chromulina, Astasia Rings, spherules with a dark Hall Amoeba proteus (Fig. rim Rings, crescents, globules, Brown 25) granules Pyrsonympha, Di- Rings, crescents, spherules; Brown nenympha granules break down to form network near pos- terior end Euglena gracilis Spherical, discoidal with dark rim; tend to group around or near nucleus Brown Blepharisma undulans Rings in the cytoplasm Moore in certain sporozoans the Golgi apparatus is granular and may be the center of enzyme production. The exact morphological and physiological information of the Golgi apparatus must be looked for in future observations. The chondriosomes Widely distributed in many metazoan cells, the chondriosomes have also been recognized in various Protozoa. The chondriosomes possess a low refractive index, and are composed of substances easily MORPHOLOGY 71 soluble in alcohol, acetic acid, etc. Osmium tetroxide blackens the chondriosomes, but the color bleaches faster than in the Golgi bodies. Janus green B stains them even in 1 : 500,000 solution, but stains also other inclusions, such as the Golgi bodies (in some cases) and certain bacteria. According to Horning (1926), janus red is said to be a more exclusive chondriosome stain, as it does not stain bacteria. The chemical composition of the chondriosome seems to be somewhat similar to that of the Golgi body; namely, it is a protein compounded with a lipoidal substance. If the protein is small in amount, it is Fig. 26. The chrondiosomes in Peranema trichophorum, X1750 (Hall) a, b, surface views and c, optical section of a single individual. said to be unstable and easily attacked by reagents; on the other hand, if the protein is relatively abundant, it is more stable and resistant to reagents. The chondriosomes occur as small spherical to oval granules, rod- like or filamentous bodies, and show a tendency to adhere to or re- main near protoplasmic surfaces. In many cases they are distributed without any definite order; in others, as in Paramecium or Opalina, they are regularly arranged between the basal granules of cilia (Horning). In Peranema trichophorum (Fig. 26), according to Hall, the chondriosomes are said to be located along the spiral striae of the pellicle. Causey (1925) noticed in Leishmania hrasiliensis usu- ally eight spherical chondriosomes in each individual, which become rod-shaped when the organism divides. He further observed spher- ical and rod-like chondriosomes in Notiluca scintillans. 72 PROTOZOOLOGY In certain Protozoa, the chondriosomes are not always demon- strable. For example, Horning states in Monocystis the chondrio- somes present throughout the asexual life-cycle as rod-shaped bodies, but at the beginning of the spore formation they decrease in size and number, and in the spore none exists. The chondriosomes appear as soon as the sporozoites are set free. Thus it would appear that the chondriosomes are reformed de novo. On the other hand, Faure- Fremiet, the first student of the chondriosomes in Protozoa, main- tained that they reproduce by division, which has since been con- firmed by many observers. As a matter of fact. Horning found in Opalina, the chondriosomes are twisted filamentous structures and undergo multiple longitudinal fission in asexual division phase. Be- fore encystment, the chondriosomes divide repeatedly transversely and become spherical bodies which persist during encystment and in the gametes. In zygotes, these spherical bodies fuse to produce longer forms which break up into elongate filamentous structures. Richardson and Horning further succeeded in bringing about divi- sion of the chondriosomes in Opalina by changing pH of the medium. As to the function of chondriosomes, opinions vary. A number of observers hold that they are concerned with the digestive process. After studying the relationship between the chondriosomes and food vacuoles of Amoeba and Paramecium, Horning suggested that the chondriosomes are the seat of enzyme activity and it is even probable that they actually give up their own substance for this purpose. Mast and Doyle hold that the "excretory granules" (chon- driosomes) in Amoeba proteus contribute to the formation of the contractile vacuole. The view that the chondriosomes may have something to do with the cell-respiration expressed by Kingsbury was further elaborated by Joyet-Lavergne through his studies on certain Sporozoa. That the chondriosomes are actively concerned with the development of the gametes of the Metazoa is well known. Zweibaum's observation, showing an increase in the amount of fatty acid in Paramecium just prior to conjugation, appears to suggest this function. On the othr hand. Calkins found that in Uroleptus, the chondriosomes became abundant in exconjugants, due to trans- formation of the macronuclear material into the chondriosomes. It may be stated that the chondriosomes appear to be associated with the formation of enzymes which participate actively in the processes of catalysis or synthesis in the protozoan body. The author agrees with McBride and Hewer who wrote: "it is a remarkable thing that so little is known positively about one of the 'best known' proto- plasmic inclusions." MORPHOLOGY 73 The contractile and other vacuoles The majority of Protozoa possess one or more vacuoles known as pulsating or contractile vacuoles. They occur regularly in all freshwater inhabiting Sarcodina and Mastigophora, and in Cilio- phora regardless of habitat. In the Sporozoa, which are all parasitic, and the Sarcodina and Mastigophora, which live either in salt water or in the body of other animals, there is no contractile vacuole. In various species of free-living amoebae, the contractile vacuole is formed by accumulation of wate-r in one or more droplets which finally fuse into one. It enlarges itself continuously until it reaches a maximum size (diastole) and suddenly bursts through the thin cytoplasmic layer above it (systole), discharging its content to out- %' % '•^'.*.. V Fig. 27. Diagrams showing the contractile vacuole, the accessory vacu- oles and the aperture, during diastole and systole in Conchophthirus (Kidder). side. The location of the vacuole is not definite in such forms and, therefore, it moves about with the cytoplasmic movements; and, as a rule, it is confined to the temporary posterior region of the body. Although almost spherical in form, it may occasionally be irregular in shape, as in Amoeba striata (Fig. 161, /). In many testaceans and heliozoans, the contractile vacuoles which are variable in number, are formed in the ectoplasm and the body surface bulges out above the vacuoles at diastole. In the Mastigophora, the contractile vacuole appears to be more or less constant in position. In Phytomastigina, they are usually located in the anterior region and, in Zoomastigina, as a rule, in the posterior half of the body. The number of the vacuoles present in an individual varies from one to several. In the Ciliophora, except Protociliata, there occur one to many contractile vacuoles, which seem to be located in the deepest part of the ectoplasm and therefore constant in position. Directly above each vacuole is found a pore in the pellicle, through which the con- tent of the vacuole is discharged to outside. In the species of Con- 74 PROTOZOOLOGY chophthirus, Kidder (1934) observed a narrow slit in the pellicle just posterior to the vacuole on the dorsal surface (Fig. 27). The margin of the slit is thickened and highly refractile. During diastole, the slit is nearly closed and, at systole, the wall of the contractile vacuole appears to break and the slit opens suddenly, the vacuolar content pouring out slowly. When there is only one contractile vacuole, it is usually located either near the cytopharynx or, more often, in the posterior part of the body. When several to many vacuoles are present, they may be distributed without apparent order, in linear series, or along the body outline. When the contrac- tile vacuoles are deeply seated, there is a delicate duct which con- nects the vacuole with the pore on the pellicle as in Paramecium Fig. 28. Diagrams showing the successive stages in the formation of the contractile vacuole in Paramecium muliimicromicleatum (King) ; up- per figures are side views; lower figures front views; solid lines indicate permanent structures; dotted lines temporary structures, a, full diastole; b-d, stages of systole; e, content of ampulla passing into injection canal; f, formation of vesicles from injection canals; g, fusion of vesicles to form contractile vacuole; h, full diastole. woodruffi, or in Ophryoscolecidae. In Balantidium, Nyctotherus, etc., the contractile vacuole is formed very close to the permanent cyto- pyge located at the posterior extremity, through which it empties its content. In a number of ciliates there occur radiating or collecting canals besides the main contractile vacuole. These canals radiate from the central vacuole in Paramecium, Frontonia, Disematostoma, etc. But when the vacuole is terminal, the collecting canals of course do not MORPHOLOGY 75 radiate, in which case the number of the canals varies among different species: one in Spirostomum, Stentor, etc., 2 in Clima- costomum, Eschaneustyla, etc., and several in Tillina. In Peritricha, Fig. 29. Contractile vacuoles of Paramecium muUimicronucleatum, X1200 (King), a, early systole, side view; b, diastole, front view; c, com- plete systole, front view; d, systole, side view. 76 PROTOZOOLOGY the contractile vacuole occurs near the posterior region of the peri- stome and its content is discharged through a canal into the vesti- bule, and in Ophrydium ectaium, the contractile vacuole empties its content into the cytopharynx through a long duct (Mast). Of numerous observations concerning the operation of the con- tractile vacuole, that of King (1935) on Paramecium multimicro- nucleatum (Figs. 28, 29) may be quoted here. In this ciliate, there are 2 to 7 contractile vacuoles which are located below the ecto- plasm on the aboral side. There is a permanent pore above each vacuole. Leading to the pore is a short tube-like invagination of the pellicle, with inner end of which the temporary membrane of the vacuole is in contact (Fig. 28, a). Each vacuole has 5-10 long col- lecting canals with strongly osmiophilic walls (Fig. 29), and each canal is made up of terminal portion, a proximal injection canal, and an ampulla between them. Surrounding the distal portion, there is osmiophilic cytoplasm which may be granulated or finely reticu- lated, and which Nassonov interpreted as homologous to the Golgi apparatus of the metazoan cell. The injection canal extends up to the pore. The ampulla becomes distended first with fluid transported discontinuously down the canal and the fluid next moves into the injection canal. The fluid now is expelled into the cytoplasm just beneath the pore as a vesicle, the membrane of which is derived from a membrane which closed the end of the injection canal. These fluid vesicles coalesce presently to form the contractile vacuole in full diastole and the fluid is discharged to exterior through the pore, which becomes closed by the remains of the membrane of the dis- charged vacuole. In Haptophrya michiganensis, MacLennan (1944) observed that accessory vacuoles appear in the wall of the contractile canal which extends along the dorsal side from the sucker to the posterior end, as the canal contracts. The canal wall expands and enlarging acces- sory vacuoles fuse with one another, followed by a full expansion of the canal. Through several excretory f)ores with short ducts the con- tent of the contractile canal is excreted to the exterior. The function of the contractile vacuole is considered in the following chapter (p. 103). Various other vacuoles or vesicles occur in different Protozoa. In the ciliates belonging to Loxodidae, there are variable numbers of MuUer's vesicles or bodies, arranged in 1-2 rows along the aboral sur- face. These vesicles (Fig. 30, a-c) vary in diameter from 5 to 8.5/i and contain a clear fluid in which one large spherule or several small highly refractile spherules are suspended. In some, there is a fila- MORPHOLOGY 77 mentous connection between the spherules and the wall of the vesicle. Penard maintains that these bodies are balancing cell-organs and called the vesicle, the statocyst, and the spherules, the stato- liths. Another vacuole, known as concrement vacuole, is a character- istic organella in Biitschliidae and Paraisotrichidae. As a rule, there is a single vacuole present in an individual in the anterior third of body. It is spherical to oval and its structure appears to be highly complex. According to Dogiel, the vacuole is composed of a pellicu- lar cap, a permanent vacuolar wall, concrement grains and two Fig. 30.a-c, Miiller's vesicles in Loxodes (a, b) and in Remanella (c) (a, Penard; b, c, Kahl); d, concrement vacuole of Blepharoprosthium (Dogiel). cf, centripetal fibril; eg, concrement grains; cp, cap; fw, fibrils of wall; p, pellicle; vp, vacuolar pore; w, wall. fibrillar systems (Fig. 30, d). When the organism divides, the an- terior daughter individual retains it, and the posterior individual de- velopes a new one from the pellicle into which concrement grains enter after first appearing in the endoplasm. This vacuole shows no external pore. Dogiel believes that its function is sensory and has named the vacuole, the statocyst, and the enclosed grains, the statoliths. Food vacuoles are conspicuously present in the holozoic Protozoa which take in whole or parts of other organisms as food. The food 78 PROTOZOOLOGY vacuole is a space in the cytoplasm, containing the fluid medium which surrounds the protozoans and in which are suspended the food matter, such as various Protophyta, other Protozoa or small Metazoa. In the Sarcodina, the Mastigophora and the Suctoria, which do not possess a cytostome, the food vacuoles assume the shape of the food materials and, when these particles are large, it is difficult to make out the thin film of water which surrounds them. When minute food particles are taken through a cytostome, as is the case with the majority of euciliates, the food vacuoles are usually spherical and of approximately the same size within a single proto- zoan. In the saprozoic Protozoa, which absorb fluid substances through the body surface, food vacuoles containing solid food, of course, do not occur. The chromatophore and associated organellae In the Phytomastigina and certain other forms which are green- colored, one to many chromatophore s (Fig. 31) or chloroplasts con- taining chlorophyll occur in the cytosome. The chromatophores vary in form among different species; namely, discoidal, ovoid, band- form, rod-hke, cup-like, fusiform, network or irregularly diffused. The color of the chromatophore depends upon the amount and kinds of pigment which envelops the underlying chlorophyll substance. Thus the chromatophores of Chrysomonadina are brown or orange, as they contain one or more accessory pigments, including phyco- chrysin, and those of Cryptomonadina are of various types of brown with very diverse pigmentation. In Chloromonadina, the chromato- phores are bright green, containing an excess of xanthophyfl. In dinoflagellates, they are dark yellow or brown, because of the pres- ence of pigments: carotin, phylloxanthin, and peridinin (Kylin), the last of which is said to give the brown coloration. A few species of Gymnodinium contain blue-green chromatophores for which phyco- cj^anin is held to be responsible. The chromatophores of Phytomon- adina and Euglenoidina are free from any pigmentation, and there- fore green. Aside from various pigments associated with the chro- matophores, there are carotinoid pigments which occur often outside the chromatophores, and are collectively known as haematochrome. The haematochrome occurs in Haematococcus pluvialis, Euglena sanguinea, E. rubra, Chlamydomonas, etc. In Haematococcus, it in- creases in volume and in intensity when there is a deficiency in phos- phorus and especially in nitrogen; and when nitrogen and phos- phorus are present sufficiently in the culture medium, the haemato- chrome loses its color completely (Reichenow; Pringsheim). Steinecke MORPHOLOGY 79 also noticed that the frequent yellow coloration of phytomonads in moorland pools is due to a development of carotin in the chro- matophores as a result of deficiency in nitrogen. Johnson (1939) noted that the haematochrome granules of Euglena rubra become collected in the central portion instead of being scattered through- out the body when sunlight becomes weaker. Thus this Euglena appears green in a weak light and red in a strong light. Flagella Stigma Pyrenoids Chromotophores — Nucleus — Shell Chromatophores Pyrenoids Fig. 31. a, Trachelomonas hispida, X530 (Doflein); b, c, living and stained reproductive cells of Pleodorina illinoisensis, XlOOO (Merton); d-f, terminal cells of Hydrurus foetidus, showing division of chromato- phore and pyrenoid (Geitler); g-i, Chlavujdomonas sp., showing the di- vision of pyrenoid (Geitler). In association with the chromatophores are found the pyrenoids (Fig. 31) which are usually embedded in them. The pyrenoid is a viscous structureless mass of protein (Czurda), and may or may not be covered by tightly fitting starch-envelope, composed of several pieces or grains which appear to grow by apposition of new material on the external surface. A pyrenoid divides when it reaches a certain size, and also at the time of the division of the organism in which it occurs. As to its function, it is generally agreed that the pyrenoid is concerned with the formation of the starch and allied anabolic prod- ucts of photosynthesis. 80 PROTOZOOLOGY Chromatophore-bearing Protozoa usually possess also a stigma (Fig. 31) or eye-spot. The stigma may occur in exceptional cases in colorless forms, as in Khawkinea, Polytomella, etc. It is ordi- narily situated in the anterior region and appears as a reddish or brownish red dot or short rod, embedded in the cortical layer of the cytoplasm. The color of the stigma is due to the presence of droplets of haematochrome in a cytoplasmic network. The stigma is incapable of division and a new one is formed de novo at the time of cell divi- sion. In many species, the stigma possesses no accessory parts, but, according to Mast, the pigment mass in Chlamydomonas, Pando- rina, Eudorina, Euglena, Trachelomonas, etc., is in cup-form, the concavity being deeper in the colonial than in solitary forms. There is a colorless mass in the concavity, which appears to function as a lens. In certain dinoflagellates, there is an ocellus (Fig. 107, c, d, g, h) which is composed of amyloid lens and a dark pigment mass (melan- osome) that is sometimes capable of amoeboid change of form. The stigma is, in general, regarded as an organella for the perception of light intensity. Mast (1926) considers that the stigma in the Volvo- cidae is an organella which determines the direction of the move- ment. References Belar, K. 1926 Der Formwechsel der Protistenkerne. Ergebn. u. Fortschr. Zool., Vol. 6. Brodsky, a. 1924 Die Trichocysten der Infusorien. Arch. rus. protist., Vol. 3. Brown, V. E. 1930 The Golgi apparatus of Amoeba proteus. Biol. Bull., Vol. 59. 1930 The Golgi apparatus of Pyrsonympha and Dine- nympha. Arch. f. Protistenk., Vol. 71. Calkins, G. N. and F. M. Summers (editors). 1941 Protozoa in biological research. New York. Causey, D. 1925-1926 Mitochondria and Golgi bodies in Enda- moeba gingivalis. Mitochondria in Leishniania brasiliensis. Mito- chondria in Noctiluca scintillans. Univ. Calif. Publ. Zool., Vol. 28. Chatton, E. and A. Lwoff 1935 Les cili^s apostomes. Arch. zool. exp. et gen., Vol. 77. Cleveland, L. R., S. R. Hall, E. P. Sanders and J. Collier 1934 The wood-feeding roach Cryptocercus, its Protozoa, and the symbiosis between Protozoa and roach. Mem. Amer. Acad. Arts Sci., Vol. 17. CusHMAN, J. A. 1933 Foraminifera: their classification and economic use. Second edition. Sharon, Mass. DoFLEiN, F. 1916 Studien zur Naturgeschichte der Protozoen. VII. Zool. Jahrb. Abt. Anat., Vol. 39. MORPHOLOGY 81 DoGiEL, V. 1923 Cellulose als Bestandteil des Skellettes bei einigen Infusorien. Biol. Zentralbl., Vol. 43. 1929 Die sog. "Konkrementenvakuole" der Infusorien als eine Statocyste betrachtet. Arch. f. Protistenk., Vol. 68. DuBOSCQ, O. and P. P. Grasse 1933 L'appareil parabasal des flagelles. Arch. zool. exp. et gen., Vol. 63. Gelei, J. VON 1926 Zur Kenntnis des Wimperapparates. Zeitschr. f. ges. Anat., Abt. I, Vol. 81. GiESE, A. C. 1938 Reversible bleaching of Blepharisma. Trans. Amer. Micr. Soc, Vol. 57. Hall, R. P. 1929 Reaction of certain cytoplasmic inclusions to vital dyes and their relation to mitochondria and Golgi appara- tus in the flagellate Peranema trichophorum. Jour. Morph. Physiol., Vol. 48. and T. L. Jahn 1929 On the comparative cytology of cer- tain euglenoid flagellates and the systematic position of the families Euglenidae and Astasiidae. Trans. Amer. Micro. Soc, Vol. 48. Hayes, M. L. 1938 Cytological studies on Dilepius anscr. Ibid., Vol. 57. Hertwig, R. 1902 Die Protozoen und die Zelltheorie. Arch. f. Protistenk., Vol. 1. Horning, E. S. 1926 Observations on mitochondria. Austral. Jour. Exp. Biol. Med. Sci., Vol. 3. 1927 On the orientation of mitochondria on the surface cytoplasm of infusorians. Ibid., Vol. 4. 1929 Mitochondrial behavior during the life cycle of a sporozoan (Monocystis). Quart. Jour. Micr. Sci., Vol. 73. Janicki, C. v. 1911 Zur Kenntnis des Parabasalapparates bei parasitischen Flagellaten. Biol. Zentralbl., Vol. 31. Kidder, G. W. 1933 On the genus Ancistruma Strand (Ancistrum Maupas). Biol. Bull, Vol. 64. 1933 ConcJwphthirus caryoclada sp. nov. Ibid., Vol. 65. 1934 Studies on the ciliates from freshwater mussels. Ibid., Vol. 66. King, R. L. 1935 The contractile vacuole of Paramecium multi- micronucleatum. Jour. Morph., Vol. 58. KiRBY, Jr., H. 1931 The parabasal body in trichomonad flagel- lates. Trans. Amer. Micr. Soc, Vol. 50. Klein, B. M. 1926 Ergebnisse mit einer Silbermethode bei Cilia- ten. Arch. f. Protistenk., Vol. 56. 1927 Die Silverliniensystem der Ciliaten. Ibid., Vol. 58. 1929 Weitere Beitrage zur Kenntnis des Silberliniensys- tems der Ciliaten. Ibid., Vol. 65. 1930 Das Silberliniensystem der Ciliaten. Ibid., Vol. 69. KoFOiD, C. A. and Olive Swezy 1921 The free-living unarmored Dinoflagellata. Mem. Univ. California. Vol. 5. Koltzoff, N. K. 1911 Untersuchung iiber die Kontraktilitat des Stieles von Zoothamnium alternans. Biol. Zeitschr. Moskau., Vol. 2. 82 PROTOZOOLOGY Kruger, F. 1934 Untersuchungen iiber die Trichocysten einiger Prorodon-Arten. Arch. f. Protistenk., Vol. 83. Kudo, R. R. 1924 A biologic and taxonomic study of the Micro- sporidia. Illinois Biol. Monogr., Vol. 9. ■ — ■ 1926 Observations on Lophomonas blattarum, a flagellate inhabiting the colon of the cockroach, Blatta orientalis. Arch. f. Protistenk., Vol. 53. 1936 Studies on Nyctotherus ovalis Leidy, with special refer- ence to its nuclear structure. Ibid., Vol. 87. Lund, E. E. 1933 A correlation of the silverline and neuromotor systems of Paramecium. Univ. Calif. Publ. Zool., Vol. 39. Lynch, J. E. 1930 Studies on the ciliates from the intestine of Strongylocentrotus. II Lechriopyla mystax, gen. nov., sp. nov. Ibid. Vol. 33. MacLennan, R. F. 1944 The pulsatory cycle of the contractile canal in the ciliate Haptophrya. Trans. Amer. Micro. Soc, Vol. 63. Mast, S. O. 1928 Structure and function of the eye-spot in unicel- lular and colonial organisms. Arch. f. Protistenk., Vol. 60. 1944 A new peritrich belonging to the genus Ophrydium. Trans. Amer. Micro. Soc, VoK 63. Nassonov, D. 1924 Der Exkretionsapparat (kontraktile Vakuole) der Protozoen als Homologen des Golgischen Apparatus der Metazoenzelle. Arch. mikr. Anat., Vol. 103. Penard, E. 1922 Etudes sw les infusoires d'eau douce. Geneva, Piney, a. 1931 Recent advances in microscopy. London. Pringsheim, E. 1914 Die Ernahrung von Haematococcus pluvialis. Beitr. Biol. Pfianzen, Vol. 12. Reichenow, E. 1909 Untersuchungen an Haematococcus pluvialis nebst Bemerkungen iiber andere Flagellaten. Arch, kaiserl. Ge- sundheitsamt.. Vol. 33. 1928 Ergebnisse mit der Nuklealfarbung bei Protozoen. Arch. f. Protistenk., Vol. 61. ' Richardson, K. C. and E. S. Horning 1931 Cytoplasmic struc- tures in binucleate opalinids with special reference to the Golgi apparatus. Jour. Morph. Physiol., Vol. 52. RosKiN, G. 1923 La structure des Myonemes des infusoires. Bull. biol. France et Belg., Vol. 57. 1925 Ueber de Axopodien der Heliozoa und die Greif- tentakel der Ephelotidae. Arch. f. Protistenk., Vol. 52. RuMJANTZEW, A. and E. Wermel 1925 Untersuchungen ueber den Protoplasmabau von Actinosphaerium eichhorni. Ibid., Vol. 52. Schroder, O. 1906 Beitrage zur Kenntnis von Stentor coeruleus und St. roeselii. Ibid., Vol. 8. Schuberg, a. 1888 Die Protozoen des Wiederkauermagens. I. Zool. Jahrb. Abt. System., Vol. 3. Sharp, R. 1914 Diplodiniiim ecaudatum with an account of its neuromotor apparatus. Univ. Calif. Publ. Zool., Vol. 13. Strelkow, a. 1929 Morphologische Studien iiber oligotriche In- fusorien aus dem Darme des Pferdes. I. Arch. f. Protistenk., Vol. 68. MORPHOLOGY 83 Taylor, C. V. 1920 Demonstration of the function of the neuro- motor apparatus in Euplotes by the method of micro-dissection. Univ. Calif- Publ. ZooL, Vol. 19. TEN Kate, C. G. B. 1927 Ueber das Fibrillensystem der Ciliaten. Arch. f. Protistenk., Vol. 57. ToNNiGES, C. 1914 Die Trichocysten von Frontonia leucas und ihr chromidialer Ursprung. Ibid., Vol. 32. Turner, J. P. 1933 The external fibrillar system of Euplotes with notes on the neuromotor apparatus. Biol. Bull. Vol. 64. Verworn, M. 1903 Allgemeine Physiologic. Fourth edition. Jena. VisscHER, J. P. 1926 Feeding reactions in the ciliate Dileptus gigas, with special reference to the trichocysts. Biol. Bull., Vol. 45. Vlk, W. 1938 Ueber den Bau der Geissel. Arch. f. Protistenk., Vol. 90. Woodruff, L. L. and H. Spencer 1922 Studies on Spathidium spathula. I. Jour. Exp. Zool., Vol. 35. YocoM, H. B. 1918 The neuromotor apparatus of Euplotes patella. Univ. Calif. Publ. Zool, Vol. 18. Chapter 4 Physiology THE morphological consideration which has been given in the last chapter, is, though necessarily brief, indicative of the occur- rence of various and often complex organellae in Protozoa. The physiological activity of the whole protozoan is the sum-total of all the functions which are carried on by numerous minute parts or organellae of the cell body, unlike the condition found in a metazoan. Indeed, as Calkins (1933) stated, "physiological problems (of Protozoa) for the most part begin where similar problems of the Metazoa leave off, namely the ultimate processes of the single cell. Here the functional activities have to do with the action and inter- action of different substances which enter into the make-up of protoplasm and, for the most part, these are beyond our powers of analysis." A full discussion of various physiological problems per- taining to Protozoa is out of question in the present work and, there- fore, a general consideration on protozoan physiology will suffice for our purpose. Nutrition Protozoa obtain nourishment in manifold ways. Information on the nutrition of the Protozoa is undergoing an accelerated progress through improvements in technique in experimental cultivation of these organisms. Doyle (1943) has given an excellent review on the subject. It will be here briefly considered under three types: holozoic, holophytic, and saprozoic. Holozoic (zootrophic, heterotrophic) nutrition. This is the method by which all higher animals obtain their nourishment; namely, the protozoan uses other animals or plants as sources of food. It involves the food-capture and ingestion, digestion and assimilation, and re- jection of indigestible portions. The methods of food-capture vary among different forms. In the Sarcodina, the food organisms are captured and taken into the body at any point. The methods however vary. According to Rhumbler's oft-quoted observations, four methods of food-ingestion occur in amoebae (Fig. 32); namely, (1) by ''import," in which the food is taken into the body upon contact, with very little movement on the part of the amoeba (a); (2) by "circumfluence," in which the cytoplasm flows around the food organism as soon as it comes in contact with it on all sides and engulfs it (b) ; (3) by "circumvalla- tion," in which the amoeba without contact with the food, forms 84 PHYSIOLOGY 85 pseudopodia which surround the food on all sides and ingest it (c) ; (4) by "invagination," in which the amoeba touches and adheres to the food, and the ectoplasm in contact with it is invaginated into the endoplasm as a tube, the cytoplasmic membrane later disappears (d-h). Jennings, Kepner, Schaeffer and others, have made studies with reference to the food-ingestion in amoebae. Fig. 32. Various ways b^^ which amoebae capture food organisms, a, A moeba verrucosa feeding on Oscillatoria by 'import' (Rhumbler) ; b, ^ . proteus feeding on bacterial glea by 'circumfluence'; c, on Paramecium by 'circumvallation' (Kepner and Whitlock); d-h, A. verrucosa ingesting a food particle by 'invagination' (Gross- Allermann). In certain testaceans, such as Gromia, several rhizopodia cooper- ate in engulfing the prey and, in Lieberkiihnia (Fig. 33), Verworn noted ciliates are captured by and digested in rhizopodia. Similar observation was made by Schaudinn in the heliozoan Camptonema in which several axopodia anastomose to capture a prey (Fig. 109, d). In the holozoic Mastigophora, such as Hypermastigina, which do not possess cytostome, the food-ingestion is by pseudopodia also. The food particles become attached to the pseudopodium and are 86 PROTOZOOLOGY held there on account of the viscid nature of the pseudopodium. The sudden immobihty of active organisms upon coming in contact with pseudopodia of certain forms, such as Actinophrys, Actinosphaer- ium, Gromia, Elphidium, etc., suggests, however, probable discharge of poisonous substances. In the Suctoria which lack a cytostome, the tentacles serve as food-capturing organellae. The suctorial tentacle bears on its distal end a rounded knob which, when it comes in con- tact with an actively swimming ciliate, stops the latter immediately (Parapodophrya typha, Fig. 329, a). The prehensile tentacles of Ephelotidae are said to be similar in structure to the axopodia, in Fig. 33. Rhizopodia of Lieberkiihnia, capturing and digesting Colpiditun colpoda (Verworn). that each possesses a bundle of axial filaments around a cytoplasmic core (Roskin). These tentacles are capable of piercing through the body of a prey. In some suctorians, such as Choanophrya (Fig. 334, a), the tentacles are said to be tubular, and both solid and liquid food materials are sucked in through the cavity. The rapidity with which tentacles of a suctorian stop a very actively swimming ciliate is attributed to a certain substance secreted by the tentacles, which paralyses the prey. In the cytostome-bearing Mastigophora, the lashing of flagella will aid in bringing about the food particles to the cytostome, where it is taken into the endoplasm. In the ciliates there are numerous types of cytostomes and associated organellae. But food-capturing seems to be in general of two kinds. When the cytostome is perma- nently open, the organism ingests food particles which are small enough to pass the cytostome and cytopharynx, as in the case of Paramecium. Another type is one, such as noted in Coleps, Didi- PHYSIOLOGY 87 nium, etc., where the ciliate attacks other organism and sucks in the body substance of the latter through the enlarged cytostome. The ingested food particles are always surrounded by a film of fluid which envelops the organism and the whole is known as the food vacuole (p. 77). The quantity of fluid taken in with the food varies greatly and, generally speaking, it seems to be inversely pro- portional to the size, but proportional to the activity, of the food organisms. Food vacuoles composed entirely of surrounding liquid medium have occasionally been observed. Edwards (1925) observed ingestion of fluid medium by an amoeba by forming food-cups under changed chemical composition. Brug (1928) reports seeing Ent- amoeba histolytica engulf liquid culture medium by formation of lip- /T^ ^^ n n g; I Fig. 34. Ingestion of brine by Rhopalophrya salina (Kirby). like elevation of the ectoplasm and Kirby (1932) figures ingestion of the brine containing no visible organisms by the cytostome of Rhopalophrya salina (Fig. 34). Mast and Doyle (1934) state that if Amoeha protcus, A. duhia, A. dofleini, or A. radiosa is placed in an albumin solution, a hypertonic balanced salt solution, or a hyper- tonic solution of calcium gluconate it rapidly decreases in volume, and forms numerous tubes filled with fluid, which disintegrate sooner or later and release their fluid content in the cytoplasm. At times 50 or more such tubes may be present, which indicates that the organism ingests considerable quantities of fluid in this way. The two authors consider that it is *'a biological adaptation which serves to compen- sate for the rapid loss of water." The food vacuoles finally reach the endoplasm and in forms such as Amoebina the vacuoles are carried about by the moving endo- plasm. In the ciliates, the fluid endoplasm shows often a definite rotation movement. In Paramecium, the general direction is along the aboral side to the anterior region and down the other side, with PROTOZOOLOGY a short cyclosis in the posterior half of the body. In Carchesium, ac- cording to Greenwood, the food-vacuoles pass down to one end of the macronucleus and then move close along its concave surface to the anterior end of the nucleus where defecation to the vestibule takes place (Fig. 35). As stated above, in a number of species the food organisms are paralyzed or killed upon contact with pseudopodia, tentacles or ex- ploded trichocysts. In numerous other cases, the captured organism is taken into the food vacuole alive, as will easily be noted by ob- serving Chilomonas taken in by Amoeba proteus or actively moving bacteria ingested by Paramecium. But the prey ceases to move in a Fig. 35. Diagram showing the digestion within the food vacuoles in Carchesium polypinurn (Greenwood), a, digestion area; b, region of little change; c, region of acid reaction; d, region of neutral reaction; e, defeca- tion area. very short time. It is generally believed that some substances are se- creted into the food vacuole by the protoplasm of the organisms, to stop the activity of the prey within the food vacuole. Engelmann (1878) demonstrated that the granules of blue litmus, when ingested by Paramecium or Amoeba, became red in a few minutes. Brandt PHYSIOLOGY 89 (1881) examined the staining reactions of amoebae by means of haematoxylin, and found that the watery vacuoles contained an acid. Metschnikoff (1889) also showed that there appears an acid secretion around the ingested litmus grains in Mycetozoa. Green- wood and Saunders (1884) found in Carchesium that ingestion of food particles stimulated the cytoplasm to secrete a mineral acid (Fig. 35). According to Nirenstein (1925), the food vacuole in Paramecium undergoes change in reaction which can be grouped in two periods. The first is acid reaction and the second alkaline reaction, in which albumin digestion takes place. On the other hand, Khainsky (1910) observed that the food vacuole of ciliates, such as Paramecium, is cv Fig. 36. Diagram showing changes in reactions in food-vacuoles of Paramecium caudatum, after ingesting litmus (Shapiro), b, blue; cv, con- tractile vacuole; lb, light blue; Ir, light red; r, red. acid during the entire period of protein digestion, and becomes neu- tral to finally alkaline when the solution of the food substance is ended. Metalnikoff (1912) found that in the food vacuoles of Para- mecium, besides acid-alkaline reaction change, some vacuoles never show acid reaction and others occasionally show sustained acid reac- tion. Shapiro (1927) studied the reaction change of the food vacuoles 90 PROTOZOOLOGY in Paramecium caudatum (Fig. 36) by using phenol red, neutral red, Congo red, and litmus, and found that when the organism is kept in a medium with pH 7, its food vacuoles are first alkaline (pH 7.6), soon reach a maximum acidity (pH 4.0), while still in the posterior half of the body. Later, the vacuoles show a decreased acidity, finally reaching pH 7.0. In Vorticella sp. and Stylonychia pustulata, the range of pH observed in the food vacuoles was said to be 4.5- 7.0 and 4.8-7.0 respectively. The food vacuoles of Actinosphaer- ium, according to Howland (1928), possess at the beginning pH 6.0-7.0 for 5 to 10 minutes, but this soon changes to acid (pH 4.3) in which digestion appears to be carried on. In older food vacuoles which are of less acid (pH 5.4-5.6), the digestion appears to be at an end. In the species of Bresslaua, Claff, Dewey and Kidder (1941) noted that a Colpoda taken into the food vacuole is instantly killed with a sudden release of an acid which shows pH 3.0-4.2. During digestion the protoplasm of the prey becomes alkaline and the un- digested residue becomes acid before extrusion. Mast's recent obser- vations (1942) on the food vacuoles in Amoeba proteus and A. duhia containing Chilomonas or Colpidium indicate: (1) the fluid in the vacuoles becomes first acid and then alkaline; (2) the increase in the acidity of the fluid in the vacuole is not due to cytoplasmic secre- tion, but is probably due to respiration in the ingested organisms, chemical changes associated with their death, etc. ; and (3) the death of the organisms taken in the food vacuoles is probably caused by the decrease in oxygen in the vacuoles, owing to the respiration of the organisms in them. Just exactly what processes take place in the food vacuole have been observed only in a few cases. Nirenstein noticed the appear- ance of numerous neutral red-stainable granules around the food vacuole which pass into the interior of the vacuole, and regarded them as carriers of a tryptic ferment, while Roskin and Levinsohn demonstrated the oxidase reaction in these granules. A number of enzymes have been reported in the Protozoa, some of which are mentioned in Table 3. These findings suffice to indicate that the digestion in Protozoa is carried on also by enzymes and its course appears to vary among different Protozoa. The albuminous substances are digested and de- composed into simpler compounds by enzymes and absorbed by the surrounding cytoplasm. The power to digest starch into soluble sugars is widely found among various Protozoa. It has been re- ported in Mycetozoa, Foraminifera, Pelomyxa, Amoeba, Enta- moeba, Ophryoscolecidae and other ciliates by several investigators. PHYSIOLOGY 91 In Pelomyxa, Stole (1900) found that the so-called refringent bodies are intimately associated with the carbohydrate metabolism in that they are filled with glycogen which amount is proportionate to the food matter the organism obtains. The members of Vampyrella (p. 330) are known to dissolve the cellulose wall of algae, especially Spirogyra in order to feed on their contents. Pelomyxa (Stole), Foraminifera (Schaudinn), Amoeba (Rhumbler), Hypermastigina, Polymastigina (Cleveland), etc., have also been known for possessing the power of cellulose digestion. Many of the Hypermastigina and Polymastigina which lead symbi- Table 3. — Enzymes in Protozoa Protozoa Enzymes Observers Aethalium septicujn Pelomyxa palustris Soil amoebae Balantidium coli Euglena gracilis Glaucoma pyriformis Colpidium striatum Poly- and Hyper- mastigina in wood roach Pepsin-like enzyme, dissolving albumin in acid medium Pepsin-like and diastatic en- zymes "Amoebodiastase": trypsin- like, active in neutral or slightly alkaline medium, liquefies gelatin, coagulates albumin, inactive at 60°C. Diastatic enzyme Proteolytic enzyme in cultures Proteolytic enzyme, capable of hydrolyzing casein Proteolytic enzyme, capable of hydrolyzing casein Cellulase; Cellobiase Krukenberg (1886) Hartog and Dixon (1893) Mouton (1902) Glaessner (1908) Jahn (1931) Lwoff (1932) Elliott (1933) Cleveland et al. (1934) otic life in the intestine of the termite and of the wood roach, as dem- onstrated by Cleveland and his co-workers, digest by enzymes the cellulose which the host insect ingests. The assimilation products produced by an enormous number of these flagellates are seemingly sufficient to support the protozoans as well as the host. The cili- ate commensals inhabiting the stomach of ruminants also appar- ently digest the cellulose, since the faecal matter as a rule does not contain this substance. The digestion of fat by Protozoa had not been known, although oils and fat have been observed in numerous Protozoa, until Dawson and Belkin (1928) injected different oils into Amoeha duhia and found that from 1.4 to 8.3 per cent of the injected oil was digested. Mast (1938) noticed that the neutral fat 92 PROTOZOOLOGY globules of Colpidium are digested by Amoeba proteus and trans- formed into fatty acid and glycerine which unite and form neutral fat. The indigestible residue of the food is extruded from the body. The extrusion may take place at any point on the surface in many Sarcodina by a reverse process of the ingestion of food. But in pelli- cle-bearing forms, the defecation takes place either through the cytopyge located in the posterior region of the body or through an aperture to the vestibule (in Carchesium). Permanent cytopyge is lacking in some forms. In Fdbrea salina, Kirby (1934) noticed that a large opening is formed at the posterior end, the contents of food vacuoles are discharged, and the opening closes over. At first the margin of the body is left uneven, but soon the evenly rounded out- line is restored. The same seems to be the case with Spirostomum (Fig. 37), Blepharisma, etc. Fig. 37. Outline sketches showing the defecation process in Spirostomum ambiguum (Blattner). Holophytic (autotrophic, phytotrophic) nutrition. This is the type of nutrition in which the Protozoa are able to decompose carbon dioxide by means of chlorophyll contained in chromatophores (p. 78) in the presence of the sunlight, liberating the oxygen and combining the carbon with other elements derived from water and inorganic salts. The pyrenoids (p. 79) are inseparably connected with the reserve carbohydrate formation in this nutrition. Aside from the Phytomastigina, chromatophores were definitely observed in a cili- ate Cyclotrichium meunieri (Fig. 268, o) by Powers. In a number of other cases, the organism itself is without chromatophores but is apparently not holozoic, because of the presence of chlorophyll- bearing organisms within it. For example, in the testacean Paulinella (Fig. 182, c) in which occur no food vacuoles, chromatophores of peculiar shape are always present. The latter appear to be a species of alga which holds a symbiotic relationship with the testacean, and perhaps acts for the sarcodinan as the chromatophores of the Phyto- PHYSIOLOGY 93 mastigina. A similar relationship seems to exist between Paramecium hursaria and a zoochlorella, Paraeuplotes tortugensis and a zooxanthella and others (p. 25). Pringsheim showed that organic matters from zoochlorellae are passed on to their host, Paramecium hursaria, to be used as food. Through studies of relationships between zooxanthellae and invertebrates Yonge observed that the zooxan- thellae utilize carbon dioxide, nitrogen and phosphorus which are the cataboHc products of the host and supply in return oxygen, fats and carbohydrates to the host. Saprozoic (saprophytic) nutrition. In this nutrition, the Protozoa obtain nourishment by diffusion through the body surface. This is accomplished without any special organellae. Perhaps the only in- stance in which the saprozoic nutrition is accomplished through a special organella is the pusules (Figs. 107, 108) in marine dinoflagel- lates which, according to Kofoid and Swezy, appear to contain de- composed organic matter and aid the organisms in carrying on this process. The dissolved food matters are simpler compounds which originate in animal or vegetable matter due to the decomposing activities of bacterial organisms. Numerous free-living Zoomas- tigina nourish themselves with this method. Recently a number of investigators found that saprozoic Protozoa could be cultivated in bacteria-free media of known compositions. For example, Prings- heim observed in Polytoma uvella (Fig. 97, h) that sodium acetate is needed from which the starch among others is produced and carbo- hydrates have no direct bearing upon the nutrition, but fatty acids derived from them participate in the metabolism. Hall, Jahn, Loefer and others are following the same line of work which may lead to a better understanding of saprozoic nutrition as found in Proto- zoa. The Protozoa which live within the body of another organism are able to nourish themselves by absorbing the digested or decomposed substances of the host and could be considered as saprozoic, though the term parasitic has sometimes been used. Coelozoic Protozoa be- long to this group, as for example, Protociliata, astomatous ciliates, Trypanosomatidae, etc. In the case of cytozoic or certain histozoic forms, such as Cnidosporidia, the host cytoplasm is apparently liquefied or hydrolyzed by enzymes before being absorbed by them. The parasitic Protozoa, which actually feed on host tissue cells, such as Entamoeba histolytica, Balantidium coli, etc., or endocommensals, employ, of course, the holozoic nutrition. Many Protozoa nourish themselves by more than one method at the same or different times, subject to a change in external condi- 94 PROTOZOOLOGY tions. This is sometimes referred to as mixotrophic nutrition (Pfeif- fer). For example, Euglena gracilis, according to Zumstein (1900) and Lwoff (1932) may lose its green coloration and becomes Astasia- like in the dark, or even in the light when the culture medium is very abundant in decomposed organic substances, which may indicate that this organism is capable of carrying on both holophytic and saprozoic nutrition. With the introduction of bacteria-free culture technique in recent years, it has now become well established that a protozoan species exhibits conspicuous differences in form, size and structure, which are exclusively due to differences in the kind and amount of food material. For example, Kidder, Lilly and Claff (1940) noted in Tetrahymena vorax (Fig. 38), bacteria-feeders are tailed (50-75ju long), saprozoic forms are fusiform to ovoid (30-70iu long), forms feeding on sterile dead ciliates are fusiform (60-80ju long), and carni- vores and cannibals are irregularly ovoid (100-250^ long), in the latter form of which a large preparatory vacuole becomes developed. In Chilomonas Paramecium, Mast (1939) observed the individuals grown in sterile glucose-peptone solution were much smaller than those cultured in acetate-ammonium solution and moreover the former contained many small starch grains, but no fat, while the latter showed many larger starch grains and a little fat. Amoeba proteus when fed exclusively on Colpidium, became very large and extremely "fat" and sluggish, growing and multiplying slowly, but indefinitely; when fed on Chilomonas only, they grew and multi- plied for several days, then decreased in number and soon died, but lived longer on Chilomonas cultured in the glucose-peptone. Since the fact that endocrines influence greatly the metabolic ac- tivity and growth in higher animals became known, many workers undertook to determine the effects of various endocrines of verte- brates upon Protozoa. Nowikoff (1908) first noticed the apparent increase in number of Paramecium caudatum when cultured in a solu- tion of desiccated sheep thyroid as compared with the culture in a hay infusion. Shumway (1914, 1917) found that the emulsions of fresh thyroid, boiled thyroid and commercial powder, produced an increase of about 65 per cent in the division rate in Paramecium over common hay infusions. These animals were smaller and more ac- tively motile, and showed more vacuolated cytoplasm. Abderhalden and Schiffmann (1922) made a similar observation by using thyroid "optone." Shumway found further that suspensions of thymus, spleen, ovary, suprarenal, and pituitary body, did not have any ef- fect on Paramecium. By using freshly prepared thyroid extracts of PHYSIOLOGY 95 cat, bird, turtle, frog, and fish, on Paramecium and Stylonychia, Budington and Harve}^ (1915) noticed also that all extracts in- creased the division rate. Flather (1919) saw the contraction of the contractile vacuoles of Paramecium accelerated by adrenaline and pineal extract. Cori (1923) noted the acceleration (about 12 per cent) of the division Fig. 38. Form and size variation in Tetrahymena vorax, due to differ- ences in kind and amount of food material, as seen in life. X400 (Kidder, Lilly and Claff). a, bacteria-feeder; b, c, saprozoic forms; d, individual which has fed on killed Colpidium camjnjlum ; e, starved individual from a killed-Oolpidium culture; f-i, progressive form and size changes of saprozoic form in the presence of living Colpidium; j, a young carnivore which has been removed to a culture with living yeast. 96 PROTOZOOLOGY rate in P. putrinum occurred only in faintly alkaline thyroid ex- tract in hay infusions. Riddle and Torrey (1923) on the other hand found that the thja-oxine brought about a slight fall in the rate of division, an increased rate of pulsation of the contractile vacuoles, and a decrease in number of excretory crystals in Para- mecium. The two investigators suggested that the thyroxine acceler- ates catabolic, and not anabolic, processes. Woodruff and Swingle (1923, 1924), using a pedigree culture of P. aurelia found that (1) neither thyroid, pineal, nor pituitary material possesses intrinsic properties which accelerate division in Paramecium and (2) thyrox- ine does not accelerate the division and above certain concentrations, it depresses the division in this ciliate. Ball (1925) found different clones of P. caudatum and P. aurelia, respond differently to similar conditions and obtained following re- sults: (1) with an uncontrolled bacterial food supply, individuals of the same clone may divide at a higher rate in solutions of the desic- cated thyroid, liver, and hypophysis, than in hay infusions; (2) if ap- proximately equal number of bacteria are provided, thyroid does not bring about any significant increase in the division rate; and (3) the evidence indicates that thyroid accelerates the division rate of Paramecium by providing a favorable bacterial food supply, and not by any specific action of the thyroid hormone. Solutions of both the anterior and the posterior lobes of the pituitary gland produce no significantly higher rate of division than does a solution of liver. Unlike the observations made by some previous workers. Ball finds no demonstrable increase in the metabolic rate in thyroid-fed ani- mals as compared with those cultured in hay infusions. The importance of vitamins has abundantly been demonstrated in recent years for many higher animals. It is, therefore, natural to find attempts made to discover the influence of certain vitamins on Protozoa. Lwoff and Dusi (1937, 1938) found the growth of Chilo- monas Paramecium in asparagin media was favorably supported by thiamine, or by thiazole, and in ammonium acetate media, thiamine could be replaced by thiazole and pyrimidine. Thiamine has no ac- celerating effect on the growth of Euglena gracilis in light (Elliott, 1937), but either this substance or pyrimidine is necessary for the growth of the organism if cultured in asparagin and acetate media in darkness (Lwoff and Dusi). It is probable that chromatophore-bear- ing forms are able to synthesize thiamine from the constituents of inorganic media in sunlight. E. pisciformis on the other hand is said to require thiamine for growth even in light (Dusi, 1939). Many colorless flagellates require thiamine for growth as in Chilo- PHYSIOLOGY 97 monas 'Paramecium mentioned above, others appear to be capable of synthesizing it as in Polytoma uvella (Lwoff and Dusi). In a number of ciliates such as Colpidium campylum, C. striatum, Tetrahymena geleii, etc., thiamine seems to support growth according to several workers. For example, Elliott (1939) observed crystalline thiamine chloride to be a limiting factor for the growth of Colpidium striatum in media free from this substance. Vitamin Bi was found most effec- tive in concentration of 1 : 10,000 to 1 : 10,000,000. This worker further found that crystalline riboflavin and vitamin Be (concentrate) cannot supplant thiamine in the nutrition of this ciliate. According to Hall and Shottenfeld (1941), the density of population in bacteria-free cultures of Glaucoma pyriformis is related quantitatively to the con- centration of thiamine and the phases of death also are influenced markedly by the available concentration of this vitamin. For Col- pidium campylum, Hall (1942) observed thiamine and riboflavin to be essential for growth in a de-ashed gelatin medium, and thiamine to be necessary for growth in a silk-peptone culture which has been subjected to prolonged heating in strongly alkaline .solution. Lilly (1942) succeeded in growing bacteria-free several strains of Stylonychia pustulata and Pleurotricha lanceolata on ciliates (5 spe- cies), flagellates (3 species) and a strain of Saccharomyces cerevisiae, all cultured in sterile condition. He found that for continued growth of the two ciliates, it was necessary to supply in addition to the food organisms, a supplementary growth factor which was found in the largest quantity in yeast cells and less so in infusions of a wide vari- ety of plant materials, but which was not found in effective concen- trations in media made from animal organs or tissues. This substance was soluble in water and in 70 per cent alcohol, was stable to heat and alkali, and was adsorbed on charcoal and on Fuller's earth. The in- vestigator considers it as not identical with any of the known vita- mins of the B complex. Johnson and Baker (1943) have examined certain B vitamins in relation to populations of Tetrahymena geleii and found: (1) the addition of thiamine to fresh proteose-peptone medium produced a higher maximum population; (2) all of the long- time cultures containing added thiamine, had secondary increase in population, almost to the original peaks, after 64 days; (3) cultures with a mixture of thiamine, riboflavin, and pyridoxine, maintained the highest level of living population; and (4) cultures with para- aminobenzoic acid had higher maximum populations than those ob- tained under other conditions, but died out sooner than the other types of cultures (addition of thiamine prevented this early dying- out). 98 PROTOZOOLOGY Ascorbic acid has been found to be an essential factor for the growth in Leishmania donovani, L. tropica, Trypanosoma cruzi (Lwoff), Tritrichomonas foetus (Cailleau), etc. Haematin is said to be a necessary growth factor for the two species of Leishmania and Try- panosoma cruzi (Lwoff). Observations on the effect of vitamins as ap- plied to host infected by Protozoa are meager. Becker and his associ- ates (1941) have shown that when a ration somewhat restricted in vitamins Bi and Be was used as basal, the addition of moderate amounts of thiamine chloride resulted in a reduction in the number of oocysts of Eimeria nieschulzi eliminated by host rats. The same was true when vitamins Bi and Be were administered to infected rats intraperitoneally in normal salt solution. On the other hand, vitamin Be supplement alone produced an increase in the oocyst production. Certain substances which are sometimes called growth stimulants have also been applied to Protozoa in recent years. Elliott (1935) found that pantothenic acid brings about a doubling of the growth of Colpidium campylum in sterile culture at pH 5.5-6.6, but not at pH 7.0 or above, and it does not accelerate the growth of Haemato- coccus pluvialis in bacteria-free cultures. Thus it appears that panto- thenic acid has no effect on chlorophyll-bearers. As to the effect of auxins (plant growth substances), the same investigator demon- strated that Euglena gracilis grew faster in a medium at pH 5.6 in light and in the presence of auxins, while these substances did not bring about any noticeable effect on such colorless forms as Khawk- inea halli and Colpidium striatum. Hall (1939) examined the effect of pimelic acid on Colpidium campylum in sterile cultures and found that it exerts some sort of catalytic effect on the metabolism of this ciliate in peptone and gelatin media, as shown by an increase in the growth rate and in the density of population, but the effect may be masked, or perhaps, eliminated by the addition of dextrose to the medium. Fuller information on the relationships between endocrines, vita- mins and growth-promoting substances and Protozoa is dependent upon a greater application of sterile culture method and standard- ization of basal culture media to many Protozoa in future. The reserve food matter The anabolic activities of Protozoa result in the growth and in- crease in the volume of the organism, and also in the formation and storage of reserve food-substances which are deposited in the cy- toplasm to be utilized later for growth or reproduction. The re- serve food stuff is ordinarily glycogen or glycogen ous substances, PHYSIOLOGY 99 which seem to be present widely. Thus, in saprozoic Gregarinida, there occur in the cytoplasm numerous refractile bodies which stain brown to brownish-violet in Lugol's solution; are insoluble in cold water, alcohol, and ether; become swollen and later dissolved in boil- ing water; and are reduced to a sugar by boiling in dilute sulphuric acid. This substance which composes the refractile bodies is called paraglycogen (Biitschli) or zooamylon. The abundant glycogen bod- ies of Pelomyxa have already been mentioned (p. 91). Rumjantzew and Wermel demonstrated glycogen in Actinosphaerium. In loda- moeba, glycogen body is conspicuously present and is looked upon as a characteristic feature of the organism. The iodinophile vacuole of the spores of Myxobolidae is a conspicuously well-defined vacuole containing glycogenous substance and is also considered as possess- ing a taxonomic value. In many ciliates, both free-living (Parame- cium, Glaucoma, Vorticella, etc.) and parasitic (Ophryoscolecidae, Nyctotherus, Balantidium, etc.), glycogenous bodies are always present. According to MacLennan (1936), the development of the paraglycogen in Ichthyophthirius is associated with the chondrio- somes. In Eitneria tenella, glycogenous substance does apparently not occur in the schizonts, merozoites, or microgametocytes; but becomes apparent first in the macrogametoc3^te, and increases in amount with its development, a small amount being demonstrable in the sporozoites (Edgar et al., 1944). Fig. 39. a-d, two types of paramylon present in Euglena gracilis (Biitschli); e-h, paramylon of E. sanguinea, XllOO (Heidt). e, natural appearance; f, g, dried forms; h, strongly pressed bodies. The anabolic products of the holophytic nutrition are starch, paramylon, oil and fats. The paramylon bodies are of various forms among different species, but appear to maintain a certain character- istic form within a species and can be used to a certain extent in taxonomic consideration. According to Heidt (1937), the paramylon of Euglena sanguinea (Fig. 39) is spirally coiled which confirms Biitschli's observation. The paramylon appears to be a polysac- 100 PROTOZOOLOGY charide which is insoluble in boiling water, but dissolves in concen- trated sulphuric acid, potassium hydroxide, and slowly in formalde- hyde. It does not stain with either iodine or chlor-zinc-iodide and when treated with a dilute potassium hydroxide, the paramylon bodies become enlarged and frequently exhibit a concentric stratifi- cation. In the Chrysomonadina, the reserve food material is in the form of refractile bodies which are collectively called leucosin, probably a carbohydrate. Oils occur in various Protozoa and when there is a sufficient number of oil-producing forms in a body of water, the water may develop various odors. Table 4 shows kinds of odor pro- duced by certain Protozoa when they are present in the water in large numbers: Table 4. — Protozoa and odors of water Protozoa Odor produced by them Cryptomonas candied violets Mallomonas aromatic, violets, fishy Synura ripe cucumber, muskmelon, bitter and spicy taste Uroglenopsis fishy, cod-liver oil-like Dinobryon fishy, like rockweed Chlamydomonas fishy, unpleasant or aromatic Eudorina faintly fishy Pandorina faintly fishy Volvox fishy Ceratium vile stench Glenodinium fishy Peridinium fishy, like clam-shells Bursaria Irish moss, salt marsh, fishj^ (Whipple) Pelomyxa ripe cucumber (Schaeffer) Fats have also been detected in many Protozoa, such as Myxo- sporidia, Protociliata, certain Eucihata, Trypanosoma, etc. Accord- ing to Panzer, the fat content of Eimeria gadi was 3.55 per cent and Pratje reports that 12 per cent of the dry matter of Noctiluca scintil- lans appeared to be the fatty substance present in the form of granules and is said to give luminescence upon mechanical or chemi- cal stimulation. A number of other dinoflagellates, such as Peridi- nium, Ceratium, Gonyaulax, Gymnodinium, etc., also emit lumi- nescence. In other forms the fat may be hydrostatic in function, as is the case with a number of pelagic Radiolaria, many of which are also luminous. Another reserve food-stuff which occurs widely in Protozoa, ex- PHYSIOLOGY 101 cepting Ciliophora, is the so-called volutin or metachromatic gran- ule. It is apparently equally widely present in Protophyta. In fact it was first discovered in the protophytan Spirillum volutans. Meyer coined the name and held it to be made up of a nucleic acid. It stains deeply with nuclear dyes. Reichenow (1909) demonstrated that if Haematococcus pluvialis (Fig. 40) is cultivated in a phosphorus-free medium the volutin is quickly used up and does not reappear. If however, the organisms are cultivated in a medium rich in phos- phorus, the volutin increases greatly in volume and, as the culture becomes old, it gradually breaks down. In Polytomella agilis (Fig. 98, c, d), Doflein showed that an addition of sodium phosphate re- sulted in an increase of volutin. Reichenow, Schumacher, and others, hold that the volutin appears to be a free nucleic acid, and is a spe- cial reserve food material for the nuclear substance. Recently Sas- FiG. 40. Haematococcus pluvialis, showing the development of volutin in the medium rich in phosphorus and its disintegration in an exhausted medium, X570 (Reichenow). a, second day; b, third day; c, fourth day; d, e, sixth day; f, eighth day. suchin (1935) studied the volutin in Spirillum volutans and Sarcina flava and found that the volutin appears during the period of strong growth, nourishment and multiplication, disappears in unfavorable condition of nourishment and gives a series of characteristic carbo- hydrate reactions. Sassuchin considers that the volutin is not related to the nucleus, but is a reserve food material of the cell, and is composed of glycoprotein. Respiration In order to carry on various vital activities, the Protozoa, like all other organisms, must transform the potential energy stored in highly complex chemical compounds present in the cytoplasm, into various forms of active energy by oxidation. The oxygen involved in this process appears to be brought into contact with the sub- stances in two ways in Protozoa. The great majority of free-living, and certain parasitic forms absorb free molecular oxygen from the surrounding media. The absorption of oxygen appears to be carried on by the permeable body surface, since there is no special organella for this purpose. The polysaprobic Protozoa are known 102 PROTOZOOLOGY to live in water containing no free oxygen. For example, Noland (1927) observed Metopus es in a pool, 6 feet in diameter and 18 inches deep, filled with dead leaves which gave a strong odor of hj^drogen sulphide. The water in it showed pH 7.2 at 14°C., and contained no dissolved oxygen, 14.9 c.c. per liter of free carbon dioxide, and 78.7 c.c. per liter of fixed carbon dioxide. The parasitic Protozoa of metazoan digestive systems live also in a medium containing no molecular oxygen. All these forms appear to possess capacity of splitting complex oxygen-bearing substances present in the body to produce necessary oxygen. Several investigators studied the influence of abundance or lack of oxygen upon different Protozoa. For example, Putter demon- strated that several ciliates reacted differently when subjected to anaerobic condition, some perishing rapidly, others living for a con- siderable length of time. Death is said by Lohner to be brought about by a volume-increase due to accumulation of the waste prod- ucts. When first starved for a few days and then placed in anaerobic environment, Paramecium and Colpidium died much more rapidly than unstarved individuals. Putter, therefore, supposed that the dif- ference in longevity of aerobic Protozoa in anaerobic conditions was correlated with that of the amount of reserve food material such as protein, glycogen and paraglj^cogen present in the body. Putter fur- ther noticed that Paramecium is less affected by anaerobic condition than Spirostomum in a small amount of water, and maintained that the smaller the size of body and the more elaborate the contractile vacuole system, the organisms suffer the less the lack of oxygen in the water, since the removal of catabolic products depends upon these factors. The variety of habitats and results of artificial cultivations of various Protozoa indicate clearly that the oxygen requirements vary a great deal among different forms. Attempts were made in recent years to determine the oxygen requirement of Protozoa. The results of the observations are not always convincing. The oxygen consump- tion of Paramecium is said, according to Lund (1918) and Amberson (1928), to be fairly constant over a wide range of oxygen concentra- tion. Specht (1934) found the measurements of the oxygen con- sumption and carbon dioxide production in Spirostomum ambiguum vary because of the presence of a base produced by the organism. Soule (1925) observed in the cultural tubes of Trypanosoma lewisi and Leishmania tropica, the oxygen contained in about 100 c.c. of air of the test tube is used up in about 12 and 6 days respectively. A single Paramecium caudatum is said to consume in one hour at PHYSIOLOGY 103 21°C. from 0.0052 c.c. (Kalmus) to 0.00049 c.c. (Howland and Bern- stein) of oxygen. Amoeba proteus, according to Hiilpieu (1930), suc- cumbs slowly when the amount of oxygen in water is less than 0.005 per cent and also in excess, which latter confirms Putter's observation on Spirostomum. According to Clark (1942), a normal Amoeba pro- teus consumes 1.4X10~^ mm^ of oxj^gen per hour, while an enucle- ated amoeba only 0.2X10~^ mm.' He suggests that "the oxygen- carriers concerned wdth 70 per cent of the normal respiration of an amoeba are related in some way to the presence of the nucleus." The Hypermastigina of termites are killed, according to Cleveland, when the host animals are kept in an excess of oxygen. Jahn (1935) found that Chilomonas Paramecium in bacteria-free cultures in heavily buf- fered peptone-phosphate media at pH 6.0 required for rapid growth carbon dioxide which apparently brings about a favorable intracel- lular hydrogen-ion concentration. Excretion and secretion The catabolic waste material composed of water, carbon dioxide, urea and other nitrogenous compounds, all of which are soluble, pass out of the bod}^ by diffusion through the surface or by means of the contractile vacuole (p. 73). The protoplasm of the Protozoa is gen- erally considered to possess a molecular make-up which appears to be similar among those living in various habitats. In the freshwater Protozoa, the water diffuses through the body surface and so in- creases the water content of the body protoplasm as to interfere with its normal function. The contractile vacuole, which is invari- ably present in all freshwater forms, is the means of getting rid of this excess water from the body. On the other hand, marine or para- sitic Protozoa live in nearly isotonic media and there is no excess of water entering the body, hence the contractile vacuoles are not found in them. Just exactly w^hy all euciliates and suctorians possess the contractile vacuole regardless of habitat, has not fully been ex- plained. It is assumed that the pellicle of the ciliate is impermeable to salts and slowly permeable to water (Kitching). If this is true in all ciliates, it is not difficult to understand the universal occurrence of the contractile vacuole in the ciliates and suctorians. That the elimination of excess amount of water from the body is one of the functions of the contractile vacuole appears to be be- yond doubt judging from the observations of Zuelzer (1907), Finley (1930) and others, on Amoeba verrucosa which lost gradually its con- tractile vacuole as sodium chloride was added to the water, losing the organella completely in the seawater concentration. Herf (1922) 104 PROTOZOOLOGY studied the pulsation of the contractile vacuoles of Paramecium caudatum in fresh water as well as various salt concentrations, and obtained the following measurements: Per cent NaCl in water 0 0.25 0.5 0.75 1.00 Contraction period in second 6.2 9.3 18.4 24.8 163.0 Excretion per hour in body volumes 4.8 2.82 1.38 1.08 0.16 The contractile vacuole also serves to remove from the body part of soluble catabolic wastes, judged by numerous observations. Weatherby (1929) showed that the excretory vacuole of Spiros- tomum contains urea, and that of Didinium contains ammonia and occasionally trace of uric acid. The number of the contractile vacu- oles present in a given species as in various species of Paramecium, is not always constant. Nor is its size constant. According to Taylor (1920) the average size of the contractile vacuole of Euplotes patella is 29/x at maximum diastole, but may become 45-50m in diameter upon disturbance or after incision. The rate of pulsation is subject to change with temperature, physiological state of the organism, amount of food substances present in the water, etc. For example, Rossbach observed in the three ciliates mentioned below the pulsation of the contractile vacuole increased first rapidly and then more slowly with the rise of the temperature of the water: Time in seconds between two systoles at different temperature (C.) 5° 10° 15° 20° 25° 30° Euplotes char on 61 48 31 28 22 23 Stylonychia pustulata 18 14 10-11 6-8 5-6 4 Chilodonella cuculluhis 9 7 5 4 4 — In Amoeba mira, Hopkins (1938) found that small vacuoles (acid reaction) appear and coalesce with one another and also with bacteria taken in as food, thus giving rise to larger ones (alkaline reaction). These larger vacuoles after giving off substances to the protoplasm by diffusion, are discharged. Thus the vacuole system in this amoeba appears to perform not only digestive func- tion, but also excretory function as excess water, food residues and a substance stainable by janus green B, are extruded by way of this system. Aside from the soluble forms, there often occur in the protozoan body insoluble catabolic products in the forms of crystals and gran- ules of various kinds. Schewiakoff (1893) first noticed that Para- mecium often contained crystals (Fig. 41) composed of calcium phos- phate, which disappeared completely in 1-2 days when the organ- PHYSIOLOGY 105 isms were starved, and reappeared when food was given. Schewiakoff did not see the extrusion of these crystals, but considered that these crystals were first dissolved and excreted by the contractile vacuoles, as they were seen collected around the vacuoles. In Amoeba proteus, Schubotz (1905) noted that the crystals were of similar chemical composition and of usually bipyramidal or rhombic form, and that they measured about 2-5^ in length and doubly refractile. Schaeffer (1920) observed calcium phosphate cr3^stals in three species of B □ Fig. 41. Examples of crystals present in Protozoa, a-e, in Paramecium caudatum (Schewiakoff), (a-d, XlOOO, e, X2600); f, in Amoeba proteus; g, in A. discoides; h-1, in A. duhia (Schaeffer). Amoeba and was inclined to think that the forms and dimensions of these crystals were characteristic of each species. Thus in Amoeba proteus, they are truncate bipyramids, rarely fiat plates, up to 4.5jLt long; in A. discoides, abundant, truncate bipyramids, up to 2.5^ long; and in A. dubia, variously shaped (4 kinds), few, but large, up to 10m, 12/x, 30m long (Fig. 41). Rowland detected uric acid in Paramecium caudatum and Amoeba verrucosa. Luce and Pohl (1935) noticed that at certain times amoe- bae in culture are clear and contain relatively a few crystals but, as the culture grows older and the water becomes more neutral, the crystals become abundant and the organisms become opaque in transmitted light. These crystals are tubular and six-sided, and vary in length from 0.5 to 3.5m. They considered the crystals were com- posed of calcium chlorophosphate. Mast and Doyle (1935), on the other hand, noted in Amoeba proteus two kinds of crystals, plate- like and bipyramidal, which vary in size up to 7m in length and which are suspended in alkaline fluid to viscous vacuoles. These two authors believed that the plate-like crystals are probably leucine, while the bipyramidal crystals consist of a magnesium salt of a sub- stituted glycine. Other crystals are said to be composed of urate, carbonate, oxalate, etc. Another catabolic product is the haemozoin (melanin) grains 106 PROTOZOOLOGY which occur in many haemosporidians and which appear to be com- posed of a derivative of the haemoglobin of the infected erythrocyte. In certain Radiolaria, there occurs a brownish amorphous mass which is considered as cataboHc waste material and, in Foraminifera, the cytoplasm is frequently loaded with masses of brown granules which appear also to be catabolic waste and are extruded from the body periodically. While intracellular secretions are usually difficult to recognize, because the majority remain in fluid form except those which pro- duce endoskeletal structures occurring in Heliozoa, Radiolaria, cer- tain parasitic ciliates, etc., the extracellular secretions are easily recognizable as loricae, shells, envelopes, stalks, collars, mucous sub- stance, pigments which give the body a characteristic coloration (p. 38), etc. Furthermore, many Protozoa secrete, as was stated be- fore, certain substances through the pseudopodia, tentacles or tricho- cysts which possess paralyzing effect upon the preys. Movements Protozoa move about by means of the pseudopodia, flagella, or cilia, which may be combined with internal contractile organellae. Movement by pseudopodia. Amoeboid movements have long been studied by numerous observers. The first attempt to explain the movement was made by Berthold (1886), who held that the differ- ence in the surface tension was the cause of amoeboid movements, which view was supported by the observations and experiments of Biitschli (1894) and Rhumbler (1898). According to this view, when an amoeba forms a pseudopodium, there probably occurs a diminu- tion of the surface tension of the cytoplasm at that point, due to certain internal changes which are continuously going on within the body and possibly to external causes, and the internal pressure of the cytoplasm will then cause the streaming of the cytoplasm. This results in the formation of a pseudopodium which becomes attached to the substratum and an increase in tension of the plasma-mem- brane draws up the posterior end of the amoeba, thus bringing about the movement of the whole body. Jennings (1904) found that the movement of Amoeba verrucosa (Fig. 42, a) could not be explained by the surface tension theory, since he observed "in an advancing amoeba substance flows for- ward on the upper surface, rolls over at the anterior edge, coming in contact with the substratum, then remains quiet until the body of the amoeba has passed over it. It then moves upward at the posterior end, and forward again on the upper surface, continuing PHYSIOLOGY 107 in rotation as long as the amoeba continues to progress." Thus Amoeba verrucosa may be compared with an elastic sac filled with fluid. Bellinger (1906) studied the movement of Amoeba proteus, A. verrucosa and Difflugia spiralis. Studying in side view, he found Fig. 42. a, diagram showing the movement of Amoeba verrucosa in side view (Jennings) ; b, a marine limax-amoeba in locomotion (Pantin from Reichenow). ac, area of conversion; cet, contracting ectoplasmic tube; fe, fluid ectoplasm; ge, gelated ectoplasm. that the amoeba (Fig. 43) extends a pseudopod, ''swings it about, brings it into the line of advance, and attaches it" to the substratum and that there is then a concentration of the substance back of this point and a flow of the substance toward the anterior end. Bellinger Fig. 43. Outline sketches of photomicrographs of Amoeba proteus during locomotion, as viewed from side (Bellinger). held thus that ''the movements of amoebae are due to the presence of a contractile substance," which was said to be located in the endo- plasm as a coarse reticulum.' In the face of advancement of our knowledge on the nature of protoplasm, Rhumbler realized the difficulties of the surface tension 108 PROTOZOOLOGY Fig. 44. Diagram of Amoeba proteus, showing the solation and gelation of the cytoplasm during amoeboid movement (Mast), c, crystal; cy, con- tractile vacuole; f, food vacuole; he, hyaline cap; n, nucleus; pg, plasma- gel; pgs, plasmagel sheet; pi, plasmalemma; ps, plasmasol. PHYSIOLOGY 109 theory and later suggested that the conversion of the ectoplasm to endoplasm and vice versa were the cause of the cytoplasmic move- ments, which was much extended by Hyman (1917). Hyman con- sidered that: (1) a gradient in susceptibility to potassium cyanide exists in each pseudopodium, being the greatest at the distal end, and the most recent pseudopodium, the most susceptible; (2) the susceptibility gradient (or metabolic gradient) arises in the amoebae before the pseudopodium appears and hence the metabolic change which produces increased susceptibility, is the primary cause of pseudopodium formation; and (3) since the surface is in a state of gelation, amoeboid movement must be due to alterations of the col- loidal state. Solation, which is brought about by the metabolic change, is regarded as the cause of the extension of a pseudopodium, and gelation of the withdrawal of pseudopodia and of active con- traction. Schaeffer (1920) mentioned the importance of the surface layer which is a true surface tension film, the ectoplasm, and the streaming of endoplasm in the amoeboid movement. Pantin (1923) studied a marine limax-type amoeba (Fig. 42, h) and came to recognize acid secretion and absorption of water at the place where the pseudopodium was formed. This results in swelling of the cytoplasm and the pseudopodium is formed. Because of the acidity, the surface tension increases and to lower or reduce this, concentra- tion of substances in the "wall" of the pseudopodium follows. This leads to the formation of a gelatinous ectoplasmic tube which, as the pseudopodium extends, moves toward the posterior region where the acid condition is lost, gives up water and contracts finally becoming transformed into endoplasm near the posterior end. The contraction of the ectoplasmic tube forces the endoplasmic streaming to the front. This observation is in agreement with that of Mast (1923, 1926, 1931) who after a series of carefully conducted observations on Amoeba proteus came to hold that the amoeboid movement is brought about by "four primary processes; namely, attachment to the substratum, gelation of plasmasol at the anterior end, solation of plasmagel at the posterior end and the contraction of the plasmagel at the posterior end" (Fig. 44). As to how these processes work, Mast states: "The gelation of the plasmasol at the anterior end ex- tends ordinarily the plasmagel tube forward as rapidly as it is broken down at the posterior end by solation and the contraction of the plasmagel tube at the posterior end drives the plasmasol forward. The plasmagel tube is sometimes open at the anterior end and the plasmasol extends forward and comes in contact with the plasma- 110 PROTOZOOLOGY lemma at this end (Fig. 45, a), but at other times it is closed by a thin sheet of gel which prevents the plasmasol from reaching the anterior end (6). This gel sheet at times persists intact for consider- able periods, being built up by gelation as rapidly as it is broken down by stretching, owing to the pressure of the plasmagel against it. Usually it breaks periodically at various places. Sometimes the breaks are small and only a few granules of plasmasol pass through and these gelate immediately and close the openings (d). At other times the breaks are large and plasmasol streams through, filling the hyaline cap (c), after which the sol adjoining the plasmalemma gel- FiG. 45. Diagrams of varied cytoplasmic movements at the tip of a pseudopodium in Amoeba 'proteus (Mast), g, plasmagel; he, hyaline cap; hi, hyaline layer; pi, plasmalemma; s, plasmasol. ates forming a new gel sheet. An amoeba is a turgid system, and the plasmagel is under continuous tension. The plasmagel is elastic and, consequently, is pushed out at the region where its elasticity is weakest and this results in pseudopodial formation. When an amoeba is elongated and undergoing movement, the elastic strength of the plasmagel is the highest at its sides, lowest at the anterior end and intermediate at the posterior end, which results in continuity of the elongated form and in extension of the anterior end. If pressure is brought against the anterior end, the direction of streaming of plas- masol is immediately reversed, and a new hyaline cap is formed at the posterior end which is thus changed into a new anterior end. " Flagellar movement. The flagellar movement is in a few instances observable as in Peranema, but in most cases it is very difficult to observe in life. Since there is difference in the number, location, size, and probably structure (p. 45) of flagella occurring in Protozoa, it is supposed that there are varieties of flagellar movements. The first explanation was advanced by Biitschli, who observed that the flagel- lum undergoes a series of lateral movements and, in so doing, a pres- PHYSIOLOGY 111 sure is exerted on the water at right angles to its surface. This pres- sure can be resolved into two forces: one directed parallel, and the other at right angles, to the main body axis. The former will drive the organism forward, while the latter will tend to rotate the animal on its own axis. Gray (1928), who gave an excellent account of the movement of flagella, points out that "in order to produce propulsion there must be a force which is always applied to the water in the same direction and which is independent of the phase of lateral movement. There can be little doubt that this condition is satisfied in flagellated organ- isms not because each particle of the flagellum is moving laterally to and fro, but by the transmission of the waves from one end of the flagellum to the other, and because the direction of the transmission is always the same. A stationary wave, as apparently contemplated by Biitschli, could not effect propulsion since the forces acting on the water are equal and opposite during the two phases of the move- ment. If however the waves are being transmitted in one direction only, definite propulsive forces are present which alwaj^s act in a direction opposite to that of the waves." Because of the nature of the flagellar movement, the actual proc- ess has often not been observed. Verworn observed long ago that in Peranema trichophomm the undulation of the distal portion of flagel- lum is accompanied by a slow forward movement, while undulation along the entire length is followed by a rapid forward movement. Recently Krijgsman (1925) studied Monas sp. (Fig. 46) which he found in soil cultures, under the darkfield microscope and stated: (1) when the organism moves forward with the maximum speed, the flagellum starting from cl, with the wave beginning at the base, stretches back (c 1-6), and then waves back (d, e), which brings about the forward movement. Another type is one in which the flagellum bends back beginning at its base (/) until it coincides with the body axis, and in its effective stroke waves back as a more or less rigid structure (g); (2) when the organism moves forward with moderate speed, the tip of the flagellum passes through 45° or less (h-j); (3) when the animal moves backward, the flagellum under- goes undulation which begins at its base (k-o) ; (4) when the animal moves to one side, the flagellum becomes bent at right angles to the body and undulation passes along it from its base to tip (p); and (5) when the organism undergoes a slight lateral movement, only the distal end of the flagellum undulates (q). Ciliary movement. The cilia are the locomotor organella present permanently in the ciliates and vary in size and distribution among 112 PROTOZOOLOGY different species. Just as flagellates show various types of move- ments, so do the ciliates. Individual cilium on a progressing ciliate bends throughout its length and strikes the water so that the organ- ism tends to move in a direction opposite to that of the effective beat, while the water moves in the direction of the beat (Fig. 47, Fig. 46. Diagrams illustrating ftagellar movements of Monas sp. (Krijgsman). a-g, rapid forward movement (a, b, optical image of the movement in front and side view; c, preparatory and d, e, effective stroke; f, preparatory and g, effective stroke); h-j, moderate forward movement (h, optical image; i, preparatory and j, effective stroke); k-o, undulatory movement of the fiagellum in backward movement; p, lateral movement; q, turning movement. PHYSIOLOGY 113 a-d). In the Protociliata and the majority of holotrichous and heterotrichous cOiates, the ciHa are arranged in longitudinal, or oblique rows and it is clearly noticeable that the cilia are not beating in the same phase, although they are moving at the same rate. A cilium (Fig. 47, e) in a single row is slightly in advance of the cilium behind it and shghtly behind the one just in front of it, thus the cilia on the same longitudinal row beat metachronously. On the other hand, the cilia on the same transverse row beat synchronously, the condition clearly being recognizable on Opahna among others, which is much like the waves passing over a wheat field on a wind}^ ,,i /'"^^ 7 1 2 w/'r.i^im^^^ii Fig. 47. Diagrams illustrating ciliary movements (Verworn). a-d, movement of a marginal cilium of Urostyla grandis (a, preparatory and b, effective stroke, resulting in rapid movement; c, preparatory, and d, effective stroke, bringing about moderate speed) ; e, metachronous move- ments of cilia in a longitudinal row. day. The organized movements of cilia, cirri, membranellae and un- dulating membranes are probably controlled by the neuromotor system (p. 54) which appears to be conductile as judged by the results of micro-dissection experiments of Taylor (p. 57). The Protozoa which possess myonemes are able to move by con- traction of the body or of the stalk, and others combine this with the secretion of mucous substance as is found in Haemogregarina and Gregarinida. Irritability Under natural conditions, the Protozoa do not behave always in the same manner, because several stimuli act upon them usually in combination and predominating stimulus or stimuU vary under dif- 114 PROTOZOOLOGY ferent circumstances. Many investigators have, up to the present time, studied the reactions of various Protozoa to external stimula- tions, full discussion of which is beyond the scope of the present work. Here one or two examples in connection with the reactions to each of the various stimuli will only be mentioned. Of various responses expressed by a protozoan against a stimulus such as changes in body form, movement, structure, behavior, etc., the movement is the most clearly recognizable one and, therefore, free- swimming forms, particularly ciliates, have been the favorite ob- jects of study. We consider the reaction to a stimulus in pratozoans as the movement response, and this appears in one of the two direc- tions: namely, toward, or away from, the source of the stimulus. Here we speak of positive or negative reaction. In forms such as Amoeba, the external stimulation is first received by the body sur- face and then by the whole protoplasmic body. In flagellated or ciliated Protozoa, the flagella or cilia act in part sensory; in fact in a number of cihates are found non-vibratile cilia which appear to be sensory in function. In a comparatively small number of forms, there are sensory organellae such as stigma, ocellus, statocysts, concretion vacuoles, etc. In general, the reaction of a protozoan to any external stimulus depends upon its intensity so that a certain chemical substance may bring about entirely opposite reactions on the part of the protozoans in different concentrations and, even under identical conditions, different individuals of a given species may react diffferently. Reaction to mechanical stimuli. One of the most common stimuli a protozoan would encounter in the natural habitat is that which comes from contact with a solid object. When an amoeba which Jennings observed, came in contact with the end of a dead algal filament at the middle of its anterior surface (Fig. 48, a), the amoe- boid movements proceeded on both sides of the filament (5), but soon motion ceased on one side, while it continued on the other, and the organism avoided the obstacle by reversing a part of the current and flowing in another direction (c). When an amoeba is stimulated mechanically by the tip of a glass rod (d), it turns away from the side touched, by changing endoplasmic streaming and forming new pseudopodia (e). Positive reactions are also often noted, when a suspended amoeba (/) comes in contact with a solid surface with the tip of a pseudopodium, the latter adheres to it by spreading out (g). Streaming of the cytoplasm follows and it becomes a creeping form (h). Positive reactions toward solid bodies account of course for the ingestion of food particles. PHYSIOLOGY 115 In Paramecium, according to Jennings, the anterior end is more sensitive than any other parts, and while swimming, if it comes in contact with a soHd object, the response may be either negative or positive. In the former case, avoiding movement (Fig. 49, c) follows and in the latter case, the organism rests with its anterior end or the whole side in direct contact with the object, in which position it ingests food particles through the cytostome. Fig. 48. Reactions of amoebae to mechanical stimuli (Jennings), a-c, an amoeba avoiding an obstacle; d, e, negative reaction to mechanical stimulation; f-h, positive reaction of a floating amoeba. Reaction to gravity. The reaction to gravity varies among dif- ferent Protozoa, according to body organization, locomotor organ- ellae, etc. Amoebae, Testacea and others which are usually found attached to the bottom of the container, react as a rule positively toward gravity, while others manifest negative reaction as in the case of Paramecium (Jensen; Jennings), which explains in part why Paramecium in a culture jar are found just below the surface film in mass, although the vertical movement of P. caudatum is undoubt- edl.y influenced by various factors, as was pointed out by Dem- bowski (1929). Reaction to current. Free-swimming Protozoa appear to move or orientate themselves against the current of water. In the case of Paramecium, Jennings observed the majority place themselves in line with the current, with anterior end upstream. The mycetozoan is said to exhibit also a well-marked positive reaction. 116 PROTOZOOLOGY Reaction to chemical stimuli. When methylgreen, methylene blue, or sodium chloride is brought in contact with an advancing amoeba, the latter organism reacts negatively (Jennings). Jen- nings further observed various reactions of Paramecium against chemical stimulation. This ciliate shows positive reaction to weak solutions of many acids and negative reactions above certain con- centrations. For example, Paramecium enters and stays wdthin the >M:^^M«. Fig. 49. Reactions of Paramecium (Jennings), a, collecting in a drop of 0.02% acetic acid; b, ring-formation around a drop of a stronger solu- tion of the acid; c, avoiding reaction. area of a drop of 0.02 per cent acetic acid introduced to the prepara- tion (Fig. 49, a) ; and if stronger acid is used, the organisms collect about its periphery where the acid is diluted by the surrounding water (Fig. 49, h). The reaction to chemical stimuli is probably of the greatest importance for the existence of Protozoa, since it leads them to proper food substances, the ingestion of which is the found- ation of metabolic activities. In the case of parasitic Protozoa, possibly the reaction to chemical stimuli results in their finding specifi.c host animals and their distribution in different organs and tissues within the host body. Recent investigations tend to indicate that chemotaxis plays an important role in the sexual reproduction in Protozoa. PHYSIOLOGY 117 Reaction to light stimuli. Most Protozoa seem to be indifferent to the ordinary light, but when the light intensity is suddenly in- creased, there is usually a negative reaction. Verworn saw the di- rection of movements of an amoeba reversed when its anterior end was subjected to a sudden illumination; Rhumbler observed that an amoeba, which was in the act of feeding, stopped feeding when it was subjected to strong light. According to Mast, Amoeba pro- tens ceases to move when suddenly strongly illuminated, but con- tinues to move if the increase in intensity is gradual and if the il- lumination remains constant, the amoeba begins to move. According to Jennings, Stentor coeruleus reacts negatively against light. The positive reaction to light is most clearly shown in stigma- bearing Mastigophora, as is well observable in a jar containing Euglena, Phacus, etc., in which the organisms collect at the place where the light is strongest. If the light is excluded completely, the organisms become scattered throughout the container, inac- tive and sometimes encyst, although the mixotrophic forms would continue activities by saprozoic method. The positive reaction to light by chromatophore-bearing forms enables them to find places in the water where photosynthesis can be carried on to the maximum degree. All Protozoa seem to be more sensitive to ultraviolet rays. Inman found that amoeba shows a greater reaction to the rays than others and Hertel observed that Paramecium which was indifferent to an ordinary light, showed an immediate response (negative reaction) to the rays. MacDougall brought about mutations in Chilodonella by means of these rays (p. 181). When ciliates are vitally stained with eosin, erythrosin, etc., they react sometimes positively or negatively as in Paramecium (Metzner), or always negatively, as in Spiro- stomum(Blattner). According toEfimoff, this "induced phototaxis" is not limited to fluorescent dyes, but also is possessed by all vital- staining dyes. Zuelzer (1905) studied the effects of radium rays upon various Protozoa and found that the effect was not the same among different species. For example, limax amoeba was more resistant than others. In all cases, however, long exposure to the rays was fatal to Protozoa, the first ejffect of exposure being shown by accele- rated movement. Halberstaedter and Luntz (1929) studied injuries and death of Eudorina elegans by exposure to radium rays. Joseph and Prowazek (1902) found Paramecium and Volvox gave negative response to the rontgen-ray. Reaction to temperature stimuli. As was stated before, there seems to be an optimum temperature range for each protozoan, 118 PROTOZOOLOGY although it can withstand temperatures which are lower or higher than that range. As a general rule, the higher the temperature, the greater the metabolic activities, and the latter condition results in turn in a more rapid growth and more frequent reproduction. It has been suggested that change to different phases in the life-cycle of a protozoan in association with the seasonal change may be largely due to temperature changes of the environment. In the case of parasitic Protozoa which pass their life-cycle in two hosts: warm- blooded and cold-blooded animals, such as Plasmodium and mam- malian trypanosomes, the change in body temperature of host animals may bring about specific stages in their development. Reaction to electrical stimuli. Since Verworn's experiments, several investigators studied the effects of electric current which is passed through Protozoa in water. Amoeba shows negative re- action to the anode and moves toward the cathode either by revers- ing the cytoplasmic streaming (Verworn) or by turning around the body (Jennings). The free-swimming ciliates move mostly toward the cathode, but a few may take a transverse position (Spirostomum) or swim to the anode (Paramecium, Stentor, etc.). Of flagellates, Verworn noticed that Trachelomonas and Peridinium moved to the cathode, while Chilomonas, Cryptomonas, and Polytomella, swam to the anode. References Ball, G. H. 1925 Studies on Paramecium. I. Uni. Cal. Publ. Zool., Vol. 2o. Becker, E. R. 1941 Effect of parenteral administration of vita- min Bi and vitamin Be on a Coccidium infection. Proc. Soc. Exper. Biol. Med., Vol. 46. and R. I. Dilworth. 1941 Nature of Eimeria nieschulzi growth-promoting potency of feeding stuffs. II. Vitamins Bi and Be. Jour. Infect. Dis., Vol. 68. Berthold, C. 1886 Studien liber Protoplasmamechanik. Leipzig. Brug, S. L. 1928 Observations on a culture of Entamoeha histoly- tica. Med. Dienst Volksges. Ned. Indie for 1928. Calkins, G. N. and F. M. Summers (editors). 1941 Protozoa in biological research. New York. Claff, C. L., V. C. Dewey and G. W. Kidder 1941 Feeding mechanisms and nutrition in three species of Bresslaua. Biol. Bull., Vol. 81. Clark, A. M. 1942 Some effects of removing the nucleus from Amoeba. Australian Jour. Exp. Biol, and Med. Sci., Vol. 20. Cleveland, L. R. 1925 Toxicity of oxygen for Protozoa in vivo and in vitro. Animals defaunated without injury. Biol. Bull., Vol. 48. , S. R. Hall, E. P. Sanders and J. Collier 1934 The wood-feeding roach Cryptocercus, its Protozoa, and the sym- biosis between Protozoa and roach. Mem. Amer. Acad. Arts and Sci., Vol. 17. PHYSIOLOGY 119 Dawson, J. A. and M. Belkin 1928 The digestion of oil by Amoeba duhia. Proc. Soc. Exp. Biol, and Med., Vol. 25. Bellinger, 0. P. 1906 Locomotion of amoebae and allied forms. Jour. Exp. Zool., Vol. 3. Dembowski, J. 1929 Die Vertikalbewegungen von Paramecium caudatum. II. Arch. f. Protistenk., Vol. 68. DoFLEiN, F. 1918 Ueber Pohjtomella agilis Aragao. Zool. Jahrb. Abt. Anat., Vol. 41. Doyle, W. L. 1943 The nutrition of the Protozoa. Biol. Rev., Vol. 18. Edgar, S. A., C. A. Herrick and L. A. Eraser. 1944 Glycogen in the life cycle of the coccidium, Eimeria tenella. Trans. Amer. Micr. Soc.,Vol. 63. Elliott, A. M. 1938 The influence of certain plant hormones on the growth of Protozoa. Physiol. Zool., Vol. 11. Gray, J. 1928 Ciliary movement. Cambridge. Greenwood, M. 1894 Constitution and formation of "food vacu- oles" in Infusoria. Phil. Trans. (B), Vol. 185. and E. R. Saunders 1884 The role of acid in protozoan digestion. Jour. Physiol., Vol. 16. Hall, R. P. 1939 Pimelic acid as a growth stimulant for Colpidium campylum. Arch. f. Protistenk., Vol. 92. 1942 Incomplete proteins as nitrogen sources, and their re- lation to vitamin requirements in Colpidium campylum. Physiol. Zool., Vol. 15. 1943 Growth-factors for Protozoa. In Harris and Thimann: Vitamins and hormones. Vol. 1. and A. Shottenfeld 1941 Maximal density and phases of death in populations of Glaucoma piriformis. Physiol, Zool,, Vol. 14. Harvey, E. N. 1940 Living light. Princeton. Heidt, K. 1937 Form und Struktur der Paramylonkorner von Euglena sanguinea. Arch. f. Protistenk., Vol. 88. Herfs, a. 1922 Die pulsierende Vakuole der Protozoen, ein Schutz- organ gegen Aussiissung. Ibid., Vol. 44. Hopkins, D. L. 1938 The vacuoles and vacuolar activity in the marine amoeba, Flabellida mira Schaeffer and the nature of the neutral red system in Protozoa. Biodynamica, No. 34. HowLAND, R. B. 1928 The pH of gastric vacuoles. Protoplasma, Vol. 5. and A. Bernstein 1931 A method for determining the oxy- gen consumption of a single cell. Jour. Gen. Physiol., Vol. 14. HuLPiEU, H. R. 1930 The effect of oxygen on Amoeba proteus. Jour. Exp. Zool., Vol. 56. Hyman, L. H. 1917 Metabolic gradients in amoeba and their rela- tion to the mechanism of amoeboid movement. Jour. Exp. Zool., Vol. 24. Jennings, H. S. 1904 Contributions to the study of the behavior of the lower organisms. Publ. Carnegie Inst. Washington, No. 16. 1906 Behavior of the lower organisms. New York. 120 PROTOZOOLOGY Johnson, W. H. 1941 Nutrition in the Protozoa. Quart. Rev. Biol., Vol. 16. and E. G. S. Baker 1943 Certain B vitamins on popula- tions of Tetrahymena geleii. Physiol. Zool., Vol. 16. Khainsky, a. 1910 Zur Morphologie unci Physiologic einiger In- fusorien (Paramecium caudaium) auf Grund einer neuen his- tologischen Methode. Arch. f. Protistenk., Vol. 21. Kidder, G. W., D. M. Lilly and C. L. Claff. 1940 Growth stud- ies on ciliates. IV. Biol. Bull., Vol. 78. KiRBY, H. Jr., 1934 Some ciliates from salt marshes in California. Arch. f. Protistenk., Vol. 82. KoFoiD, C. A. and O. Swezy 1921 The free-living unarmored Dino- fiagellata. Mem. Univ. Calif., Vol. 5. Krijgsman, B. J. 1925 Beitrage zum Problem der Geisselbe- wegung. Arch. f. Protistenk., Vol. 52. Kudo, R. R. 1921 On the nature of structures characteristic of cnidosporidian spores. Trans. Amer. Micr. Soc, Vol. 40. Lilly, D. M. 1942 Nutritional and supplementary factors in the growth of carnivorous ciliates. Physiol. Zool., Vol. 15. Mast, S. O. 1923 Mechanics of locomotion in amoeba. Proc. Nat. Acad. Sci., Vol. 9. 1926 Structure, movement, locomotion, and stimulation in amoeba. Jour. Morph. Physiol., Vol. 41. 1931 Locomotion in Amoeba proteus. Protoplasma, Vol. 14. 1938 Digestion of fat in Amoeba proteus. Biol. Bull., Vol. 75. 1939 The relation between kind of food, growth, and struc- ture in Amoeba. Ibid., Vol. 77. 1942 The hydrogen ion concentration of the content of the food vacuoles and the cytoplasm in Amoeba and other phe- nomena concerning the food vacuoles. Biol. Bull., Vol. 83. and W. L. Doyle 1934 Ingestion of fluid by amoeba. Ibid., Vol. 20. 1935 Structure, origin and function of cytoplasmic constituents in Amoeba proteus with special reference to mito- chondria and Golgi substance. Arch. f. Protistenk., Vol. 86. Meldrum, N. U. 1934 Cellular respiration. London. Metalnikoff, S. 1912 Contribution a I'etude de la digestion intra- cellulaire chez les protozoaires. Arch. zool. exp. (ser. 5), Vol. 9. Mouton, H. 1902 Recherches sur la digestion chez les amibes et sur leur diastase intracellulaire. Ann. Inst. Pasteur. Vol. 16. Nirenstein, E. 1925 Ueber die Natur und Starke der Saurebildung in den Nahrungsvakuolen von Paramecium caudatum. Zeitschr. wiss. Zool., Vol. 125. Noland, L. E. 1927 Conjugation in the ciliate Metopus sigmoides. Jour. Morph. Physiol., Vol. 44. Pantin, C. F. a. 1923 On the physiology of amoeboid movement I. Jour. Marine Biol. Assn. Plymouth, N. S., Vol. 13. Panzer, T. 1913 Beitrag zur Biochemie der Protozoen. Hoppe- Seylers Zeitschr. phys. Chemie, Vol. 86. Powers, P. B. A. 1932 Cyclotrichium meunieri sp. nov. ; cause of red water in the gulf of Maine. Biol. Bull., Vol. 63. PHYSIOLOGY 121 Pratjb, a. 1921 Makrochemische, quantitative Bestimmung des Fettes und Cholesterins, sowie ihrer Kennzahlen bei Noctiluca miliaris. Biol. Zentralbl., Vol. 21. Pringsheim, E. G. 1923 Zur Physiologie saprophytischer Flagella- ten. Beitr. allg. Bot., Vol. 2. Putter, A. 1905 Die Atmung der Protozoen. Zeitschr. allg. Physiol, Vol. 5. 1908 Methoden zur Erforschung des Lebens der Protistenk. Tigerstedt's Handb. physiol. Methodik, Vol. 1. RosKiN, G. and L. Levinsohn 1926 Die Oxydasen und Peroxy- dasen bei Protozoen. Arch. f. Protistenk., Vol. 56. Rhumbler, L. 1910 Die verschiedenartigen Nahrungsaufnahmen bei Amoeben als Folge verschiedener Colloidalzustande ihrer Oberflachen. Arch. Entw. Organism., Vol. 30. Sassuchin, D. N. 1935 Zum Studium der Protisten- und Bak- terien-kerne. Arch. f. Protistenk., Vol. 84. Schaeffer, a. a. 1920 Amoeboid movement. Princeton. ScHEWiAKOFF, W. 1894 Ueber die Natur der sogenannten Exkret- korner der Infusorien. Zeitschr. wiss. Zool., Vol. 57. ScHOPFER, W. H. (translated by N. L. Noecker). 1943 Plants and vitamins. Waltham, Mass. Shapiro, N. N. 1927 The cycle of hydrogen-ion concentration in the food vacuoles of Paramecium, Vorticella, and Stylonychia. Trans. Amer. Micro. Soc, Vol. 46. SouLE, M. H. 1925 Respiration of Trypanosoma Icwisi and Leish- mania tropica. Jour. Infec. Dis., Vol. 36. Stolc, a. 1900 Beobachtungen und Versuche ueber die Verdauung und Bildung der Kohlenhydrate bei einen amoebenartigen Or- ganismen, Pclomyxa palustris. Zeitschr. wiss. Zool. Vol. 68. Verworn, M. 1889 Psycho-physiologische Protisten-studien. Jena. 1903 Allgemeine Physiologie. 4te Aufl. Jena. Weatherby J. H. 1929 Excretion of nitrogenous substances in Pro- tozoa. Physiol. Zool., Vol. 2. Whipple, G. C. 1927 The microscopy of drinking water. 4 ed. New York. Woodruff, L. L. and W. W. Swingle 1924 The effects of thyroid and some other endocrine products on Paramecium. Amer. Jour. Physiol., Vol. 69. Zuelzer, M. 1907 Ueber den Einfluss des Meerwassers auf die pul- sierende Vacuole. Berhn. Sitz.-Ber. Ges. naturf. Freunde. Zumstein, H. 1900 Zur Morphologic und Physiologie der Euglena gracilis Klebs. Pringsheims Jahrb. wiss. Botanik, Vol. 34. Chapter 5 Reproduction THE mode of reproduction in Protozoa is highly variable among different groups, although it is primarily a cell division. The reproduction is initiated by the nuclear division in all cases, which will therefore be considered first. Nuclear division Between a simple direct division on the one hand and a com- plicated indirect division which is comparable with the typical metazoan mitosis on the other hand, all types of nuclear division occur. Direct nuclear division. Although not so widely found as it was thought to be in former years, amitosis occurs normally and regu- larly in many forms. While the micronuclear division of the Cilio- phora is mitotic (p. 137), the macronuclear division is invariably amitosis. The sole exception to this general statement appears to be the so-called promitosis reported by Ivanic (1938) in the macro- nucleus in the "Vermehrungsruhe" stage of Chilodenella uncinata in which chromosomes and spindle-fibers were observed. In Para- mecium caudatum (Fig. 50), the micronucleus initiates the division by mitosis and the macronucleus elongates itself without any visible changes in its internal structure. The elongated nucleus becomes constricted through the middle and two daughter nuclei are pro- duced. It is assumed that the nuclear components undergo solation during division, since the formed particles of nucleus which are stationary in the resting stage, manifest a very active Brownian movement as was observed in vivo in Endamoeba blattae (Fig. 51). Furthermore, in some cases the nuclear components may undergo phase reversal, that is to say, the chromatin granules which are dispersed phase in the non-staining fluid dispersion medium in the resting nucleus, be- come dispersion medium in which the latter is suspended as dis- persed phase. By using Feulgen's nucleal reaction, Reichenow (1928) demonstrated this reversal phenomenon in the division of the macronucleus of Chilodonella cucullulus (Fig. 52). The macronucleus becomes at the time of its division somewhat enlarged and its chromatin granules are more deeply stained than before. But chromosomes which characterize the mitotic division are entirely absent, although in a few forms in which mating types 122 REPRODUCTION 123 occur, the type difference and certain other characters, according to Sonneborn and Kimball, appear to be under control of genie consti- tuents of the macronucleus. Since the number of chromatin granules appear approximately the same in the macronuclei of different gen- erations of a given species, the reduced number of chromatin gran- FiG. 50. Nuclear and cytosomic division of Paramecium caudatum as seen in stained smears, X260 (Kudo). ules must be restored sometime before the next division takes place. Calkins (1926) is of the opinion that "each granule elongates and divides into two parts, thus doubling the number of chromomeres." Reichenow (1928) found that in Chilodonella cucullulus the lightly Feulgen positive endosome appeared to form chromatin granules and Kudo (1936) maintained that the large chromatin spherules of Fig. 51. Division of Endamoeba blattae as seen in life, X250 (Kudo). The entire process took one hour and seven minutes. Fig. 52. The solation of chromatin during the macronuclear division of Chilodonella cucullulus, as demonstrated by Feulgen's nucleal reaction, Xl800(Reichenow). REPRODUCTION 125 the macronucleus of Nyctotherus ovalis probablj^ produce smaller spherules in their alveoli. When the macronucleus is elongated as in Spirostomum, Stentor, Euplotes, etc., the nucleus becomes condensed into a rounded form prior to its division. When the macronuclear material is distrib- uted throughout the cytoplasm as numerous grains as in Dileptus anser (Fig. 239, c), ''each granule divides where it happens to be and with the majority of granules both halves remain in one daugh- ter cell after division" (Calkins). Hayes noticed a similar division, but at the time of simultaneous division prior to cell division, each macronucleus becomes elongated and breaks into several small nuclei. During the "shortening period" of the elongated macronuclei prior to division, there appear 1-3 characteristic zones which have Macronuclear reorganization before division in Euplotes X240 (Turner), a, reorganization band appearing at a tip of the macronucleus; b-d, later stages. been called by various names, such as nuclear clefts, reconstruction bands, reorganization bands, etc. In Euplotes patella (E. eurystomus) , Turner (1930) observed prior to division of the macronucleus a re- organization band consisting of a faintly staining zone ("recon- struction plane") and a deeply staining zone ("solution plane"), ap- pears at each end of the nucleus (Fig. 53, a) and as each moves to- ward the center, a more chromatinic area is left behind (b-d). The two bands finally meet in the center and the nucleus assumes an ovoid form. This is followed by a simple division into two. In the T-shaped macronucleus of E. woodruffi, according to Pierson (1943), a reorganization band appears first in the right arm and the posterior tip of the stem of the nucleus. When the anterior band reaches the junction of the arm and stem, it splits into two, one part moving along the left arm to its tip, and the other entering and passing down 126 PROTOZOOLOGY the stem to join the posterior band. According to Summers (1935) a process similar to that of E. eurystomus occurs in Diophrys ap- pendiculata and Stylonychia pustulata; but in Aspidisca lynceus (Fig. 54) a reorganization band appears first near the middle region of the macronucleus (6), divide into two and each moves toward an end, leaving between them a greater chromatinic content of the Fig. 54. Macronuclear reorganization prior to division in Aspidisca lynceus, X1400 (Summers), a, resting nucleus; b-i, successive stages in reorganization process; j, a daughter macronucleus shortly after division. reticulum (c-i). Summers suggested that "the reorganization bands are local regions of karyolysis and resynthesis of macronuclear materials with the possibility of an elimination of physically or possibly chemically modified nonstaining substances into the cyto- plasm." The extrusion of a certain portion of the macronuclear material during division has been observed in a number of species. In Urolep- tus halseyi, Calkins actually noticed each of the eight macronuclei REPRODUCTION 127 is "purified" by discarding a reorganization band and an "x-body" into the cytoplasm before fusing into a single macronucleus which then divides into two nuclei. In the more or less rounded macro- nucleus that is commonly found in many ciliates, no reorganization band has been recognized. A number of observers have however noted that during the nuclear division there appears and persists a small body within the nuclear figure, Ipcated at the division plane as in the case of Loxocephalus (Behrend), Eupoterion (MacLennan and 't^M^. Fig. 55. Macronuclear division in Coyichophlhirus mytili, X440 (Kidder). Connell) and even in the widely different protozoan, Endamoeha blattae (Kudo) (Fig. 51). We owe Kidder for a careful comparative study of this body. Kidder (1933) observed that during the division of the macronucleus of Conchophthirus mytili (Fig. 55), the nucleus "casts out a part of its chromatin at every vegetative division," which "is broken down and disappears in the cytoplasm of either daughter organism." A similar phenomenon has since been found further in C. anodontae, C. curtus, C. magna (Kidder), Urocentrum turbo, Colpidium colpoda, C. campylum, Glaucoma scintillans (Kidder and Diller), and Allosphaerium convexa (Kidder and Summers). Kidder and his associates believe that the process is probably 128 PROTOZOOLOGY elimination of waste substances of the prolonged cell-division, since chromatin extrusion does not take place during a few divisions sub- sequent to reorganization after conjugation in Conchophthirus mytili and since in Colpidium and Glaucoma, the chromatin elimination appears to be the cause of high division rate and infrequency of con- jugation. Woodruff and Erdmann (1914)^ observed that in Pararnecium aurelia (Fig. 56, a) at regular intervals of about 30 days, the old Fig. 56. Diagram showing the endomixis in Paramecium aurelia (Wood- ruff), a, normal individual; b, degeneration of macronucleus and first micronuclear division; c, second micronuclear division; d, degeneration of 6 micronuclei; e, cell division; f, g, first and second reconstruction micro- nuclear divisions; h, transformation of 2 micronuclei into 2 macronuclei; i, micronuclear and cell divisions; j, typical nuclear condition is restored. macronucleus breaks down and disappears, while each of the two micronuclei divides twice, forming eight nuclei (b, c). Of these, six disintegrate. At this point the organism divides into two, each daughter individual receiving one micro nucleus {d, e). This nucleus soon divides twice into four, two of which develop into macronuclei if-h), and the other two divide again. Here the organisms divide once more by binary fission (i), each bearing cne macronucleus and two micronuclei (j). This process which is "a complete periodic nuclear reorganization without cell fusion in a pedigreed race of Parame- REPRODUCTION 129 cium" was called by the two authors endomixis. In the case of P. caudatum, they found endomixis occurs at intervals of about 60 days. Endomixis has since been reported in Spathidium spathula, Euplotes longipes, Chilodonella uncinata, Didinium nasutum, Para- mecium multimicronucleatum, Urostyla grandis, Paraclevelandia sim- plex, etc. It appears to be another process of nuclear reorganization. As has already been stated, two types of nuclei: macronucleus and micronucleus, occur in Euciliata and Suctoria. The macro- nucleus is the center of the whole metabolic activity of the organism and in the absence of this nucleus, the animal perishes. The waste substances which become accumulated in the macronucleus through its manifold activities, are apparently eliminated at the time of division, as has been cited above in many species. On the other hand, it is also probable that under certain circumstances, the macro- nucleus becomes impregnated with waste materials which cannot be eliminated through this process. Prior to and during conjugation (p. 154) and autogamy (p. 161), the macronucleus becomes trans- formed, in many species, into irregularly coiled thread-like sti;ucture (Fig. 79) which undergoes segmentation into pieces and finally is absorbed by the cytoplasm. New macronuclei are formed from some of the division-products of micronuclei (synkarya) by probably in- corporating the old macronuclear material. In most cases this sup- position is not demonstrable. However, Kidder (1938) has shown in the encysted Paraclevelandia simplex, an endocommensal of the colon of certain wood-feeding roaches, this is actually the case; namely, one of the divided micronuclei fuses directly with a part of macronucleus (endomixis) to form a macronuclear anlage which then develops into a macronucleus after passing through "ball-of- yarn" stage similar to that which appears in an exconjugant of Nyctotherus (Fig. 79). Since the macronucleus originates in a micronucleus, it must con- tain all structures which characterize the micronucleus. Why then does it not divide mitotically as does the micronucleus? During conjugation or autogamy in a ciliate, the macronucleus degenerates, disintegrates and finally becomes absorbed in the cytoplasm. In Paramecium aurelia, Sonneborn (1940, 1942) observed that in amicronucleate animals or when the micronuclei fail to give rise to macronuclei, many (40 or more) pieces of the disintegrated old macronucleus do not degenerate, but instead regenerate into new macronuclei, which are segregated out to daughter individuals formed at successive divisions, until one such regenerated macro- nucleus is present in each individual. These macronuclei grow and 130 PROTOZOOLOGY behave in the same way as do those which arise from microniiclei. Thus the macronucleus in this ciHate appears to be a compound structure with its 40 or more component parts, each containing all that is needed for development into a complete macronucleus. From these observations, Sonneborn concludes that the macronucleus in P. aurelia appears to undergo amitosis, since it is a compound nu- cleus composed of 40 or more "sub-nuclei" and since at fission all that is necessary to bring about genetically equivalent functional macronuclei is to segregate these multiple subnuclei into two random groups. a b c d e Fig. 57. Amitosis of the vegetative nucleus in the trophozoite of Myxosoma catostonii, X2250 (Kudo). Other examples of amitosis are found in the vegetative nuclei in the trophozoite of Myxosporidia, as for example, Myxosoma catos- tomi (Fig. 57), Thelohanellus notatus (Debaisieux), etc., in which the endosome divides first, followed by the nuclear constriction. In Strehlomastix strix, the compact elongated nucleus was found to undergo a simple division by Kof oid and Swezy. Indirect nuclear division. The indirect division which occurs in the protozoan nuclei is of manifold types as compared with the mitosis in the metazoan cell, in which, aside from minor variations, the change is of a uniform pattern. Chatton, Alexeieff and others, have proposed several terms to designate the various types of indirect nuclear division, but no one of these types is sharply defined. For our purpose, mentioning of examples will suffice. A veritable mitosis was noted by Dobell in the heliozoan Oxnerella maritima (Fig. 58), which possesses an eccentrically situated nucleus containing a large endosome and a central centriole, from which radiate many axopodia (a). The first sign of the nuclear division is the slight enlargement, and migration toward the centriole, of the nucleus (6). The centriole first divides into two (c, d) and the nucleus becomes located between the two centrioles (e). Presently spindle fibers are formed and the nuclear membrane disappears (/, g) . After passing through an equatorial-plate stage, the two groups of 24 chromosomes move toward the opposite poles {g-4). As the spindle fibers become indistinct, radiation around the centrioles becomes REPRODUCTION 131 conspicuous and the two daughter nuclei are completely recon- structed to assume the resting phase (j-l). The mitosis of another heliozoan Acanthocystis aculeata is, according to Schaudinn and Stern, very similar to the above. Aside from these two species, the centriole has been reported in many others, such as Hartmanella Fig. 58. Nuclear and cytosomic division in Oxnerella maritima, X about 1000 (Dobell). a, a living individual; b, stained specimen; c-g, prophase; h, metaphase; i, anaphase; j, k, telophase; 1, division completed. (Arndt), Euglypha, Monocystis (Belaf), Aggregata (Dobell; Belaf; Naville), various Hypermastigina (Kofoid; Duboscq, Grasse; Kirby; Cleveland and his associates). In numerous species the division of the centriole (or blepharo- plast) and a connecting strand between them, which has been called desmose (centrodesmose or paradesmose), have been observed. Ac- 132 PROTOZOOLOGY Fig. 59. Mitosis in Trichonympha campanula, XSOO (Kofoid and Swezy). a, resting nucleus; b-g, prophase; h, metaphase; i, j, anaphase; k, telophase; 1, a daughter nucleus being reconstructed. cording to Kofoid and Swezy (1919), in Trichonympha campanula (Fig. 59), the prophase begins early, during which 52 chromosomes are formed and become split. The nucleus moves nearer the anterior end where the centriole divides into two, between which develops a I REPRODUCTION 133 desmose. From the posterior end of each centriole; astral rays extend out and the spHt chromosomes form loops, pass through "tangled skein" stage, and emerge as 26 chromosomes. In the metaphase, the equatorial plate is made up of V-shaped chromosomes as each of the Fig. 60. Development of spindle and astral rays during the mitosis in Barbulanympha, X930 (Cleveland), a, interphase centrioles and centro- somes; b, prophase centrioles with astral rays developing from their distal ends through the centrosomes; c, meeting of astral rays from two cen- trioles; d, astral rays developing into the early central spindle; e, a later stage showing the entire mitotic figure. split chromosomes are still connected at one end, which finally be- comes separate in anaphase, followed by reformation of two daugh- ter nuclei. 134 PROTOZOOLOGY As to the origin and development of the achromatic figure, vari- ous observations and interpretations have been advanced. Certain Hypermastigina po.ssess very large filiform centrioles and a large rounded nucleus. In Barbulanympha (Fig. 60), Cleveland (1938a) found that the centrioles vary from 15 to 30/x in length in the four species of the genus which he studied. They can be seen, according to Cleveland, in life as made up of a dense hyaline protoplasm. When stained, it becomes apparent that the two centrioles are joined at their anterior ends by a desmose and their distal ends 20 to 30m apart, each of which is surrounded by a special centrosome (a). In the resting stage no fibers extend from either centriole, but in the prophase, astral rays begin to grow out from the distal end of each centriole (6). As the rays grow longer (c), the two sets soon meet and the individual rays or fibers join, grow along one another and over- lap to form the central spindle (d). In the resting nucleus, there are large irregular chromatin granules which are connected by fibrils with one another and also with the nuclear membrane. As the achro- matic figure is formed and approaches the nucleus, the chromatin be- comes arranged in a single spireme imbedded in matrix. The spireme soon divides longitudinally and the double spireme presently breaks up transversely into paired chromosomes. The central spindle begins to compress the nuclear membrane and the chromosomes become shorter and move apart. The intra- and extra-nuclear fibrils unite as the process goes on (e), the central spindle now assumes an axial position, and two groups of V-shaped chromosomes are drawn to opposite poles. In the telophase, the chromosomes elongate and be- come branched, thus assuming conditions seen in the resting nucleus. In the unique resting nucleus of Spirotrichomjmpha polygyra (Fig. 61), Cleveland (1938) found four chromosomes, each of which con- tains a distinct coil within a sheath and its one end connected with the anterior margin of the nuclear membrane by an intranuclear chromosomal fiber, and the other end with a deeply staining endo- some (a). The spindle fibers appear between the separating flagellar bands which come in contact with the nuclear membrane. Soon some of the astral rays become connected with the intranuclear chromosomal fibers and one long and one short chromosomes which become thicker and shorter move toward each pole. During the telo- phase, each chromosome splits lengthwise and forms the resting nucleus (g). In Lophomonas hlattarum, the nuclear division (Fig. 62) is initiated by the migration of the nucleus out of the calyx. On the nuclear membrane is attached the centriole which probably originates in the REPRODUCTION 135 blepharoplast ring; the centriole divides and the desmose which grows, now stains very deeply, the centrioles becoming more con- spicuous in the anaphase when new flagella develop from them. Chromatin granules become larger and form a spireme, from which 6-8 chromosomes are produced. Two groups of chromosomes move toward the opposite poles, and when the division is completed, each centriole becomes the center of formation of all motor organellae. Fig. 61. Mitosis in Spirotrichonympha polygyra (Cleveland), a, resting nucleus with 4 chromosomes; b, c, prophase; d, chromosomes moving apart; e, elongation of nucleus; f, telophase; g, a daughter nucleus in which the chromosomes are splitting, a-e, X3800; f, g, X2400. In some forms, such as Noctiluca (Calkins), Actinophrys(Bglaf), etc., there may appear at each pole, a structureless mass of cyto- plasm (centrosphere), but in a very large number of species there appear no special structures at poles and the spindle fibers become stretched seemingly between the two extremities of the elongating 136 PROTOZOOLOGY nuclear membrane. Such is the condition found in Cryptomonas (Belaf), Rhizochrysis (Doflein), Aulacantha (Borgert), and in micro- nuclear division of the majority of Euciliata and Suctoria. The behavior of the endosome during the mitosis differs among different species as are probably their functions. In Eimeria schuhergi (Schaudinn), Euglena viridis (Tschenzoff), Oxyrrhis marina (Hall), Colacium vesiculosum (Johnson), Haplosporidium limnodrili (Gran- FiG. 62. Nuclear division in Lophomonas hlattarum, X1530 (Kudo), a, resting nucleus; b, c, prophase; d, metaphase; e-h, anaphase; i-k, telo- phase. ata), etc., the conspicuously staining endosome divides by elongation and constriction along with other chromatic elements, but in many other cases, it disappears during the early part of division and reap- pears when the daughter nuclei are reconstructed as observed in Monocystis, Dimorpha, Euglypha, Pamphagus (Belaf), Acantho- cystis (Stern), Chilomonas (Doflein), Dinenympha (Kirby), etc. In the vegetative division of the micronucleus of Conchophthirus anodontae (Fig. 63), Kidder (1934) found that prior to division the micronucleus moves out of the pocket in the macronucleus and the REPRODUCTION 137 chromatin becomes irregularly disposed in a reticulum; swelling continues and the chromatin condenses into a twisted band, a spireme, which breaks into many small segments, each composed of large chromatin granules. With the rapid development of the spindle fibers, the twelve bands become arranged in the equatorial plane and condense. Each chromosome now splits longitudinally and two groups of 12 daughter chromosomes move to opposite poles and m m feSsS^iaSt Fig. 63. Mitosis of the micronucleus of Conchophthirus anodontae, X2640 (Kidder), a-c, prophase; d, e, metaphase; f, g, anaphase; h, i, telophase. transform themselves into two compact daughter nuclei. In Zeller- iella intermedia (Fig. 64), Chen (1936) saw the formation of 24 chromosomes, each of which is connected with a fiber of the intra- nuclear spindle and splits lengthwise in the metaphase. While in the majority of protozoan mitosis, the chromosomes split longitudinally, there are observations which suggest a transverse division. As exam- 138 PROTOZOOLOGY pies may be mentioned the chromosomal divisions in Astasia laevis (Belaf), Entosiphon sulcatum (Lackey), and a number of ciliates. In a small number of species observations vary within a species, as, for example, in Peranema trichophorum in which the chromosomes were observed to divide transversely (Hartmann and Chagas) as well as longitudinally (Hall and Powell; Brown). It is inconceivable that the division of the chromosome in a single species of organism is haphazard. The apparent transverse division might be explained Fig. 64. Stages in mitosis in Zelleriella inter iriedia, X1840 (Chen), a, early prophase; b, metaphase; c, anaphase; d, telophase. by assuming, as Hall (1937) showed in Euglena gracilis, that the splitting is not completed at once and the pulling force acting upon them soon after division brings forth the long chromosomes still connected at one end. Thus the chromosomes remain together before the anaphase begins. In the instances considered on the preceding pages, the so-called chromosomes found in them, appear to be essentially similar in structure and behavior to typical metazoan chromosomes. In many other cases, the so-called chromosomes or "pseudochromosomes" are slightly enlarged chromatin granules which differ from the ordin- ary chromatin granules in their time of appearance and movement only. In these cases it is of course not possible at present to deter- mine how and when their division occurs before separating to the respective division pole. In Table 5 are listed the number of the "chromosomes" which have been reported by various investigators in the Protozoa that are mentioned in the present work: REPRODUCTION Table 5. — Chromosomes in Protozoa 139 Protozoa Number of chromosomes Observers Rhizochrysis scherffeli 22 Doflein H aematococcus pluvialis 20-30 Elliott Polytomella agilis 5 Doflein Chlamydomonas spp. 10 (haploid) Pascher Polytoma uvella 16 (diploid); 8 (haploid) Moewus Euglena pisciformis 12-15(?) Dangeard E. viridis 30 or more Dangeard Phacus pyrurn 30-40 Dangeard Menoidium incurimm About 12 Hall Vacuolaria virescens About 30 Fott Syndinium turbo 5 Chatton Anthophysis vegetans 8-10 Dangeard Gercomonas longicauda 4-5 Dangeard Collodictyon triciliatum About 20 Belaf Chilomastix gallinarum About 12 Boeck and Tanabe Eidrichomastix serpentis 5 Kofoid and Swezy Dinenympha fimbricata 25-30 Kirby Metadevescovina debilis About 4 Light Trichomonas elongatum 3 Hinshaw Tritrichomonas batrachorum 4 or 8 Kuczynski 6 Bishop T. augusta 5 Kofoid and Swezy 4 or 8 Kuczynski Hexamita salmonis 5 or 6 Davis Giardia intestinalis 4 Kofoid and Swezy G. muris 4 Kofoid and Christiansen Colony mpha grassii 4 or 5 Janicki Spirotrichonympha polygyra 2 doubles Cup 2 Cleveland Lophomonas blattarum 16 or 8 doubles Janicki 8 or 6 Kudo 12 or 6 doubles Belaf L. striata 12 or 6 doubles Belaf Barbtdanynipha laurabuda 40 Cleveland B. uf alula 50 Cleveland Rhynchonympha tarda 19 Cleveland Urinympha talea 14 Cleveland Staurojoenia assimilis 24 Kirby Trichonympha campanula 52 or 26 doubles Kofoid and Swezy T. grandis 22 Cleveland Plasmodiophora brassicae 8 (diploid); 4 (haploid) Terby Dimastig amoeba bistadialis 16-18 Kuhn 140 PROTOZOOLOGY Table 5. — Continued Protozoa Number of chromosomes Observers Endamoeba disparata About 12 Kirby Entamoeba histolytica 6 Kofoid and Swezy; Uribe E. coli 6 Swezy; Stabler E. gingivalis 5 Stabler Dientamoeba fragilis 4 Wenrich 6 Dobell Hydramoeba hydroxena 8 Reynolds and Threlkeld Spirillina vivipara 12 (diploid); 6 (haploid) Myers Patellina corrugata 24 (diploid) ; 12 (haploid) Myers Pontigulasia vas 8-12 Stump Actinophrys sol 44 (diploid); 22 (haploid) Belaf Oxnerella maritima About 24 Dobell Thalassicolla nucleata 4 Belaf Aulacantha scolymantha More than 1600 Borgert 4 in gamogony Belaf Zygosoma globosum 12 (diploid); 6 (haploid) Noble Diplocystis schneideri 6 (diploid) ; 3 (haploid) Jameson Gregarina blattarum 6 (diploid) ; 3 (haploid) Sprague Nina gracilis 5 (haploid) Leger and Duboscq Actinocephalus parvus 8 (diploid); 4 (haploid) Weschenfelder Aggregata eberthi 12 (diploid); Dobell and Jameson; 6 (haploid) Belaf; Naville Merocystis kathae 6 (haploid) Patten Adelea ovata 8-10 (diploid); 4-5 (haploid) Greiner Adelina deronis 20 (diploid) ; 10 (haploid) Hauschka Orcheobius herpobdellae 10-12 Kunze Chloromyxum leydigi 4 (diploid) ; 2 haploid) Naville Sphaerospora polymorphc I 4 (diploid); 2 (haploid) Kudo Myxidium lieberkuhni 4 Bremer M. serotinum 4 (diploid) ; 2 (haploid) Kudo Sphaeromyxa sabrazesi 6 Debaisieux; Belaf 4 Naville S. balbianii 4 Naville REPRODUCTION 141 Table 5. — Continued Protozoa Number of chromosomes Observers Myxobolus pfeifferi 4 Keysselitz; Mercier; Georgevitch Protoopalina intestinalis 8 (diploid); 4 (haploid) Metcalf Zelleriella antilliensis 2(?) Metcalf Z. intermedia 24 Chen Didinium nasutum 16 (diploid); 8 (haploid) Prandtl Chilodonella uncinata 4 (dilpoid); 2 (haploid) Enrique; MacDougall C. uncinata (tetraploid) 8; 4 MacDougall Conchophthirus anodontae 12 (diploid) Kidder C. mytili 16 (diploid); 8 (haploid) Kidder Ancistruma isseli About 5 (haploid) Kidder Paramecium aurelia 30-40 Diller Stentor coeruleus 28 (diploid) ; 14 (haploid) Mulsow Oxytricha fallax 24 (diploid) ; 12 (haploid) Gregory Uroleptus halseyi 24 (diploid); 12 (haploid) Calkins Pleurotricha lanceolata About 40 (dipl.); 20 (haploid) Manwell Stylonychia pustulata 6 Prowazek Euplotes patella 6 (diploid) Yocom; Ivanic 8 (diploid) ; Turner 4 (haploid) Carchesium polypinum 16 (diploid); 8 (haploid) Popoff Trichodina sp. 4-6 Diller In man}^ other Protozoa, the division figure, especially the achromatic figure, suggests strongly a mitosis, but the chromatin substance which makes up the equatorial plate can hardly be called chromosomes. A typical example of this type is found in the nuclear division of Amoeba proteus (Fig. 65). According to Chalkley and Daniel (1933), the conspicuous granules present, in the resting nu- cleus, under the membrane contain very little chromatin, while abundant chromatin is lodged in the central area. The peripheral granules appear to give rise to achromatic figure. At the beginning of division, the chromatin granules become aggregated in a zone (6); they then assume a ring-form along the periphery of the central mass 142 PROTOZOOLOGY of network (c); at this stage, the cytoplasm around the nucleus is much vacuolated. A little later appears a discoid equatorial plate or ring which is connected with the nuclear membrane by numerous fibrils, and the nucleus becomes markedly flattened with its mem- brane still intact (d), which is considered as the end of the prophase. In the metaphase, the nuclear membrane becomes extremely faint and the portion over one side of the plate is without it (e). At the Fig. 65. Nuclear division in Amoeba proteus, Xl80 (Chalkley and Daniel), a, resting stage; b-d, prophase; e, metaphase; f, g, anaphase; h, a daughter nucleus. anaphase the membrane completely disappears, the equatorial plate splits and each half contracts in the plane of the plate, producing two daughter-plates. In some specimens a faint spindle formation is noted. At about this time, vacuolated condition of the perinuclear cytoplasm disappears (/). In later phases of anaphase the plates are more widely separated and are slightly less in diameter as compared with earlier stages. There are distinct polar caps of fibrillar material at the poles of the spindle (g) , fi.nally each plate transforms itself into a resting nucleus (h). The two investigators added that if the chro- matin granules located in the equatorial plate are chromosomes, "they must be extremely numerous." Liesche (1938) estimates the number of these granules which he called chromosomes as between 500 and 600. REPRODUCTION 143 Cytosomic division Binary fission. As in metazoan cells, the binary fission occurs very widely among the Protozoa. It is a division of the body through middle of the extended long axis into two nearly equal daughter individuals (Fig. 51). In Amocha proteus, Chalkley and Daniel found that there is a definite correlation between the stages of nuclear divi- sion and external morphological changes (Fig. 66). During the pro- \j^':. b o\SS^ j(..-.^-. '^-'i5/^:f '^i^- r^d ^\, ■ Fig. 66. External morphological changes during division of Amoeba proteus, as viewed in life in reflected light, X about 20 (Chalkley and Daniel), a, shortly before the formation of the division sphere; b, a later stage; c, prior to elongation; d, further elongation; e, division almost completed. phase, the organism is rounded, studded with fine pseudopodia and exhibits under reflected light a clearly defined hyaline area near its center (a), which disappears in the metaphase (6, c). During the anaphase the pseudopodia rapidly become coarser; in the telophase the elongation of body, cleft formation, and return to normal pseudopodia, take place. In Testacea, one of the daughter individuals remains, as a rule, within the old test, while the other moves into a newly formed one, as in Arcella, Pj^xidicula, Euglypha, etc. According to Doflein, the division plane coincides with the axis of body in Cochliopodium, Pseudodifflugia, etc., and the delicate homogeneous test also divides 144 PROTOZOOLOGY into two parts. In the majority of the Mastigophora, the division is longitudinal, as is shown by that of Menoidium incurvum (Fig. 67). In certain dinoflagellates, such as Ceratium, Cochliodinium, etc., the division plane is oblique, while in forms such as Oxyrrhis (Dunk- erly; Hall), the fission is transverse. In Strehlomastix strix (Kofoid and Swezy), Lophomonas striata (Kudo), Spirotrichomjmpha hispira Fig. 67. Nuclear and cytosomic division in Menoidium incurvum, X about 1400 (Hall), a, resting stage; b, c, prophase; d, equatorial plate; 8, f, anaphase; g, telophase. (Cleveland), etc., the division takes place transversely but the polar- ity of the posterior individual is reversed so that the posterior end of the parent organism becomes the anterior end of the posterior daughter individual. In the ciliate Bursaria, Lund (1917), observed reversal of polarity in one of the daughter organisms at the time of division of normal individuals and also in those which regenerated after being cut into one-half the normal size. In the Ciliophora the division is as a rule transverse (Fig. 50), in which the cytosome without any enlargement or elongation divides by constriction through the middle so that the two daughter indivi- duals are about half as large at the end of division. Both individuals usually retain their polarity. Multiple division. In multiple division the body divides into a number of daughter individuals, with or without residual cyto- REPRODUCTION 145 plasmic masses of the parent body. In this process the nucleus may undergo either simultaneous multiple division, as in Aggregata, or more commonly, repeated binary fission, as in Plasmodium (Fig. 225) to produce large numbers of nuclei, each of which becomes the center of a new individual. The number of daughter individuals often varies, not only among the different species, but also within one and the same species. Multiple division occurs commonly in the Fora- minifera (Fig. 184); the Radiolaria (Fig. 194), and various groups of Sporozoa in which the trophozoite multiplies abundantly by this method. Budding. Multiplication by budding which occurs in the Proto- zoa is the formation of one or more smaller individuals from the parent organism. It is either exogenous or endogenous, depending upon the location of the developing buds or gemmules. Exogenous budding has been reported in Acanthocystis, Noctiluca (Fig. 107), Myxosporidia (Fig. 68, h), astomatous ciliates (Fig. 266), Chono- tricha, Suctoria (Fig. 331, k), etc. Endogenous budding has been found in Testacea, Gregarinida, Myxosporidia (Figs. 247, e; 249, j), and other Sporozoa as well as Suctoria (Fig. 331, A). Collin observed a unique budding in Tokophrya cyclopum in which the entire body, excepting the stalk and pellicle, transforms itself into a yoUng ciliated bud which leaves sooner or later the parent pellicle as a swarmer. Plasmotomy. Occasionally the multinucleate body of a protozoan divides into two or more small, mutinucleate individuals, the cyto- somic division taking place independently of nuclear division. This has been called plasmotomy by Doflein. It has been observed in the trophoxoites of several coelozoic myxosporidians, such as Chloro- myxum leydigi (Fig. 68), Sphaeromyxa halbianii (Fig. 68), etc. It occurs further in Mycetozoa (Fig. 156), Protociliata and certain Sarcodina (Pelomyxa). Colony formation When the division is repeated without a complete separation of the daughter individuals, a colonial form is produced. The compon- ent individuals of a colony may either have protoplasmic connections among them or be grouped within a gelatinous envelope if completely separated. Or, in the case of loricate or stalked forms, these exo- skeletal structures may become attached to one another. Although varied in appearance, the arrangement and relationship of the com- ponent individuals are constant, and this makes the basis for dis- tinguishing the types of protozoan colonies, as follows: 146 PROTOZOOLOGY Catenoid or linear colony. The daughter individuals are attached endwise, forming a chain of several individuals. It is of compara- tively rare occurrence. Examples: Astomatous ciliates such as Radiophrya (Fig. 266), Protoradiophrya (Fig. 266) and dinoflagel- lates such as Ceratium, Haplozoon (Fig. 109) and Polykrikos (Fig. 110). Arboroid or dendritic colony. The individuals remain connected with one another in a tree-form. The attachment may be by means '^^"^^^^^ ml <^mv--j Fig. 68. a, b, budding in Myxidium lieberkuhni; c, d, plasmotomy in Chloromijxum leydigi; e, plasmotomy in Syhaeromyxa balbianii. of the lorica, stalk, or gelatinous secretions. It is a very common colony found in different groups. Examples: Dinobryon (Fig. 92), Hyalobryon (Fig. 92), etc. (connection by lorica); Colacium (Fig. 102), many Peritricha (Figs. 322; 324), etc. (by stalk); Poterioden- dron (Fig. 116), Stylobryon (Fig. 130), etc. (by lorica and stalk); Hydrurus (Fig. 93), Spongomonas (Fig. 129), Cladomonas (Fig. 129) and Anthophysis (Fig. 130) (by gelatinous secretions). Discoid colony. A small number of individuals are arranged in a single plane and grouped together by a gelatinous substance. Exam- REPRODUCTION 147 pies: Cyclonexis (Fig. 92), Gonium (Fig. 99), Platydorina (Fig. 100), Protospongia (Fig. 114), Bicosoeca (Fig. 116), etc. Spheroid colony. The individuals are grouped in a spherical form. Usually enveloped by -a distinct gelatinous mass, the component individuals may possess protoplasmic connections among them. Examples: Uroglena (Fig. 92, c), Uroglenopsis (Fig. 92, d), Volvox (Fig. 99), Pandorina (Fig. 100,/), Eudorina (Fig. 100, h), etc. Such forms as Stephanoon (Fig. 100, a) appear to be intermediate between this and the discoid type. The component cells of some spheroid colonies show a distinct differentiation into somatic and reproductive individuals, the latter developing from certain somatic cells during the course of development. The gregaloid colony, which is sometimes spoken of, is a loose group of individuals of one species, usually of Sarcodina, which become attached to one another by means of pseudopodia in an ir- regular form. Asexual reproduction The Protozoa nourish themselves by certain methods, grow and multiply, by the methods described in the preceding pages. This phase of the life-cycle of a protozoan is the vegetative stage or the trophozoite. The trophozoite repeats its asexual reproduction process under favorable circumstances. Generally speaking, the Sporozoa increase to a much greater number by schizogony and the tropho- zoites are called schizonts. Under certain conditions, the trophozoite undergoes encystment (Fig. 69). Prior to encystment, the trophozoites cease to ingest, and extrude remains of, food particles, resulting in somewhat smaller forms which are usually rounded and inactive. This phase is some- times called the precystic stage. The whole organism becomes de- differentiated; namely, various cell organs such as cilia, cirri, flagella, axostyle, peristome, etc., become absorbed. Finally the organism secretes substances which become solidified into a resistant wall, and thus the cyst is formed. In this condition, the protozoan is apparently able to maintain its vitality for a certain length of time under unfavorable conditions. The causes of encystment are still the matter which many investigators are attempting to comprehend. It appears certain at least in some cases that the encystment is brought about by changes in temperature, chemical composition, amount of water, food material, and catabolic waste substances, etc., in the medium in which the organisms live. In some cases, the organisms encyst temporarily in order to undergo nuclear reorgani- 148 PROTOZOOLOGY zation and multiplication as in Colpoda cucullus (Kidder and Claff, 1938). Because of the latter condition and also of the failure in at- tempting to cause certain Protozoa to encyst under experimental conditions, some suppose that certain internal factors play as great Encystment of Lopho)nonas blattarum, X1150 (Kudo). a part as do the external conditions in the phenomenon of encyst- ment. Ordinarily a single cyst wall seems to be sufficient to protect the protoplasm against unfavorable external conditions. In some cases there may be a double cyst wall, the inner one usually being more delicate. The cyst wall is generally composed of homogeneous substances, but it may contain calcareous scales as in Euglypha (Fig. 70). While chitin is the common material of which the cyst wall Fig. 70. Encystment of Euglypha acanthophora, X320 (Kiihn). is composed, cellulose makes up the cyst membrane of numerous Phytomastigina. The capacity of Protozoa to produce cyst is probably one of the reasons why they are so widely distributed over the surface of the globe. The minute protozoan cysts are easily carried from place to REPRODUCTION 149 place by wind, attached to soil particles, debris, etc., by the flowing water of rivers or the current in oceans or by insects, birds, other animals to which they become readily attached. When a cyst en- counters a proper environment, a redifferentiation process takes place within the cyst. Various organellae which characterize the organism, are regenerated and reformed, and the trophozoite excysts. The emerged organism once more returns to its trophic phase of cm ® ® ® 0 Fig. 71. Diagram illustrating the life-cycle of Thelohania legeri (Kudo). a, extrusion of the polar filament in gut of anopheline larva; b, emerged amoebula; c-f, schizogony in fat body; g-m, sporont-formation; m-x, stages in spore-formation. existence. Although encystment is a general occurrence among Protozoa, there are some species in which this phenomeonon has never been observed. Paramecium belongs to this group (p. 600). In Sporozoa, no encystment occurs. Here at the end of active schizogony, sexual reproduction usually initiates the production of large numbers of the spores (Fig. 71). Sexual reproduction and life-cycles Besides reproducing bj' the asexual method, numerous Protozoa reproduce themselves in a manner comparable with the sexual re- 150 PROTOZOOLOGY production which occurs universally in the Metazoa. Various types of sexual reproduction have been reported in literature, of which a few will be considered here. The sexual fusion or syngamy which is a complete union of two gametes, has been reported from various groups, while the conjugation which is a temporary union of two individuals for the purpose of exchanging the nuclear material, is found almost exclusively in the Ciliophora. Sexual fusion. The gametes which develop from trophozoites, may be morphologically alike (isogametes) or unlike (anisogametes), both of which are, in well-studied forms, physiologically different as judged by their behavior toward each other. If a gamete does not meet with another one, it perishes. Anisogametes are called micro- gametes and macrogametes. Difference between them is comparable in many instances (Figs. 74; 76; 225) with that which exists between Fig. 72. a, macrogamete, and b, microgamete of Volvox aureus, XlOOO (Klein). the spermatozoa and ova of Metazoa. The microgametes are motile, relatively small and usually numerous, while the macrogametes are usually not motile, much more voluminous and fewer in number. Therefore, they have sometimes been referred to as male and female gametes (Fig. 72). While morphological differences between the gametes have long been known and studied by many workers, whatever information we possess on physiological differences between them is of recent origin. Since 1933, Moewus and his co-workers have published a series of papers based upon their extended studies of bacteria-free cultures of many species (and strains) of Chlamydomonas (p. 217) which throw some light on the gamete differentiation among these phytomonadinans. The gametes in Chlamydomonas are mostly isogamous, except in a few forms. Sexual fusion takes place in the majority of species and strains between the gametes produced in different clones, and there is no gametic fusion within a single clone. Moewus obtained "sex substances" from some of the cultures and showed that these are chemotactic substances. Each gamete secretes substances that attract the other and each reacts to the substances REPRODUCTION 151 secreted by the other. Kuhn, Moewus and Wendt (1939) recognized "hormones," and named them, termones (sex-determining hor- mones), anderotermone (male-determining hormone) and gynoter- mone (female-determining hormone). In a few strains or species of Chlamydomonas, sexual fusion is found to take place among the gametes that develop within a single clone. Moewus considers in these cases there exist two types of gametes in a clone. However, Pascher, Pringsheim, and others ob- tained results which seem to indicate that there is no physiological or sex differentiation between the fusing gametes. In the much- studied Sporozoa, for example, Plasmodium, the two gametes are both morphologically and physiologically differentiated, and sexual fusion always takes place between two anisogametes. Fig. 73. Sexual fusion in Coprompnas subtilis, X1300 (Dobell). The isogamy is typically represented by the flagellate Copro- monas suhtilis (Fig. 73), in which there occurs, according to Dobell, a complete nuclear and cytoplasmic fusion between two isogametes. Each nucleus, after casting off a portion of its nuclear material, fuses with the other, thus forming a zygote containing a synkaryon. In Stephanosphaera pluvialis (Fig. 74), both asexual and sexual re- productions occur, according to Hieronymus. Each individual multiplies and develops into numerous biflagellate gametes, all of which are alike. Isogamy between two gametes results in formation of numerous zygotes which later develop into trophozoites. Anisogamy has been observed in certain Foraminifera. It perhaps occurs in the Radiolaria also, although positive evidence has yet to be presented. Anisogamy seems to be more widely distributed. In Pandorina niorum (Fig. 75), Pringsheim observed that each cell de- velops asexually into a young colony (a, b) or into anisogametes (c) which undergo sexual fusion {d-g) and encyst (/i).-The organism emerged from the cyst, develops into a young trophozoite (i-m). A similar life-cycle was found by Goebel in Eudorina elegans (Fig. 76). 152 PROTOZOOLOGY Among the Sporozoa, anisogamy is of common occurrence. In Coccidia, the process was well studied in Eimeria schuhergi (Fig. 215), Aggregata eberthi (Fig. 217), Adelea ovata (Fig. 222), etc., and the resulting products are the oocysts (zygotes) in which the spores Fig. 74. The life-cycle of Stephanosphaera pluvialis (Hieronymus). a-e, asexual reproduction; f-m, sexual reproduction. or sporozoites develop. Similarly in Haemosporidia such as Plasmo- dium vivax (Fig. 225), anisogamy results in the formation of the ookinetes or motile zygotes which give rise to a large number of sporozoites. Among Myxosporidia, a complete information as to how the initiation of sporogony is associated with sexual reproduc- REPRODUCTION 153 Fig. 75. The life-cycle of Pandorina morum, X400 (Pringsheim). a, b, asexual reproduction; c-m, sexual reproduction. ■^')^i- Fig. 76. The life-cycle of Eudorina elegans (Goebel). a, asexual repro- duction; b, sexual reproduction, a female colony with clustered and iso- lated microgametes. 154 PROTOZOOLOGY tion, is still lacking. Naville, however, states that in the trophozoite of Sphaeromyxa sahrazesi (Fig. 245), micro- and macro-gametes develop, each with a haploid nucleus. Anisogamy, however, is pe- culiar in that the two nuclei remain independent. The microgametic nucleus divides once and the two nuclei remain as the vegetative nuclei of the pansporoblast, while the macrogamete nucleus multi- plies repeatedly and develop into two spores. Anisogamy has been suggested to occur in some members of Amoebina, particularly in Endamoeha hlattae. Mercier (1909) believed that in this amoeba there occurs anisogamy soon after excystment in the host's intestine, but this still awaits confirmation. Cultural studies of various para- sitic amoebae in recent years show no evidence of sexual reproduc- tion. Among the Ciliophora, the sexual fusion occurs only in Protociliata (Fig. 263). Conjugation. The conjugation is a temporary union of two indivi- duals of one and the same species for the purpose of exchanging part of the nuclear material and occurs almost exclusively in the Euci- liata and Suctoria. The two individuals which participate in this process may be either isogamous or anisogamous. In Paramecium caudatum (Fig. 77), two similar individuals come in contact on their oral surface (a). The micronucleus in each conjugant divides twice (h-e), forming four micro nuclei, three of which degenerate and do not take active part during further changes (f-h). The remaining micronucleus divides once more, producing a wandering pronucleus and a stationary pronucleus (/, g). The wandering pronucleus in each of the conjugants enters the other individual and fuses with its sta- tionary pronucleus (h, r). The two conjugants now separate from each other and become exconjugants. In each exconjugant, the synkaryon divides three times in succession (i-m) and produces eight nuclei (n), four of which remain as micronuclei, while the other four develop into new macronuclei (o). Cytosomic fision follows then, producing first, two individuals with four nuclei (p) and then, four small indivi- duals, each containing a micronucleus and a macronucleus (a). Ac- cording to Jennings, however, of the four smaller nuclei formed in the exconjugant indicated in Fig. 77, o, only one remains active, and the other three degenerate. This active nucleus divides prior to the cytosomic division so that in the next stage {p), there are two de- veloping macronuclei and one micronucleus which divides once more before the second and last cytosomic division (q). During these changes the original macronucleus disintegrates, degenerates, and finally becomes absorbed in the cytoplasm. In 1937, Sonneborn discovered that in certain races of P. aurelia, I REPRODUCTION 155 Fig. 77. Diagram illustrating the conjugation of Paramecium caudatum. a-q, X about 130 (Calkins); r, a synkaryon, X1200 (Dehorne). there are two classes of individuals with respect to "sexual" differ- entiation and that the members of different classes conjugate with each other, while the members of each class do not. These classes 156 PROTOZOOLOGY were called the mating types. Soon a similar phenomenon has been reported by several workers in five other species of the genus ; namely, P. hursaria, P. caudatum, P. trichium, P. calkinsi, and P. multimi- cronucleatum. When organisms which belong to different mating types are brought together, they adhere to one another in large clumps ("agglutination") of numerous individuals (Fig. 78, h). --7; J'' l- 1 - ■> ' J - ' ' -%». *^-. V V *- « o ' r • 4 '> ;% ♦ v« • Fig. 78. Mating behavior of Paramecium hursaria (Jennings), a, indi- viduals of a single mating type; b, 6 minutes after individuals of two mat- ing types have been mixed; c, after about 5 hours, the large masses have been broken down into small masses; d, after 24 hours, paired conjugants. After a few to several hours, the large masses break down into small masses (Fig. 78, c) and still later, conjugants appear in pairs (Fig. 78, d). The only other ciliate in which mating types are definitely known to occur is Euplotes patella in which, according to Kimball (1939), there occurs no agglutination mating reaction. How widely mating types occur is not known at present. But as REPRODUCTION 157 was pointed out by Jennings, the mating types may be of general oc- currence among ciliates; for example, Maupas (1889) observed that in Lionotus {Loxophyllum) fasciola, Leucophrys patula, Siylonychia pustulata, and Onychodromus graridis, conjugation took place be- tween the members of two clones of different origin, and not among the members of a single clone. Precise information on the occurrence among different ciliates depends on future research. In Paramecium aurelia, Sonneborn distinguishes seven varieties which possess the same morphological characteristics. There occurs no conjugation between the clones of different varieties. Within each of the six varieties, there are two mating types, while there is only one type in the seventh variety. Animals belonging to the same variety, but to different mating types only conjugate when put together (Table 6). In P. hursaria, Jennings (1938, 1939) finds three varieties, but each of two varieties contains four mating types and in the third variety eight mating types occur (Table 6). In Euplotes patella, Kimball (1939) observed six mating types (Table 6). These mating types cannot be considered as the true sex types, since the conjugants mutually fertilize each other. Recent studies of mating types have revealed much information regarding conjugation. Conjugation usually does not occur in well- fed or extremely starved animals, and appears to take place shortly after the depletion of food. Temperature also plays a role in con- jugation, as it takes place within a certain range of temperature which varies even in a single species among different varieties (Sonneborn). Light seems to have different effects on conjugation in different varieties of P. aurelia. The time between two conju- gations also varies in different species and varieties. In P. hursaria, Jennings found that in some races the second conjugation would not take place for many months after the first, while in others such an "immature" period may be only a few weeks. In P. aurelia, in some varieties there is no "immature" period, while in others there is 6 to 10 days' "immaturity." Very little is known about the physiological state of conjugants as compared with vegetative individuals. Several investigators ob- served that animals which participate in conjugation show much viscous body surface. Boell and Woodruff (1941) found that the mating individuals of Paramecium calkinsi show a lower respiratory rate than not-mating individuals. Neither is the mechanism of con- jugation understood at present. Kimball (1942) discovered in Euplotes patella, the fluid taken from cultures of animals of one type induces conjugation among the animals of other types. Pre- 158 PROTOZOOLOGY sumably certain substances are secreted by the organisms and be- come diffused in the culture fluid. In the case of P. aurelia, Sonne- born considers that there are also some substances which however do not diffuse into the surrounding medium, and possibly transported from one individual to another by contact and subsequent migration. Fuller understanding of the phenomenon of mating types depends upon future investigations. When the ciliate possesses more than one micronucleus, the first division ordinarily occurs in all and the second may or may not take place in all, varying apparently even among individuals of the same species. According to Woodruff, in Paramecium aurelia, of the eight micronuclei formed by two fissions of the two original micjonuclei, only one undergoes the third division to produce two pronuclei. This is the case with the majority, although more Table 6. — Varieties and mating types in Paramecium aurelia, P. bursaria and Ewplotes patella. + indicates that conjugation occurs; — indicates that it does not. Paramecium aurelia (Sonneborn) Va- riety 1 2 3 4 5 6 7 mat- ing type I II III IV V VI VII VIII IX X XI XII XIII 1 I II + + - - - - - - - - - - - 2 III IV - - - + + - - - - - - - - - - 3 V VI - - - - - + + - - - - - - - - 4 VII VIII - - - - - - - + + - - - - - - 5 IX X - - - - - - - + + - - - - 6 XI XII - - - - - - - - - + + - - 7 XIII - - _ - - - - - - - - - REPRODUCTION Table 6. — Continued Paramecium hursaria (Jennings) 159 Variety 1 2 3 Type A B c D E F G H J K L M N 0 P Q A _ + + + _ — - - _ - - - - _ _ _ 1 B C D + + + + + + + + + — _ - _ _ - - - - _ _ _ E _ — _ _ - + + + + + + + _ _ _ _ F - - - - + - + + + + + + - - - - G — — — — + + — + + + + + — _ _ _ 2 H - - - - + + + - + + + + - _ _ _ J — — — — + + + + - + + + — _ _ _ K - - - - + + + + + - + + - _ _ _ L - - - - + + + + + + - + - - - - M - - - - + + + + + + + - - - - - N _ _ _ _ _ _ _ _ _ _ _ _ _ + + + 3 0 P Q - - _ - - - - - + + + - + + + - + + + - Euplotes patella (Kimball) Type I II III IV V VI I _ + + + + + II + - + + + + III + + - + + + IV + + + - + + V + + + + + VI + + + + + - than one micronucleus may divide for the third time to produce several pronuclei, for example, two in Euplotes patella, Stylonychia pustulata ; two to three in Oxytricha fallax and two to four in Uro- leptus mobilis. This third division is always characterized by long extended nuclear membrane stretched between the division prod- ucts. Ordinarily the individuals which undergo conjugation appear to be morphologically similar to those that are engaged in the trophic activity, but in some species, the organism divides just prior to conjugation. According to Wichterman (1936), conjugation in 160 PROTOZOOLOGY Nyctotherus cordiformis (Fig. 79) takes place only among those which live in the tadpoles undergoing metamorphosis (f-j). The conjugants are said to be much smaller than the ordinary tropho- FiG. 79. The life-cycle of Nyctotherus cordiformis in Hyla versicolor (Wichterman). a, a cyst; b, excystment in tadpole; c, d, division is repeated until host metamorphoses; e, smaller preconjugant; f-j, con- jugation; k, exconjugant; 1, amphinucleus divides into 2 nuclei, one micro- nucleus and the other passes through the "spireme ball" stage before developing into a macro nucleus; k-n, exconjugants found nearly exclu- sively in recently transformed host; o, mature trophozoite; p-s, binary fission stages; t, precystic stage. REPRODUCTION 161 zoites, because of the preconj ligation fission {d~e). The micronuclear divisions are similar to those that have been described for Para- mecium caudatum and finally two pronuclei are formed in each con- jugant. Exchange and fusion of pronuclei follow. In each excon jug- ant, the synkaryon divides once to form the micronucleus and the macronuclear anlage {k-l) w^hich develops into the "spireme ball" and finally into the macronucleus (m-o). A sexual process which is somewhat intermediate between the sexual fusion and conjugation, is noted in several instances. Ac- cording to Maupas' classical work on Vorticella nehuUfera, the or- dinary vegetative form divides twice, forming four small individuals, which become detached from one another and swim about inde- pendently. Presently each becomes attached to one side of a stalked individual. In it, the micronucleus divides three times and produces eight nuclei, of which seven degenerate; and the remaining nucleus divides once more. In the stalked form the micronucleus divides twice, forming four nuclei, of which three degenerate, and the other dividing into two. During these changes the cytoplasm of the two conjugants fuse completely. The wandering nucleus of the smaller conjugant unites with the stationary nucleus of the larger conjugant, the other two pronuclei degenerating. The synkaryon divides several times to form a number of nuclei, from some of which macronuclei are differentiated and exconjugant undergoes multiplication. Another example of this type has been observed in Metopus es (Fig. 80). According to No land (1927), the conjugants fuse along the anterior end (a), and the micronucleus in each individual divides in the same way as was observed in Paramecium caudatum (h-e). But the cytoplasm and both pronuclei of one conjugant pass into the other (/), leaving the degenerating macronucleus and a small amount of cytoplasm behind in the shrunken pellicle of the smaller conjugant which then separates from the other (j). In the larger exconjugant, two pronuclei fuse, and the other two degenerate and disappear (g, h). The synkaryon divides into two nuclei, one of which condenses into the micronucleus and the other grows into the macro- nucleus (i, k-m). This is followed by the loss of cilia and encystment. Automixis. In certain Protozoa, the fusion occurs between two nuclei which originate in a single nucleus of an individual. This process has been called automixis by Hartmann, in contrast to the amphimixis (Weismann) which is the complete fusion of two nuclei originating in two individuals, as was discussed in the preceding pages. If the two nuclei w^hich undergo a complete fusion are present in a single cell, the process is called autogamy, but, if they are in two 162 PROTOZOOLOGY different cells, then paedogamy. The autogamy is of common occur- rence in the myxosporidian spores. The young sporoplasm contains two nuclei which fuse together prior to or during the process of ger- mination in the alimentary canal of a specific host fish, as for exam- ple in Sphaeromyxa sabrazesi (Figs. 244; 245) and Myxosoma cato- stomi (Fig. 243). In the Microsporidia, autogamy appears to initiate the spore-formation at the end of schizogonic activity of individuals as in Thelohania legeri (Fig. 71). Fig. 80. Conjugation of Metopus es (Noland). a, early stage; b, first micronuclear division; c, d, second micronuclear division; e, third micro- nuclear division; f, migration of pronuclei from one conjugant into the other; g, large conjugant with two pronuclei ready to fuse; h, large con- jugant with the synkaryon, degenerating pronuclei and macronucleus; i, large exconjugant with newly formed micronucleus and macronucleus j, small exconjugant with degenerating macronucleus; k-m, development of two nuclei, a, X290; b-j, X250, k-m, X590. REPRODUCTION 163 Diller (1936) observed in solitary Paramecium aurelia (Fig. 81), certain micronuclear changes similar to those which occur in conjugating individuals. The two micronuclei divide twice, form- ing eight nuclei (a-d), some of which divide for the third time (e), producing two functional and several degenerating nuclei (/). The two functional nuclei then fuse in the "paroral cone" and form the Fig. 81. Diagram illustrating autogamy in Paramecium aurelia (Diller). a, normal animal; b, first micronuclear division; c, second micronuclear division; d, individual with 8 micronuclei and macronucleus preparing for skein formation; e, two micronuclei dividing for the third time; f, two gamete-nuclei formed by the third division in the paroral cone; g, fusion of the nuclei, producing synkaryon; h, i, first and second division of synkaryon; j, with 4 nuclei, 2 becoming macronuclei and the other 2 re- maining as micronuclei; k, macronuclei developing, micronuclei dividing; 1, one of the daughter individuals produced by fission. synkaryon {g, h) which divides twice into four {i, j). The original macronucleus undergoes fragmentation and becomes absorbed in the cytoplasm. Of the four micronuclei, two transform into the new macronuclei and two remain as micronuclei (k) each dividing into two after the body divided into two (l). Another sexual process appears to have been observed by Diller (1934) in conjugating Paramecium trichium in which there was no nuclear exchange between the two conjugants. Wichterman (1939, 1940) observed a similar process in P. caudatum and named it cytogamy. Two small (about 200m long) individuals of P. caudatum 164 PROTOZOOLOGY fuse on their oral surfaces. There occur three micronuclear divisions as in the case of conjugation, but there is no nuclear exchange be- tween the members of the pair. The two gametic nuclei in each indi- vidual are said to fuse and form a synkaryon as in autogamy. The paedogamy occurs in at least two species of Myxosporidia, namely, Leptotheca ohlmacheri (Fig. 247) and Unicapsula muscularis (Fig. 248). The spores of these myxosporidians contain two uninu- cleate sporoplasms which are independent at first, but prior to emergence from the spore, they undergo a complete fusion to meta- :^I ^sS^?-^ ^U Fig. 82. Paedogamy in Adinophrys sol, X460 (Belaf). a, withdrawal of axopodia; b, c, division into two uninucleate bodies, surrounded by a common gelatinous envelope; d-f, the first reduction division; g-i, the second reduction division; j-1, synkaryon formation. morphose into a uninucleate amoebula. Perhaps the classical exam- ple of the paedogamy is that which was found by Hertwig (1898) in Actinosphaerhim eichhorni. The organism encysts and the body di- vides into numerous uninucleate secondary cysts. Each secondary cyst divides into two and remains together within a common cyst- wall. In each the nucleus divides twice, and forms four nuclei, one of which remains functional, the remaining three degenerating. The paedogamy results in formation of a zygote in place of a secondary cyst. Belaf (1922) observed a similar process in Adinophrys sol (Fig. 82). This heliozoan withdraws its axopodia and divides into two uninucleate bodies which become surrounded by a common REPRODUCTION 165 gelatinous envelope. Both nuclei divide twice and produce four nu- clei, three of which degenerate. The two daughter cells, each with one haploid nucleus, undergo paedogamy and the resulting individual now contains a diploid nucleus. In Paramecium aurelia, Diller (1936) found simple fragmentation of the macronucleus which was not correlated with any special micronuclear activity and which could not be stages in conjugation or autogamy. Diller suggests that if conjugation or autogamy is to create a new nuclear complex, as is generally held, it is conceivable that somewhat the same result might be achieved by 'purification act' (through fragmentation) on the part of the macronucleus itself, without involving micronuclei. He coined the term hemixis to in- clude these reorganizations. Fig. 83. Mitotic and meiotic micronuclear divisions in conjugating Didinium nasutum. (Prandtl, modified), a, normal micronucleus;b, equa- torial plate in the first (mitotic) division; c, anaphase in the first division; d, equatorial plate in the second division; e, anaphase in the second (meiotic) division. Meiosis. In the foregoing sections, references have been made to the divisions which the nuclei undergo prior to sexual fusion or con- jugation. In all Metazoa, during the development of the gametes, the gametocytes undergo reduction division or meiosis, by which the number of chromosomes is halved; that is to say, each fully mature gamete possesses half (haploid) number of chromosomes typical to the species (diploid). In the zygote, the diploid number is reestab- lished. In the Protozoa in which sexual reproduction occurs during their life-cycle, meiosis presumably takes place to maintain the con- stancy of chromosome-number, but the process is understood only in a small number of species. In conjugation, the meiosis seems to take place in the second micronuclear division, although in some, for example, Oxytricha fallax, according to Gregory, the actual reduction occurs during the first division. Prandtl (1906) was the first to note a reduction in number of chromosomes in the Protozoa. In conjugating Didinium nasutum (Fig. 83), he observed 16 chromosomes in each of the 166 PROTOZOOLOGY daughter micronuclei during the first division, but only 8 in the second division. Since that time, the fact that meiosis occurs during the second micronuclear division has been observed in Chilodonella uncinata (Enrique; MacDougall), Carchesium polypinum (Popoff), Uroleptus halseyi (Calkins), etc. (note the ciliates in Table 5 on p. 141). In various species of Paramecium and many other forms, the number of chromosomes appears to be too great to allow a precise counting, but Sonneborn's work on the mating types in Parame- cium as quoted elsewhere (p. 186), indicates clearly the occurrence of meiosis during conjugation. Information on the meicsis involved in the complete fusion of gam- etes is even more scanty and fragmentary. In Monocystis rostrata, a parasite of the earthworm, Mulsow (1911) noticed that the nuclei of two gametocytes which encyst together, multiply by mitosis in which eight chromosomes are constantly present, but in the last division in gamete formation, each daughter nucleus receives only 4 chromosomes. In another species of Monocystis, Calkins and Bowl- ing (1926) observed that the diploid number of chromosomes was 10 and that haploid condition is established in the last gametic division thus confirming Mulsow's finding. In the paedogamy of Actinophrys sol, Belaf finds 44 chromosomes in the first nuclear division, but after two meiotic divisions, the remaining functional nucleus contains only 22 chromosomes so that when paedogamy is completed the diploid number is restored. In Polytoma uvella, Moewus finds each of the two gametes is haploid (8 chromosomes) and the zygotes are diploid. The synkaryon divides twice, and during the first division reduction division takes place. In the coccidian Aggregata eherthi (Fig, 217), according to Dobell and Jameson, Belar, and Naville, and in the gregarine Diplocystis schneideri, according to Jameson, there is no reduction in the number of chromosomes during the gamete-formation, but the first zygotic division is meiotic, 12 to 6 and 6 to 3, respectively. A similar reduc- tion takes place also in Gregarina hlattarum (6 to 3, after Sprague, 1941) and in Adelina deronis (20 to 10, after Hauschka, 1943). Thus in these forms, the zygote is the only stage in which diploid nucleus occurs, while the nuclei in stages in the remainder of the life-cycle are haploid. Some sixty years ago Weismann pointed out that a protozoan grows and muliplies by binary fission or budding into two equal or unequal individuals without loss of any protoplasmic part and these in turn grow and divide, and that thus in Protozoa there is neither senescence nor natural death which occur invariably in Metazoa in REPRODUCTION 167 which germ and soma cells are differentiated. Since that time, the problem of potential immortality of Protozoa has been a matter which attracted the attention of numerous investigators. Because of large dimensions, rapid growth and reproduction, and ease with which they can be cultivated in the laboratory, the majority of Protozoa used in the study of the problem have been free-living freshwater ciliates that feed on bacteria and other microorganisms. The very first extended study was made by Maupas (1888) who isolated Stylonychia pustulata on Februar}^ 27, 1886, and observed 316 binary fissions until July 10. During this period, there was noted a gradual decrease in size and increasing abnormality in form and Fig. 84. Degeneration or aging in Stylonychia pustulata. X340 (Maupas, modified), a, Beginning stage with reduction in size and completely atrophied micronucleus; b, c, advanced stages in which disappearance of the frontal zone, reduction in size, and fragmentation of the macronucleus occurred; d, final stage before disintegration. structure, until the animals could no longer divide and died (Fig. 84). A large number of isolation culture experiments have since been carried on numerous species of ciliates by many investigators. The results obtained are not in agreement. However, the bulk of ob- tained data indicates that the vitality of animals decreases with the passing of generations until finally the organisms suffer inevitable death, and that in the species in which conjugation or other sexual reproduction occurs, the declining vitality becomes restored. Perhaps the most thorough experiment was carried on by Calkins (1919, 1933) with Uroleptus mohilis. Starting with an exconjugant on 168 PROTOZOOLOGY November 17, 1917, a series of pure-line cultures was established by the daily isolation method. It was found that no series lived longer than a year, but when two of the progeny of a series were allowed to conjugate after the first 75 generations, the exconjugants repeated the history of the parent series, and did not die when the parent series died. In this way, lines of the same organism have lived for more than 12 years, passing through numerous series. In a series, the average division for the first 60 days was 15.4 divisions per 10 days, but the rate gradually declined until death. Woodruff and Spencer (1924) also found the isolation cultures of Spathidium spatula (fed on Colpidium colpoda) died after a gradual decline in the division rate, but were inclined to think that improper environ- mental conditions rather than internal factors were responsible for the decline. On the other hand. Woodruff (1932) found that 5071 generations produced by binary fission from a single individual of Paramecium aurelia between May 1, 1907 and May 1, 1915, did not manifest any decrease in vitality after eight years of uninterrupted asexual reproduction without conjugation. With a race of P. caudatum, Metalnikov (1924) observed a similar continued asexual reproduc- tion. Dawson (1919) subjected an amicronucleate race of Oxytricha hymenostoma to isolation culture and found that it declined in divi- sion-rate and finally died out; but in mass cultures, the organisms lived indefinitely. He attributed the decline in isolation culture to improper environmental conditions. With Actinophrys sol Belaf (1924) carried on isolation cultures (thus preventing paedogamy (p. 164) for 1244 generations for a period of 32 months and noticed no decline in the division rate. Hartmann (1921) made a similar obser- vation on Eudorina elegans. It would appear that in these forms the life continues indefinitely without apparent decrease in vital activity. As has been noted in the beginning part of the chapter, the macronucleus in the ciliates undergoes, at the time of binary fission a reorganization process before dividing into two parts and undoubt- edly, there occurs at the same time extensive cytoplasmic reorgani- zation as judged by the degeneration and absorption of the old, and formation of the new, organellae. It is reasonable to suppose that this reorganization of the whole body structure at the time of divi- sion is an elimination process of waste material accumulated by the organism during the various phases of vital activities as was con- sidered by Kidder and others (p. 127) and that this elimination, though not complete, enables the protoplasm of the products of divi- sion to carry on their metabolic functions more actively. REPRODUCTION 169 As the generations are multiplied, the general decline in vitality is manifest not only in the decreased division-rate, slow growth, abnormal form and function of certain organellae, etc., but also in inability to complete the process involved in conjugation. Jennings found that when individuals of aging stock of Paramecium hursaria conjugate with those of a young vigorous stock, certain numbers of exconjugants die without multiplication, or give rise to weak and abnormal descendants. As the stock grows older, the number of ex- conjugants that die or are weak increases until a period arrives at which time all the exconjugants die without multiplication. How- ever, if conjugation takes place before the decline in vitality becomes too great, such stocks in some cases are able to restore to high vital ity. Endomixis and autogamy have also been considered to have a similar effect on the vitality of the progeny of the individuals in which they occur. Experimental data indicate that conjugation of still vigorous young stocks does not bring about any greater vitality to their progeny, but that of older stocks results in many strains with restored vitality. Sonneborn (1942) mentions the appearance of varied characters after macronuclear regeneration (p. 129) in P. aurdia. The animals become smaller and of different form; they reproduce more slowly ; they are less viable and die out after a period of few weeks or months. Thus regenerated macronuclei are unable to produce high vitality. It is probable that the process of replacing old macronuclei by micronuclear material which are derived from the products of fusion of two micronuclei of either the same (autogamy) or two different animals (conjugation), would perhaps result in a complete elimina- tion of waste substances from the newly formed macronuclei, and divisions which follow this fusion may result in shifting the waste substances unequally among different daughter individuals. Thus in some individuals there may be a complete elimination of waste material and consequently a restored high vitality, while in others the influence of waste substances present in the cytoplasm may offset or handicap the activity of new macronuclei, giving rise to stocks of low vitality which will perish sooner or later. In addition in conjuga- tion, the union of two haploid micronuclei produces diverse genetic constitutions which would be manifest in progeny in manifold ways. Experimental evidences indicate clearly such is actually the case. In many ciliates, the elimination of waste substances at the time of binary fission and sexual reproduction (conjugation, and autog- amy), seemingly allow the organisms continued existence through 170 PROTOZOOLOGY a long chain of generations indefinitely. Jennings (1929, 1942) who has recently reviewed the whole problem states: "Some Protozoa are so constituted that they are predestined to decline and death after a number of generations. Some are so constituted that decline occurs, but this is checked or reversed by substitution of reserve parts for those that are exhausted; they can live indefinitely, but are dependent on this substitution. In some the constitution is such that life and multiplication can continue indefinitely without visible substitution of a reserve nucleus for an exhausted one ; but whether this is due to the continued substitution, on a minute scale, of re- serve parts for those that are outworn cannot now be positively stated. This perfected condition, in which living itself includes con- tinuously the necessary processes of repair and elimination, is found in some free cells, but not in all." Regeneration The capacity of regenerating the lost parts, though variable among different species, is characteristic of all Protozoa from simple forms to those with highly complex organizations, as shown by ob- servations of numerous investigators. Brandt (1877) studied regen- eration in Actinosphaerium eichhorni and found that only nucleate portions containing at least one nucleus regenerated, and enucleate portions or isolated nuclei degenerated. Similarly Gruber (1886) found in Amoeba proteus the nucleate portion regenerated completely, while enucleate part became rounded and perished in a few days. The parts which do not contain nuclear material, may continue to show certain metabolic activities such as locomotion, contraction of contractile vacuoles, etc., for some time; for example, Grosse-Aller- mann (1909) saw enucleate portions of Amoeba verrucosa alive for 20 to 25 days, while Stole (1910) found enucleate Amoeba proteus living for 30 days. Clark (1942, 1943) showed that Amoeba proteus lives for about seven days after it has been deprived of its nucleus. Enucleated individuals show a 70 per cent depression of respiration and are unable to digest food due to the failure of zymogens to be activated in the dedifferentiating cytoplasm. It is now a well estab- lished fact that when a protozoan is cut into two parts and the parts are kept under proper environmental conditions, the enucleated portion is able to carry on catabolic activities, but unable to under- take anabolic activities, and consequently degenerates sooner or later. In Arcella (Martini; Hegner) and Difflugia (Verworn; Penard), when the tests are partially destroyed, the broken tests remain un- REPRODUCTION 171 changed. Verworn considered that in these testaceans test-forming activity of the nucleus is limited to the time of asexual reproduction of the organisms. On the other hand several observers report in Foraminifera the broken shell is completely regenerated at all times. Verworn pointed out that this indicates that here the nucleus con- trols the formation of shell at any time. In a radiolarian, Thalassi- colla nucleata, the central capsule, if dissected out from the rest of body, will regenerate into a complete organism (Schneider). A few regeneration studies on Sporozoa have not given any results to be considered here, because of the difficulties in finding suitable media for cultivation in vitro. An enormous number of regeneration experiments have been con- ducted on more than 50 ciliates by numerous investigators. Here also the general conclusion is that the nucleus is necessary for re- generation. In many cases, the macronucleus seems to be the only essential nucleus for regeneration, as judged by the continued divi- sion on record of several amicronucleate ciliates and by experiments such as Schwartz's in which there was no regeneration in Stentor coeruleus from which the whole macronucleus had been removed. A remarkably small part of a protozoan is known to be able to re- generate completely if nuclear material is included. For example, Sokoloff found 1/53-1/69 of Spirostomum amhiguum and 1/70-1/75 of Dileptus anser regenerated and Philips showed portions down to 1/80 of an amoeba were able to regenerate. In Stentor coeruleus, Lillie and Morgan found pieces as small as 1/27 and 1/64 respect- ively of the original organisms regenerated. Burnside cut 27 speci- mens of this ciliate belonging to a single clone, into two or more parts in such a way that some of the pieces contained a large portion of the nucleus while others a small portion. These fragments re- generated and multiplied, giving rise to 268 individuals. No dimen- sional differences resulted from the different amounts of nuclear material present in the cut specimens. Apparently regulatory pro- cesses took place and in all cases normal size was restored, re- gardless of the amount of the nuclear material in ancestral pieces. Thus biotypes of diverse sizes are not produced by causing inequali- ties in the proportions of nuclear material in different individuals. Information on regeneration in individuals in division or encyst- ment is incomplete. While Calkins observed that the regenerative reaction in Uronychia was slowed down in late division stages, in Stentor and Paramecium other investigators found no difference in regeneration between vegetative individuals and those under- going fission. 172 PROTOZOOLOGY In addition to these restorative regenerations, there are physio- logical regenerations in which as in the case of asexual and sexual re- production, various organellae such as cilia, flagella, cytostome, contractile vacuoles, etc., are completely regenerated due to certain internal conditions. References Balamuth, W. 1940 Regeneration in Protozoa: a problem of mor- phogenesis. Quart. Rev. Biology, Vol. 15. Belar, K. 1924 Untersuchungen an Actinophrijs sol Ehrenberg. II. Beitrage zur Physiologic des Formwechsels. Arch. f. Protistenk., Vol. 48. 1926 Der Formwechsel der Protistenkerne. Ergebn. u. Fortsch. Zool., Vol. 6. BoELL, E. J. and L. L. Woodruff 1941 Respiratory metabolism of mating types in Paramecium calkinsi. Jour. Exp. Zool., Vol. 87. BuRNSiDE, L. H. 1929 Relation of body size to nuclear size in Stentor coerulens. Ibid., Vol. 54. Calkins, G. N. 1919 Uroleptus mohilis Engelm. II. Renewal of vi- tality through conjugation. Ibid., Vol. 29. 1933 The biology of the Protozoa. Second edition. Philadel- phia. and R. C. Bowling 1926 Gametic meiosis in Monocystis. Biol. Bull, Vol. 51. and F. M. Summers, editors. 1941 Protozoa in biological re- search. New York. Chalkley, H. W. and G. E. Daniel. 1933 The relation between the form of the living cell and the nuclear phases of division in Amoeba proteus. Physiol. Zool., Vol. 6. Chen, T. T. 1936 Observations on mitosis in opalinids. I. Proc. Nat. Acad. Sci., Vol. 22. Clark, A. M. 1942 Some effects of removing the nucleus from Amoeba. Austral. Jour. Exp. Biol. & Med. Sci., Vol. 20. 1943 Some physiological functions of the nucleus in Amoeba, investigated by micrurgical methods. Ibid., Vol. 21. Cleveland, L. R. 1938 Longitudinal and transverse division in two closely related flagellates. Biol. Bull., Vol. 74. 1938a Origin and development of the achromatic figure. Ibid. , S. R. Hall, E. P. Sanders and J. Collier 1934 The wood- feeding roach Cryptocercus, its Protozoa, and the symbiosis be- tween Protozoa and roach. Mem. Amer. Acad. Arts and Sci., Vol. 17. Dawson, J. A. 1919 An experimental study of an amicronucleate Oxytricha. Jour. Exp. Zool., Vol. 29. DiLLER, W. F. 1936 Nuclear reorganization processes in Parame- cium aurelia, with descriptions of autogamy and 'hemixis.' Jour. Morph., Vol. 59. DoBELL, C. 1908 The structure and life history of Copromonas suh- tilis. Quart. Jour. Micr. Sci., Vol. 52. REPRODUCTION 173 1917 On Oxnerclla maritima, nov. gen., nov. spec, a new heliozoan, and its method of division, with some remarks on the centroplast of the Heljozoa. Ibid., Vol. 62. 1925 The Hfe-history and chromosome cycle of Aggregata eberthi. Parasitology, Vol. 17. GiESE, A. C. 1939 Studies on conjugation in Paramecium multi- micronucleatum. Amer. Nat., Vol. 73. Oilman, L. C. 1941 Mating types in diverse races of Paramecium caudatum. Biol. Bull., Vol. 80. Hall, R. P. 1923 Morphology and binary fission of Menoidium incurvum. Univ. California Publ. Zool., Vol. 20. Hartmann, M. 1917 Ueber die dauernde rein agame Zuchtung von Eudorina elegans and ihre Bedeutung fiir das Befruchtungs- und Todproblem. Ber. preuss. Akad. Wiss., Phys.-Math. Klasse, pp. 760-776. Hauschka, T. S. 1943 Life history and chromosome cycle of the coccidian, Adelina deronis. Jour. Morph., Vol. 73. IvANic, M. 1938 Ueber die mit der Chromosomenbildung verbun- dene promitotische Orosskernteilung bei den Vermehrungsruhe Stadien von Chilodon uncinatus. Arch. f. Protistenk., Vol. 91. Jameson, A. P. 1920 The chromosome cycle of gregarines with spe- cial reference to Diplocystis schneideri. Quart. Jour. Micr. Sci., Vol. 64. Jennings, H. S. 1929 Oenetics of the Protozoa. Bibliogr. Oen., Vol. 5. 1938 Sex reaction types and their inheritance in Parame- cium hursaria. I. II. Clones collected from natural habitats. Proc. Nat. Acad. Sci., Vol. 24. 1939 Oenetics of Paramecium hursaria. I. Oenetics, Vol. 24. 1941 Oenetics of Paramecium hursaria. II. Proc. Amer. Phil. Soc, Vol. 85. ■ — 1942 Genetics of Parameciumhursaria. III. Oenetics, Vol. 27. 1942 Senescence and death in Protozoa and invertebrates. In E. V. Cowdry: Problems of ageing. Second edition. Balti- more. , D. Raffel, R. S. Lynch and T. M. Sonneborn 1932 The diverse biotypes produced by conjugation within a clone of Paramecium aurelia. Jour. Exp. Zool., Vol. 62. Kidder, O. W. 1933 Studies on Conchophthirus mytili de Morgan. I. Arch. f. Protistenk., Vol. 79. 1938 Nuclear reorganization without cell division in Para- clevelandia simplex, an endocommensal ciliate of the wood-feed- ing roach, Panesthia. Ibid., Vol. 91. and C. L. Claff 1938 Cytological investigations of Col- poda cucullus. Biol. Bull., Vol. 74. and W. F. Diller 1934 Observations on the binaiy fission of four species of common free-living ciliates, with special refer- ence to the macronuclear chromatin. Ibid., Vol. 67. and F. M. Summers 1935 Taxonomic and cytological stud- ies on the ciliates associated with the amphipod family Orchesti- idae from the Woods Hole district. Ibid., Vol. 68. 174 PROTOZOOLOGY Kimball, R. F. 1939 Change of mating type during vegetative re- production in Paramecium aurelia. Jour. Exp. Zool., Vol. 81. ■ 1939 Mating types in Euplotes. Amer. Nat., Vol. 73. 1942 The nature and inheritance of mating tj^pes in Eu- plotes patella. Genetics, Vol. 27. 1943 Mating types in the ciliate Protozoa. Quart. Rev. Biology, Vol. 18. KoFOiD, C. A. and O. Swezy 1919 On Strehlomastix strix, a poly- mastigote flagellate with a linear plasmodial phase. Univ. Calif. Publ. Zool., Vol. 20. — 1919 On Trichonympha campanula sp. nov. Ibid. KoRSCHELT, E. 1927 Regeneration und Transpla7itation. Vol. 1. Ber- lin. Kudo, R. R. 1925 Observations on Endmnoeha hlattae. Amer. Jour. Hyg., Vol. 6. 1926 Observations on Lophomonas hlattarum, a flagellate inhabiting the colon of the cockroach, Blatta orientalis. Arch. f. Protistenk., Vol. 53. 1926 A cytological stud}^ of Lophomonas striata. Ibid., Vol. 55. ■ — 1936 Studies on Nyctotherus ovalis Leidy, with special refer- ence to its nuclear structure. Ibid., Vol. 87. LiESCHE, W. 1938 Die Kern- und Fortpflanzungsverhaltnisse von Amoeba proteus. Ibid., Vol. 91. Lund, E. J. 1917 Reversibility of morphogenetic processes in Bur- saria. Jour. Exp. Zool., Vol. 24. Maupas, E. 1888 Recherches experimentales sur la multiplication des infusoires cilies. Arch. zool. exp. et gen. (2), Vol. 6. — 1889 Le rejeunissement karyogamique ches les cilies. Ibid., Vol. 7. Mulsow, K. 1911 Ueber Fortpflanzungserschneinungen bei Mono- cystis rostrata n. sp. Arch. f. Protistenk., Vol. 22. Noland, L. E. 1927 Conjugation in the ciliate Metopus sigrnoides. Jour. Morph. Physiol., Vol. 44. Prandtl, H. 1906 Die Konjugation von Didinium nasidum. Arch, f. Protistenk., Vol. 7. Reichenow, E. 1928 Ergebnisse mit der Nuclealfarbung bei Pro- tozoen. Ibid., Vol. 61. SoKOLOFF, B. 1924 Das Regenerationsproblem bei Protozoen. Ibid., Vol. 47. SoNNEBORN, T. M. 1937 Sex, sex inheritance and sex determina- tion in Paramecium aurelia. Proc. Nat. Acad. Sci., Vol. 23. 1938 Mating types in Paramecium aurelia: diverse condi- tions for mating in different stocks; occurrence, number and in- terrelations of the types. Proc. Amer. Phil. Soc, Vol. 79. 1940 The relation of macronuclear regeneration in Parame- cium aurelia to macronuclear structure, amitosis and genetic determination. Anat. Record, Vol. 78. 1942 Sex hormones in unicellular organisms. Cold Spring Harbor Symp. Quant. Biol., Vol. 10. REPRODUCTION 175 1942a Inheritance in ciliate Protozoa. Amer. Nat., Vol. 76. Sprague, V. 1941 Studies on Gregarina hlattarum with particular reference to the chromosome cycle. 111. Biol. Monogr., Vol. 18. Summers, F. M. 1935 The division and reorganization of the macronuclei of Aspidisca lynccus, Diophrys appendiculata and Stylonychia pustulata. Arch. f. Protistenk., Vol. 85. Turner, J. P. 1930 Division and conjugation in Euplotes patella with special reference to the nuclear phenomena. Univ. Calif. Publ. ZooL, Vol. 33. WiCHTERMAN, R. 1936 Divisiou and conjugation in Nydotherus cordiformis with special reference to the nuclear phenomena. Jour. Morph., Vol. 60. 1940 Cytogamy: a sexual process occurring in living joined pairs of Paramecium caudatum and its relation to other sexual phenomena. Ibid., Vol. 66. Woodruff, L. L. 1932 Paramecium aurelia in pedigree culture for twenty-five years. Trans. Amer. Micr. Soc, Vol. 51. and R. Erdmann 1914 A normal periodic reorganization process without cell fusion in Paramecium. Jour. Exp. ZooL, Vol. 17. and H. Spencer 1921 The survival value of conjugation in the life history of Spathidium spathida. Proc. Soc. Exp. Biol, and Med., Vol. 18. Chapter 6 Variation and heredity IT IS generally recognized that individuals of all species of organ- ism show a greater or less variation in morphological and physio- logical characteristics. Protozoa are no exceptions, and manifest a wide variation in size, form, structure, and physiological characters among the members of a single species. The different groups in a species are spoken of as the races, varieties, strains, etc. It is well known that dinoflagellates show a great morphological variation in different localities. Schroder (1914) found at least nine varieties of Ceraiium hirundinella (Fig. 85) occurring in various waters of Europe, and List found that the organisms living in shallow ponds possess a marked morphological difference from those living in deep ponds. Cyphoderia ampulla is said to vary in size among those in- habiting the same deep lakes; namely, individuals from the deep water may reach 200m in length, while those from the surface layer measure only about 100m long. In many species of Foraminifera, the shell varies in thickness ac- cording to the part of ocean in which the organisms live. Thus the strains which live floating in surface water have a much thinner shell than those that dwell on the bottom. For example, according to Rhumbler, Orhulina universa inhabiting surface water has a com- paratively thin shell, 1.28-18m thick, while individuals living on the bottom have a thick shell, up to 24m in thickness. According to Uyemura, a species of Amoeba living in thermal waters, showed a distinct dimensional difference in different springs. It measured 10-40m in diameter in sulphurous water and 45-80m in ferrous water; in both types of water the amoebae were larger at 36-40°C. than at 51°C. ' Such differences or varieties appear to be due to the influence of diverse environmental conditions, and will continue to exist under these conditions; but when the organisms of different varieties are subjected to a similar environment, the strain differences disappear sooner or later. That the differences in kind and amount of foods bring about extremely diverse individuals in Tetrahymena vorax and Chilomonas Paramecium in bacteria-free cultures has already been mentioned(p. 94). Chlamydomonas dcbaryana are represented by many races differing in form, size, and structure, in various localities as well as under different laboratory conditions. Moewus (1934) dis- 176 VARIATION AND HEREDITY 177 tinguished 12 such varieties and showed that any variety could be changed into another by using different culture media. This trans- formation, however, did not occur at the same rate among different Fig. 85. Varieties of Ceratiuvi hirundinella from various European waters (Schroder), a, furcoides-type (130-300/x by 30-45ju); b, brachy- ceroides-type (130-145ju by 30-45^t); c, silesiaciun-type (148-280/x by 28-34/x); d, carinthiacum-type (120-145/x by 45-60/i); e, gracile-type (140-200M by 60-75m); f, austriacum-type (120-160^ by 45-60)u); g, robustum-type (270-310^ by 45-55/i); h, scotticum-type (160-210/x by 50-60/i); i, piburgense-type (180-260^ by 50-60)u). races. It was found that the longer a strain has remained under con- ditions producing a given type, the greater the time and the number of generations needed to change it to a new type under a new condi- tion, as is shown in Table 7. While in many species, the races or varieties have apparently been brought about into being under the influence of environmental con- ditions, in others the inherited characters persist for a long period, and still in others the biotype may show different inherited char- 178 PROTOZOOLOGY acters. To the last-mentioned category belongs perhaps a strain of Tetrahymena geleii in which, according to Fiirgason (1940), a pure- line bacteria-free culture derived from a single individual was found to be composed of individuals differing in shape and size which be- came more marked in older cultures. The first comprehensive study dealing with the variation in size and its inheritance in uniparental or vegetative reproduction of Table 7. — Relation between the number of days cultivated in peptone medium and the number of days \cultivated in salt-sugar medium needed to change from type\l tojype 5\in Chlamydomonas]debaryana (^Moewus). Days in peptone medium Days in salt-sugar medium needed as type 1 to change to type 5 28 28 140 49 273 133 441 175 567 231 609 370 644 459 672 531 690 534 Protozoa was conducted by Jennings (1909). From a "wild" lot of Paramecium caudaium, eight races or biotypes with the relative mean lengths of 206, 200, 194, 176, 142, 125, 100, and 45/i were isolated. It was found that within each clone derived from a single parent, the size of individuals varies greatly (which is attributable to growth, amount of food, and other environmental conditions), any one of which may give rise to progenj^ of the same mean size. Thus selection within the pure race has no effect on the size, and the differ- ences brought about merely by environment are not inherited. Jen- nings (1916) examined the inheritance of the size and number of spines, size of shell, diameter of mouth, and size and number of teeth of the testacean Difflugia coro/m, and showed that "a popula- tion consists of many hereditarily diverse stocks, and a single stock, derived from a single progenitor, gradually differentiates into such hereditarily diverse stocks, so that by selection marked results are produced." Root (1918) with Centropyxis aculeata, Hegner (1919) with Arcella dentata, and Reynolds (1924) with A. polypora, ob- tained similar results. Jennings (1937) studied the inheritance of teeth in Difflugia corona in normal fission and by altering through VARIATION AND HEREDITY 179 operation, and found that operated mouth or teeth were restored to normal form in 3 or 4 generations and that three factors appeared to determine the character and number of teeth: namely, the size of the mouth, the number and arrangement of teeth in the parent, and "something in the constitution of the clone (its genotype) which tends toward the production of a mouth of a certain size, with teeth of a certain form, arrangement, and number." Numerous strains have been recognized in all intensively studied parasitic Protozoa such as Entamoeba, Trypanosoma, Plasmodium, etc. For example, Dobell and Jepps (1918) noticed five races in Entamoeba histolytica on the basis of differences in the size of cysts. Spector (1936) distinguished two races in the trophozoite of this amoeba. The large strain was found to be pathogenic to kittens, but the small strain was not. Meleney and Frye (1933, 1935) and Frye and Meleney (1939) also hold that there is a small race in Entamoeba histolytica which has a weak capacity for invading the intestinal wall and not pathogenic to man. Sapero, Hakansson and Louttit (1942) similarly notice two races which can be distinguished by the diameters of cysts, the division line being 10m and 9/i in living and balsam-mounted specimens respectively. The race with large cysts gives rise to trophozoites which are more actively motile, ingest erythrocytes, culture easily and is pathogenic to man and kitten, while the race with small cysts develops into less actively motile amoebae which do not ingest erythrocytes, difficult to culture, and is not pathogenic to hosts, thus not being histozoic. Recent investigations by Boyd and his co-workers show beyond doubt that the species of Plasmodium are composed of many strains which vary in diverse physiological characters. In an extended study on Try-pavosoma lewisi, Taliaferro (1921-1926) found that this flagel- late multiplies only during the first ten days in the blood of a rat after inoculation, after which the organisms do not reproduce. In the adult trypanosomes, the variability for total length in a population is about 3 per cent. Inoculation of the same pure line into different rats some- times brings about small but significant differences in the mean size and passage through a rat-flea generally results in a significant vari- ability of the pure line. It is considered that some differences in dimensions among strains are apparently due to environment (host), but others cannot be considered as due to this cause, since they per- sist when several strains showing such differences are inoculated into the same host. Hoare (1943) reviewed recently the "biological" races of certain parasitic Protozoa. Jollos (1921) subjected Paramecium caudatum to various environ- 180 PROTOZOOLOGY mental influences such as temperature and chemicals, and found that the animals develop tolerance which is inherited through many gen- erations even after removal to the original environment. For exam- ple, one of the clones which tolerated only 1.1% of standard solution of arsenic acid, was cultivated in gradually increasing concentrations for four months, at the end of which the tolerance for this chemical was raised to 5%. After being removed to water without arsenic acid, the tolerance changed as follows: 22 days, 5%; 46 days, 4.5%; 151 days, 4%; 166 days, 3%; 183 days, 2.5%; 198 days, 1.25% and 255 days, 1%. As the organisms reproduced about once a day, the acquired increased tolerance to arsenic was inherited for about 250 generations. There are also known inherited changes in form and structure which are produced under the influence of certain environmental conditions. Jollos designated these changes long-lasting modifica- tions (Dauermodifikationen) and maintained that a change in en- vironmental conditions, if applied gradually, brings about a change, not in the nucleus, but in the cytoplasm, of the organism which when transferred to the original environment, is inherited for a number of generations. These modifications are lost usually during sexual processes at which time the whole organism is reorganized. The long-lasting morphological and physiological modifications induced by chemical substances have long been known in parasitic Protozoa. Werbitzki (1910) discovered that Trypanosoma hrucei loses its blepharoplast when inoculated into mice which have been treated with pyronin, acridin, oxazin and allied dyes. Laveran and Roudsky (1911) found that these dyes have a special affinity for, and bring about the destruction by auto-oxidation of, the blepharo- plast. Such trypanosomes lacking blepharoplast behave normally and remain in that condition during many passages through mice. When subjected to small doses of certain drugs repeatedly, species of Trypanosoma often develop into drug-fast or drug-resistant strains which resist doses of the drug greater than those used for the treatment of the disease for which they are responsible. These modi- fications may also persist for several hundred passages through host animals and invertebrate vectors, but are eventually lost. Long-lasting modifications have also been produced by several investigators by subjecting Protozoa to various environmental in- fluences during the nuclear reorganization at the time of fission, conjugation, or autogamy. In Stentor (Popoff) and Glaucoma (Chatton), long-lasting modifications appeared during asexual divi- sions. Calkins (1924) observed a double-type Uroleptus mohilis VARIATION AND HEREDITY 181 which was formed by a complete fusion of two conjugants. This ab- normal animal underwent fission 367 times for 405 days, but finally reverted back to normal forms, without reversion to double form. Jennings (1941) outlined five types of long-lasting inherited changes during vegetative reproduction, as follows: (1) changes that occur in the course of normal life history, immaturity to sexual ma- turity which involves many generations; (2) degenerative changes resulting from existence under unfavorable conditions; (3) adaptive changes or inherited acclimitization or immunity ; (4) changes which are neither adaptive nor degenerative, occurring under specific en- vironmental conditions; and (5) changes in form, size, and other characters, which are apparently not due to environment. Whatever exact mechanism by which the long-lasting modifica- tions are brought about may be, they are difficult to distinguish from permanent modification or mutation, since they persist for hundreds of generations, and cases of mutation have in most instan- ces not been followed by sufficiently long enough pure-line cultures to definitely establish them as such. Jollos observed that if Paramecium were subjected to environ- mental change during late stages of conjugation, certain individuals, if not all, become permanently changed. Possibly the recombining and reorganizing nuclear materials are affected in such a way that the hereditary constitution or genotype becomes altered. MacDougall subjected Chilodonella uncinata to ultraviolet rays and produced many changes which were placed in three groups: (1) abnormalities which caused the death of the organism; (2) temporary variations which disappeared by the third generation ; and (3) variations which were inherited through successive generations and hence considered as mutations. The mutants were triploid, tetraploid, and tailed diploid forms (Fig. 86), which bred true for a variable length of time in pure-line cultures, either being lost or dying off finally. The tailed form differed from the normal form in the body shape, in the number of ciliary rows and contractile vacuoles, and in the mode of move- ment, but during conjugation it showed the diploid number of chro- mosomes as in the typical form. The tailed mutant remained true and underwent 20 conjugations during ten months. In biparental inheritance, the nuclei of two individuals partici- pate in producing new combinations which would naturally bring about diverse genetic constitutions. The new combination is ac- complished either by sexual fusion in Sarcodina, Mastigophora, and Sporozoa, or by conjugation in Euciliata and Suctoria. The genetics of sexual fusion is only known in a few forms. Perhaps 182 PROTOZOOLOGY the most complete information was obtained by Moewus through his extended studies of certain Phytomonadina. In Polytoma (p. 222), Chlamydomonas (p. 217), and allied forms, the motile indi- viduals are usually haploid. Two such individuals (gametes) fuse with each other and produce a diploid zygote which becomes en- cysted. The zygote later undergoes at least two divisions within the cyst wall, in the first division of which chromosome reduction takes place. These swarmers when set free become trophozoites and Fig. 86. Chilodonella uncinata (MacDougall). a, b, ventral and side view of normal individual; c, d, ventral and side view of the tailed mutant. multiply asexually by division for many generations, the descend- ants of each s warmer giving rise to a clone. Moewus (1935) demonstrated the segregation and independent as- sortment of factors by hybridization of Polytoma. He used two va- rieties each of two species: P. uvella and P. pascheri, both of which possess 8 haploid chromosomes. Their constitutions were as follows: P. uvella Form A: Oval (F), without papilla (p), with stigma (S), large (D) (Fig. 87, a). Form B: Oval (F), without papilla (p), without stigma (s), large (D) (Fig. 87, 6). P. pascheri Form C: Pyriform (f), with papilla (P), without stigma (s), large (D)(Fig.87,c). Form D: Pyriform (f), with papilla (P), without stigma (s), small (d)(Fig.87,6;). VARIATION AND HEREDITY 183 Thus six different crosses were possible from the four pairs of characters. When A (FpSD) and B (FpsD) fuse, the zygote divides into four swarmers, two swarmers have stigma (S), and the other two lack this cell organ, which indicates the occurrence of segrega- tion of the two characters (S, s) during the reduction division. When B (FpsD) is crossed with C (fPsD), thus differing in two pairs of characters, two swarmers possess one combination or type and the other two another combination. Different pairs of combinations are E Fig. 87. a, b. Polytoma uvella. a, Form A; b, Form B. c, d. P. pascheri. c, Form C; d, Form D. e, f. Crosses between Forms B and C. (Moewus) of course found. It was found that about half the zygotes gives rise to the two parental combinations (Fig. 87, h, c), while the other half gives rise to FPsD (Fig. 87, e) and fpsD (Fig. 87,/). When B (FpsD) is crossed with D (fPsd) or A (FpSD) is crossed with D (fPsd), only two types of swarmers are also formed from each zygote, and in the case of BXD, eight different combinations are produced, while in the case of AXD, sixteen different combina- tions, which appear in about equal numbers, are formed. Thus these four factors or characters show independent assortment during divi- sions of the zygote. Furthermore, Moewus noticed that certain other characters ap- peared to be linked with some of the four characters mentioned above. For example, the length of flagella, if it is under control of a factor, is linked on the same chromosome with the size-controlling factors (D, d), for large individuals have invariably long flagella and small individuals short flagella. During the experiments to de- termine this linkage, it was found that crossing over occurs between two entire chromosomes that are undergoing synapsis. 184 PROTOZOOLOGY In certain races of Polytoma pascheri and Chlamydomonas euga- metos, the sexual fusion takes place between members of different clones only. The zygote gives rise as was stated before to four swarm- ers by two divisions, which are evenly divided between the two sexes, which shows that the sex-determining factors are lodged in a single chromosome pair. In a cross between Chlamydomonas para- doxa and C. pseudoparadoxa, both of which produce only one type of gamete in a clone, the majority of the zygotes yield four clones, two producing male gametes and the other two female gametes; but a small number of zygotes gives rise to four clones which contain both gametes. It is considered that this is due to crossing-over that brought the two sex factors (P and M) together into one chromo- some, and hence the "mixed" condition, while the other chromosome which is devoid of the sex factors gives rise to individuals that soon perish. In crosses between Chlamydomonas eugametos which possesses a stigma and 10 haploid chromosomes and C. paupera which lacks a stigma and 10 haploid chromosomes, 12 pairs of factors including sex factor are distinguishable. Consequently at least two chromo- somes must have two factors in them. Thus adaptation to acid or alkaline culture media was found to be linked with differences in the number of divisions in zygote. That there occurs a sex-linked in- heritance in Chlamydomonas was demonstrated by crossing stigma- bearing C. eugametos of one sex with stigma-lacking C. paupera of the opposite sex. The progeny that were of the same sex as C. euga- metos parent possessed stigma, while those that were of the same sex as C. paupera parent lacked stigma. Thus it is seen that the sex factor and stigma factor are located in the same chromosome. The genetics of conjugation which takes place between two diploid conjugants has been studied by various investigators. Pure-line cultures of exconjugants show that conjugation brings about diverse inherited constitutions in the clones characterized by difference in size, form, division-rate, mortality-rate, vigor, resistance, degene- ration, etc. The diversities brought about by autogamy are not as varied as those produced by conjugation. In Paramecium much in- formation has in recent years been brought to light through the studies of Sonneborn, Jennings, Kimball, and others on the mating type (p. 156). The mating type is as a rule inherited without change to descendants through vegetative reproduction. Sonneborn (1939) has made extended studies of variety 1 of Paramecium aurelia (p. 158) and found that genetically diverse ma- terials show different types of inheritance, as follows: VARIATION AND HEREDITY . 185 (1) Stocks containing two mating types. When types I and II conjugate, among a set of exconjugants some produce all of one mating type, others all of the other mating type and still others both types (one of one type and the other of the other type) . In the last mentioned exconjugants, the types segregate usually at the first division, since of the two individuals produced by the first divi- sion, one and all its progeny, are of one mating type, and the other and all its progeny are of the other mating type. A similar change was also found to take place at autogamy. Sonneborn considers that the mating types are determined by macronuclei, as judged by segregation at first or sometimes second division in exconjugants and by the influence of temperature during conjugation and the first division. (2) Stocks containing only one mating type. No conjugation oc- curs in such stocks. Autogamy does not produce any change in type which is always type I. Stocks that contain type II only have not yet been found. (3) Hybrids between stocks containing one and two mating types. When the members of the stock containing both types I and II (two-type condition) conjugate with those of the stock containing one type (one-type condition), all the descendants of the hybrid exconjugants show two-type condition, which shows the dominancy of two-type condition over one-type condition. The factor for the two-type condition may be designated A and that for the one-type condition a. The parent stocks are AA and aa, and all Fi hybrids Aa. When the hybrids (Aa) are backcrossed to recessive parent (aa) (158 conjugating pairs in one experiment), approximately one-half (81) of the pairs give rise to two-type condition (Aa) and the remain- ing one-half (77) of the pairs to one-type condition (aa), thus showing a typical Mendelian result. When Fi hybrids (Aa) were interbred by 120 conjugating pairs, each exconjugant in 88 of the pairs gave rise to two-type condition and each exconjugant in 32 pairs pro- duced one-t3^pe condition, thus approximating an expected Men- delian ratio of 3 dominants to 1 recessive. That the F2 dominants are composed of two-thirds heterozygotes (Aa) and one-third homo- zygotes (AA) was confirmed by the results obtained by allowing F2 dominants to conjugate with the recessive parent stock (aa). Of 19 pairs of conjugants, 6 pairs gave rise to only dominant progeny, which shows that they were homoz^^gous (AA) and their progeny heterozygous (Aa), while 13 pairs produced one-half dominants and one-half recessives, which indicates that they were heterozygous (Aa) and their progeny half homozygous (aa) and half heterozygous 186 . PROTOZOOLOGY (Aa). Thus the genie agreement between two conjugants of a pair and the relative frequency of various gene combinations as shown in these experiments confirm definitely the occurrence of meiosis and chromosomal exchange during conjugation which have hitherto been known only on cytological ground. In Euplotes patella, Kimball (1942) found that the six mating types (p. 159) are determined by six possible combinations of a series of three allelic genes. There is no dominance among these alleles, the three heterozygous combinations determining three mating types being different from one another and from the three determined by homozygous combination. Kimball (1939, 1941) had shown that the fluid obtained free of Euplotes from a culture of one mating type will induce conjugation among animals of certain other mating types. When all possible combinations of fluids and animals are made it was found that the fluid from any of the heterozygous types in- duces conjugation among animals of any types other than its own and the fluid from any of the homozygous types induces conjugation only among animals of the types which do not have the same allele as the type from which the fluid came. These reactions are explained by an assumption that each of the mating type alleles is responsible for the production by the animal of a specific conjugation-inducing substance. Thus the two alleles in a heterozygote act independently of each other; each brings about the production by the animal of a substance of its own. Thus heterozygous animals are induced to con- jugate only by the fluids from individuals which possess an allele not present in the heterozygotes. The relation between the cytoplasm and nucleus in respect to in- heritance has become better known in recent years in some ciliates. De Garis (1935) succeeded in bringing about conjugation in Para- mecium caudatum, between the members of a large clone (198m long) and of a small clone (73/i long). The exconjugants of a pair are dif- ferent only in the cytoplasm as the nuclei are alike through exchange of a haploid set of chromosomes. The two exconjugants divide and give rise to progeny which grow to size characteristic of each parent clone, division continuing at the rate of once or twice a day. How- ever, as division is repeated, the descendants of the large clone be- come gradually smaller after successive fissions, while the descend- ants of the small clone become gradually larger, until at the end of 22 days (in one experiment) both clones produced individuals of inter- mediate size (about 135^ long) which remained in generations that followed. Since the exconjugants differed in the cytoplasm only, it must be considered probable that at first the cytoplasmic character VARIATION AND HEREDITY 187 was inherited through several vegetative divisions, but ultimately the influence of the new nucleus gradually changed the cytoplasmic character. The ultimate size between the two clones is not always midway between the mean sizes of the two parent clones, and is ap- parently dependent upon the nuclear combinations brought about by conjugation. It has also become known that different pairs of con- jugants between the same two clones give rise to diverse progeny, similar to those of sexual reproduction in Metazoa, which indicates that clones of Paramecium caudatum are in many cases heterozygous for size factors and recombination of factors occur at the time of conjugation. In P. aurelia, Kimball (1939) observed that there occasionally occurs a change of one mating type into another following autogamy. When the change is from type II to type I, not all animals change type immediately. Following the first few divisions of the product of the first division after autogamy there are present still some type II animals, although ultimately all become transformed into type I. Here also the cytoplasmic influence persists and is inherited through vegetative divisions. Jennings (1941) in his recent review writes as follows: "The primary source of diversities in inherited characters lies in the nucleus. But the nucleus by known material interchanges impresses its constitution on the cytoplasm. The cytoplasm retains the constitution so impressed for a considerable length of time, dur- ing which it assimilates and reproduces true to its impressed char- acter. It may do this after removal from contact with the nucleus to which its present constitution is due, and even for a time in the presence of another nucleus of different constitution. During this period, cytoplasmic inheritance may occur in vegetative reproduc- tion. The new cells produced show the characteristics due to this cytoplasmic constitution impressed earlier by a nucleus that is no longer present. But in time the new nucleus asserts itself, impressing its own constitution on the cytoplasm. Such cycles are repeated as often as the nucleus is changed by conjugation." Sonneborn (1943) has recently found in the four races of variety 4 of P. aurelia a pair of characters which he designated as "killer" and "sensitive." Fluid in which the killer race has lived kills individuals of the sensitive races. Race 51 is a killer, while races 29, 32, and 47 are sensitive. It appears that the killer and sensitive characters never occur together in the same individual. All progeny in race 51 are killers, and all progeny of the sensitive races are sensitive. When the pure killer race 51 is crossed with the pure sensitive race 32, the two exconjugants of each pair produce phenotypically different 188 PROTOZOOLOGY clones: one is a killer and the other is sensitive. He was able to dem- onstrate that the Fi killer clones are those that derive their cyto- plasm from the killer parent and the Fi sensitive clones are those which contain the cytoplasm of the sensitive parent — a result con- tradictory to the hitherto prevailing notion that the two exconju- gants possess the same genotype and should produce clones alike in their hereditary characters. Through a series of experiments, he has come to realize that there exist certain "relations between a gene and a cytoplasmic substance, both of which are required for the development of a hereditary character. When some of the cyto- plasmic substance is present, the gene controls its continued produc- tion; but when the cytoplasmic substance is absent, the gene cannot initiate its production. Addition of the cytoplasmic substance to an organism, lacking the character dependent on it, but containing the required gene, results in the continued production of the substance, in the development of the character determined by the combined presence of gene and cytoplasmic substance, and in the hereditary maintenance of the character in successive generations." References Calkins, G. N. 1924 Uroleptus mohilis. V. Jour. Exp. Zool., Vol. 41. De Garis, C. F. 1935 Heritable effects of conjugation between free individuals and double monsters in diverse races of Paramecium. Ibid., Vol. 71. FuRGASON, W. H. 1940 The significant cytostomal pattern of the "Glaucoma-Colpidium group," and a proposed new genus and species, Tetrahymena geleii. Arch. f. Protistenk., Vol. 94. Hegner, R. W. 1919 Heredity, variation, and the appearance of diversities during the vegetative reproduction of Arcella dentata Genetics, Vol. 4. HoARE, C, A. 1943 Biological races in parasitic Protozoa. Biol. Re- views, Vol. 18. Jennings, H. S. 1909 Heredity and variation in the simplest or- ganisms. Amer. Nat., Vol. 43. 1916 Heredity, variation and the results of selection in the uniparental reproduction of Difflugia corona. Genetics, Vol. 1. 1929 Genetics of the Protozoa. BibUographia Genetica, Vol. 5. 1937 Formation, inheritance and variation of the teeth in Difflugia corona. Jour. Exp. Zool., Vol. 77. 1939 Genetics of Paramecium hursaria. I. Mating types and groups, their interrelations and distribution; mating behavior and self-sterility. Genetics, Vol. 24. 1941 Inheritance in Protozoa. In G. N. Calkins and F. M. Summers (editors) : Protozoa in biological research. New York. VARIATION AND HEREDITY 189 , D. Raffel, R. S. Lynch and T. M. Sonneborn 1932 The diverse biotypes produced by conjugation within a clone of Paramecium. Jour. Exp. Zool., Vol. 63. JoLLOS, V. 1913 Experimentelle Untersuchungen an Infusorien Biol. Zentralbl, Vol. 33. — \ 1921 Experimentelle Protistenstudien. I. Untersuchungen iiber Variabilitat und Vererbung bei Infusorien. Arch. f. Pro- tistenk., Vol. 43. 1934 Dauermodifikationen und Mutationen bei Protozoen. Ibid., Vol. 83. Kimball, R. F. 1939 A delayed change of phenotype following a change of genotype in Paramecium aurelia. Genetics, Vol. 24. — 1939 Mating types in Euplotes. Amer. Nat., Vol. 73. 1942 The nature and inheritance of mating types in Eu- plotes 'patella. Genetics, Vol. 27. MacDougall, M. S. 1929 Modifications in Chilodon uncinatus produced by ultraviolet radiations. Jour. Exp. Zool., Vol. 54. 1931 Another mutation of Chilodon uncinatus produced by ultraviolet radiation, with a description of its maturation pro- cess. Ibid., Vol. 58. MoEWUS, F. 1934 Ueber Dauermodifikation bei Chlamydomona- den. Arch. f. Protistenk., Vol. 83. 1935 Ueber die Vererbung des Geschlechts bei Polytoma pascheri und bei Polytoma uvella. Zeitschr. Induk. Abstamm.- u. Vererb., Vol. 69. 1936 Faktorenaustausch, insbesondere der Realisatoren bei Chlamydomonas-Kreuzungen. Berichte deutsch. Bot. Ges., Vol. 54. 1938 Vererbung des Geschlechts bei Chlamydomonas eu- gametos und verwandten Arten. Biol. Zentralbl., Vol. 58 Reynolds, B. D. 1924 Interactions of protoplasmic masses in rela- tion to the study of heredity and environment in Arcella poly- pora. Biol. Bull,., Vol. 46. Root, F. M. 1918 Inheritance in the asexual reproduction in Cen- tropyxis aculeata. Genetics, Vol. 3. Sapero, J. J., E. G. Hakansson and C. M. Louttit 1942 The occurrence of two significantly distinct races of Endanioeha his- tolytica. Amer. Jour. Trop. Med., Vol. 22. Sonneborn, T. M. 1937 SeX; sex inheritance and sex determina- tion in Paramecium aurelia. Proc. Nat. Acad. Sci., Vol. 23. 1939 Paramecium aurelia: mating types and groups; lethal interactions; determination and inheritance. Amer. Nat., Vol. 73. — 1942 Inheritance in cihate Protozoa. Ibid., Vol. 76. 1943 Gene and Cytoplasm. I and II. Proc. Nat. Acad. Sci. Vol. 29. Taliaferro, W. H. 1926 Variability and inheritance of size in Try- panosoma lewisi. Jour. Exp. Zool., Vol. 43. 1929 The immunology of parasitic infections. New York. and C. G. Huff 1940 The genetics of the parasitic Pro- tozoa. Amer. Assoc. Adv. Sci., Publication No. 12. PART II: TAXONOMY AND SPECIAL BIOLOGY Chapter 7 Major groups and phylogeny of Protozoa THE Protozoa are grouped into two subphyla: Plasmodroma (p. 198) and Ciliophora (p. 545). The Plasmodroma are more primi- tive Protozoa and subdivided into three classes: Mastigophora (p. 198), Sarcodina (p. 328), and Sporozoa (p. 427). The Ciliophora possess more complex body organizations, and are divided into two classes : Ciliata (p. 545) and Suctoria (p. 695). In classifying Protozoa, the natural system would be one which is based upon the phylogenetic relationships among them in conform- ity with the doctrine that the present day organisms have descended from primitive ancestral forms through organic evolution. Unlike Metazoa, the great majority of Protozoa now existing do not possess skeletal structures, which condition also seemingly prevailed among their ancestors, and when they die, they disintegrate and leave nothing behind. The exceptions are Foraminifera (p. 394) and Radiolaria (p. 417) which produce multiform varieties of skeletal structures composed of inorganic substances and which are found abundantly preserved as fossils in the earliest fossiliferous strata. These fossils show clearly that the two classes of Sarcodina were already w^ell-difTerentiated groups at the time of fossilization. The sole information the palaeontological record reveals for our reference is that the differentiation of the major groups of Protozoa must have occurred in an extremely remote period of the earth history. There- fore, consideration of phylogeny of Protozoa had to depend ex- clusively upon the data obtained through morphological, physio- logical, and developmental observations of the present-day forms. The older concept which found its advocates until the beginning of the present century, holds that the Sarcodina are the most primi- tive of Protozoa. It was supposed that at the very beginning of the living world, there came into being undifferentiated mass of pro- toplasm which later became differentiated into the nucleus and the cytosome. The Sarcodina represented by amoebae and allied forms do not have any further differentiation and lack a definite body wall, they are, therefore, able to change body form by forming pseudopodia. These pseudopodia are temporary cytoplasmic proc- esses and formed or withdrawn freely, even in the more or less permanent axopodia. On the other hand, flagella and cilia are per- manent cell-organs possessing definite structural plans. Thus from 193 194 PROTOZOOLOGY the morphological viewpoint, the advocates of this concept main- tained that the Sarcodina are the Protozoa which were most closely related to ancestral forms and which gave rise to Mastigophora, Cihata, and Sporozoa. This concept is however difficult to follow, since it does not agree with the general belief that the plant came into existence before the animal ; namely, holophytic organisms living on inorganic substances anteceded holozoic organisms living on organic substances. There- fore, from the physiological standpoint the Mastigophora which include a vast number of chlorophyll-bearing forms, must be con- sidered as more primitive than the holozoic Sarcodina. The class Mastigophora is composed of Phytomastigina (chromatophore-bear- ing flagellates and closely related colorless forms) and Zoomastigina (colorless flagellates). Of the former, Chrysomonadina (p. 200) are mostly naked, and are characterized by possession of 1-2 flagella, 1-2 yellow chromatophores and leucosin. Though holophytic nutri- tion is general, many are also able to carry on holozoic nutrition. Numerous chrysomonads produce pseudopodia of different types; some possess both flagellum and pseudopodia; others such as Chrys- amoeba (p. 203) may show flagellate and ameoboid forms (Klebs; Scherffel); still others, for example, members of Rhizochrysidina (p. 209), may lack flagella completely, though retaining the char- acteristics of Chrysomonadina. When individuals of Rhizochrysis (p. 210) divide, Scherffel (1901) noticed unequal distribution of the chromatophore resulted in the formation of colorless and colored individuals (Fig. 94, a, h). Pascher (1917) also observed that in the colonial chrysomonad, Chrysarachnion (p. 210), the division of component individuals produces many in which the chromatophore is entirely lacking (Fig. 94, c, d). Thus these chrysomonads which lack chromatophores, resemble Sarcodina rather than the parent Chryosomonadina. Throughout all groups of Phytomastigina, there occur forms which are morphologically alike except the presence or absence of chromatophores. For example, Cryptomonas (p. 214) and Chilo- monas (p. 214), the two genera of Cryptomonadina, are so mor- phologically alike that had it not been for the chromatophore, the former can hardly be distinguished from the latter. Other examples are Euglena, Astasia, and Khawkinea; Chlorogonium and Hyalo- gonium; Chlamydomonas and Polytoma; etc. The chromatophores of various Phytomastigina degenerate read- ily under experimental conditions. For instance, Zumstein (1900) showed that Euglena gracilis loses its green coloration even in light MAJOR GROUPS AND PHYLOGENY 195 if cultured in fluids rich in organic substances ; in a culture fluid with a small amount of organic substances, the organisms retain green color in light, lose it in darkness; and when cultured in a pure inor- ganic culture fluid, the flagellates remain green even in darkness. Therefore, it would appear reasonable to consider that the mor- phologically similar forms with or without chromatophores such as are cited above, are closely related to each other phylogenetically, that they should be grouped together in any scheme of classification, and that the apparent heterogeneity among Ph3^tomastigina is due to the natural course of events. The newer concept which is at pres- ent followed widely is that the Mastigophora are the most primitive unicellular animal organisms. Of Mastigophora, Phytomastigina are to be considered on the same ground more primitive than Zoomastigina. According to the studies of Pascher, Scherffel and others, Chrysomonadina appear to be the nearest to ancestral forms from which other groups of Phyto- mastigina arose. Among Zoomastigina, Rhizomastigina possibly gave rise to Protomonadina, from which Polymastigina and Hyper- mastigina later arose. The last-mentioned group is the most highly advanced one of Mastigophora in which an increased number of flagella is an outstanding characteristic. As to the origin of Sarcodina, many arose undoubtedly from vari- ous Zoomastigina, but there are indications that they may have evolved directly from Phytomastigina. As was stated already, Rhizochrysidina possess no flagella and the chromatophore often de- generates or is lost through unequal distribution during division, apparently being able to nourish themselves by methods other than holophytic nutrition. Such forms may have given rise to Amoebina. Some chrysomonads such as Cyrtophora (p. 203) and Palatinella, have axopodia, and it may be considered that they are closer to the ancestral forms from which Heliozoa arose through stages such as shown by Actinomonas (p. 265), Dimorpha (p. 265), and Pteri- domonas (p. 265) than any other forms. Another chrysomonad, Porochrysis (p. 204), possesses a striking resemblance to Testacea. The interesting marine |chrysomonad, Chrysothylakion (p. 210) that produces a brownish calcareous test from which extrudes an- astomosing rhizopodial network, resembling a monothalamous foraminiferan, and forms such as Distephanus (p. 209) with siliceous skeletons, may depict the ancestral forms of Foraminifera and Radiolaria respectively. The flagellate origin of these two groups of Sarcodina is also seen in the appearance of flagellated swarmers dur- ing their development. The Mycetozoa show also flagellated phase 196 PROTOZOOLOGY during their life cycle, which perhaps suggests their origin in flagel- lated organisms. In fact, in the chrysomonad Myxochrysis (p. 205), Pascher (1917) finds a multinucleate and chromatophore-bearing organism (Fig. 90, e-j) that stands intermediate between Chr3^so- monadina and Mycetozoa. Thus there are a number of morpho- logical, developmental, and physiological observations which sug- gest the flagellate origin of various Sarcodina. The Sporozoa appear to be equally polyphyletic. The Telosporidia contain three groups in which flagellated microgametes occur, which suggests their derivation from flagellated organisms. Leger and Duboscq even considered them to have arisen from Bodonidae (p. 289) on the basis of flagellar arrangement. Obviously Gregarinida are the most primitive of the three groups. The occurrence of such a form as Selenococcidium (p. 466), would indicate the gregarine- origin of the Coccidia and the members of Haemogregarinidae (p. 480) suggest the probable origin of the Haemosporidia in the Coc- cidia. The Cnidosporidia are characterized by multinucleate tro- phozoites and by the spore in which at least one polar capsule with a coiled filament occurs. Some consider them as having evolved from Mycetozoa-like organisms, because of the similarity in multi- nucleate trophozoites, while others compare the polar filament with the flagellum. It is interesting to note here that the nematocyst, similar to the polar capsule, occurs in certain Dinoflagellata (p. 245) independent of flagella. The life cycle of Acnidosporidia is still in- completely known, but the group may have differentiated from such Sarcodina as Mycetozoa. The Ciliata and Suctoria are distinctly separated from the other groups. They possess the most complex body organization seen among Protozoa. All ciliates possess cilia or cirri which differ from flagella essentially only in size. Apparently Protociliata and Eucili- ata have different origins, as judged by their morphological and physiological differences. It is probable that Protociliata arose from forms which gave rise to Hypermastigina. Among Euciliata, one finds such forms as Coleps, Urotricha, Plagiocampa, Microregma, Trimyema, Anophrys, etc., which have, in addition to numerous cilia, a long flagellum-like process at the posterior end, and Ileonema that possesses an anterior vibratile flagellum and numerous cilia, which also indicates flagellated organisms as their ancestors. It is reasonable to assume that Holotricha are the most primitive ciliates from which Spirotricha, Chonotricha, and Peritricha evolved. The Suctoria are obviously very closely related to Ciliata and most prob- ably arose from ciliated ancestors by loss of cilia during adult stage MAJOR GROUPS AND PHYLOGENY 197 and by developing tentacles in some forms from cytostomes as was suggested by Collin (Fig. 13). References BuTSCHLi, O. 1883-1887 Bronn's Klassen und Ordnungen des Thierreichs. Vol 1. DoFLEiN, F. and E. Reichenow 1929 Lehrhuch der Protozoenkunde. Jena. MiNCHiN, E. A. 1912 Introduction to the study of the Protozoa. Lon- don. Pascher, a. 1912 Ueber Rhizopoden- und Palmellastadien bei Flagellaten. Arch. f. Protistenk.,, Vol. 25. 1917 Rhizopodialnetz als Fangvorrichtung bei einer Plas- modialen Chrysomonade. Ibid., Vol. 37. 1917 Fusionsplasmodien bei Flagellaten und ihre Bedeut- ung fiir die Ableitung der Rhizopoden von den Flagellaten. Ibid. 1917 Flagellaten und Rhizopoden in ihren gegenseitigen Beziehungen. Ibid., Vol. 38. ScHERFFEL, A. 1901 Kleiner Beitrag zur Phylogenie einiger Grup- pen niederer Organismen. Bot. Zeit., Vol. 59. ZuMSTEiN, H. 1900 Zur Morphologic von Euglena gracilis Klebs. Pringsheims Jahrb., Vol. 34. T Chapter 8 Phylum Protozoa Goldfuss Subphylum 1 Plasmodroma Doflein HE Plasmodroma possess pseudopodia which are used for loco- motion and food-getting or flagella that serve for cell-organs of locomotion. In Sporozoa, the adult stage does not possess any cell- organs of locomotion. The body structure is less complicated than that of Ciliophora. In some groups, are found various endo- and exo-skeletons. The nucleus is of one kind, but may vary in number. Nutrition is holozoic, holophytic, or saprozoic. Sexual reproduction is exclusively by sexual fusion ; asexual reproduction is by binary or multiple fission or budding. The majority are free-living, but numer- ous parasitic forms occur, Sporozoa being all parasitic. The Plasmodroma are subdivided into three classes as follows: Trophozoite with flagellum Class 1 Mastigophora Trophozoite with pseudopodium Class 2 Sarcodina (p. 328) Without cell-organs of locomotion; producing spores; all parasitic Class 3 Sporozoa (p. 427) Class 1 Mastigophora Diesing The Mastigophora includes those Protozoa which possess one to several flagella. Aside from this common characteristic, this class makes a very heterogeneous assemblage and seems to prevent a sharp distinction between the Protozoa and the Protophyta, as it includes Phytomastigina which are often dealt with by botanists. In the majority of Mastigophora, each individual possesses 1-4 flagella during the vegetative stage, although species of Polymasti- gina may possess up to 8 or more flagella and of Hypermastigina a greater number of flagella. The palmella stage (Fig. 88) is common among the Phytomastigina and the organism is capable in this stage not only of metabolic activity and growth, but also of reproduction. In this respect, this group shows also a close relationship to algae. All three types of nutrition, carried on separately or in combina- tion, are to be found among the members of Mastigophora. In holo- phytic forms, the chlorophyll is contained in the chromatophores which are of various forms among different species and which differ in colors, from green to red. The difference in color appears to be due to the pigments which envelop the chlorophyfl body (p. 78). Many forms adapt their mode of nutrition to changed environmental con- 198 MASTIGOPHORA, CHRYSOMONADINA 199 ditions ; for instance, from holophytic to saprozoic in the absence of the simhght. Holozoic, saprozoic and holophytic nutrition are said to be combined in such a form as Ochromonas. In association with chromatophores, there occurs refractile granules or bodies, the pyrenoids, which are connected with starch-formation. Reserve food substances are starch, oil, etc, (p. 98). In less complicated forms, the body is naked except for a slight cortical differentiation of the ectoplasm to delimit the body surface and is capable of forming pseudopodia. In others, there occurs a thin plastic pellicle produced by the cytoplasm, which covers the body surface closely. In still others, the body form is constant, being en- cased in a shell, test, or lorica, which is composed of chitin, pseudo- chitin, or cellulose. Not infrequently a gelatinous secretion envelops the body. In three families of Protomonadina there is a collar-like structure located at the anterior end, through which the flagellum protrudes. The great majority of Mastigophora possess a single nucleus, and only a few are multinucleated. The nucleus is vesicular and contains a conspicuous endosome. Contractile vacuoles are always present in the forms inhabiting fresh water. In simple forms, the contents of the vacuoles are discharged directly through the body surface to the exterior; in others there occurs a single contractile vacuole near a reservoir which opens to the exterior through the so-called cyto- pharynx. In the Dinoflagellata, there are apparently no contractile vacuoles, but non-contractile pusules (p. 246) occur in some forms. In chromatophore-bearing forms, there occurs usually a stigma which is located near the base of the flagellum and seems to be the center of phototactic activity of the organism which possesses it. Asexual reproduction is, as a rule, by longitudinal fission, but in some forms multiple fission also takes place under certain circum- stances, and in others budding may take place. Colony-formation (p. 145), due to incomplete separation of daughter individuals, is widely found among this group. Sexual reproduction has been re- ported in a number of species. The Mastigophora are free-living or parasitic. The free-living forms are found in fresh and salt waters of every description; many are free-swimming, others creep over the surface of submerged ob- jects, and still others are sessile. Together with algae, the Mastigoph- ora compose a major portion of plankton life which makes the foundation for the existence of all higher aquatic organisms. The parasitic forms are ecto- or endo-parasitic, and the latter inhabit either the digestive tract or the circulatory system of the host ani- 200 PROTOZOOLOGY mal. Trypanosoma, a representative genus of the latter group, in- cludes important disease-causing parasites of man and of domestic animals. The Mastigophora are divided into two subclasses as follows : With chroraatophores Subclass 1 Phytomastigina Without chromatophores Subclass 2 Zoomastigina (p. 263) Subclass 1 Phytomastigina Doflein The Phytomastigina possess the chromatophores and their usual method of nutrition is holophytic, though some are holozoic, sapro- zoic or mixotrophic; the majority are conspicuously colored; some that lack chromatophores are included in this group, since their structure and development resemble closely those of typical Phyto- mastigina. 1-4 flagella, either directed anteriorly or trailing Chromatophores yellow, brown or orange Anabolic products fat, leucosin Order 1 Chrysomonadina Anabolic products starch or similar carbohydrates Order 2 Cryptomonadina (p. 213) Chromatophores green Anabolic products starch and oil. Order 3 Phytomonadina (p. 217) Anabolic products paramylon Order 4 Euglenoidina (p. 232) Anabolic products oil Order 5 Chloromonadina (p. 243) 2 flagella, one of which transverse Order 6 Dinoflagellata (p. 245) Order 1 Chrysomonadina Stein The chrysomonads are minute organisms and are plastic, since the majority lack a definite cell-wall. Chromatophores are yellow to brown and usually discoid, though sometimes reticulated, in form. Metabolic products are leucosin and fats. Starches have not been found in them. 1-2 flagella are inserted at or near the anterior end of body where a stigma is present. Many chrysomonads are able to form pseudopodia for obtaining food materials which vary among different species. Nutrition, though chiefly holophytic, is also holozoic or saprozoic. Contractile vacuoles are invariably found in freshwater forms, and are ordinarily of simple structure. Under conditions not fully understood, the chrysomonads lose their flagella and undergo division with development of mucilaginous envelope and thus transform themselves often into large bodies known as the palmella phase and undertake metabolic activities as well as multiplication (Fig. 88). Asexual reproduction is, as a rule, by longitudinal division during either the motile or the palmella MASTIGOPHORA, CHRYSOMONADINA 201 stage. Incomplete separation of the daughter individuals followed by repeated fission, results in numerous colonial forms mentioned elsewhere (p. 146). Some resemble higher algae very closely. Sexual (^^ Fig. 88. The life-cycle of Chromulina, X about 200 (Kiihn). a, encyst- ment; b, fission; c, colony-formation; d, palmella-formation. reproduction is unknown in this group. Encystment occurs com- monly ; in this the fiagellum is lost and the cyst is often enveloped by a silicious wall possessing an opening with a plug. The chrysomonads inhabit both fresh and salt waters, often occur- ring abundantly in plankton. Motile stage dominant Suborder 1 Euchrysomonadina Palmella stage dominant Sarcodina-like; flagellate stage unknown Suborder 2 Rhizochrysidina (p. 209) With flagellate phase Suborder 3 Chrysocapsina (p. 210) Suborder 1 Euchrysomonadina Pascher With or without simple shell One flagellum Family 1 Chromulinidae 2 flagella Flagella equally long Family 2 Syncryptidae (p. 205) Flagella unequally long Family 3 Ochromonadidae (p. 206) With calcareous or silicious shell Bearing calcareous discs and rods. . . .Family 4 Coccolithidae (p. 208) Bearing silicious skeleton. Family 5 Silicoflagellidae (p. 209) Family 1 Chromulinidae Engler Minute forms, naked or with sculptured shell; with a single flagel- lum; often with rhizopodia; a few colonial; free-swimming or at- tached. 202 PROTOZOOLOGY Genus Chromulina Cienkowski. Oval; round in cross-section; amoeboid; 1-2 chromatophores ; palmella stage often large; in fresh water. Numerous species. The presence of a large number of these organisms gives a golden-brown color to the surface of the water. Fig. 89. a, b, Chromulina pascheri, X670 (Hofeneder); c, Chrysapsis sagene, XlOOO (Pascher); d, Chrysococcus ornatus, X600 (Pascher); e, Mallomonas litomosa, X400 (Stokes); f, Pyramidochrysis modesta, X670 (Pascher); g, Sphalero mantis ochracea, X600 (Pascher); h, Kephyrion ovum, X1600 (Pascher); i, Chrysopyxis cyathus, X600 (Pascher); j, Gyrtophora pedicellata, X400 (Pascher); k, Palaiinella cyrtophora, X400 (Lauterborn);!, Chrysosphaerellalongispina, X600 (Lauterborn). MASTIGOPHORA, CHRYSOMONADINA 203 C. pascheri Hofeneder (Fig. 89, a, b). 15-20)Lt in diameter. Genus Chrysamoeba Klebs. Body naked; flagellate stage ovoid, with 2 chromatophores, sometimes slender pseudopodia at the same time; flagellum may be lost and the organism becomes amoeboid, resembling Rhizochrysis (p. 210); standing fresh water. C. radians K. (Fig. 90, a, b). Flagellated form 16-20^ long; amoe- boid stage about 15/x with 10-20^ long radiating pseudopodia; fresh water. Genus Chrysapsis Pascher. Solitary; plastic or rigid; chromato- phore diffused or branching; with stigma; amoeboid movement; holophytic, holozoic; fresh water. Several species. C. sagene P. (Fig. 89, c). Anterior region actively plastic; stigma small; 8-14/n long; flagellum about SO/x long. Genus Chrysococcus Klebs. Shell spheroidal or ovoidal, smooth or sculptured and often brown-colored; through an opening a flagel- lum protrudes; 1-2 chromatophores; one of the daughter individuals formed by binary fission leaves the parent shell and forms a new one; fresh water. C. ornatus Pascher (Fig. 89, d). 14-16^ by 7-10m. Genus Mallomonas Perty (Pseudomallomonas Chodat). Body elongated; with silicious scales and often spines; 2 chromatophores rod-shaped; fresh water. Numerous species. M. litomosa Stokes (Fig. 89, e). Scales very delicate, needle-like projections at both ends; flagellum as long as body; 24-32^ by 8/x. Genus Pyramidochrysis Pascher. Body form constant; pyriform with 3 longitudinal ridges; flagellate end drawn out; a single chro- matophore; 2 contractile vacuoles; fresh water. P. modesta P. (Fig. 89,/). 11-13^ long. Genus Sphaleromantis Pascher. Triangular or heart-shaped; highly flattened; slightly plastic; 2 chromatophores; 2 contractile vacuoles; stigma large; long flagellum; fresh water. S. ochracea P. (Fig. 89, g). 6-13^ long. Genus Kephyrion Pascher. With oval or fusiform lorica; body fills posterior half of lorica; one chromatophore; a single short flagellum; small; fresh water. K. ovum P. (Fig. 89, h). Lorica up to 7n by 4^. Genus Chrysopyxis Stein. With lorica of various forms, more or less flattened; 1-2 chromatophores; a flagellum; attached to algae in fresh water. C. cyathus Pascher (Fig. 89, i). One chromatophore; flagellum twice body length; lorica 20-25^ by 12-15/x. Genus Cyrtophora Pascher. Body inverted pyramid with 6-8 204 PROTOZOOLOGY axopodia and a single flagellum; with a contractile stalk; a single chromatophore ; a contractile vacuole; fresh water. C. pedicellata P. (Fig. 89, j). Body 18-22^ long; axopodia 40-60m long ; stalk 50-80^ long. Genus Palatinella Lauterborn. Lorica tubular; body heartshaped; Fig. 90. a, flagellate and b, amoeboid phase of Chrysamoeba radians, X670 (Klebs); c, surface view and d, optical section of Porochrysis asper- gillus, X400 (Pascher); e-j, Myxochrysis paradoxa (Pascher). e, a medium large Plasmodium with characteristic envelop; the large food vacuole contains protophytan, Scenedesmus, X830; f, diagrammatic side view of a Plasmodium, engulfing a diatom; moniliform bodies are yellowish chromatophores, XlOOO; g-i, development of swarmer into Plasmodium (stippled bodies are chromatophores), X1200. anterior border with 16-20 axopodia; a single flagellum; a chromato- phore; several contractile vacuoles'; fresh water. P. cyrtophora L. (Fig. 89, k). Lorica 80-1 50/i long; body 20-25^ by 18-25/i; axopodia 50)u long. Genus Chrysosphaerella Lauterborn. In spherical colony, indivi- dual cell, oval or pyriform, with 2 chromatophores; imbedded in gelatinous mass ; fresh water. C. longispina L. (Fig. 89, I). Individuals up to 15/i by 9//; colony up to 250m in diameter; in standing water rich in vegetation. Genus Porochrysis Pascher. Shell with several pores through which rhizopodia are extended; a flagellum passes through an apical MASTIGOPHORA, CHRYSOMONADINA 205 pore; a single small chromatoi^hore; leucosin grain, contractile vacuole; fresh water. P. aspergillus P. (Fig. 90, c, d). Shell about 35/i long by 25m wide; chromatophore very small ; a large leucosin grain ; fresh water. Genus Myxochrysis Pascher. Body multinucleate, amoeboid; with yellowish moniliform chromatophores, many leucosin granules and contractile vacuoles; holozoic; surrounded by a brownish envelop which conforms with body form; flagellated swarmers develop into multinucleate Plasmodium; i)lasmotomy and plasmogamy; fresh water. M. paradoxa P. (Fig. 90, e-j). Plasmodium 15-18/i or more in diameter; in standing water. Family 2 Syncryptidae Poche Solitary or colonial chrysomonads with 2 equal flagella; with or without pellicle (when {)resent, often sculptured) ; some possess stalk. Genus Syncrypta Ehrcnbcrg. Spherical colonies; individuals with 2 lateral chromatophores, embedded in a gelatinous mass; 2 con- tractile vacuoles; without stigma; cysts unknown; fresh water. S. volvox E. (Fig. 91, a). 8-14^ by7-12M; colony 20-70ai in diam- eter; in standing water. Genus Synura Ehrenberg. Spherical or ellipsoidal colony com- posed of 2-50 ovoid individuals arranged radially; body usually covered by short bristles; 2 chromatophores lateral; no stigma; asexual reproduction of individuals is by longitudinal division ; that of colony by bipartition ; cysts spherical ; fresh water. S. uvella E. (Fig. 91, 6). Cells oval; bristles conspicuous; 20-40)u by 8-17/x; colony 100-400^ in diameter; if present in large numbers, the organism is said to be responsible for an odor of the water re- seml)ling that of ripe cucumber (Moore). aS. adamsi Smith (Fig. 91, c). Spherical colony with individuals radiating; individuals long spindle, 42-47^ by 6.5-7m; 2 flagella up to 17ai long; in fresh water i)ond. Genus Hymenomonas Stein. Solitary; ellipsoid to cylindrical; membrane brownish, often sculptured; 2 chromatophores; without stigma; a contractile vacuole anterior; fresh water. H. roseola S. (Fig. 91, d). 17-50m by 10-20^. Genus Derepyxis Stokes. With cellulose lorica, with or without a short stalk; body ellipsoid to spherical with 1-2 chromatophores; 2 equal flagella; fresh water. D. amphora S. (Fig. 91, c). Lorica 25-30m by 9-18^; on algae in standing water. 206 PROTOZOOLOGY D. ollula S. (Fig. 91,/). Lorica 20-25^ by 15^. Genus Stylochrysallis Stein. Body fusiform; with a gelatinous stalk attached to Volvocidae; 2 equal fiagella; 2 chromatophores; without stigma; fresh water. S. parasita S. (Fig. 91, g). Body 9-1 l^u long; stalk about 15/x long; on phytomonads. Fig. 91. a, Syncrypta volvox, X430 (Stein); b, Synura uvella, X500 (Stein); c, S. admnsi, X280 (Smith); d, Hymenomonas roseola, X400 (Klebs); e, Derepyxis amphora, X540 (Stokes); f, D. ollula, X600 (Stokes); g, Stylochrysallis parasitica, X430 (Stein). Family 3 Ochromonadidae Pascher With 2 unequal fiagella ; no pellicle and plastic ; contractile vacu- oles simple; with or without a delicate test; solitary or colonial; free-swimming or attached. Genus Ochromonas W3^ssotzki. Solitary or colonial; body surface delicate; posterior end often drawn out for attachment; 1-2 chro- matophores; usually with a stigma; encystment; fresh water. Many species. 0. muiahilis Klebs (Fig. 92, a). Ovoid to spherical; plastic, 15-30m by 8-22/i. 0. ludibunda Pascher (Fig. 92, b). Not plastic; 12-17m by 6-12^. Genus Uroglena Ehrenberg. Spherical or ovoidal colony, com- posed of ovoid or ellipsoidal individuals arranged on periphery of a MASTIGOPHORA, CHRYSOMONADINA 207 gelatinous mass; all individuals connected with one another by gelatinous processes running inward and meeting at a point; with a stigma and a plate-like chromatophore; asexual reproduction of Fig. 92. a, Ochromonas mutabilis, X670 (Senn); b, 0. ludihunda, X540 (Pascher); c, Uroglena volvox, X430 (Stein); d, Uroglenopsis americana, X470 (Lemmermann) ; e, Cyclonexis annularis, X540 (Stokes); f, Dino- bryon sertularia, X670 (Scherffel) ; g, Hyalohryonramosum, X540 (Lauter- born); h, Stylopyxis nmcicola, X470 (Bolochonzew). individuals by longitudinal fission, that of colony by bipartition; cysts spherical with spinous projections, and a long tubular process; fresh water. One species. U. volvox E. (Fig. 92, c). Cells 12-20m by 8-13m; colony 40-400/* in diameter; in standing water. Genus Uroglenopsis Lemmermann. Similar to Uroglena, but individuals without inner connecting processes. U. americana (Calkins) (Fig. 92, d). Each cell with one chro- matophore; 5-8^ long; fiagellum up to 32/i long; colony up to 300^ 208 PROTOZOOLOGY in diameter; when present in abundance, the organism gives an of- fensive odor to the water (Calkins). U. europaea Pascher. Similar to the last-named species; but chromatophores 2; cells up to 7/i long; colony 150-300^ in diameter. Genus Cyclonexis Stokes. Wheel-like colony, composed of 10-20 wedge-shaped individuals; young colony funnel-shaped; chromato- phores 2, lateral; no stigma; reproduction and encystment unknown; fresh water. C. annularis S. (Fig. 92, e). Cells 11-14^ long; colony 25-30^ in diameter; in marshy water with sphagnum. Genus Dinobryon Ehrenberg. Solitary or colonial; individuals with vase-like, hyaline, but sometimes, yellowish cellulose test, drawn out at its base; elongated and attached to the base of test with its attenuated posterior tip; 1-2 lateral chromatophores; usually with a stigma; asexual reproduction by binary fission; one of the daughter individuals leaving test as a swarmer, to form a new one; in colonial forms daughter individuals remain attached to the inner margin of aperture of parent tests and there secrete new tests; encystment common; the spherical cysts possess a short process; Ahlstrom (1937) studied variability of North American species and found the organisms occur more commonly in alkaline regions than elsewhere; fresh water. Numerous species. D. sertularia E. (Fig. 92,/). 30-44^ by 10-14^. D. divergens Imhof. 31-53)U long; great variation in different lo- calities (Ahlstrom). Genus Hyalobryon Lauterborn. Solitary or colonial; individual body structure similar to that of Dinobryon; lorica in some cases tubular, and those of 'young individuals are attached to the exterior of parent tests; fresh water. H. ramosum L. (Fig. 92, g). Lorica 50-70iu long by 5-9iu in diame- ter; body up to 30m by 5ix; on vegetation in standing fresh water. Genus Stylopyxis Bolochonzew. Solitary; body located at bottom of a delicate stalked lorica with a wide aperture; 2 lateral chromato- phores; fresh water. S. mucicola B. (Fig. 92, h). Lorica 17-18m long; stalk about 33/^ long; body 9-1 Iju long: fresh water. Family 4 Coccolithidae Lohmann The members of this family occur, with a few exceptions, in salt water only; with perforate (tremalith) or imperforate (discolith) discs, composed of calcium carbonate; 1-2 flagella; 2 yellowish MASTIGOPHORA, CHRYSOMONADINA 209 chromatophores ; a single nucleus; oil drops and leucosin; holophytic. Examples : Pontosphaera haeckeli Lohmann (Fig. 93, a). , Discosphaera tubifer Murray and Blackman (Fig. 93, h). Family 5 Silicoflagellidae Borgert Exclusively marine planktons; with siliceous skeleton which en- velops the body. Example: Distephanus speculum (Miiller) (Fig. 93, c). Fig. 93. a, Pontosphaera haeckeli, X1070 (Kiihn); b, Discosphaera tubi- fer, X670 (Klihn); c, Distephanus speculum, X530 (Kiihn); d, Rhizo- chrijsis scherffeli, X670 (Doflein); e-g, Hydrurus foetidus (e, entire colony; f, portion; g, cyst), e (Berthold), f, X330, g, X800 (Klebs); h, i, Chrysocapsa paludosa, X530 (West); j, k, Phaeosphaera gelatinosa (j, part of a mass, X70; k, three cells, X330) (West). Suborder 2 Rhizochrysidina Pascher No flagellate stage is known to occur; the organism possesses pseu- dopodia; highly provisional group, based wholly upon the absence of flagella; naked or with test; various forms; in some species chroma- 210 PROTOZOOLOGY tophores are entirely lacking, so that the organisms resemble some members of the Sarcodina. Several genera. Genus Rhizochrysis Pascher. Body naked and amoeboid; with 1-2 chromatophores : fresh water. R. scherffeli P. (Figs. 93, d; 94, a, h). 10-14/i in diameter; 1-2 chromatophores : branching rhizopods ; fresh water. Genus Chrysidiastrum Lauterborn. Naked; spherical; often sev- eral in linear association by pseudopodia; one j^ellow-brown chro- matophore; fresh water. C. catenaium L. Cells 12-14)u in diameter. Genus Chrysarachnion Pascher. Ameboid organism; with a chro- matophore, leucosin grain and contractile vacuole; many individuals arranged in a plane and connected by extremely fine rhizopods, the whole forming a cobweb network. Small animals are trapped by the net; chromatophores are small; nutrition both holophytic and holo- zoic; during division the chromatophore is often unevenly distrib- uted so that many individuals without any chromatophore are produced; fresh water. C. insidians P. (Fig. 94, c, d). Highly amoeboid individuals 3-4^ in diameter; chromatophore pale yellowish brown, but becomes blu- ish green upon death of organisms; a leucosin grain and a contractile vacuole; colony made up of 200 or more individuals. Genus Chrysothylakion Pascher. With retort-shaped calcareous shell with a bent neck and an opening; shell reddish brown (with iron) in old individuals ; through the aperture are extruded extremely fine anastomosing rhizopods; protoplasm which fills the shell is colorless; a single nucleus, two spindle-form brown chromatophores, several contractile vacuoles and leucosin body; marine water. C. vorax P. (Fig. 94, e,f). The shell measures 14-18/x long, 7-10/x broad, and 5-6/x high; on marine algae. Suborder 3 Chrysocapsina Pascher Palmella stage prominent; flagellate forms transient; colonial; individuals enclosed in a gelatinous mass; 1-2 flagella, one chromato- phore, and a contractile vacuole; one group of relatively minute forms and the other of large organisms. Genus Hydrurus Agardh. In a large (1-30 cm. long) branching gelatinous cylindrical mass; cells yellowish brown; spherical to ellipsoidal; with a chromatophore; individuals arranged loosely in gelatinous matrix; apical growth resembles much higher algae; mul- tiplication of individuals results in formation of pyrimidal forms MASTIGOPHORA, CHRYSOMONADINA 211 with a flagellum, a chromatophore, and a leucosin mass; cyst may show a wing-like rim; cold freshwater streams. Fig. 94. a, b, Rhizochrysis scherffeli, X500 (Scherffel). a, 4 chroma- tophore-bearmg individuals and an individual without chromatophore- b, the last-mentioned individual after 7 hours, c, d, Chrysarachnion insi- dians (Pascher). c, part of a colony composed of individuals with and without chromatophore, X1270; d, products of division, one individual lacks chromatophore, but with a leucosin body, X2530. e, f, Chrysothy- lakion vorax (Pascher). e, an individual with anastomosing rhizopodia and excretion granules," X870; f, optical section of an individual; the cyto- plasm contains two fusiform brownish chromatophores, a spheroid nucleus, a large leucosin body and contractile vacuole, X about 1200. 212 PROTOZOOLOGY H. foetidus Kirschner (Figs. 31, d-f; 93, e-g). Olive-green, feath- ery tufts, 1-30 cm. long, develops an offensive odor; sticky to touch; occasionally encrusted with calcium carbonate; in running fresh water. Genus Chrysocapsa Pascher. In a spherical to ellipsoidal gelati- nous mass; cells spherical to ellipsoid; 1-2 chromatophores; wither without stigma; freshwater. C. paludosa P. (Fig. 93, h, i). Spherical or ellipsoidal with cells distributed without order; with a stigma; 2 chromatophores; swarmer pyriform with 2 flagella; cells 11^ long; colony up to lOO/x in diameter. Genus Phaeosphaera West and West. In a simple or branching cylindrical gelatinous mass; cells spherical with a single chroma- tophore ; fresh water. P. gelatinosa W. and W. (Fig. 93, j, k). Cells 14-17. 5^ in diameter. References BtJTSCHLi, O. 1883-1887 Mastigophora. In: Bronn's Klassen und Ordnungen des Thierreichs. Vol. 1, part 2. DoFLEiN, F. and E. Reichenow. 1929 Lehrhuch der Protozoen- kunde. Jena. Kent, S. 1880-1882 A manual of Infusoria. London. Pascher, A. 1914 Flagellatae: Allgemeiner Teil. In: Die Siisswas- serflora Deutschlands. Part 1. Stein, F. 1878, 1883 Der Organismus der Infusionsthiere. 3 Abt. Der Organismus der Flagellate oder Geisselinfusorien. Parts 1 and 2. Leipzig. Ahlstrom, E. H. 1937 Studies on variability in the genus Dino- bryon (Mastigophora). Trans. Amer. Micr. Soc, Vol. 56. Fritsch, F. E. 1935 The structure and reproduction of the algae. Cambridge. Pascher, A. 1916 Studien iiber die rhizopodiale Entwicklung der Flagellaten. Arch. f. Protistenk., Vol. 36. 1917 Rhizopodialnetz als Fangvorrichtung bei einer plas- modialen Chxysomonade. Ibid., Vol. 37. 1917 Fusionsplasmodien bei Flagellaten und ihre Bedeut- ung fiir die Ableitung der Rhizopoden von den Flagellaten. Ibid. 1917 Flagellaten und Rhizopoden in ihren gegenseitigen Beziehungen. Ibid., Vol. 38. Scherffel, a. 1901 Kleiner Beitrag zur Phylogenie einiger Grup- pen niederer Organismen. Bot. Zeit., Vol. 59. Smith, G. M. 1933 The freshwater algae of the United States. New York. West, G. S. and F. E. Fritsch 1927 A treatise on the British fresh- water algae. Cambridge. Chapter 9 Order 2 Cryptomonadina Stein THE cryptomonads differ from the chrysomonads in having a constant body form. Pseudopodia are very rarely formed, as the body is covered by a pelHcle. The majority show dorso-ventral differentiation, with an oblique longitudinal furrow. 1-2 unequal flagella arise from the furrow or from the cytopharynx. In case 2 flagella are present, both may be directed anteriorly or one poster- iorly. These organisms are free-swimming or creeping. One or two chromatophores are usually present. They are discoid or band-form. The color of chromatophores varies: yellow, brown, red, olive-green. The nature of the pigment is not well understood, but it is said to be similar to that which is found in the Dinofiagel- lata (Pascher). One or more spherical pyrenoids which are enclosed within a starch envelope appear to occur outside the chromato- phores. Nutrition is mostly holophytic; a few are saprozoic or holo- zoic. Assimilation products are solid discoid carbohydrates which stain blue with iodine in Cryptomonas or which stain reddish violet by iodine as in Cryptochrysis; fat and starch are produced in holo- zoic forms which feed upon bacteria and small Protozoa. The stigma is usually associated with the insertion point of the flagella. Con- tractile vacuoles, one to several, are simple and are situated near the cj^topharynx. A single vesicular nucleus is ordinarily located near the middle of the body. Asexual reproduction, by longitudinal fission, takes place in either the active or the non-motile stage. Sexual reproduction is un- known. Some cryptomonads form palmella stage and others gelati- nous aggregates. In the suborder Phaeocapsina, the palmella stage is permanent. Cysts are spherical, and the cyst wall is composed of cellulose. The Cryptomonadina occur in fresh or sea water, living also often as symbionts in marine organisms. Flagellate forms predominant Suborder 1 Eucryptomonadina Palmella stage permanent Suborder 2 Phaeocapsina (p. 216) Suborder 1 Eucryptomonadina Pascher Truncate anteriorly; 2 anterior flagella; with an oblique furrow near anterior end Family 1 Oryptomonadidae (p. 214) Reniform; with 2 lateral flagella; furrow equatorial Family 2 Nephroselmidae (p. 215) 213 214 PROTOZOOLOGY Family 1 Cryptomonadidae Stein Genus Cryptomonas Ehrenberg. Body elliptical with a firm pel- licle; anterior end truncate; dorsal side convex, ventral side slightly so or flat; nucleus posterior; longitudinal furrow; tubular cavity extending to the middle of body, through which equally long flagella arise; 2 lateral chromatophores vary in color from green to blue- green, brown or rarely red; holophytic; with small starch-like bodies Fig. 95. a, Cryptomonas ovata, X800 (Pascher); b, Chilomonas Para- mecium, X1330 (Biitschli); c, d, ChrysideUa schaiidinni, X1330 (Winter); e, Cyathomonas truncata, X670 (Ulehla); f, Cryptochrysis commutata, X 670 (Pascher); g, Rhodomonas lens, X1330 (Ruttner); h, Nephroselmis olvacea, X670 (Pascher); i, Protochrysis phaeophycearum, X800 (Pascher); j, k, Phaeothamnion confer vicoluvi, X600 (Kiihn). which stain blue in iodine; 1-3 contractile vacuoles anterior; fresh water. Several species. C. ovata E. (Fig. 95, a). 20-30/x long; among vegetation. Genus Chilomonas Ehrenberg. Similar to Cryptomonas in general body form and structure, but colorless because of the absence of chromatophores; without pyrenoid; cytopharynx deep, lower half marked by "rudimentary trichocysts" ; 1-2 contractile vacuoles, anterior; nucleus in posterior half; endoplasm often filled with poly- gonal starch grains ; fresh water. C. Paramecium E. (Fig. 95, h). Posterior end narrowed, slightly bent "dorsally"; 20-40^^ long; saprozoic; widely distributed in stag- nant water and hay infusion. CRYPTOMONADINA 215 C. ohlonga Pascher. Oblong; posterior end broadly rounded; 20- 50/1 long. Genus Chrysidella Pascher. Somewhat similar to Cryptomonas, but much smaller; yellow chromatophores much shorter; those oc- curring in Foraminifera or Radiolaria as symbionts are known as Zooxanthellae. Several species. C. schaudinni (Winter) (Fig. 95, c, d). Body less than 10/x long; in the f oraminiferan Peneroplis pertusus. Genus Cyathomonas Fromentel. Body small, somewhat oval; without chromatophores; much flattened; anterior end obliquely truncate; with 2 equal or subequal anterior flagella; colorless; nu- cleus central; anabolic products, stained red or reddish violet by iodine; contractile vacuole usually anterior; a row of refractile granules, protrichocysts (p. 65), close and parallel to anterior margin of body; asexual reproduction by longitudinal fission; holozoic; in stagnant water and infusion. One species. C. truncata Ehrenberg (Fig. 95, e). 15-30iu long. Genus Cryptochrysis Pascher. Furrow indistinctly granulated; 2 or more chromatophores brownish, olive-green, or dark green, rarely red; pyrenoid central; 2 equal flagella; some lose flagella and may assume amoeboid form; fresh water. C. commutata P. (Fig. 95, /). Bean-shaped; 2 chromatophores; 19m by 10m. Genus Rhodomonas Karsten. Furrow granulated; chromatophore one, red (upon degeneration the coloring matter becomes dissolved in water) ; pyrenoid central ; fresh water. R. lens Pascher and Ruttner (Fig. 95, g). Spindle-form; about 16m long; in fresh water. Family 2 Nephroselmidae Pascher Body reniform; with lateral equatorial furrow; 2 flagella arising from furrow, one directed anteriorly and the other posteriorly. Genus Nephroselmis Stein. Reniform; flattened; furrow and c3^topharynx distinct; no stigma; 1-2 chromatophores, discoid, brownish green; nucleus dorsal; a central pyrenoid; 2 contractile vacuoles; with reddish globules; fresh water. N. olvacea S. (Fig. 95, h). 20-25m by 15m. Genus Protochrysis Pascher. Reniform; not flattened; with a dis- tinct furrow, but without cytopharynx; a stigma at base of flagella; 1-2 chromatophores, brownish yellow; p3^renoid central; 2 contrac- tile vacuoles; fission seems to take place during the resting stage; fresh water. 216 PROTOZOOLOGY P. phaeophycearum P. (Fig. 95, i). 15-17)u by 7-9 fi. Suborder 2 Phaeocapsina Pascher Palmella stage predominant; perhaps border-line forms between brown algae and cryptomonads. Example: Phaeothamnion confer- vicolum Lagerheim (Fig. 95, j, k) which is less than 10/z long. References Feitsch, F. E. 1935 The structure and reproduction of the algae. Cambridge. Pascher, A. 1913 Cryptomonadinae. Susswasserflora Deutschlands, etc. part 2. Jena. West, G. S, and F. E. Fritsch. 1927 A treatise on the British _ water algae. Cambridge. Chapter 10 Order 3 Phytomonadina Blochmann THE phytomonads are small, more or less rounded, green flagel- lates, with a close resemblance to the algae. They show a definite body form, and most of them possess a cellulose membrane, which is thick in some and thin in others. There is a distinct opening in the membrane at the anterior end, through which 1-2 (or seldom 4 or more) flagella protrude. The majority possess numerous grass-green chromatophores, each of which contains one or more pyrenoids. The method of nutrition is mostly holophytic or mixotrophic; some color- less forms are, however, saprozoic. The metabolic products are usually starch and oils. Some phytomonads are stained red, owing to the presence of haematochrome. The contractile vacuoles may be located in the anterior part or scattered throughout the body. The nucleus is ordinarily centrally located, and its division seems to be mitotic, chromosomes having been definitely noted in several species. Asexual reproduction is by longitudinal fission, and the daughter individuals remain within the parent membrane for some time. Sexual reproduction seems to occur widely. Colony formation also occurs, especially in the family Volvocidae. Encystment and forma- tion of the palmella stage are common among many forms. The phytomonads have a much wider distribution in fresh than in salt water. Solitary Membrane a single piece; rarely indistinct 2 flagella Family 1 Chlamydomonadidae 3 flagella Family 2 Trichlorididae (p. 222) 4 flagella Family 3 Carteriidae (p. 222) 5 flagella. Family 4 Chlorasteridae (p. 224) 6 or more flagella Family 5 Polyblepharididae (p. 224) Membrane bivalve Family 6 Phacotidae (p. 225) Colonial, of 4 or more individuals; 2 (1 or 4) flagella Family 7 Volvocidae (p. 225) Family 1 Chlamydomonadidae Butschli Solitary; spheroid, oval, or ellipsoid; with a cellulose membrane; 2 flagella; chromatophores, stigma, and pyrenoids usually present. Genus Chlamydomonas Ehrenberg. Spherical, ovoid or elongated; sometimes flattened; 2 flagella; membrane often thickened at an- terior end; a large chromatophore, containing one or more pyrenoids; stigma; a single nucleus; 2 contractile vacuoles anterior; asexual 217 218 PROTOZOOLOGY reproduction and palmella formation known; sexual reproduction isogamy or anisogamy ; fresh water. Numerous species. C. monadina Stein (Fig. 96, a-c). 15-30/x long; fresh water; Landacre noted that the organisms obstructed the sand filters used in connection with a septic tank, together with the diatom Navicula. C. angulosa Dill. About 20/i by 12-15^; fresh water. C. epiphytica Smith (Fig. 96, d). 8-9fi by 7-8m; in freshwater lakes. C. globosa Snow (Fig. 96, e). Spheroid or ellipsoid; 5-7/x in dia- meter; in freshwater lakes. C. gracilis S. (Fig. 96,/). 10-13m by 5-7/x; fresh water. Genus Haematococcus Agardh (Sphaerella Sommerfeldt). Sphe- roidal or ovoid with a gelatinous envelope; chromatophore peripheral and reticulate, with 2-8 scattered pyrenoids; several contractile vacuoles; haematochrome frequently abundant in both motile and encysted stages; asexual reproduction in motile form; sexual repro- duction isogamy ; fresh water. H. pluvialis (Flotow) (Figs. 40; 96, g). Spherical; with numerous radial cytoplasmic processes ; chromatophore U-shape in optical sec- tion; body 8-50/1, stigma fusiform, lateral; fresh water. Reichenow (1909) noticed the disappearance of haematochrome if the culture medium was rich in nitrogen and phosphorus. In bacteria-free cul- tures, Elliott (1934) observed 4 types of cells: large and small flagel- lates, palmella stage and haematocysts. Large flagellates predominate in liquid cultures, but when conditions become unfavorable, palmella stage and then haematocysts develop. When the cysts are placed in a favorable environment after exposure to freezing, desiccation, etc., they give rise to small flagellates which grow into palmella stage or large flagellates. No syngamy of small flagellates was noticed. Hae- matochrome appears during certain phases in sunlight and its ap- pearance is accelerated by sodium acetate under sunlight. Genus Sphaerellopsis Korschikoff (Chlamydococcus Stein). With gelatinous envelope which is usually ellipsoid with rounded ends; body elongate fusiform or pyriform, no protoplasmic processes to envelope; 2 equally long flagella; chromatophore large; a pyrenoid; with or without stigma; nucleus in anterior half; 2 contractile vacu- oles; fresh water. S. fluviaiilis (Stein) (Fig. 96, h). 14-30m by 10-20m; fresh water. Genus Brachiomonas Bohlin. Lobate; with horn-like processes, all directed posteriorly; contractile vacuoles; ill-defined chromato- phore; pyrenoids; with or without stigma; sexual and asexual re- production ; fresh, brackish or salt water. PHYTOMONADINA 219 Fig. 96. a-c, Chlamydomonas monadina, X470 (Goroschankin) ; d, C. epiphytica, X1030 (Smith); e, C. globosa, X2000 (Snow); f, C. gracilis, X770 (Snow); g, Haematococcus pluvialis, X500 (Reichenow); h. Sphaerel- lopsis fluviatilis, X490 (Korschikoff) ; i, Brachiomonas wesliana X960 (West); j, Lobomonas rostrata, X1335 (Hazen); k, Diplostauron penta- gonium, XlllO (Hazen); 1, Gigantochloris permaxima, X370 (Pascher); m, Gloeomonas ovalis, X330 (Pascher); n, Scourfieldia complanata, X1540 (West); o, Thorakomonas sabulosa, X670 (Korschikoff). B. wesliana Pascher (Fig. 96, i). 15-24/i by 13-23)u; brackish water. Genus Lobomonas Dangeard. Ovoid or irregularly angular; chro- matophore cup-shaped; pyrenoid; stigma; a contractile vacuole; fresh water. 220 PROTOZOOLOGY L. rostrata Hazen (Fig. 96, j). 5-1 2^ by 4-8^. Genus Diplostauron Korschikoff. Rectangular with raised cor- ners; 2 equally long fiagella; chromatophore; one pyrenoid; stigma; 2 contractile vacuoles anterior; fresh water. D. pentagonium (Hazen) (Fig. 96, k). lO-lSju by 9-lOAt. Genus Gigantochloris Pascher. Unusually large form, equalling in size a colony of Eudorina; flattened; oval in front view; elongate ellipsoid in profile; membrane radially striated; 2 fiagella widely apart, less than body length; chromatophore in network; numerous pyrenoids; often without stigma; in woodland pools. G. permaxima P. (Fig. 96, 1). 70-150m by 40-80m by 25-50/x. Genus Gloeomonas Klebs. Broadly ovoid, nearly subspherical; with a delicate membrane and a thin gelatinous envelope ; 2 fiagella widely apart; chromatophores numerous, circular or oval discs; pyrenoids (?); stigma; 2 contractile vacuoles anterior; freshwater. G. ovalis K. (Fig. 96, m). 38-42/^ by 23-33/1 ; gelatinous envelope over 2/t thick. Genus Scourfieldia West. Whole body flattened; ovoid in front view; membrane delicate; 2 fiagella 2-5 times body length; a chro- matophore; without pyrenoid or stigma; contractile vacuole anter- ior; nucleus central; fresh water. S. compla7iata W . (Fig. 96, n). 5.2-5.7/iby 4.4-4.6^; freshwater. Genus Thorakomonas Korschikoff. Flattened; somewhat irregu- larly shaped or ellipsoid in front view; membrane thick, enclustered with iron-bearing material, deep brown to black in color; proto- plasmic body similar to that of Chlamydomonas; a chromatophore with a pyrenoid; 2 contractile vacuoles; standing fresh water. T. sahulosa K. (Fig. 96, o). Up to 16m by 14m. Genus Coccomonas Stein. Shell smooth; globular; body not filling intracapsular space; stigma; contractile vacuole; asexual reproduc- tion into 4 individuals ; fresh water. C. orbicularis S. (Fig. 97, a). 18-25^ in diameter; fresh water. Genus Chlorogonium Ehrenberg. Fusiform; membrane thin and adheres closely to protoplasmic body; plate-like chromatophores usually present, sometimes ill-contoured; one or more pyrenoids; numerous scattered contractile vacuoles; usually a stigma; a central nucleus; asexual reproduction by 2 successive transverse fissions during the motile phase; isogamy reported; fresh water. C. euchlorum E. (Fig. 97, 6). 25-7 Om by 4-1 5m; in stagnant water. Genus Phyllomonas Korschikoff. Extremely flattened ; membrane delicate; 2 fiagella; chromatophore often faded or indistinct; numer- ous pyrenoids; with or without stigma; many contractile vacuoles; fresh water. PHYTOMONADINA 221 P. phacoides K. (Fig. 97, c). Leaf -like; rotation movement; up to IOOm long; in standing fresh water. Genus Sphaenochloris Pascher. Body truncate or concave at flagel- late end in front view; sharply pointed in profile; 2 flagella widely apart; chromatophore large; pyrenoid; stigma; contractile vacuole anterior; fresh water. S. printzi P. (Fig. 97, d). Up to 18m by 9/x. Genus Korschikoffia Pascher. Elongate pyriform with an undu- lating outline; anterior end narrow, posterior end more bluntly Fig. 97. a, Coccomonas orbicularis, X500 (Stein); b, Chlorogonium euchlorum, X430 (Jacobsen); c, Phyllomonas -phacoides, X200 (Kor- schikoff); d, Sphaenochloris printzi, X600 (Printz); e, Korschikoffia guttula, X1670 (Pascher); f, Furcilla lobosa, X670 (Stokes); g, Hyalo- gonium klebsi, X470 (Klebs); h, Polytoma uvella, X670 (Dangeard); i, Parapolytoma satura, X1600 (Jameson); j, Trichloris paradoxa, X990 (Pascher). rounded; plastic; chromatophores in posterior half; stigma absent; contractile vacuole anterior; 2 equally long flagella; nucleus nearly central ; salt water. K. guttula P. (Fig. 97, e). 6-1 0/z by 5m ; brackish water. Genus Furcilla Stokes. U-shape, with 2 posterior processes; in side view somewhat flattened ; anterior end with a papilla ; 2 flagella equally long; 1-2 contractile vacuoles anterior; oil droplets; fresh water. F. lobosa S. (Fig. 97,/). 11-14^ long; fresh water. Genus Hyalogonium Pascher. Elongate spindle-form; anterior end bluntly rounded; posterior end more pointed; 2 flagella; protoplasm 222 PROTOZOOLOGY colorless; with starch granules; a stigma; asexual reproduction re- sults in up to 8 daughter cells ; fresh water. H. klebsi P. (Fig. 97, g). 30-80m by up to 10m; stagnant water. Genus Polytoma Ehrenberg (Chlamydohlepharis France; Tussetia Pascher). Ovoid; no chromatophores ; membrane yellowish to brown; pyrenoid unobserved; 2 contractile vacuoles; 2 flagella about body length; stigma if present, red or pale-colored; many starch bodies and oil droplets in posterior half of body; asexual re- production in motile stage; isogamy; saprozoic; in stagnant fresh water. P. uvella E. (Figs. 8, e; 97, h). Oval to pyriform; stigma may be absent; 15-30^ by 9-20m. Genus Paxapolytoma Jameson. Anterior margin obliquely trun- cate, resembling a cryptomonad, but without chromatophores; with- out stigma and starch; division into 4 individuals within envelope; fresh water. P. saturaJ. (Fig. 97, i). About 15ai by lO/x; fresh water. Family 2 Trichlorididae With three flagella. Genus Trichloris Scherffel and Pascher. Bean-shape; flagellate side flattened or concave; opposite side convex; chromatophore large, covering convex side; 2 pyrenoids surrounded by starch granules; a stigma near posterior end of chromatophore; nucleus central; numerous contractile vacuoles scattered; 3 flagella near anterior end. T. paradoxa S and P. (Fig. 97, j). 12-15m broad by 10-12^ high; flagella up to 30m long. Family 3 Carteriidae With four flagella arising from anterior pole. Genus Carteria Diesing {Corhierea, Pithiscus Dangeard; Tetra- mastix Korschikoff). Ovoid, chromatophore cup-shaped; pyrenoid; stigma; 2 contractile vacuoles; fresh water. Numerous species. C. cordiformis (Carter) (Fig. 98, a). Heart-shaped in front view; ovoid in profile; chromatophore large; 18-23m by 16-20^. C. ellipsoidalis Bold. Ellipsoid; chromatophore; a small stigma; division into 2, 4, or 8 individuals in encysted stage; 6-24m long; fresh water, Maryland (Bold, 1938). Genus Pyramimonas Schmarda (Pyramidomonas Stein). Small pyramidal or heart-shaped body; with bluntly drawn-out posterior end; usually 4 ridges in anterior region; 4 flagella; green chromato- PHYTOMONADINA 223 phores cup-shaped ; with or without stigma ; with a large pyrenoid in the posterior part; contractile vacuoles in the anterior portion; fresh water. Several species. P. tetrarhynchus S. (Fig. 98, h). 20-28^ by 12-18^; fresh water; Wisconsin (Smith, 1933). P. montana Geitler. Bluntly conical; anterior end 4-lobed or truncate ; posterior end narrowly rounded ; plastic ; pyrif orm nucleus Fig. 98. a, Carteria cordiformis, X600 (Dill); b, Pyraviimonas tetra- rhynchus, X400 (Dill); c, d, Polyiomella agilis, XlOOO (Doflein); e, Spirogonium chlorogonioides, X670 (Pascher); f, Tetrablepharis multifilis, X670 (Pascher); g, Spermatozopsis exultans, X1630 (Pascher); h, Chlo- r aster gyrans, X670 (Stein); i, Polyhlepharides singularis, X870 (Dan- geard); j, k, Pocillomonas flos aquae, X920 (Steinecke); 1, m, Phacotus lenticularis, X430 (Stein); n, Pteromonas angulosa, X670 (West); o, p, Dysmorphococcus variabilis, XlOOO (Bold). anterior, closely associated with 4 flagella; stigma; 2 contractile vacuoles anterior; chromatophore cup-shaped, granular, with scat- tered starch grains and oil droplets; a pyrenoid with a ring of small starch grains; 17-22.5m long (Geitler); 12-20m by 8-16m (Bold); flagella about body length; fresh water, Maryland (Bold, 1938). 224 PROTOZOOLOGY Genus Polytomella Aragao. Ellipsoid, or oval, with a small papilla at anterior end, where 4 equally long flagella arise; with or without stigma ; starch ; fresh water. P. agilis A. (Fig. 98, c, d). Numerous starch grains; S-lS^t by 5-9/x; flagella 12-17/x long; fresh water; hay infusion. P. caeca Pringsheim. Ovoid with bluntly pointed posterior end; 12-20m by 10-12^; membrane delicate; a small papilla at anterior end; no stigma; two contractile vacuoles below papilla; cytoplasm ordinarily filled with starch grains ; fresh water. Genus Medusochloris Pascher. Hollowed hemisphere with 4 proc- esses, each bearing a flagellum at its lower edge; a lobed plate- shaped chromatophore; without pyrenoid below convex surface. One species. M. phiale P. In salt water pools with decaying algae in the Baltic. Genus Spirogonium Pascher. Body spindle-form; membrane deli- cate; flagella a little longer than body; chromatophore conspicuous; a pyrenoid; stigma anterior; 2 contractile vacuoles; fresh water. One species. S. chlorogonioides (P). (Fig. 98, e). Body up to 25m by 15m. Genus Tetrablepharis Senn. Ellipsoid to ovoid; pyrenoid present; fresh water. T. multifilis (Klebs) (Fig. 98,/). 12-20m by 8-15m ; stagnant water. Genus Spermatozopsis Korschikoff. Sickle-form; bent easily, oc- casionally plastic; chromatophore mostly on convex side; a distinct stigma at more rounded anterior end; flagella equally long; 2 con- tractile vacuoles anterior; fresh water infusion. S. exultans K. (Fig. 98, g). 7-9m long; also biflagellate; in fresh water with algae, leaves, etc. Family 4 Chlorasteridae With 5 flagella arising from anterior pole. Genus Chloraster Ehrenberg. Similar to Pyramimonas, but an- terior half with a conical envelope drawn out at four corners; with 5 flagella ; fresh or salt water. C. gyrans E. (Fig. 98, h). Up to 18m long; standing water; also re- ported from salt water. Family 5 Polyblepharididae Dangeard With 6 or more flagella arising from anterior end. Genus Polyblepharides Dangeard. Ellipsoid or ovoid; flagella 6-8, shorter than body length; chromatophore; a pyrenoid; a central nucleus; 2 contractile vacuoles anterior; cysts; a questionable genus; fresh water. PHYTOMONADINA 225 P. singularis D. (Fig. 98, i). lO-lifx by 8-9/^. Genus Pocillomonas Steinecke. Ovoid with broadly concave an- terior end; covered with gelatinous substance with numerous small projections; 6 flagella; chromatophores disc-shaped; 2 contractile vacuoles anterior; nucleus central; starch bodies; without pyrenoid. P.flos aquae S. (Fig. 98, j, k). 13m by lOyu; fresh water pools. Family 6 Phacotidae Poche The shell typically composed of 2 valves; 2 flagella protrude from anterior end; with stigma and chromatophores ; asexual reproduction within the shell; valves may become separated from each other ow- ing to an increase in gelatinous contents. Genus Phacotus Perty. Oval to circular in front view; lenticular in profile; protoplasmic body does not fill dark-colored shell com- pletely; flagella protrude through a foramen; asexual reproduction into 2 to 8 individuals ; fresh water. P. lenticularis (Ehrenberg) (Fig. 98, I, m). 13-20/x in diameter; in stagnant water. Genus Pteromonas Seligo. Body broadly winged in plane of suture of 2 valves;. protoplasmic body fills shell; chromatophore cup- shaped; one or more pyrenoids; stigma; 2 contractile vacuoles; asexual reproduction into 2-4 individuals; sexual reproduction by isogamy ; zygotes usually brown; fresh water. Several species. P. angulosa (Lemmermann) (Fig. 98, n). With a rounded wing and 4 protoplasmic projections in profile; 13-17iu by 9-20ai; fresh water. Genus Dysmorphococcus Takeda. Circular in front view; anterior region narrowed; posterior end broad; shell distinctl,y flattened pos- teriorly, ornamented by numerous pores; sutural ridge without pores; 2 flagella; 2 contractile vacuoles; stigma, pyrenoid, cup-shaped chromatophore; nucleus; multiplication by binary fission; fresh water. D. variahilis T. (Fig. 98, o, p). Shell 14-1 9m by 13-17m; older shells dark brown; fresh water; Maryland (Bold, 1938). Family 7 Volvocidae Ehrenberg An interesting group of colonial flagellates; individual similar to Chlamydomonadidae, with 2 equally long flagella (one in Mastigo- sphaera; 4 in Spondylomorum) , green chromatophores, pyrenoids, stigma, and contractile vacuoles; body covered by a cellulose mem- brane and not plastic; colony or coenobium is discoid or spherical; exclusively freshwater inhabitants. 226 PROTOZOOLOGY Genus Volvox Linnaeus. Often large spherical or subspherical colonies, consisting of a large number of cells which are differen- tiated into somatic and reproductive cells; somatic cells numerous, embedded in gelatinous matrix, and contains a chromatophore, one or more pyrenoids, a stigma and several contractile vacuoles; in some species protoplasmic connections occur between adjacent cells; generative cells few and large. Both mono- and bi-sexual re- productions occur; monosexual gametes usually fewer and larger in size than bisexual ones, each producing a young colony by repeated division; bisexual reproduction anisogamy; zygotes usually brown- ish red in color, with smooth, undulating, or spinous envelopes; fresh water. Many species. Smith (1944) made a comprehensive study of the known species. V. globator L. (Fig. 99, a). Monoecious. Sexual colonies 350-500m in diameter; 5000-15,000 cells, with cytoplasmic connections; 3-7 microgametocytes, each of which develops into over 250 microgam- etes; 10-40 macrogametes; zygotes 35-45m in diameter, covered with many sharply pointed spines. Partheno genetic colonies 400-600/x in diameter; 4-10 gonidia, 10-13ju in diameter; young colonies up to 250m. Europe and North America. V. aureus Ehrenberg (Figs. 72; 99, h). Dioecious. Male colonies 300-350ju in diameter; 1000-1500 cells, with cytoplasmic connec- tions; numerous microgametocytes; clusters of some 32 microgam- etes, 15-18m in diameter. Female colonies 300-400^; 2000-3000 cells; 10-14 macrogametes; zygotes 40-60ju with smooth surface. Parthenogenetic colonies up to 500/x; 4-12 gonidia; young colonies 150)u in diameter. Europe and North America. V. tertius Meyer. Dioecious. Male colonies up to 170/x in diameter; 180-500 cells, without cytoplasmic connections; about 50 micro- gametocytes. Female colonies up to 500jLt; 500-2000 cells; 2-12 macrogametes; zygotes 60-65^ with smooth wall. Parthenogenetic colonies up to 600m in diameter; 500-2000 cells; 2-12 gonidia. Europe and North America. V. spermatosphaera Powers. Dioecious, Male colonies up to 100m in diameter; cells, without connection, up to 128, each becoming microgametocyte. Female colonies up to 500m in diameter; 6-16 macrogametes; zygotes 35-45m; with smooth membrane. Partheno- genetic colonies up to 650m in diameter; 8-10 gonidia; young colonies ellipsoid, up to 100m in diameter. North America. V . weismannia P. Dioecious. Male colonies 100-150m in diameter; 250-500 cells; 6-50 microgametocytes; clusters of microgametes (up to 128) discoid, 12-15m in diameter. Female colonies up to 400m; PHYTOMONADINA 227 Fig. 99. a, Volvox globator, X200 (Janet); b, V. aureus, XllO (Klein); c, Gonium. sociale, X270 (Chlordat); d, G. pedorale, X670 (Hartmann); e, G.formosum, X600 (Pascher). 228 PROTOZOOLOGY 2000-3000 cells; 8-24 macrogametes; zygotes 30-50/i in diameter, with reticulate ridges on shell. Partheno genetic colonies up to 400/x; 1500-3000 cells; 8 or 10 gonidia, 40-60ju in diameter; young colonies 100-200/i in diameter. North America. V. perglohator P. Dioecious. Male colonies 300-450^; 5000-10,000 cells, with delicate cytoplasmic connections; 60-80 microgameto- cytes. Female colonies 300-550/x; 9000-13,000 cells; 50-120 macro- gametes; zygotes 30-34)Lt, covered with bluntly pointed spines. Parthenogenetic colonies up to 1.1 mm; 3-9 gonidia; young colonies 250-275M. North America. Genus Gonium Miiller. 4 or 16 individuals arranged in one plane; cell ovoid or slightly polygonal; with 2 flagella arranged in the plane of coenobium; with or without a gelatinous envelope; protoplasmic connections among individuals occur occasionally; asexual reproduc- tion through simultaneous divisions of component cells; sexual re- production isogamy; zygotes reddish; fresh water. G. socials (Dujardin) (Fig. 99, c). 4 individuals form a discoid colony; cells 10-22^ by 6-16ai wide; in open waters of ponds and lakes. G. pedorale M. (Fig. 99, d). 16 (rarel}^ 4 or 8) individuals form a colony; 4 cells in center; 12 peripheral, closely arranged; cells 5-14/^ by lOyu; colony up to 90/x in diameter; fresh water. G. formosum Pascher (Fig. 99, e) 16 cells in a colony further apart; peripheral gelatinous envelope reduced; cells similar in size to those of G. sociale but colony somewhat larger; freshwater lakes. Genus Stephanoon Schewiakoff. Spherical or ellipsoidal colony, surrounded by gelatinous envelope, and composed of 8 or 16 bi- flagellate cells, arranged in 2 alternating rows on equatorial plane; fresh water. S. askenasii S. (Fig. 100, a). 16 individuals in ellipsoidal colony; cells 9/x in diameter; flagella up to 30At long; colony 78/i by 60m- Genus Platydorina Kofoid. 32 cells arranged in a slightly twisted plane; flagella directed alternately to both sides; fresh water. P. caudata K. (Fig. 100, 6). Individual cells 10-15^ long; colony up to 165/x long, 145/i wide, and 25)U thick; rivers and lakes. Genus Spondylomorum Ehrenberg. 16 cells in a compact group in 4 transverse rings; each with 4 flagella; asexual reproduction by simultaneous division of component cells; fresh water. One species. S. quaternarium E. (Fig. 100, c). Cells 12-26/x by 8-15/i; colony up to 60/i long. Genus Chlamydobotrys Korschikoff. Colony composed of 8 or 16 individuals; cells with 2 flagella; chromatophore ; stigma ; no pyrenoid ; fresh water. PHYTOMONADINA 229 C. stellata K. (Fig. 100, d). Colony composed of 8 individuals arranged in 2 rings; individuals 14-15^ long; colony 30-40m in diameter; Maryland (Bold, 1933). Genus Stephanosphaera Cohn. Spherical or subspherical colony, with 8 (rarely 4 or 16) cells arranged in a ring; cells pyriform, but Fig. 100. a, Stephanoon askenasii, X440 (Schewiakoff) ; b, Platydorina caudata, X280 (Kofoid); c, Spondylomorum qiiaternarium, X330 (Stein); d, Chlamydobotrys stellata, X430 (Korschikoff); e, Stephanosphaera plu- vialis, X250 (Hieronymus); f, Pandorina niorum, X300 (Smith); g, Mastigosphaera gobii, X520 (Schewiakoff); h, Eiidorina elegans, X310 (Goebel); i, Pleodorina illinoisensis, X200 (Kofoid). with several processes; 2 flagella on one face; asexual reproduction and isogamy (p. 152) ; fresh water. S. pluvialis C. (Figs. 74; 100, e). Cells 7-13m long; colony 30-60/i in diameter. Genus Pandorina Bory. Spherical or subspherical colony of usu- ally 16 (sometimes 8 or 32) biflagellate individuals, closely packed 230 PROTOZOOLOGY within a gelatinous, but firm and thick matrix; individuals often angular; with stigma and chromatophores; asexual reproduction through simultaneous division of component individuals; anisogamy preceded by division of each cell into 16 to 32 gametes; zygotes colored and covered by a smooth wall; fresh water. One species. P. morum (Miiller) (Figs. 75; 100, /). Cells 8-17m long; colony 20-40/x, up to 250/i in diameter; ponds and ditches. Genus Mastigosphaera Schewiakoff. Similar to Pandorina; but individuals with a single flagellum which is 3.5 times the body length; fresh water. M. gohii S. (Fig. 100, g). Individual 9m long; colony 30-33^. Genus Eudorina Ehrenberg. Spherical or ellipsoidal colony of usually 32 or sometimes 16 spherical cells; asexual reproduction similar to that of Pandorina; sexual reproduction with 32-64 spheri- cal green macrogametes and numerous clustered microgametes; red- dish zygote with a smooth wall; fresh water. E. elegans E. (Figs. 76; 100, h). Cells 10-24^ in diameter; colony 40-1 50^1 in diameter; in ponds, ditches and lakes. Genus Pleodorina Shaw. Somewhat similar to Eudorina, being composed of 32, 64, or 128 ovoid or spherical cells of 2 types: small somatic and large generative, located within a gelatinous matrix; fresh water. P. illinoisensis Kofoid (Figs. 31, h, c; 100, i). 32 cells in ellipsoid colony, 4 vegetative and 28 reproductive individuals; arranged in 5 circles, 4 in each polar circle, 8 at equator and 8 on either side of equator; 4 small vegetative cells at anterior pole; vegetative cells 10-16m in diameter; reproductive cells 19-25/x in diameter; colony up to 160/x by 130m. P. californica S. Spherical colony with 64 or 128 cells, of which 1/2-2/3 are reproductive cells; vegetative cells 13-15/i; reproductive cells up to 27m; colony up to 450m, both in diameter. References Bold, H. C. 1938 Notes on Maryland Algae. Bull. Torrey Bot. Club., Vol. 65. Crow, W. B. 1918 The classification of some colonial chlamy- domonads. New Phytologist, Vol. 17. Dangeard, p. 1900 Observations sur la structure and le developpe- ment du Pandorina morum. Le Botaniste, Vol. 7. Elliott, A. M. 1934 Morphology and life history of Haematococcus pluvialis. Arch. f. Protistenk., Vol. 82. Entz, G. Jr. 1913 Cytologische Beobachtungen an Polytoma uvella. Verb. Deutsch. Zool. Ges. Ver., Vol. 23. PHYTOMONADINA 231 Fritsch, F. E. 1935 The structure and reproduction of the algae. Cambridge. Gerloff, J. 1940 Beitrage zur Kenntnis der Variabilitat und Sys- tematik der Gattung Chlamydomonas. Arch. f. Protistenk., Vol. 94. Janet, C. 1912, 1922, 1923 Le Volvox. I, II, and III Memoires. Paris. KoFOiD, C. A. 1900 Plankton Studies, Nos. 2 and 3. Ann. Mag. Nat. Hist., Ser. 7, Vol. 6. Mast, S. 0. 1928 Structure and function of the eye-spot in unicel- lular and colonial organisms. Arch. f. Protistenk., Vol. 60. Pascher, a. 1927 Volvocales — Phytomonadinae. In: Die Siisswasser- flora Deutschlands, Part 4. Pringsheim, E. G. 1937 Zur Kenntnis saprotropher Algen und Flagellaten. II. Arch. f. Protistenk., Vol. 88. Shaw, W. R. 1894 Pleodorina, a new genus of the Volvocideae. Bot. Gaz., Vol. 19. Smith, G. M. 1933 The freshwater algae of the United States. New York. — '■ 1944 A comparative study of the species of Volvox. Trans. Amer. Micr. Soc, Vol. 63. West, G. S. and F. E. Fritsch 1927 A treatise on the British fresh- water algae. Cambridge. Chapter 11 Order 4 Euglenoidina Blochmann THE body is as a rule elongated; some are plastic, others have a definite body form with a well-developed, striated or variously sculptured pellicle. At the anterior end, there is an opening through which a flagellum protrudes. In holophytic forms the so-called cyto- stome and cytopharynx, if present, are apparently not concerned with the food-taking, but seem to give a passage-way for the flagellum and also to excrete the waste fluid matters which become collected in one or more contractile vacuoles located around the reservoir. In holozoic forms, a well-developed cytostome and cytopharynx are present. Ordinarily there is only one flagellum, but some possess two or three. Chromatophores are present in the majority of the Eu- glenidae, but absent in two families. They are green, vary in shape, such as spheroidal, band-form, cup-form, discoidal, or fusiform, and usually possess pyrenoids. Some forms may contain haematochrome. A small but conspicuous stigma is invariably pres- ent near the anterior end of the body in chromatophore-bearing forms. Reserve food material is the paramylon body, fat, and oil, the presence of which depends naturally on the metabolic condition of the organism. The paramylon body assumes diverse forms in dif- ferent species, but is, as a rule, constant in each species, and this facilitates specific identification to a certain extent. Nutrition is holophytic in chromatophore-possessing forms, which, however, may be saprozoic, depending on the amount of light and organic sub- stances present in the water. The holozoic forms feed upon bacteria, algae, and smaller Protozoa. The nucleus is, as a rule, large and distinct and contains almcJst always a large endosome. Asexual reproduction is by longitudinal fission; sexual reproduction has been observed in a few species. En- cystment is common. The majority inhabit fresh water, but some live in brackish or salt water, and a few are parasitic in animals. With stigma Family 1 Euglenidae Without stigma With 1 flagellum Family 2 Astasiidae (p. 239) With 2 flagella Family 3 Anisonemidae (p. 241) Family 1 Euglenidae Stein Body plastic ("euglenoid"), but, as a rule, more or less spindle- 232 EUGLENOIDINA 233 shaped during movement; the majority possess a single anterior flagellum (with the exception of Eutreptia and Euglenamorpha) ; green chromatophores (except one genus) and stigma occur, though in some cases absent; haematochrome often coexists; metaboHc products oil and paramylon; asexual reproduction by longitudinal fission in either active or resting stage; mostly freshwater inhabit- ants. Genus Euglena Ehrenberg. Short or elongated spindle, cylindrical, or band-form; pellicle usually marked by longitudinal or spiral striae; some highly plastic with a thin pellicle; others regularly spi- rally twisted; stigma usually anterior; chromatophores numerous and discoid, band-form, or fusiform; pyrenoids may or may not be sur- rounded by starch envelope; metabolic products paramylon bodies which may be two in number, one being located on either side of nucleus, and rod-like to ovoid in shape or numerous and scattered throughout; contractile vacuole small, near reservoir; asexual repro- duction by longitudinal fission; sexual reproduction reported in Euglena sanguinea; common in stagnant water, especially where algae occur; when present in large numbers, the active organisms may form a green film on the surface of water and resting or en- C3'sted stages may produce conspicuous green spots on the bottom of pond or pool; in fresh water. Numerous species. E. pisciformis Klebs (Fig. 101, a). 25-30^ by 7-10m; spindle-form with bluntly pointed anterior and sharply attenuated posterior end; slightly plastic; highly active; paramylon indistinct; a few chroma- tophores lateral and discoidal ; each with 2 pyrenoids ; flagellum fairly long. Johnson observed that division into 2 or 4 individuals occurs in enc3^sted forms. E. viridis Ehrenberg (Fig. lOl, h). 50-60/x by 14-18/x; anterior end rounded, posterior end pointed; spindle-shaped during motion, highly plastic when stationary; pellicle obliquely striated; chromato- phores more or less band-form, arranged in a stellate form; nucleus posterior; nutrition holophytic, but also able to carry on saprozoic nutrition, during which period chromatophores degenerate. Multi- plication in thin-walled cysts (Johnson). E. acus E. (Figs. 24, h; 101, c). 50-200ai long; long spindle-form; posterior end sharply pointed; flagellum short; spiral striation on pellicle very delicate; paramylon bodies several, rod-form; nucleus central; stigma distinct; numerous disc-like chromatophores; slug- gish. E. spirogyra E. (Figs. 24, c; 101, d). 80-125m by 10-20^; cylin- drical; with spiral striae, consisting of small knobs; numerous disc- 234 PROTOZOOLOGY like chromatophores ; 2 ovoidal paramylon bodies, one on either side of centrally located nucleus; flagellum short; stigma prominent; sluggish. E. oxyuris Schmarda (Fig. 101, e). 150-500m by 30-45ju; almost always spirally twisted, somewhat flattened; pellicle with spirally arranged striae; numerous chromatophores; 2 ovoid paramylon bodies conspicuous, one on either side of nucleus; flagellum short. Fig. 101. a, Euglena pisciformis, X270 (Klebs); b, E. viridis, X370 (Lemmermann) ; c, E. acus, X270 (Klebs); d, E. spirogyra, X430 (Stein); e, E. oxyuris, X430 (Stein); f, E. sanguinea, X130 (Klebs); g, E. deses, X230 (Lemmermann); h, E. gracilis, X270 (Klebs). E. sanguinea E. (Figs. 39, e-h; 101, /). 80-200ai by 25-45/x; flagellum long; pelUcular striation conspicuous; haematochrome granular, scattered in sun light; often found in crust on the surface or half-dry bed of a pool. E. deses E. (Figs. 24, a; 101, g). 85-1 55m by 15-22)u; elongate, highly plastic; body striation faintly visible; stigma distinct; nucleus EUGLENOIDINA 235 central, numerous chromatophores hemi-lenticular; several small rod-shaped paramylon bodies scattered; flagellum short. E. gracilis Klebs (Figs. 39, a-d; 101, h). 35-55m by 6-23m; cylin- drical to elongated oval; highly plastic; flagellum less than body length; fusiform chromatophores 10-20, discoid; nucleus central; pyrenoids. E. rubra Hardy. 70-170^ by 25-36//; cylindrical, rounded anteri- orly and drawn out posteriorly; pellicle spirally striated; nucleus posterior; flagellum longer than body; the base of flagellum ar- ranged as in E. acus (Fig. 24) ; stigma about 7)U in diameter, lateral to the reservoir, near which a contractile vacuole is formed; chro- matophores, many, spindle-shaped, with 3 longitudinal grooves; when taken out of body disc-shaped; haematochrome granules red, numerous, measure 0.3-0.5iu in diameter; paramylon bodies, numer- ous, ellipsoid; reproductive and temporary cysts and protective cysts (34-47/i in diameter), with gelatinous coat; multiplication noted only in encysted forms (Johnson). Johnson (1939) found that the color of this Euglena was red in the morning and dull green in the late afternoon, due to the dif- ference in the distribution of haematochrome within the body. When haematochrome granules are distributed throughout the body, the organism is bright-red, but when they are condensed in the center of the body, the organism is dull green. When part of the area of the pond was shaded with a board early in the morning, shortly after sunrise all the scum became red except the shaded area. When the board was removed, the red color appeared in 1 1 minutes while the temperature of the water remained 21°C. In the evening the change was reversed. Johnson and Jahn (1942) later found that green-red color change could be induced by raising the temperature of the water to 30-40°C. and by irradiation with infrared rays or visible light. The two workers hold that the function of haematochrome may be protective, since it migrates to a position which shields the chromatophores from very bright light. If this is true, it is easy to find the species thriving in hot weather in shallow ponds where temperature of the water rises to 35-45°C. In colder weather, it is supposed that this Euglena is less abundant and it exists in a green phase, containing a few haematochrome granules. E. vermiformis Carter. 45ju by 5/x; without flagellum; a slow spiral movement; retains cylindrical form during locomotion; among de- bris; stigma conspicuous; delicate pellicle not striated; about 8 pe- ripheral chromatophores; many small paramylon bodies in the form of flattened elliptical rings; brackish water. 236 PROTOZOOLOGY Genus Khawkinea Jahn and McKibben. Similar to Genus Eu- glena, but without chromatophores and thus permanently colorless; fresh water. K. halli J. and Mc. 40-45^ (30-65m) by 12-14^; fusiform; pellicle spirally striated; plastic; flagellum slightly longer than body; stigma 2-3/i in diameter, yellow-orange to reddish-orange, composed of many granules; numerous (25-100) paramylon bodies elliptical or polyhedral; cysts 20-30/i in diameter; putrid leaf infusion; saprozoic. K. ocellata (Khawkine). Similar to above; flagellum 1.5-2 times body length; fresh water. Genus Phacus Nitzsch. Highly flattened; asymmetrical; body- form constant; pellicle often with prominent longitudinal or oblique striae; a flagellum and a stigma; nucleus posterior; a short "cyto- pharynx"; green chromatophores rounded discoid; with or without paramylon bodies around a pja-enoid; in fresh water. Numerous species. Allegre and Jahn (1943) surveyed species of this genus in Iowa. P. pleuronectes (Miiller) (Fig. 102, a). 45-lOOju by 30-70/i; short posterior prolongation slightly curved; a prominent fold on convex side, extending to middle of body; longitudinally striated; one or more circular paramylon bodies; colorless forms sometimes appear; flagellum as long as body. P. longicaudus (Ehrenberg) (Fig, 102, 6). 120-170^ by 45-70/x; usually twisted with a long caudal prolongation; stigma prom- inent; discoidal paramylon body central; pellicle longitudinally striated. P. pyrum (E.) (Fig. 102, c). About 30-50iu long; pyriform, with a short caudal prolongation; pellicle obliquely striated. P. triqueter (E.) (Fig. 102, d). 50-55m by 30-35^; ovate; with a longitudinal ridge; posterior end acuminate; oblique striation dis- tinct; 1-2 paramylon bodies, P. anacoelus Stokes (Fig. 102, e). About 42^ long; oval or round; with flagellum as long as body. P. acuminata S. (Fig. 102, /). About 30-40/z by 20-30/x; nearly circular in outline; longitudinally striated; fold long; flagellum as long as bod}^; 2 small paramylon bodies. Genus Crumenula Dujardin {Lepocinclis Perty). Body more or less ovo-cylindrical; rigid with spirally striated pellicle; often with a short posterior spinous projection; stigma sometimes present; nu- merous discoidal chromatophores marginal; paramylon bodies usu- ally large and ring-shaped, laterally disposed; without pyrenoids; fresh water. Several species. EUGLENOIDINA 237 C. ova (Ehrenberg) (Fig. 102, g). 20-40/1 long; in fresh water with Euglena. Genus Trachelomonas Ehrenberg. With a lorica which often pos- sesses numerous spinous projections; sometimes yellowish to dark brown; a single flagellum protrudes from anterior aperture, the rim of which is frequently thickened to form a collar; chromatophores either 2 curved plates or numerous discs; paramylon bodies small grains; stigma and pyrenoids; multiplication by longitudinal fis- sion; one daughter individual retains lorica and flagellum, while the other escapes through flagellar aperture, forms a new flagellum and secretes a lorica; cysts common; specific differentiation is based upon the lorica; fresh water. Numerous species. T. hispida (Perty) (Figs. 31, a; 102, h). Lorica oval, with numer- ous minute spines; brownish; 8-10 chromatophores; 20-42/z by 15-26iu; many varieties. T. urceolata Stokes (Fig. 102, i). Lorica vasiform, smooth with a short neck; about 45/x long. T. piscatoris (Fisher) (Fig. 102, j). Lorica cylindrical with a short neck and with numerous short, conical spines; 25-40/i long; flagel- lum 1-2 times body length. T. verrucosa Stokes (Fig. 102, k). Lorica spherical, with numerous knob-like attachments; no neck; 24-25/i in diameter. T. vermiculosa Palmer (Fig. 102, I). Lorica spherical; with many sausage-form markings; 23/i in diameter. Genus Cryptoglena Ehrenberg. Body rigid, flattened; 2 band-form chromatophores lateral; a single flagellum; nucleus posterior; among freshwater algae. One species. C. pigra E. (Fig, 102, m). Ovoid, pointed posteriorly; flagellum short; stigma prominent; 10-15)U by 6-10/x; standing water. Genus Ascoglena Stein. Encased in a flexible, colorless to brown lorica, attached with its base to foreign object; solitary; without stalk; body ovoidal, plastic; attached to test with its posterior end; a single flagellum; a stigma; numerous chromatophores discoid; with or without pyrenoids; reproduction as in Trachelomonas fresh water. A. vaginicola S. (Fig, 102, n). Lorica about 43;u b}^ 15ju. Genus Colacium Ehrenberg. Stalked individuals form colony; frequently attached to animals such as copepods, rotifers, etc; stalk mucilaginous; individual cells pyriform, ellipsoidal or cylindrical; without flagellum; a single flagellum only in free-swimming stage; discoidal chromatophores numerous; with pyrenoids; multiplication by longitudinal fission; also by swarmers, possessing a flagellum and a stigma; fresh water. Several species. 238 PROTOZOOLOGY C. vesiculosum E, (Fig. 102, o). Colony of 2-8 cells; also solitary; 20-30/i by 9-18m; attached to freshwater copepods. Genus Eutreptia Perty {Eutreptiella da Cunha). With 2 flagella at Fig. 102. a, Phacus pleuronedes, X670 (Lemmermann); b, P. longi- caudus, X430 (Stein); c, P. pynim, X400 (Lemmermann); d, P. triqueter, X430 (Stein); e, P. anacoelus, X330 (Stokes); f, P. acuminata X560 (Stokes); g, Crumenula ova, X430 (Stein); h, Trachelomonas hispida, X430 (Stein); i, T. urceolata, X430 (Stokes); j, T. piscatoris, X520 (Fischer); k, T. verrucosa, X550 (Stokes); I, T. verndculosa, X800 (Pal- mer); m, Cryptoglena pigra, X430 (Stein); n, Ascoglena vaginicola, X390 (Stein); o, Colaciuvi vesictilosum, X390 (Stein); p, Eutreptia viridis, X270 (Klebs); q. E. marina, X670 (da Cunha); r, Euglenamorpha hegneri, X730 (Wenrich). anterior end; pellicle distinctly striated; plastic; spindle-shaped dur- ing movement; stigma; numerous discoid chromatophores; pyren- oids absent; paramylon bodies spherical or subcylindrical; multipli- EUGLENOIDINA 239 cation as in Euglena; cyst with a thick stratified wall; fresh or salt water. E. viridis P. (Fig. 102, p). 50-70/1 by 5-13m; in fresh water; a variety was reported from brackish water ponds. E. marina (da Cunha) (Fig. 102, q). Flagella unequal in length; longer one as long as body, shorter one f ; body 40-50/^ by S-lO/x; salt water. Genus Euglenamorpha Wenrich, Body form and structure similar to those of Euglena, but with 3 flagella; in gut of frog tadpoles. One species. E. hegneri W. (Fig. 102, r). 40-50^ long. Family 2 Astasiidae Biitschli Similar to Euglenidae in body form and general structure, but without chromatophores; body is plastic, although it assumes usually an elongated form; there is a cyto pharynx and cytostome, the former being connected with the reservoir near which contractile vacuole occurs; without stigma; fiagellum usually straight and its free end vibrates in a characteristic manner; asexual reproduction by longitudinal fission. Genus Astasia Dujardin. Body plastic, although ordinarily elongate; fresh water or endoparasitic (?) in Cyclops, etc. Several species. A. klebsi Lemmermann (Fig. 103, a). Spindle-form; posterior portion drawn out; fiagellum as long as body; plastic; paramylon bodies oval; 50-60)u by 13-20^; stagnant water. Genus Urceolus Mereschkowsky {Phialonema Stein). Body color- less; plastic; flask-shaped; striated; a funnel-like neck; posterior region stout; a single fiagellum protrudes from funnel and reaches in- ward the posterior third of body; fresh or salt water. U. cyclostomus (Stein) (Figs. 8, /; 103, h). 25-50/x long; fresh water. U. sahulosus (Stokes) (Fig. 103, c). Spindle-form; covered with minute sand-grains; about 58iu long; fresh water. Genus Peranema Dujardin. Elongate with a broad, rounded or truncate posterior end during locomotion; highly plastic when sta- tionary; delicate pellicle shows a fine striation; fiagellum long, tapers toward free end and vibrates; nucleus central; contractile vacuole; holozoic and saprozoic; in stagnant water; often in hay infusion. P. trichophorum (Ehrenberg) (Figs. 26; 103, d). 20-70jti long; body ordinarily filled with paramylon or starch grains derived from Astasia, Menoidium, etc.; very common. 240 PROTOZOOLOGY Fig. 103. a, Astasia klebsi, X500 (Klebs); b, Urceolus cyclostomus, X430 (Stein); c, U. sabulosus, X430 (Stokes); d, Peranema tricho- phoruni, X530 (Kudo); e, Petalmonas mediocanellata, XlOOO (Klebs); f, Menoidiwm incurvum, X1400 (Hall); g, Scytomonas jnisilla, X430 (Stein); h, Anisonema acinus, X400 (Klebs); i, A. truncatum, X430 (Stein); j, A. emerginatum, X530 (Stokes); k, Heteronema acus, X430 (Stein); 1, H. mutabile, Xl20 (Stokes); m, Tropidoscyphus octocostatus, X290 (Lemraermann); n, Distigma proteus, X430 (Stein); o, Entosi- phon sulcatum, X430 (Stein); p. Notosolenus apocaviptus, X1200 (Stokes): q, N. sinatus, X600 (Stokes); r, Marsupiogaster striata, X590 (Schewia- koff); s, M. picta (Faria, da Cunha and Pinto). EUGLENOIDINA 241 P. granuUfera Penard. Much smaller, 8-15/i long; spherical or elongate; pelhcle granulated; standing water. Genus Petalomonas Stein, Colorless; constant in form; pellicle often with longitudinal keels on one side; a single flagellum; ho lo zoic or saprozoic; cytostome at anterior end; cytopharynx fairly deep; in fresh water, rich in vegetable matter. Many species. P. medio canellata S. (Fig. 103, e). Ovoid with longitudinal furrow; flagellum about as long as body; 22-23 /x long. Genus Menoidium Perty. Rigid body, more or less curved; pellicle striated ; a single flagellum ; fresh water. M. incurvum (Fresenius) (Figs. 24, d; 67; 103, /). Crescentic cyl- inder; flagellum as long as body; nucleus central or terminal; 15- 25/i by 7-8^; in standing fresh water. Hall (1923) made a careful cytological study of the organism (p. 144). M. tortuosum Stokes. S-form; posterior end drawn out to a sharp point; elongate paramylon bodies; 42-78/1 long; in infusion. Genus Scytomonas Stein. Oval or pyrrform, with a delicate pel- licle; a single flagellum; a contractile vacuole with a reservoir; ho lo zoic on bacteria; longitudinal fission in motile stage; stagnant water and coprozoic. S. pusilla S. (Fig. 103, g). About 15/x long. Genus Copromonas Dobell. Elongate ovoid; with a single flagel- lum; a small cytostome at anterior end; ho lo zoic on bacteria; per- manent fusion followed by encystment (p. 151); coprozoic in faecal matters of frog, toad, and man; several authors hold that this genus is probably identical with Scytomonas which was incompletely de- scribed by Stein. C. subtilis D. (Fig. 73). 7-20^ long. Family 3 Anisonemidae Schewiakoff Colorless body plastic or rigid with a variously marked pellicle; 2 flagella, one directed anteriorly and the other usually posteriorly; contractile vacuoles and reservoir; stigma absent; paramylon bodies usually present; free-swimming or creeping. Genus Anisonema Dujardin. Generally ovoid; more or less flat- tened; asymmetrical; plastic or rigid; a slit-like ventral furrow; flagella at anterior end; cytopharynx long; contractile vacuole an- terior; nucleus posterior; in fresh water. Several species. A. acinus D. (Fig. 103, h). Rigid; oval; somewhat flattened; pel- licle slightly striated; 25-40^ by 16-22^. A. truncatum Stein (Fig. 103, i). Rigid; ovoid; 60/i by 20/x. A. emarginatum Stokes (Fig. 103, j). Rigid; 14/i long; flagella long. 242 PROTOZOOLOGY Genus Heteronema Dujardin. Plastic; rounded or elongate; flagella arise from anterior end, one directed forward and the other trailing; cytostome near base of flagella; ho lo zoic; fresh water. Sev- eral species. H. acus (Ehrenberg) (Fig. 103, k). Extended body tapers towards both ends; anterior flagellum as long as body, trailing one about 1/2; contractile vacuole anterior ; nucleus central ; 45-50/x long ; fresh water. H. mutahile (Stokes) (Fig. 103, I). Elongate; highly plastic; longi- tudinally striated; about 254;u long; in cypress swamp. Genus Tropidoscyphus Stein. Slightly plastic; pellicle with 8 longitudinal ridges; 2 unequal flagella at anterior pole; holozoic or saprozoic; fresh or salt water. T. octocostatus S. (Fig. 103, m). 35-63m long; fresh water, rich in vegetation. Genus Distigma Ehrenberg. Plastic; elongate when extended; body surface without any marking; 2 flagella unequal in length, di- rected forward; cytostome and cytopharynx located at anterior end; endoplasm usually transparent; holozoic. One species. D. proteus E. (Fig. 103, n). 50-1 lO/x long when extended; nucleus central; stagnant water; infusion. Genus Entosiphon Stein. Oval, flattened; more or less rigid; flagella arise from a cytostome, one flagellum trailing; protrusible cytophar3^nx a long conical tubule almost reaching posterior end; nucleus centro -lateral; fresh water. E. sulcatum (Dujardin) (Fig. 103, o). About 20/i long. E. ovatum Stokes. Anterior end rounded; 10-12 longitudinal striae; about 25-28/i long. Genus Notosolenus Stokes. Free-swimming; rigid oval; ventral surface convex, dorsal surface with a broad longitudinal groove; flagella anterior; one long, directed anteriorly and vibratile; the other shorter and trailing; fresh water with vegetation. N. apocamptus S. (Fig. 103, p). Oval with broad posterior end; 6-1 Iju long. N. sinuatus S. (Fig. 103, q). Posterior end truncate or concave; about 22/i long. Genus Marsupiogaster Schewiakoff. Oval; flattened; asymme- trical; cytostome occupies entire anterior end; cytopharynx con- spicuous, 1/2 body length; body longitudinally striated; 2 flagella, one directed anteriorly, the other posteriorly; spherical nucleus; contractile vacuole anterior; fresh or salt water. M. striata Schewiakoff (Fig. 103, r). About 27m by 15^; fresh water; Hawaii. EUGLENOIDINA, CHLOROMONADINA 243 M. picta Faria, da Cunha and Pinto (Fig. 103, s). In salt water; Rio de Janeiro. Order 5 Chloromonadina Klebs The chloromonads are of rare occurrence and consequently not well known. The majority possess small discoidal grass-green chro- FiG. 104. a, Gonyostomum semen, X540 (Stein); b, Vacuolaria virescens, X460 (Senn);c, Trentonia flagellata, X330 (Stokes); d, Thaumatomastix setifera, X830 (Lauterborn). matophores with a large amount of xanthophyll which on addition of an acid become blue-green. No pyrenoids occur. The metabolic products are fatty oil. Starch or allied carbohydrates are absent. Stigma is also not present. Genus Gonyostomum Diesing (Rhaphidomonas Stein). With grass-green chromatophores; highly refractile trichocyst-like struc- tures in cytoplasm; in fresh water. A few species. G. semen D. (Fig. 104, a). Sluggish animal; about 45-60^ long; in marshy water among decaying vegetation. Genus Vacuolaria Cienkowski. Highly plastic ; without trichocyst- like structures; anterior end narrow; with 2 flagella; cysts with a gelatinous envelope. One species. V. virescens. C. (Fig. 104, h). About 50-150)u long; fresh water. Genus Trentonia Stokes. Bi-flagellate as in the last genus; but flattened; anterior margin slightly bilobed. One species. T. flagellata S. (Fig. 104, c). Slow-moving organism; encystment followed by binary fission; about 60/i long; fresh water. 244 PROTOZOOLOGY Genus Thaumatomastix Lauterborn. Colorless; pseudopodia formed; 2 flagella, one extended anteriorly, the other trailmg; holo- zoic; perhaps a transitional form between the Mastigophora and the Sarcodina. One species. T. setifera L. (Fig. 104, d). About 20-35m by 15-28^; fresh water. References Allegre, C. F. and T. L. Jahn 1943 A survey of the genus Phacus Dujardin (Protozoa; Euglenoidina). Trans. Amer. Micr. Soc, Vol. 62. Dangeard, p. 1901 Recherches sur les Eugl^niens. Le Botaniste. P. 97. Fritsch, F. E. 1935 The structure and reproduction of the algae. Vol. 1. Cambridge. Hall, R. P. 1923 Morphology and binary fission of Menoidium incurvum (Fres.) Klebs. Uni. Cal. Publ. Zool., Vol. 20. Johnson, L. P. 1939 A study of Euglena rubra Hardy 1911. Trans. Amer. Micr. Soc, Vol. 58. 1944 Euglenae of Iowa. Ibid. Vol. 63. and T. L. Jahn 1942 Cause of the green-red color change in Euglena rubra. Physiol. Zool., Vol. 15. Lemmermann, E. 1913 Eugleninae. In: Siisswasserfl. Deutschlands, Part 2. Pascher, a. 1913 Chloromonadinae. Ibid. Part 2. Smith, G. M. 1933 The freshwater algae of the United States. New York. Wenrich, D. H. 1924 Studies on Euglenamorpha hegneri n. g., n. sp., a euglenoid flagellate found in tadpoles. Biol. Bull., Vol. 47. West, G. S. and F. E. Fritsch. 1927 A treatise on the British fresh- water algae. Cambridge. Chapter 12 Order 6 Dinoflagellata BUtschli THE dino flagellates make one of the most distinct groups of the Mastigophora, inhabiting mostly marine water, and to a lesser extent fresh water. In the general appearance, the arrangement of the two flagella, the characteristic furrows, and the possession of brown chromatophores, they are closely related to the Crypto- monadina. The body is covered by an envelope composed of cellulose which may be a simple smooth piece, or may be composed of two valves or of numerous plates, that are variously sculptured and possess Anterior flagellar pore Annulus or girdle Hypocone Longitudinal flagellum ( Posterior flagellar pore Fig. 105. Diagram of a typical naked dinoflagellate (Lebour). manifold projections. Differences in the position and course of the furrows and in the projections of the envelope produce numerous asymmetrical forms. The furrows, or grooves, are a transverse an- nulus and a longitudinal sulcus. The annulus is a girdle around the middle or toward one end of the body. It may be a complete, incomplete or sometimes spiral ring. While the majority show a single transverse furrow, a few may possess several. The part of the shell anterior to the annulus is called the epitheca and that posterior to the annulus the hypotheca. In case the envelope is not developed, the terms epicene and hypocone are used (Fig. 105). The sulcus may run from end to end or from one end to the annulus. The two flagella arise typically from the furrows, one being transverse and the other longitudinal. The transverse flagellum which is often band-form, encircles the body and undergoes undulating movements, which in former years were looked upon as ciliary movements (hence the name Cilioflagel- lata). In the suborder Prorocentrinea, this flagellum vibrates freely 245 246 PROTOZOOLOGY in a circle near the anterior end. The longitudinal flagellum often projects beyond the body and vibrates. Combination of the move- ments of these flagella produces whirHng movements characteristic of the organisms. The majority of dinofiagellates possess a single somewhat massive nucleus with evenly scattered chromatin, and usually several endo- somes. There are two kinds of vacuoles. One is often surrounded by a ring of smaller vacuoles, while the other is large, contains pink- colored fluid and connected with the exterior by a canal opening into a flagellar pore. The latter is known as the pusule which functions as a digestive organella (Kofoid and Swezy). In many freshwater forms a stigma is present, and in Pouchetiidae there is an ocellus composed of an amyloid lens and a dark pigment-ball. The majority of planktonic forms possess a large number of small chromatophores which are usually dark yellow, brown or sometimes slightly greenish and are located in the periphery of the body, while bottom-dwelling and parasitic forms are, as a rule, colorless, because of the absence of chromatophores. A few forms contain haematochrome. The method of nutrition is holophytic, holozoic, saprozoic, or mixotrophic. In holophytic forms, anabolic products are starch, oil, or fats. Asexual reproduction is bj^ binary or multiple fission or budding in either the active or the resting stage and differs among different groups. Encystment is of common occurrence. In some forms the cyst wall is formed within the test. The cysts remain alive for many years; for example, Ceratium cysts w^ere found to retain their vital- ity in one instance for six and one-half years. Conjugation and sexual fusion have been reported in certain forms, but definite knowledge on sexual reproduction awaits further investigation. The dinofiagellates are abundant in the plankton of the sea and play an important part in the economy of marine life as a whole. A number of parasitic forms are also known. Their hosts include vari- ous diatoms, copepods and several pelagic animals. Bivalve shell without furrows Suborder 1 Prorocentrinea Naked or with shell showing furrows. .Suborder 2 Peridiniinea (p. 248) Naked; without furrows; no transverse flagellum Suborder 3 Cystoflagellata (p. 261) Suborder 1 Prorocentrinea Poche Test bivalve; without any groove; with yellow chromatophores; 2 flagella anterior, one directed anteriorly, the other vibrates in a circle; fresh or salt water. DINOFLAGELLATA 247 Family Prorocentridae Kofoid Genus Prorocentrum Ehrenberg. Elongate oval; anterior end bluntly pointed, with a spinous projection at pole; chromatophores small, yellowish brown; salt water. P. micans E. (Fig. 106, a). 36-52jli long; a cause of "red water." P. triangulatum Martin. Triangular with rounded posterior end; shell-valves flattened; one valve with a delicate tooth; surface cov- ered with minute pores; margin striated; chromatophores yellow- FiG. 106. a, Prorocentrum micans, X420 (Schiitt); b, c, Exuviaella marina, X420 (Schiitt); d, e, Cystodinium steini, X370 (Klebs); f, Gleno- dinium cinctum, X590 (Schilling); g, G. pulvisculum, X420 (Schilling); h, G. uliginosuvi, X590 (Schilling); i, G. edax, X490 (Schilling); j, G. neglectum, X650 (Schilling). brown, irregular, broken up in small masses; 17-22/i (excluding tooth); Martin found it extremely abundant in brackish water in New Jersey. Genus Exuviaella Cienkowski. Subspherical or oval; no anterior projection, except 2 flagella; 2 lateral chromatophores, large, brown, each with a pyrenoid and a starch body; nucleus posterior; salt water. Several species. E. marina C. (Fig. 106, b, c). 36-50^ long. 248 PROTOZOOLOGY E. apora Schiller. Compressed, oval; striae on margin of valves; chromatophores numerous yellow-brown, irregular in form; S0-32fx by 21-26)u (Schiller); 17-22m by 14-19^ (Lebour; Martin); common in brackish water, New Jersey. Suborder 2 Peridiniinea Poche Typical dinoflagellates with one to many transverse annuli and a sulcus; 2 flagella, one of which undergoes a typical undulating movement, while the other usually directed posteriorly. According to Kofoid and Swezy, this suborder is divided into two tribes. Body naked or covered by a thin shell Tribe 1 Gymnodinioidae Body covered by a thick shell Tribe 2 Peridinioidae (p. 257) Tribe 1 Gymnodinioidae Poche Naked or covered by a single piece cellulose membrane with an- nulus and sulcus, and 2 flagella; chromatophores abundant, yellow or greenish platelets or bands; stigma sometimes present; asexual reproduction, binary or multiple division; holophytic, holozoic, or saprozoic; the majority are deep-sea forms; a few coastal or fresh water forms also occur. With a cellulose membrane Family 1 Cystodiniidae Without shell Furrows rudimentary Family 2 Pronoctilucidae (p. 249) Annulus and sulcus distinct Solitary With ocellus Family 3 Pouchetiidae (p. 249) Without ocellus With tentacles Family 4 Noctilucidae (p. 251) Without tentacles Free-living Family 5 Gymnodiniidae (p. 251) Parasitic Family 6 Blastodiniidae (p. 254) Permanently colonial Family 7 Polykrikidae (p. 257) Family 1 Cystodiniidae Kofoid and Swezy Genus Cystodinium Klebs. In swimming phase, oval, with ex- tremely delicate envelope; annulus somewhat acyclic; cyst-mem- brane drawn out into 2 horns. C. steini K. (Fig. 106, d, e). Stigma beneath sulcus; chromato- phores brown; swarmer about 45)u long; freshwater ponds. Genus Glenodinium Ehrenberg. (Glenodiniopsis, Stasziecella Woloszynska). Spherical; ellipsoidal or reniform in end-view; an- nulus a circle; several discoidal, yellow to brown chromatophores; horseshoe- or rod-shaped stigma in some; often with gelatinous en- velope; fresh water. Many species. DINOFLAGELLATA 249 G. cinctum E. (Fig. 106,/). Spherical to ovoid; annulus equatorial; stigma horseshoe-shaped; 43/i by 40/i. G. pulvisculum Stein (Fig. 106, g). No stigma; 38/x by 30/x. G. uUginosum Schilling (Fig. 106, h). 36-48m by 30/x. G. edax S. (Fig. 106, i). 34m by 33/x. G. neglectum S. (Fig. 106, j)- 30-32/x by 29m. Family 2 Pronoctilucidae Lebour Genus Pronoctiluca Fabre-Domergue. Body with an antero- ventral tentacle and sulcus; annulus poorly marked; salt water. P. tentaculatum (Kofoid and Swezy) (Fig. 107, a). About 54m long; off California coast. Genus Oxyrrhis Dujardin. Subovoidal, asymmetrical posteriorly; annulus incomplete; salt water. 0. marina D. (Fig. 107, b). 10-37m long. Family 3 Pouchetiidae Kofoid and Swezy Ocellus consists of lens and melanosome (pigment mass); sulcus and annulus somewhat twisted; pusules usually present; cytoplasm colored; salt water (pelagic). Genus Pouchetia Schiitt. Nucleus anterior to ocellus; ocellus with red or black pigment mass with a red, brown, yellow, or colorless central core; lens hyaline; body surface usually smooth; ho lo zoic; encystment common; salt water. Many species. P.fusus S. (Fig. 107, c). About 94m by 41m; ocellus 27m long. P. maxima Kofoid and Swezy (Fig. 107, d). 145m by 92m; ocellus 20m; off California coast. Genus Protopsis Kofoid and Swezy. Annulus and sulcus similar to those of Gymnodinium or Gyrodinium; with a simple or compound ocellus; no tentacles; body not twisted; salt water. A few species. P. ochrea (Wright) (Fig. 107, e). 55m by 45m; ocellus 22m long; Nova Scotia. Genus Nematodinium Kofoid and Swezy. With nematocysts; girdle more than 1 turn; ocellus distributed or concentrated, pos- terior; ho lo zoic; salt water. A'', partitum K. and S. (Fig. 107,/). 91m long; off California coast. Genus Proterythropsis Kofoid and Swezy. Annulus median; ocel- lus posterior; a stout rudimentary tentacle; salt water. One species, P. crassicaudata K. and S. (Fig. 107, g). 70m long; off California. Genus Erythropsis Hertwig. Epicone flattened, less than 1/4 hypocone; ocellus very large, composed of one or several hyaline lenses attached to or imbedded in a red, brownish or black pigment 250 PROTOZOOLOGY Fig. 107. a, Pronoctiluca tentaculatum, X730 (Kofoid and Swezy); b, Oxyrrhis marina, X840 (Senn); c. Pouchetia fusus, X340 (Schiitt); d, P. maxima, X330 (Kofoid and Swezy); e, Protopsis ochrea, X340 (Wright); f, Nematodinium partitum, X560 (Kofoid and Swezy); g, Pro- tenjthropsis crassicaudata, x740 (Kofoid and Swezy); h, Erythropsis cormita, X340 (Kofoid and Swezy); i, j , Nodiluca scintillans (i, side view; j, budding process), Xl40 (Robin), DINOFLAGELLATA 251 body with a red, brown or yellow core, located at left of sulcus; sulcus expands posteriorly into ventro-posterior tentacle; salt water. Several species. E. cornuta (Schiitt) (Fig. 107, h). 104/x long; off California coast (Kofoid and Swezy). Family 4 Noctilucidae Kent Contractile tentacle arises from sulcal area and extends poste- riorly; a flagellum; this group has formerly been included in the Cystoflagellata; studies by recent investigators, particularly by Kofoid, show its affinity with the present suborder ; ho lozoic; saltwater. Genus Noctiluca Suriray. Spherical, bilaterally symmetrical; peri- stome marks the median line of body; cytostome at the bottom of peristome; with a conspicuous tentacle; cytoplasm greatly vacuo- lated, and cytoplasmic strands connect the central mass with peri- phery; specific gravity is less than that of sea water, due to the pre- sence of an osmotically active substance with a lower specific gravity than sodium chloride, which appears to be ammonium chloride (Goethard and Heinsius); peripheral granules luminescent (p. 100); cytoplasm colorless or blue-green; sometimes tinged with j^ellow coloration in center; swarmers formed by budding, and each posses- ses one flagellum, annulus, and tentacle; widely distributed in salt w^ater; ho lozoic. One species. A^. scintillans (Macartney) (A^. miliaris S.) (Fig. 107, i, j). Usu- ally 500-1000/i in diameter, with extremes of 200;u and 3 mm. Gross (1934) observed that complete fusion of two swarmers (isoga- metes) results in cyst formation from which trophozoites develop. Acid content of the body fluid is said to be about pH 3. Genus Pavillardia Kofoid and SwezJ^ Annulus and sulcus similar to those of Gyimiodinium; longitudinal flagellum absent; stout finger-like mobile tentacle directed posteriori}^; salt water. One species. P. tentaculifera K. and S. 58ju by 27 /x; pale yellow; off California. Family 5 Gymnodiniidae Kofoid Naked forms with simple but distinct 1/2-4 turns of annulus; with or without chromatophores; fresh or salt water. Genus Gymnodinium Stein. Pellicle delicate; subcircular; bi- laterally symmetrical; numerous discoid chromatophores vari- colored (yellow to deep brown, green, or blue) or sometimes absent; stigma present in few; many with mucilaginous envelope; salt, brackish, or fresh water. Numerous species. 252 PROTOZOOLOGY Fig. 108. a, Gymnodinium aeruginosum, X500 (Schilling); b, G. ro- tundatum, X360 (Klebs); c, G. poZwsire, X 360 (Schilling); d, G. agile, X740 (Kofoid and Swezy); e, Hemidinium nasuttiin, X670 (Stein); f, Aviphidinium lacustre, X440 (Stein); g, A. scissiim, X880 (Kofoid and Swezy); h, Gyrodinium hiconicxim, X340 (Kofoid and Swezy); i, G. hyalinum, X670 (Kofoid and Swezy); j, Cochlodinium atromacu- latum, X340 (Kofoid and Swezy); k, Torodinium robustum, X670 (Kofoid and Swezy); 1, Massartia nieuportensis, X670 (Conrad); m, Chilodinium cruciatum, X900 (Conrad); n, o, Trochodinium prismaticum, X1270 (Conrad); p, Ceratodinium asymmetricum, X670 (Conrad). DINOFLAGELLATA 253 G. aeruginosum S. (Fig. 108, a). Chromatophores green; 33-35^ by 22/x; ponds and lakes. G. rotundatum Klebs (Fig. 108, b). 32-35^ by 22-25^; fresh water. G. palustre Schilling (Fig. 108, c). 45/Lt by 38/x; fresh water. G. agile Kofoid and Swezy (Fig. 108, d). About 28m long; along sandy beaches. Genus Hemidinium Stein. Asymmetrical; oval; annulus about half a turn, only on left half. One species. H. nasutum S. (Fig. 108, e). Sulcus posterior; chromatophores yellow to brown; with a reddish brown oil drop; nucleus posterior; transverse fission; 24-28m by 16-17^; fresh water. Genus Amphidinium Claparede and Lachmann. Form variable; epicone small; annulus anterior; sulcus straight on hypocone or also on part of epicone; with or without chromatophores; mainly holo- phytic, some holozoic; coastal or fresh water. Numerous species. A. lacustre Stein (Fig. 108, /). 30/i by 18^; in fresh and salt (?) water, A. scissum Kofoid and Swezy (Fig. 108, g). 50-60/x long; along sandy beaches. A. fusiforme Martin. Fusiform, twice as long as broad: circular in cross-section; epicone rounded conical; annulus anterior; hypo- cone 2-2.5 times as long as epicone; sulcus obscure; body filled with yellowish green chromatophores except at posterior end; stigma dull orange, below girdle; nucleus ellipsoid, posterior to annulus; pellicle delicate; 17-22^ by 8-1 1/x in diameter. Martin (1929) found that it was extremely abundant in parts of Delaware Bay and gave rise to red coloration of the water ("Red water"). Genus Gyrodinium Kofoid and Swezy. Annulus descending left spiral; sulcus extending from end to end; nucleus central; pusules; surface smooth or striated; chromatophores rarely present; cyto- plasm colored; holozoic; salt or fresh water. Many species. G. biconicum K. and S. (Fig. 108, h). 68ju long; salt water; off Cali- fornia. G. hyalinum (Schilling) (Fig. 108, i). About 24/u long ; fresh water. Genus Cochlodinium Schutt. Twisted at least 1.5 turns; annulus descending left spiral; pusules; cytoplasm colorless to highly colored; chromatophores rarely present; holozoic; surface smooth or striated; salt water. Numerous species. C. atromaculatum Kofoid and Swezy (Fig. 108, j). 183-185ju by 72m; longitudinal flagellum 45m long; off California. Genus Torodinium Kofoid and Swezy. Elongate; epicone several times longer than hypocone; annulus and hypocone form augur- 254 PROTOZOOLOGY shaped cone; sulcus long; nucleus greatly elongate; salt water. 2 species. T. rohustum K. and S. (Fig. 108, k). 67-75m long; off California. Genus Massartia Conrad. Cylindrical; epicone larger (9-10 times longer and 3 times wider) than hypocone; no sulcus; with or without yellowish discoid chromatophore. M. niewportensis C. (Fig. 108, I). 28-37iu long; brackish water. Genus Chilodinium Conrad. Ellipsoid; posterior end broadly rounded, anterior end narrowed and drawn out into a digitform process closely adhering to body; sulcus, apex to 1/5 from posterior end; annulus oblique, in anterior 1/3. C. cruciatum C. (Fig. 108, m). 40-50iu by 30-40)li; with trichocysts; brackish water. Genus Trochodinium Conrad. Somewhat similar to Amphidi- nium; epicone small, button-like; hypocone with 4 longitudinal rounded ridges; stigma; without chromatophores. T. prismaticum C. (Fig. 108, n, o). 18-22/i by 9-12/i; epicone 5-7ju in diameter; brackish water. Genus Ceratodinium Conrad. Cuneiform; asymmetrical, color- less, more or less flattened; annulus complete, oblique; sulcus on half of epicone and full length of hypocone; stigma. C. asymmetricum C. (Fig.l08,p). 68-80^ by about lO^t; brackish water. Family 6 Blastodiniidae Kofoid and Swezy All parasitic in or on plants and animals; in colony forming genera, there occur trophocyte (Chatton) by which organism is attached to host and more or less numerous gonocytes (Chatton). Genus Blastodinium Chatton. In the gut of copepods; spindle- shaped, arched, ends attenuated; envelope (not cellulose) often with 2 spiral rows of bristles; young forms binucleate; when present, chromatophores in yellowish brown network; swarmers similar to those of Gymnodinium; in salt water. Many species. B. spinulosum C. (Fig. 109, a). About 235m by 33-39)li; swarmers 5-10^; in Palacalanus parvus, Clausocalanus arcm'corm's and C. furcatus. Genus Oodinium Chatton. Spherical or pyriform; with a short stalk; nucleus large; often with yellowish pigment; on Salpa, Anne- lida, Siphonophora, etc. 0. poucheti (Lemmermann) (Fig. 109, b, c). Fully grown indivi- duals up to 170m long; bright yellow ochre; mature forms become detached and free, dividing into numerous gymnodinium-like swarmers; on the tunicate, Oikopleura dioica. DINOFLAGELLATA 255 Genus Apodinium Chatton. Young individuals elongate, spherical or pyriform; binucleate; adult colorless; formation of numerous swarmers in adult stage is peculiar in that lower of the 2 individuals formed at each division secretes a new envelope, and delays its Fig. 109. a, Blastodinium spinulosiwi, X240 (Chatton); b, c, Oodi- nium poucheti (c, a swarmer) (Chatton); d, e, Apodinium inycetoides (d, swarmer-formation, X450; e, a younger stage, X 640) (Chatton); f, Chytriodiniiim parasiticum in a copepod egg (Dogiel) ; g, Trypanodinium ovicola, X1070 (Chatton); h, Duboscqella tintinnicola (Duboscq and Collin); i, j, Haplozoon clymenellae (i, mature colony, X300; j, a swarmer, X1340) (Shumway); k, Syndinium turbo, X1340 (Chatton); 1, Paradi- niuni poucheti, X800 (Chatton); m, Ellobiopsis chattoni on Calanus fin- mar chicus (CauUery); n, Paraellobiopsis coutieri (Collin). 256 PROTOZOOLOGY further division until the upper one has divided for the second time, leaving several open cups; on tunicates. A. mycetoides C. (Fig. 109, d, e). On gill-slits of Fritillaria pel- lucida. Genus Chytriodinium Chatton. In eggs of planktonic copepods; young individuals grow at the expense of host egg and when fully formed, body divides into many parts, each producing 4 swarmers. Several species. C. parasiticum (Dogiel) (Fig. 109, /). In copepod eggs; Naples. Genus Trypanodinium Chatton. In copepod eggs; swarmer-stage only known. T. ovicola C. (Fig. 109, g). Swarmers biflagellate; about 15/x long. Genus Duboscqella Chatton. Rounded cell with a large nucleus; parasitic in Tintinnidae. One species. D. tintinnicola (Lohmann) (Fig. 109, h). Intracellular stage oval, about 100/x in diameter with a large nucleus; swarmers biflagellate. Genus Haplozoon Dogiel. In gut of polychaetes; mature forms composed of variable number of cells arranged in line or in pyramid; salt water. Many species. H. clymenellae (Calkins) (Fig. 109, i, j). In Clymenella torquata; colonial forms consist of 250 or more cells; Woods Hole. Genus Syndiniiim Chatton. In gut and body cavity of marine copepods; multinucleate round cysts in gut considered as young forms; multinucleate body in host body cavity with numerous needle-like inclusions. S. turbo C. (Fig. 109, k). In Paracalanus parvus, Corycaeus ven- ustus, Calanus finmarchicus; swarmers about 15/i long. Genus Paradinium Chatton. In body-cavity of copepods; mul- tinucleate body without inclusions; swarmers formed outside the host body. P. poucheti C. (Fig. 109, I). In the copepod, Acartia clausi; swarm- ers about 25/n long, amoeboid. Genus EUobiopsis Caullery. Pyriform; with stalk; often a septum near stalked end; attached to anterior appendages of marine cope- pods. E. chattoni C. (Fig. 109, m). Up to 700/i long; on antennae and oral appendages of Calanus finmarchicus, Pseudocalanus elongatus and Acartia clausi. Genus Paraellobiopsis Collin. Young forms stalkless; spherical; mature individuals in chain-form; on Malacostraca. P. coutieri C. (Fig. 109, n). On appendages of Nebalia hipes. DINOFLAGELLATA 257 Family 7 Polykrikidae Kofoid and Swezey Two, 4, 8, or 16 individuals permanently joined; individuals similar to Gymnodinium; sulcus however extending entire body length; with nematocysts (Fig. 110, b); greenish to pink; nuclei about 1/2 the number of individuals; holozoic; salt water. Genus Polykrikos Biitschli. With the above-mentioned char- acters; salt or brackish water, P. kofoidi (Chatton) (Fig. 110, a, b). Greenish grey to rose; com- posed of 2, 4, 8, or 16 individuals; with nematocysts; each nemato- cyst possesses presumably a hollow thread, and discharges under suitable stimulation its content; a binucleate colony composed of 4 individuals about UOm long; off California, P. barnegatensis Martin, Ovate, nearly circular in cross-section, slightly concave ventrally; composed of 2 individuals; constriction slight; beaded nucleus in center; annuli descending left spiral, dis- placed twice their width; sulcus ends near anterior end; cytoplasm colorless, with numerous oval, yellow-brown chromatophores; nem- atocysts absent; 46^ by 31.5)u; in brackish water of Barnegat Bay. Tribe 2 Peridinioidae Poche The shell composed of epitheca, annulus and hypotheca, which may be divided into numerous plates; body form variable. With annulus and sulcus Shell composed of plates; but no suture Family 1 Peridiniidae Breast plate divided by sagittal suture . Family 2 Dinophysidae (p. 261) Without annulus or sulcus Family 3 Phytodiniidae (p. 261) Family 1 Peridiniidae Kent Shell composed of numerous plates; annulus usually at equator, covered by a plate known as cingulum; variously sculptured and finely perforated plates vary in shape and number among different species; in many species certain plates drawn out into various proc- esses, varying greatly in different seasons and localities even among one and the same species; these processes seem to retard descending movement of organisms from upper to lower level in water when flagellar activity ceases; chromatophores numerous small platelets, yellow or green; some deep-sea forms without chromatophores; chain formation in some forms; mostly surface and pelagic inhabitants in fresh or salt water. Genus Peridinium Ehrenberg. Subspherical to ovoid; reniform in cross-section; annulus slightly spiral with projecting rims; hypotheca often with short horns and epitheca drawn out; colorless, green, or 258 PROTOZOOLOGY brown; stigma usually present; cysts spherical; salt or fresh water. Numerous species. P. tahulatum Claparede and Lachmann (Fig. 110, c). 48m by 44^; fresh water. Fig. 110. a, b, Pohjkrikos kofoidi (a, colony of four individuals, X340; b, a nematocyst, X1040) (Kofoid and Swezy); c, Peridinium tahulatum, X460 (Schilling); d, P. divergens, X340 (Calkins); e, Ceratiuni hirundi- nella, X540 (Stein); f. C. longipes, XlOO (Wailes); g, C. tripos, Xl40 (Wailes); h, C. fusus, XlOO (Wailes); i, Heterodinium scrippsi, X570 (Kofoid and Adamson). DINOFLAGELLATA 259 P. divergens (E.) (Fig. 110, d). About 45ju in diameter; yellowish, salt water. Genus Ceratium Schrank. Body flattened; with one anterior and 1-4 posterior horn-Uke processes; often large; chromatophores yel- low, brown, or greenish; color variation conspicuous; fission is said to take place at night and in the early morning; fresh or salt water. Numerous species; specific identification is difficult due to a great variation (p. 176). C. hirundinella (Miiller) (Figs. 85; 110, e). 1 apical and 2-3 anta- pical horns; seasonal and geographical variations (p. 177); chain- formation frequent; 95-700iu long; fresh and salt water. Numerous varieties. C. longipes (Bailey) (Fig. 110, /). About 210m by 51-57^; salt water. C. tripos (Muller) (Fig. 110, g). About 225/x by 75m; salt water. Wailes (1928) observed var. atlantica in British Columbia; Martin (1929) in Barnegat Inlet, New Jersey. C.fusus (Ehrenberg) (Fig. 110, h). 300-600m by 15-30m; salt water; widely distributed; British Columbia (Wailes), New Jersey (Martin), etc. Genus Heterodinium Kofoid. Flattened or spheroidal; 2 large antapical horns; annulus submedian; with post-cingular ridge; sulcus short, narrow; shell hyaline, reticulate, porulate; salt water. Numer- ous species. H. scrippsi K. (Fig. 110, i). 130-155m long; Pacific and Atlantic (tropical). Genus Dolichodinium Kofoid and Adamson. Subconical, elongate; without apical or antapical horns; sulcus not indenting epitheca; plate porulate; salt water. D. lineatum (Kofoid and Michener) (Fig. Ill, a). 58m long; eastern tropical Pacific. Genus Goniodoma Stein. Polyhedral with a deep annulus; epi- theca and hypotheca slightly unequal in size, composed of regularly arranged armored plates; chromatophores small brown platelets; fresh or salt water. G. acuminata (Ehrenberg) (Fig. 111,6). About 50m long; salt water. Genus Gonyaulax Diesing. Spherical, polyhedral, fusiform, elongated with stout apical and antapical prolongations, or dorso- ventrally flattened; apex never sharply attenuated; annulus equa- torial; sulcus from apex to antapex, broadened posteriorly; plates 1-6 apical, 0-3 anterior intercalaries, 6 precingulars, 6 annular plates, 6 postincingulars, 1 posterior intercalary and 1 antapical; 260 PROTOZOOLOGY porulate; chromatophores yellow to dark brown, often dense; with- out stigma; fresh, brackish or salt water. Numerous species. G. polyedra Stein (Fig. Ill, c). Angular, polyhedral; ridges along sutures, annulus displaced 1-2 annulus widths, regularly pitted; salt water. "Very abundant in the San Diego region in the summer Fig. 111. a, Dolichodinium lineatum, X670 (Kofoid and Adamson); b, Goniodoma acuminata, X340 (Stein); c, Gonaulax polyedra, X670 (Kofoid); d, G. apiculata, X670 (Lindemann).; e, Spiraulax jolliffei, right side of theca, X340 (Kofoid); f, Dinophxjsis acuta, X580 (Schutt); g, h, Oxyphysis oxytoxoides, X780 (Kofoid); i, Phytodinium simplex, X340 (Klebs); j, k, Dissodinium lunula: ], primary cyst (Dogiel); k, secondary cyst with 4 swarmers (Wailes), X220. plankton, July-September, when it causes local outbreaks of 'red water,' which extend along the coast of southern and lower Cali- fornia" (Kofoid, 1911). DINOFLAGELLATA 261 G. apiculata (Penard) (Fig. Ill, d). Ovate, chromatophores yel- lowish brown; 30-60;* long; fresh water. Genus Spiraulax Kofoid. Biconical; apices pointed; sulcus not reaching apex; no ventral pore; surface heavily pitted; salt water. S. jolliffei (Murray and Whitting) (Fig. Ill, e). 132^ by 92^; California. Family 2 Dinophysidae Kofoid Genus Dinophysis Ehrenberg. Highly compressed ; annulus wid- ened, funnel-like, surrounding small epitheca; chromatophores yel- low; salt water. Several species. D. acuta E. (Fig. 111,/). Oval ; attenuated posteriorly; 54-94/i long; widely distributed; British Columbia (Wailes). Genus Oxyphysis Kofoid. Epitheca developed; sulcus short; sulcal lists feebly developed; sagittal suture conspicuous; annulus im- pressed; salt water. 0. oxytoxoides K. (Fig. Ill, g,h). 63-68/1 by 15m; off Alaska. Fig. 112. a, Leptodiscus medusoides, X50 (Hertwig); b, Craspedotella pileolus, XllO (Kofoid). Family 3 Phytodiniidae Klebs Genus Phytodinium Klebs. Spherical or ellipsoidal; without fur- rows; chromatophores discoidal, yellowish brown. P. simplex K. (Fig. Ill, i). Spherical or oval; 42-50/i by 30-45/i fresh water. Genus Dissodinium Klebs {Pyrocystis Paulsen). Primary cyst, spherical, uninucleate; contents divide into 8-16 crescentic second- ary cysts which become set free; in them are formed 2, 4, 6, or 8 Gymnodinium-like swarmers; salt water. D. lunula (Schutt) (Fig. Ill, j, k). Primary cysts 80-155/1 in diameter; secondary cysts 104-130/i long; swarmers 22/i long; widely distributed; British Coumbia (Wailes). Suborder 3 Cystoflagellata Haeckel Since Noctiluca which had for many years been placed in this suborder, has been removed, according to Kofoid, to the second sub- order, the Cystoflagellata becomes a highly ill-defined group and 262 PROTOZOOLOGY includes two peculiar marine forms: Leptodiscus medusoides Hertwig (Fig. 112, a), and Craspedotella pileolus Kofoid (Fig. 112, h), both of which are medusoid in general body form. References Chatton, E. 1920 Les P^ridieniens parasites ; morphologie, repro- duction, ethologie. Arch. zool. exp. et g^n. Vol. 59. DiwALD, K. 1939 Ein Beitrag zur VariabiUtat und Systematik der Gattung Peridinium. Arch. f. Protistenk., Vol. 93. Fritsch, F. E. 1935 The structure and reproduction of the algae. Vol. 1. Cambridge. Gross, F, 1934 Zur Biologie und Entwicklungsgeschichte von Noctiluca miliaris. Archiv. f. Protistenk., Vol. 83. Kofoid, C. A. 1906 On the significance of the symmetry of the Dinoflagellata. Uni. Calif. Publ. Zool., Vol. 3. — 1920 A new morphological interpretation of Noctiluca and its bearing on the status of Cysto^agellata. Ibid., Vol. 19. and A. M. Adamson 1933 The Dinoflagellata: The family Heterodiniidae of the Peridinioidae. Mem. Mus. Comp. Zool., Harvard, Vol. 54. - and Olive Swezy 1921 The free-living unarmored Dino- flagellata. Mem. Uni. Calif., Vol. 5. Lebour, Marie V. 1925 The dinoflagellates of northern seas. Lon- don. Martin, G. W. 1929 Dinoflagellates from marine and brackish waters of New Jersey. Uni. Iowa Studies in Nat. Hist., Vol. 12, Reichenow, E. 1930 Parasitische Peridinea. Grimpe's Die Tierwelt der Nord- und Ostsee. Part 19. Schilling, A. 1913 Dinojiagellatae (Peridineae). Siisswasserflora Deutschlands, etc. H. 3. Wailes, G. H. 1928 Dinoflagellates and Protozoa from British Columbia. Vancouver Mus. Notes. Vol. 3. Chapter 13 Subclass 2 Zoomastigina Doflein THE Zoomastigina lack chromatophores and their body organ- izations vary greatly from a simple to a very complex type. The majority possess a single nucleus which is, as a rule, vesicular in structure. A characteristic organella, the parabasal body (p. 66) is present in numerous forms and myonemes are found in some species. Nutrition is holozoic or saprozoic (parasitic). Asexual reproduction is by longitudinal fission; sexual reproduction is unknown. Encystment occurs commonly. The Zoomastigina are free-living or parasitic in various animals. With pseudopodia besides flagella Order 1 Rhizomastigina With flagella only With 1-2 flagella Order 2 Protomonadina (p. 268) With 3-8 flagella Order 3 Polymastigina (p. 293) With more than 8 flagella Order 4 Hypermastigina (p. 318) Order 1 Rhizomastigina Biitschli A number of borderline forms between the Sarcodina and the Mastigophora are placed here. Flagella vary in number from one to several and pseudopods also vary greatly in number and in appear- ance. With many flagella Family 1 Multiciliidae With 1-3 rarely 4 flagella Family 2 Mastigamoebidae Family 1 Multiciliidae Poche Genus Multicilia Cienkowski. Generally spheroidal, but amoeboid; with 40-50 flagella, long and evenly distributed; one or more nuclei; holozoic; food obtained by means of pseudopodia; multiplication by fission; fresh or salt water. M. marina C. (Fig. 113, a). 20-30/i in diameter; uninucleate ; salt water. M. lacustris Lauterborn (Fig. 113, 6). Multinucleate; 30-40/ii in diameter; fresh water. Family 2 Mastigamoebidae With 1-3 or rarely 4 flagella and axopodia or lobo podia; uninucle- ate; flagellum arises from a basal granule which is connected with the nucleus by a rhizoplast; binary fission in both trophic and encysted stages; sexual reproduction has been reported in one spe- 263 264 PROTOZOOLOGY cies; holozoic or saprozoic; the majority are free-living, though a few parasitic. Genus Mastigamoeba Schulze {Mastigina Frenzel). Monomasti- gote, uninucleate, with finger-like pseudopodia; flagellum long and connected with nucleus; fresh water, soil or endocommensal. Fig. 113. a, MuUicilia marina, X400 (Cienkowski) ; b, M. lacustris, X400 (Lauterborn) ; c, Mastigamoeba aspera, X200 (Schulze); d, M, longifilum, X340 (Stokes); e, M. setosa, X370 (Goldschmidt); f, Masti- gellavitrea, X 370 (Goldschmidt). M. aspera S. (Fig. 113, c). Subspherical or oval; during locomotion elongate and narrowed anteriorly, while posterior end rounded or lobed; numerous pseudopods slender, straight; nucleus near flagel- late end; 2 contractile vacuoles; 150-200^ by about 50/x; in ooze of pond. M. longifilum Stokes (Fig. 113, d). Elongate, transparent; flagel- lum twice body length; pseudopods few, short; contractile vacuole anterior; body 28/i long when extended, contracted about 10/x; stag- nant water. ZOOMASTIGINA, RHIZOMASTIGINA 265 M. setosa (Goldschmidt) (Fig. 113, e). Up to 140^ long. M. hylae (Frenzel) (Fig. 114, a). In hind gut of frogs and tadpoles; 80-100m by 20)u; flagellum about 10m long. Genus Mastigella Frenzel. Flagellum apparently not connected with nucleus; pseudopods numerous, digitate; body form changes actively and continuously; contractile vacuole. M. vitrea Goldschmidt (Fig. 113,/). 150/x long; sexual reproduction (Goldschmidt). Fig. 114. a, Mastigamoeha hylae, X690 (Becker); b, Adinomonas mirabilis, X1140 (Griessmann) ; c. Dimorpha mutans, X940 (Blochmann); d, Pteridomonas pulex, X540 (Penard); e, Histomonas meleagridis, X940 (Tyzzer); f, Rhizomastix gracilis, X1340 (Mackinnon). Genus Actinomonas Kent. Generally spheroidal, with a single flagellum and radiating pseudopods; ordinarily attached to foreign object with a cytoplasmic process, but swims freely by withdrawing it; nucleus central; several contractile vacuoles; ho lo zoic. A. mirabilis K. (Fig. 114, 6). Numerous simple filopodia; about lOju in diameter; flagellum 20/i long; fresh water. Geuus Dimorpha Gruber. Ovoid or subspherical ; with 2 flagella and radiating axopodia, all arising from an eccentric centriole; nu- cleus eccentric; pseudopods sometimes withdrawn; fresh water. D. mutans G. (Fig. 114, c). 15-20^ in diameter; flagella about 20- 30m long. Genus Pteridomonas Penard. Small, heart-shaped; usually at- tached with a long cytoplasmic process; from opposite pole there 266 PROTOZOOLOGY arises a single flagellum, around which occurs a ring of extremely fine filopods; nucleus central; a contractile vacuole; holo zoic; fresh water. P. pulex P. (Fig. 114, d). 6-12m broad. Genus Histomonas Tyzzer. Actively amoeboid; mostly rounded, sometimes elongate; a single nucleus; an extremely fine flagellum arises from a blepharoplast, located close to nucleus; axostyle (?) sometimes present; in domestic fowls. One species. H. meleagridis (Smith) {Amoeba meleagridis S.) (Figs. 114, e; 115). Actively amoeboid organism; usually rounded; 8-21)u (average 10- 14 n) in the largest diameter; nucleus circular or pyriform with a large abed Fig. 115. Histomonas meleagridis as seen in smears from culture. X1650 (Bishop) a, an amoeboid form; b, rounded form with axostyle (?); c, nucleus preparing to divide; d, a stage in nuclear division. endosome; a fine flagellum; food vacuoles contain bacteria, starch grains and erythrocytes; binary fission; during division flagellum is discarded; cysts unobserved; in young turkeys, chicks, grouse, and quail (Tyzzer). This organism is the cause of enterohepatitis known as "black- head, "an infectious disease, in young turkeys in which it is often fatal and also in other fowls. Smith (1895) discovered the organism and considered it an amoeba. It invades and destroys the mucosa of the intestine and caeca as well as the liver tissues. Trophozoites voided in faeces by infected birds may become the source of new infection when taken in by young birds with drink or food. Tyzzer however demonstrated that the organism is transmissible from bird to bird in the eggs of the nematode Heterakis gallinae. Bishop (1938) made a cultural study of the organism. Dobell (1940) points out the similarity between this flagellate and Dientamoeha fragilis (p. 368). Wenrich (1943) made a comparative study of forms found in the caecal smears of wild ring-neck pheasants and of chicks. The organ- isms measured 5-SOfj. in diameter and possessed 1-4 flagella, though often there were no flagella. Genus Rhizomastix Alexeieff. Body amoeboid; nucleus central: blepharoplast located between nucleus and posterior end; a long ZOOMASTIGINA, RHIZOMASTIGINA 267 fiber runs from it to anterior end and continues into the flagellum; without contractile vacuole; division in spherical cyst. R. gracilis A. (Fig. 114, /). 8-14)u long; flagellum 20/i long; in intestine of axolotles and tipulid larvae. References Becker, E. R. 1925 The morphology of Mastigina hylae (Frenzel) from the intestine of the tadpole. Jour. Paras., Vol. 11. Bishop, Ann 1938 Histomonas meleagridis in domestic fowls (Gal- lus gallus). Cultivation and experimental infection. Parasitol- ogy, Vol. 30. DoBELL, C. 1940 Research on the intestinal Protozoa of monkeys and man. X. Ibid., Vol. 32. Lemmermann, E. 1914 Pantostomatinae. Siisswasserflora Deutsch- lands, etc. H.L. Tyzzer, E. E. 1919 Developmental phases of the protozoon of "blackhead" in Turkeys. Jour. Med. Res., Vol. 40. Wenrich, D. H. 1943 Observations on the morphology of His- tomonas from pheasants and chickens. Jour. Morph., Vol. 72. Chapter 14 Order 2 Protomonadina Blochmann THE protomonads possess one or two flagella and are composed of a heterogeneous lot of Protozoa, mostly parasitic, whose af- finities to one another are very incompletely known. The body is in many cases plastic, having no definite pellicle, and in some forms amoeboid. The method of nutrition is holozoic, or saprozoic (para- sitic). Reproduction is, as a rule, by longitudinal fission, although budding or multiple fission has also been known to occur, while sexual reproduction, though reported in some forms, has not been confirmed. With 1 flagellum With collar Collar enclosed in jelly Family 1 Phalansteriidae Collar not enclosed in jelly Without lorica Family 2 Codosigidae With lorica Family 3 Bicosoecidae (p. 270) Without collar Free-living Family 4 Oikomonadidae (p. 271) Parasitic Family 5 Trypanosomatidae (p. 272) With 2 flagella With undulating membrane Family 6 Cryptobiidae (p. 284) Without undulating membrane Flagella equally long Family 7 Amphimonadidae (p. 285) Flagella unequally long No trailing flagellum Family 8 Monadidae (p. 287) One flagellum trailing Family 9 Bodonidae (p. 289) Family 1 Phalansteriidae Kent Genus Phalansterium Cienkowski. Small, ovoid; one flagellum and a small collar; numerous individuals are embedded in gelatinous substance which presents a dendritic form, with protruding flagella; fresh water. P. digitatum Stein (Fig. 116, a). Cells about 17^ long; oval; colony dendritic; fresh water among vegetation. Family 2 Codosigidae Kent Small flagellates, sometimes with second flagellum which serves for fixation of body; delicate collar surrounds flagellum; ordinarily sedentary forms; if temporarily free, organisms swim with flagellum directed backward; holozoic on bacteria or saprozoic; often colonial; free-living in fresh water. 268 PROTOMONADINA 269 Genus Codosiga Kent {Codonocladium Stein; Astrosiga Kent). In- dividuals clustered at end of a simple or branching stalk; fresh water. C. uiriculus Stokes (Fig. 116, 6). About ll/x long; attached to fresh- water plants. C. disjuncta (Fromentel) (Fig. 116, c). In stellate clusters; cells about 15/x long; fresh water. Genus Monosiga Kent. Solitary; with or without stalk; occasion- ally with short pseudopodia; attached to freshwater plants. Several species. Fig. 116. a, Phalansterium digitatum, X540 (Stein); b, Codosiga utriculus, X1340 (Stokes); c, C. disjuncta, X400 (Kent); d, Monosiga ovata, X800 (Kent); e, M. robusta, X770 (Stokes); f. Desrnarella monili- formis, X800 (Kent); g, Protospongia haeckeli, X400 (Lemmermann); h, Sphaeroeca volvox, X890 (Lemmermann); i, Diplosiga francei, X400 (Lemmermann); j, D. socialis, X670 (Franc6). M. ovata K. (Fig. 116, d). 5-1 5^ long; with a short stalk. M. robusta Stokes (Fig. 116, e). 13/i long; stalk very long. Genus Desrnarella Kent. Cells united laterally to one another; fresh water, D. moniliformis K. (Fig. 116, /). Cells about 6m long; cluster com- posed of 2-12 individuals; standing fresh water. 270 PROTOZOOLOGY D. irregularis Stokes. Cluster of individuals irregularly branching, composed of more than 50 cells; cells 7-1 Iju long; pond water. Genus Protospongia Kent. Stalkless individuals embedded irregu- larly in a jelly mass, collars protruding; fresh water. P. haeckeli K. (Fig. 116, g). Body oval; 8/i long; flagellum 24-32^ long; 6-60 cells in a colony. Genus Sphaeroeca Lauterborn. Somewhat similar to the last genus; but individuals with stalks and radiating; gelatinous mass spheroidal; fresh water. S. volvox L. (Fig. 116, h). Cells ovoid, 8-12jli long; stalk about twice as long; flagellum long; contractile vacuole posterior; colony 82-200/i in diameter; fresh water. Genus Diplosiga Frenzel {Codonosigopsis Senn). With 2 collars; without lorica; a contractile vacuole; solitary or clustered (up to 4); fresh water. D. francei Lemmermann (Fig. 116, i). With a short pedicel; 12ju long; flagellum as long as body. D. socialis F. (Fig. 116, j). Body about IS/x long; usually 4 clus- tered at one end of stalk (15/i long). Family 3 Bicosoecidae Poche Small monomastigote; with lorica; solitary or colonial; collar may be rudimentary; holozoic; fresh water. Genus Bicosoeca James-Clark. With vase-like lorica; body small, ovoid with rudimentary collar, a flagellum extending through it; protoplasmic body anchored to base by a cytoplasmic filament (flagellum?); a nucleus and a contractile vacuole; attached or free- swimming. B. socialis Lauterborn (Fig. 117, a). Lorica cylindrical, 23^ by 12m ; body about lOju long; often in groups; free-swimming in fresh water. Genus Salpingoeca James-Clark. With a vase-like chitinous lorica to which stalked or stalkless organism is attached; fresh or salt water. Numerous species. S. fusiformis Kent (Fig. 117, b). Lorica short vase-like, about 15- 16/Lt long; body filling lorica; flagellum as long as body; fresh water. Genus Diplosigopsis France. Similar to Diplosiga but with lorica; solitary; fresh water on algae. D. affinis Lemmermann (Fig. 117, c). Chitinous lorica, spindle- form, about 15m long; body not filling lorica; fresh water. Genus Histiona Voigt. With lorica; but body without attaching filament; anterior end with lips and sail-like projection; fresh water. PROTOMONADINA 271 H. zachariasi V. (Fig. 117, d). Lorica cup-like; without stalk; about 13m long; oval body 13m long; flagellum long; standing fresh water. Genus Poteriodendron Stein. Similar to Bicosoeca; but colonial; lorica vase-shaped; with a prolonged stalk; fresh water. P. petiolatum (S.) (Fig. 117, e). Lorica 17-50^ high; body 21-35/i long; flagellum twice as long as body; contractile vacuole terminal; standing fresh water. Genus Codonoeca James-Clark. With a stalked lorica; a single flagellum; 1-2 contractile vacuoles; fresh or salt water. Fig. 117. a, Bicosoeca socialis, X560 (Lauterborn); b, Salpingoeca fusiformis, X400 (Lemmermann); c, Diplosigopsis affinis, X590 (Franc^); d, Histiona zachariasi, X440 (Lemmermann); e, Poteriodendron petiola- tuni, X440 (Stein); f, Codonoeca inclinata, X540 (Kent); g, Lagenoeca ovata, x400 (Lemmermann). C. inclinata Kent (Fig. 117, /). Lorica oval; aperture truncate; about 23m long; stalk twice as long; body oval, about 17m long; flagellum 1.5 times as long as body; contractile vacuole posterior; standing fresh water. Genus Lagenoeca Kent. Resembles somewhat Salpingoeca; with lorica; but without any pedicel between body and lorica; solitary; free-swimming; fresh water. L. ovata Lemmermann (Fig. 117, g). Lorica oval, 15m long; body loosely filling lorica; flagellum 1.5 times body length; fresh water. Family 4 Oikomonadidae Hartog Genus Oikomonas Kent. A rounded monomastigote; uninucleate; encystment common; stagnant water, soil and exposed faecal mat- ter. 272 PROTOZOOLOGY 0. termo (Ehrenberg) (Fig. 118, a). Spherical or oval; anterior end lip-like; flagellum about twice body length; a contractile vacuole; 5-20/1 in diameter; stagnant water. Hardin (1942) cultured the organism bacteria-free. Genus Thylacomonas Schewiakoff. Pellicle distinct; cytostome anterior; one flagellum; contractile vacuole anterior; rare. T. compressa S. (Fig. 118, h). 22/x by 18m; flagellum body length; fresh water. Genus Ancyromonas Kent. Ovate to triangular; free-swimming or adherent; flagellum trailing, adhesive or anchorate at its distal end, vibratile throughout remainder of its length; nucleus central; a contractile vacuole; fresh or salt water. Fig. 118. a, Oikomonas termo, X1330 (Lemmermann) ; b, Thylacomonas compressa, X640 (Lemmermann); c, Ancyromonas contorta, X2000 (Lem- mermann); d, Platytheca microspora, X650 (Stein). A. contorta (Klebs) (Fig. 118, c). Triangular, flattened; posterior end pointed; 6-7m by 5-6^; flagellum short; a contractile vacuole; standing fresh water. Genus Platytheca Stein. With a flattened pyriform lorica, with a small aperture; 1 or more contractile vacuoles; fresh water. P. microspora S. (Fig. 118, d). Lorica yellowish brown, with a small aperture; 12-18^ long; flagellum short; among roots of Lemna. Family 5 Trypanosomatidae Doflein Body characteristically leaf-like, although changeable to a certain extent; a single nucleus and a blepharoplast; a flagellum originates in a basal granule which may be independent from, or united with, the blepharoplast (Figs. 9; 119); basal portion of flagellum forms outer margin of undulating membrane which extends along one side of body; exclusively parasitic; a number of important parasitic Protozoa which are responsible for serious diseases of man and domestic animals in various parts of the world are included in it. PROTOMONADINA 273 Genus Trypanosoma Gruby. Parasitic in the circulatory system of vertebrates; highly flattened, pointed at flagellate end, and bluntly rounded, or pointed, at other; polymorphism due to differences in development common; nucleus central; near bluntly rounded end, there is a blepharoplast and usually a basal granule from which the fl^gellum arises and runs toward opposite end, marking the outer boundary of the undulating membrane; in most cases flagellum ex- tends freely beyond body; many w^ith myonemes; multiplication by binary or multiple fission. The organism is carried from host to In vertebrate host Trypanosoma In invertebrate host Trypanosoma Crithidia Leptomonas 0 Leishr Leptomonas and Phytomonas (in plant) Leishmania Crithidia In vertebrate host Herpetomonas Trypanosoma Fig. 119. Diagram illustrating the morphological differences among the genera of Trypanosomatidae (Wenyon) host by blood-sucking invertebrates and undergoes a series of changes in the digestive system of the latter (Fig. 120). A number of forms are pathogenic to their hosts and the diseased condition is termed trypanosomiasis in general. T. gamhiense Button (Fig. 121). The trypanosome, as it occurs in the blood, lymph or cerebro-spinal fluid, is extremely active; body elongate, tapering towards both ends and sinuous; 15-30^ by l-Sn; the small blepharoplast is located near the posterior end; flagellum arises from the blepharoplast and runs forward along the outer border of somewhat spiral undulating membrane, extending freely; binary fission; between long (dividing) and short (recently divided) forms, various intermediates occur; in man in central Africa. 274 PROTOZOOLOGY No other stages are found in the human host. When a "tse-tse" fly, Glossina palpalis or G. tachinoides, sucks the blood of an in- fected person, the trypanosomes remain in its stomach for a few Fig. 120. The Hfe-cycle of Trypanosoma lewisi in the flea, Ceratophyl- lus fasciatus (Minchin and Thomson, modified), a, trypanosome from rat's blood; b, individual after being in flea's stomach for a few hours; c-1, stages in intracellular schizogony in stomach epithelium; m-r, two ways in which rectal phase may arise from stomach forms in rectum; s, rectal phase, showing various types; t, secondary infection of pylorus of hind-gut, showing forms similar to those of rectum. PROTOMONADINA 275 days and undergo multiplication which produces flagellates of diverse size and form until 7th to 10th days when the organisms show a very wide range of forms. From 10th to 12th days on, long slender forms appear in great numbers and these migrate gradually towards proventriculus in which they become predominant forms. They further migrate to the salivary glands and attach themselves to the duct-wall in crithidia form. Here the development continues for 2-5 days and the flagellates finally transform themselves into small trypanosomes which are now infective. These metacyclic tryp- anosomes pass down through the ducts and hypopharynx. When the fly bites a person, the trypanosomes enter the victim. In addition to this so-called cyclic transmission, mechanical transmission may take place. Fig. 121. Trypanosoma gambiense in a stained blood film of an inoculated rat. Two individuals are in the process of division, X1150 (Kudo). Trypanosoma gambiense is a pathogenic protozoan which causes Gambian or Central African sleeping sickness. The disease occurs in, and confined to, central Africa within a zone on both sides of the equator where the vectors, Glossma palpalis and G. tachinoides (on the west coastal region) live. Many wild animals have been found naturally infected by the organisms and are considered to be reser- voir hosts. The chief lesions of infection are in the lymphatic glands and in the central nervous system. In all cases, there is an extensive small- cell infiltration of the perivascular lymphatic tissue throughout the central nervous system. T. rhodesiense Stephens and Fantham (Fig. 122). Morphologically similar to T. gambiense, but when inoculated into rats, the position of the nucleus shifts in certain proportion (usually less than 5%) of individuals toward the posterior end, near or behind the blepharo- plast, together with the shortening of body. Some consider this 276 PROTOZOOLOGY trypanosome as a virulent race of T. gambiense or one transmitted by a different vector, others consider it a human strain of T. hriocei. The disease caused by this trypanosome appears to be more virulent and runs a course of only a few months. It is known as Rhodesian or East African sleeping sickness. The organism is con- fined to south-eastern coastal areas of Africa and transmitted by Glossina morsitans. Q jO^O^ \ ^ j ^•-' % %® -?^o^' ^O ^ Fig. 122. Trypanosoma rhodesiense in a stained blood film of an inoculated rat, X1150 (Kudo). T. cruzi Chagas (Schizotrypanum cruzi C; T. triatomae Kofoid and McCulloch) (Fig. 123). A small curved (C or U) form about 20/i long; nucleus central; blepharoplast conspicuously large, located close to sharply pointed non-flagellate end; multiplication takes r I Fig. 123. Trypanosoma cruzi, X1150 (Kudo). 1, five trypanosomes in a very thin blood film of an inoculated rat; 2, leishmania forms occurring in the skeletal muscle cell of patient; 3, a flagellating individual seen in a host cell. place in the cells of nearly every organ of the host body; upon enter- ing a host cell, the trypanosome loses its flagellum and undulating membrane, and assumes a leishmania form which measures 2 to 5/^ in diameter; this form undergoes repeated binary fission, and a large number of daughter individuals are produced; they develop sooner or PROTOMONADINA 277 later into trypanosomes which, through rupture of host cells, become liberated into blood stream. This trypanosome is the causative organism of Chagas' disease or South American trypanosomiasis which is mainly a children's dis- ease, and is widely distributed in Brazil, Argentina, Uruguay, Peru, Venezuela, Colombia, Panama, Salvador, Guatemala, and Mexico. In the infected person, the heart and skeletal muscles show cyst-like bodies. The transmission of the organism is carried on by numerous spe- cies of reduviid bugs, bed bugs and certain ticks, though the first named bugs belonging to genus Triatoma (cone-nosed or kissing bug), especially T. megista, are the chief vectors. When T. niegista (nymph or adult) ingests the infected blood, the organisms undergo division in stomach and intestine, and become transformed into crithidia forms which continue to multiply. In 8-10 days the meta- cyclic or infective trypanosomes make their appearance and pass out in the faeces of the bug. Inoculation of the parasite into man appears to take place through ingestion of the insect faeces or scratching the bite-site and directly injecting the trypanosomes into the wounds. Cats, dogs, opossums, monke3^s, armadillos, bats, foxes, squirrels, wood rats, etc., have been found to be naturally infected by T. cruzi, and are considered as reservoir hosts. Vectors are also numerous. No cases of Chagas' disease have been reported from the United States, but Wood (1934) found a San Diego wood rat (Neotoma fiiscipes macrotis) in the vicinity of San Diego, California, in- fected by Trypanosoma cruzi and Packchanian (1942) observed in Texas, 1 nine-banded armadillo (Dasypis novemcinctus) , 8 opossums (Didelphys virginiana), 2 house mice {AIus musculus), and 32 wood rats (Neotoma micropus micropus), naturally infected by Trypano- soma cruzi. It has now become known through the studies of Kofoid, Wood, and others that Triatoma protracta (California, New Mex- ico), T. rubida (Arizona, Texas), T. gerstaeckeri (Texas), T. heide- manni (Texas), T. longipes (Arizona), etc., are naturally infected by T. cruzi. Wood and Wood (1941) consider it probable that human cases of Chagas' disease may exist in southwestern United States. For information on the species of Triatoma and their re- lationships to Trypanosoma cruzi, the reader is referred to Usinger (1944). T. hrucei Plimmer and Bradford (Figs. 9, a; 124, a). Polymorphic; 15-30/i long (average 20fx); transmitted by various species of tsetse flies, Glossina; the most virulent of all trypanosomes; the cause of the fatal disease known as "nagana" among mules, donkeys, horses, 278 PROTOZOOLOGY camels, cattle, swine, dogs, etc., which terminates in the death of the host animal in from two weeks to a few months; wild animals are equally susceptible; the disease occurs, of course, only in the region in Africa where the tsetse flies live. T. iheileri Laveran (Fig. 124, h). Large trypanosome which oc- curs in blood of cattle; sharply pointed at both ends; 60-7 Oju long; myonemes are well developed, T. americanum Crawley. In American cattle; probably identical with T. theileri; transmitted from cattle to cattle by tabanid flies. Fig. 124. a, Trypanosoma hrucei; b. T. theileri; c, T. melophagium ; d, T. evansi; e, T. equinum; f, T. equiperdum; g, T. lewisi; all X1330 (several authors). T. melophagium (Flu) (Fig. 124, c). A trypanosome of the sheep; 50-60m long with attenuated ends; transmitted by Melophagus ovinus. T. evansi (Steel) (Fig. 124, d). In horses, mules, donkeys, cattle, dogs, camels, elephants, etc. ; infection in horses seems to be usually fatal and known as "surra"; about 25^* long; monomorphic; trans- mitted by tabanid flies; widely distributed. T. equinum Vages (Fig. 124, e). In horses in South America, caus- ing an acute disease known as "mal de Caderas"; other domestic animals do not suffer as much as do horses; 20-25^ long; without blepharoplast. T. equiperdum Doflein (Fig. 124, /). In horses and donke,ys; causes "dourine," a chronic disease; widely distributed; 25-30/Lt long; no intermediate host; transmission takes place directly from host to host during sexual act. PROTOMONADINA 279 T. lewisi (Kent) (Figs. 120; 124, g). In blood of various species of rat; widely distributed; about 25m long; very active; slender; with a long flagellum; transmitted by the flea, Ceratophyllus fasciaius, in which the organism undergoes changes (Fig. 120); when a rat swal- lows freshly voided faecal matter containing the organisms, it be- comes infected. T. duttoni Thiroux. In the mouse; similar to T. lewisi, but rats are said not to be susceptible, hence considered as a distinct species; transmission by fleas. T. peromysci Watson. Similar to T. lewisi; in Canadian deer mice, Peromyscus maniculatus and others. T. nahiasi Railliet. Similar to T. lewisi; in rabbits, Lepus do- mesticus and L. cuniculus. T. paddae Laveran and Mesnil. In Java sparrow, Munia oryzi- vora. T. noctuae (Schaudinn). In the little owl, Athene noctua. Numerous other species are known. Crocodiles, snakes, and turtles are also hosts for Trypanosoma. Transmission by blood-sucking arthropods or leeches. T. rotatorium (Meyer) (Fig. 125, a). In tadpoles and adults of various species of frog; between a slender form with a long projecting flagellum measuring about SSju long and a very broad one without free portion of flagellum, various intermediate forms are to be noted in a single host; blood vessels of internal organs, such as kid- neys, contain more individuals than the peripheral vessels; nucleus central, hard to stain; blepharoplast small; undulating membrane highly developed; myonemes prominent; multiplication by longi- tudinal fission; the leech, Placohdella marginata, has been found to be the transmitter in some localities T. inopinatum Sergent and Sergent (Fig. 125, h). In blood of vari- ous frogs; slender; 12-20 fj. long; larger forms 30-35m long; blepharo- plast comparatively large; transmitted by leeches. Numerous species of Trypanosoma have been reported from the frog, but specific identification is difficult; it is better and safer to hold that they belong to one of the 2 species mentioned above until their development and transmission become known. T. diemyctyli Tobey (Fig. 125, c). In blood of the newt, Triturus viridescens ; a comparatively large form; slender; about 50^ by 2-5/i; flagellum 20-25m long; with well developed undulating membrane. Both fresh and salt water fish are hosts to different species of trypanosomes; what effect these parasites exercise upon the host 280 PROTOZOOLOGY fish is not understood; as a rule, only a few individuals are ob- served in the peripheral blood of the host. T. grranwZoswm Laveran and Mesnil (Fig. 125, e). In the eel, Anguilla vulgaris; 7 0-80 fj, long. T. giganteum Neumann (Fig. 125, d). In Raja oxyrhynchus; 125- ISO/x long. T. remaki Laveran and Mesnil (Fig, 125, /). In Esox lucius, E. reticulatus and probably other species; 24-33/x long. Fig. 125. a, Trypanosoma rotatorium X750 (Kudo); b, T. inopinaturn, X1180 (Kudo); c, T. diemydyli, X800 (Hegner); d, T. giganteum, X500 (Neumann); e, T. granulosum, XlOOO (Minchin); f, T. remaki, X1650 (Kudo); g, T. percae, XlOOO (Minchin); h, T. danileivskyi, XlOOO (Laveran and Mesnil); i, T. rajae, X1600 (Kudo). T. percae Brumpt (Fig. 125, g). In Perca fluviatilis; 45-50/x long. T. danilewskyi Laveran and Mesnil (Fig. 125, h). In carp and goldfish; widely distributed; 40^i long. T. rajae Laveran and Mesnil (Fig. 125, i). In various species of Raja; 30-35/1 long. Genus Crithidia Leger. Parasitic in arthropods and other inverte- brates; blepharoplast located between central nucleus and flagellum- bearing end (Fig. 119); undulating membrane not so well developed as in Trypanosoma; it may lose the flagellum and form a leptomonas or rounded leishmania stage which leaves host intestine with faecal matter and becomes the source of infection in other host animals. C. euryophthalmi McCulloch (Fig. 126, a-c). In gut of Eury- ophthalmus convivus; California coast. PROTOMONADINA 281 C. gerridis Patton (Fig. 126 d). In intestine of water bugs, Gerris and Micro velia; 22-45m long. C. hyalommae O'Farrell (Fig. 126, e, /). In body cavity of the cattle tick, Hyalomma aegyptium in Egypt; the flagellate through its invasion of ova is said to be capable of infecting the offspring while it is still in the body of the parent tick. Genus Leptomonas Kent. Exclusively parasitic in invertebrates; blepharoplast very close to flagellate end; without undulating mem- brane (Fig, 119) ; non-flagellate phase resembles Leishmania. L. ctenocephali Fantham (Fig. 126, g, h). In hindgut of the dog flea, C tenocephalus canis; widely distributed. Fig. 126. a-c, Crithidia euryophthalmi (a, b, in mid-gut; c, in rectum), X880 (McCulloch); d, C. gerridis, X1070 (Becker); e, f, C. hyalom- rnae, XlOOO (O'Farrell); g, h, Leptomonas ctenocephali, XlOOO (Wenyon); i, j, Phytomonas elmassiani (i, in milkweed, Asclepias sp.; j, in gut of a suspected transmitter, Oncopeltus fasciatus), X1500 (Holmes); k, Herpetomonas muscarum, X1070 (Becker); 1-n, H. drosophilae, XlOOO (Chatton and L^ger). Genus Phytomonas Donovan. Morphologicall}^ similar to Lep- tomonas (Fig. 119); in the latex of plants belonging to the families Euphorbiaceae, Asclepiadaceae, Apoc3^naceae, Sapotaceae and Utricaceae; transmitted by hemipterous insects; often found in enormous numbers in localized areas in host plant; infection spreads from part to part; infected latex is a clear fluid, owing to the absence of starch grains and other particles, and this results in degeneration of the infected part of the plant. Several species. P. davidi (Lafront). 15-20^ by about 1.5ai; posterior portion of body often twisted two or three times; multiplication by longitu- dinal fission; widely distributed; in various species of Euphorbia. 282 PROTOZOOLOGY P. elmassiani (Migone) (Fig. 126, i, j). In various species of milk- weeds; 9-20/x long; suspected transmitter, Oncopeltus fasciatus (Holmes) ; in South and North America. Genus Herpetomonas Kent. Ill-defined genus (Fig. 119); ex- clusively invertebrate parasites; Trypanosoma-, Crithidia-, Lep- tomonas-, and Leishmania-forms occur during development. Several species. H. muscarum (Leidy) ( H. muscae-domesticae (Burnett)). (Fig. 126, k). In gut of flies, belonging to the genera Musca, Calliphora, Sarco- phaga, LuciUa, Phormia, etc ; up to 30/i by 2-3)u. H. drosophilae (Chatton and Alilaire) (Fig. 126, l-n). In intestine of Drosophila confusa; large leptomonad forms 21-25)U long, flagel- lum body-length; forms attached to rectum 4-5m long. Genus Leishmania Ross. In man or dog, the organism is an ovoid body with a nucleus and a blepharoplast; 2-5)U in diameter; with often vacuoles and sometimes a rhizoplast near the blepharoplast; intracellular parasite in the cells of reticulo-endothelial system; multiplication by binary fission. In the intestine of blood-sucking insects or in cultures, the organism develops into leptomonad form which multiplies by longitudinal fission. There are known at present three "species" of Leishmania which are morphologically alike. They do not show any distinct differential characteristics either by animal inoculation experiments or by cul- ture method. The agglutination test which Noguchi (1924) applied for this purpose has been found to give contradictor}^ results by re- cent investigators. Species of Phlebotomus (sand-flies) have long been suspected as vectors of Leishmania. When a Phlebotomus feeds on kala-azar patient, the leishmania bodies become flagellated and undergo multiplication so that by the third day after the feeding, there are large numbers of Leptomonas flagellates in the mid-gut. These flagellates migrate forward to the pharynx and mouth cavity on the 4th or 5th day. On the 7th to 9th days (after the fly is fed a second time), the organisms may be found in the proboscis. But the great majorit}^ of the attempts to infect animals and man by the bite of infected Phlebotomus have failed, although in a number of cases small numbers of positive infection have been reported. Adler and Ber (1941) have succeeded recently in producing cutaneous leish- maniasis in 5 out of 9 human volunteers on the site of bites by lab- oratory-bred P. papatasii which were fed on the flagellates of Leishmania tropica suspended in 3 parts 2.7% saline and 1 part de- fibrinated blood and kept at a temperature of 30°C. Swaminath, PROTOMONADINA 283 Shortt and Anderson (1942) also succeeded in producing kala-azar infections in 3 out of 5 volunteers through the bites of P. argentipes. L. donovani (Laveran and Mesnil) (L. m/an^wm Nicolle) (Fig. 127). As seen in stained spleen puncture smears, the organism is rounded (l-3ju) or ovoid (2-4/x by 1.5-2.5^); cytoplasm homogeneous, but often with minute vacuoles; nucleus comparatively large, often spread out and of varied shapes; blepharoplast stains more deeply and small; number of parasites in a host cell varies from a few to over 100. This is the cause of kala-azar or visceral leishmaniasis which is widely distributed in Europe (Portugal, Spain, Italy, Malta, Greece, and southern Russia), in Africa (Morocco, Algeria, Tunisia, Libya, IS i 1 \ ^%'*|* «>«^^>» 4 »' 2 ^^ . 5 Fig. 127. Leishmania donovani, XlloO (Kudo). 1, an infected poly- morphonuclear leucocyte; 2, leishmania bodies scattered in the blood plasma; 3, a large endothelial cell infected by the organisms; 4-6, flagel- late forms which developed in the first five days of cultivation in blood- agar medium. Abyssinia, Sudan, northern Kenya and Nigeria) and in Af^ia (India, China, Turkestan, etc.). The parasite is most abundantly found in the macrophages, mononuclear leucocytes, and polymorphonuclears of the reticulo-endothelial system of various organs such as spleen, liver, bone marrow, intestinal mucosa, lymphatic glands, etc. The most characteristic histological change appears to be an in- crease in number of large macrophages and mononuclears. The spleen and liver become enlarged due in part to increased fibrous tissue and macrophages. The organism is easily cultivated in blood-agar media (p. 716). After two days, it becomes larger and elongate until it measures 14-20)Li by 2/x. A flagellum as long as body develops from the bleph- aroplast and it thus assumes leptomonad form which repeats 284 PROTOZOOLOGY longitudinal division. Dogs are naturally infected with L. donovani and may be looked upon as reservoir host. Vectors are Phlehotomus argentipes and other species of Phlebotomus. L. tropica (Wright). This is the causative organism of the Oriental sore or cutaneous leishmaniasis. It has been reported from Africa (mainly regions bordering the Mediterranean Sea), Europe (Spain Italy, France, and Greece), Asia (Syria, Palestine, Armenia, South- ern Russia, Iraq, Iran, Arabia, Turkestan, India, Indo-China, and China), and Australia (northern Queensland). The organisms are present in the endothelial cells in and around the cutaneous lesions, located on hands, feet, legs, face, etc. L. tropica is morphologically indistinguishable from L. donovani, but some believe that it shows a wider range of form and size than the latter. In addition to rounded or ovoid forms, elongate forms are often found, and even leptomonad forms have been reported from the scrapings of lesions. The insect vectors are Phlehotomus papa- tasii (p. 282), P. sergenti and others. Direct transmission through wounds in the skin also takes place. The lesion appears first as a small papula on skin; it increases in size and later becomes ulcerated. Microscopically an infiltration of corium and its papillae by lympho- cytes and macrophages is noticed; in ulcerated lesions leishmania bodies are found in the peripheral zone and below the floor of the ulcers. L. brasiliensis Vianna. This organism causes Espundia, Bubos, or South American or naso-oral leishmaniasis, which appears to be confined to South and Central America. It has been reported from Brazil, Peru, Paraguay, Argentina, Uruguay, Bolivia, Venezuela, Ecuador, Colombia, Panama, Costa Rica, and Mexico. Its morphological characteristics are identical with those of L. tropica, and a number of investigators combine the two species into one. However, L. brasiliensis produces lesions mainly in the mucous membrane of the nose, mouth and pharynx. Vectors appear to be Phlehotomus intermedius and other species of the genus. Direct transmission through wounds is also probable. Family 6 Cryptobiidae Poche Biflagellate trypanosome-like pro to monads; 1 flagellum free, the other marks outer margin of undulating membrane; blepharoplast an elongated rod-like structure, often referred to as the parabasal body; all parasitic. Genus Cryptobia Leidy (Trypanoplasma Laveran and Mesnil). PROTOMONADINA 285 Parasitic in reproductive organs of molluscs and other invertebrates and in blood and gut of fish. C. helicis L. (Fig. 128, a). In reproductive organs of various species of Helix in America and Europe; Q-20fx long; asexual reproduction through binary fission. C. horreli (Laveran and Mesnil) (Fig. 128, b). In blood of various freshwater fishes such as Catostomus, Cyprinus, etc.; 20-25^ long. C. cyprini (Plehn) (Fig. 128, c). In blood of carp and goldfish; 10-30julong; rare. C. grohheni (Keysselitz). In coelenteric cavity of Siphonophora; about 65m by 4^. Fig. 128. a, Cryptobia helicis, X1690 (Belaf); b, C. borreli, X580 (Mavor); C. cyprini, X600 (Plehn). Family 7 Amphimonadidae Kent Body naked or with a gelatinous envelope; 2 equally long anterior flagella; often colonial; 1-2 contractile vacuoles; free-swimming or attached ; mainly fresh water. Genus Amphimonas Dujardin. Small oval or rounded amoeboid; flagella at anterior end; free-swimming or attached by an elongated stalk-like posterior process; fresh or salt water. A. globosa Kent (Fig. 129, a). Spherical; about IS/z in diameter; stalk long, delicate; fresh water. Genus Spongomonas Stein. Individuals in granulated ^gelatinous masses; flagella with 2 basal granules; one contractile vacuole; colo- nial; with pointed pseudopodia in motile stage; fresh water. S. uvella S. (Fig. 129, b). Oval; 8-12/i long; flagella 2-3 times as long; colony about 50/i high; fresh water. 286 PROTOZOOLOGY Genus Cladomonas Stein. Individuals are embedded in dichot- omous dendritic gelatinous tubes which are united laterally; fresh water. C . fruticulosa S. (Fig. 129, c). Oval; about 8/x long; colony up to 85m high. Genus Rhipidodendron Stein. Similar to Cladomonas, but tubes are fused lengthwise ; fresh water. Fig. 129. a, Amphimonas globosa, X540 (Kent); b, Spongomonas uvella, X440 (Stein); c, Cladomonas fruticulosa, X440 (Stein); d, e, Rhipidoden- dron splendidum (d, a young colony, X440; e, a freeswimming individual, X770) (Stein); f, Spiroynonas augusta, XlOOO (Kent); g, Diplomita soci- alis, XlOOO (Kent); h, Streptonionas cordata, X890 (Lemmermann); i, Dinomonas vorax, X800 (Kent). R. splendidum S. (Fig. 129, d, e). Oval; about 13^ long; flagella about 2-3 times body length; fully grown colony 350|u high. Genus Spiromonas Perty. Elongate; without gelatinous covering; spirally twisted; 2 flagella anterior; solitary; fresh water. *S. augusta (Dujardin) (Fig. 129,/). Spindle-form; about 10/x long; stagnant water. Genus Diplomita Kent. With transparent lorica; body attached to bottom of lorica by a retractile filamentous process; a rudimen- tary stigma (?) ; fresh water. PROTOMONADINA 287 D. socialis K. (Fig. 129, g). Oval flagellum about 2-3 times the body length; lorica yellowish or pale brown; broadly spindle in form; about ISjLt long; pond water. Genus Streptomonas Klebs. Free-swimming; naked; distinctly keeled ; fresh water, S. cordata (Perty) (Fig. 129, h). Heart-shaped; 15/x by 13/x; rota- tion movement. Genus Dinomonas Kent. Ovate or pyriform, plastic, free-swim- ming; 2 flagella, equal or sub-equal, inserted at anterior extremity, where large oral aperture, visible only at time of food ingestion, is also located, feeding on other flagellates; in infusions. D. vorax K. (Fig. 129, i). Ovoid, anterior end pointed; 15-16^. long; flagella longer than body; hay infusion and stagnant water. Family 8 Monadidae Stein Two unequal flagella; one primary and the other secondary; swim- ming or attached; 1-2 contractile vacuoles; colony formation fre- quent; free-living. Genus Monas Mliller (Physomonas Kent). Plastic and actively motile ("dancing movement"); often attached to foreign objects; not longer than 20ju; known for a long time, but still very incom- pletely. Krijgsman (1925) studied the flagellar movements (p. 111). M. guttula Ehrenberg (Fig. 130, a). Spherical to ovoid; 14-16/x long; free-swimming or attached; longer flagellum about 1-2 times body length; cysts 12ju in diameter; stagnant water. M. elongata (Stokes) (Fig. 130, b). Elongate; about ll/x long; free- swimming or attached; anterior end obliquely truncate; fresh water. M. socialis (Kent) (Figs. 8, g; 130, c). Spherical; 5-10/i long; among decaying vegetation in fresh water. M. vestita (Stokes) (Fig. 130, d). Spherical; about 13. 5m in diam- eter; stalk about 40/x long; pond water. Reynolds (1934) made a careful study of the organism. M. sociabilis Meyer. Body 8-10^ long by 5^; two unequal flagella; the longer one is as long as the body and the shorter one about one- fourth; 20-50 individuals form a spheroid colony, resembling a detached colony of Anthophysis; polysaprobic. Genus Stokesiella Lemmermann. Body attached by a fine cyto- plasmic thread to a delicate and stalked vase-like lorica; 2 contrac- tile vacuoles; fresh water. S. dissimilis (Stokes) (Fig. 130. e). Solitary; lorica about 28/i long. S. leptostoma (S.) (Fig. 130, /). Lorica about IT/n long; often in groups ; on vegetation. 288 PROTOZOOLOGY Genus Stylobryon Fromentel. Similar to Stokesiella; but colonial; on algae in fresh water. S. abhotti Stokes (Fig. 130, g). Lorica campanulate; about 17/x long; main stalk about lOO/x high; body oval or spheroidal; flagella short. Genus Dendromonas Stein. Colonial; individuals without lorica, located at end of branched stalks; fresh water among vegetation. Fig. 130. a, Monas guttula, X620 (Fisch); b, M. elongata, X670 (Stokes); c, M. socialis, X670 (Kent); d, M. vestita, X570 (Stokes); e, Stokesiella dissijnilis, X500 (Stokes); f, S. leptostoma, X840 (Stokes); g, Stylobryon abhotti, X480 (Stokes); h, Dendromonas virgaria, a young colony of, X670 (Stein); i, Cephalothamnium cyclopum, X440 (Stein); j, k, Anthophysis vegetans (j, part of a colony, X230; k, an individual, X770) (Stein). W_D. virgaria (Weisse) (Fig. 130, h). About 8m long; colony 200ju high; pond water. Genus Cephalothamnium Stein. Colonial; without lorica, but in- dividuals clustered at the end of a stalk which is colorless and rigid; fresh water. C. cyclopum S. (Fig. 130, i). Ovoid; 5-10/i long; attached to body of Cyclops and also among plankton. Genus Anthophysis Bory (Anthophysa). Colonial forms, some- PROTOMONADINA 289 what similar to Cephalothamnium; stalks yellow or brownish and usually bent; detached individuals amoeboid with pointed pseudo- podia. A. vegetans (Miiller) (Fig. 130, y, k). About 5-6^ long; common in stagnant water and infusion. Family 9 Bodonidae Biitschli With 2 flagella; one directed anteriorly and the other posteriorly and trailing; flagella originate in anterior end which is drawn out to a varying degree; one to several contractile vacuoles; asexual re- production by binary fission; holozoic or sap ro zoic (parasitic). Genus Bodo Ehrenberg (Prowazekia Hartman and Chagas). Small, ovoid, but plastic; cytostome anterior; nucleus central or anterior; flagella connected with 2 blepharoplasts in some species; encystment common; in stagnant water and coprozoic. Numerous species. B. caudatus (Dujardin) (Fig. 131, a, h). Highly flattened, usually tapering posteriorly; 11-22^ by 5-10/x; anterior flagellum about body length, trailing flagellum longer; blepharoplast; cysts spherical; stagnant water. B. edax Klebs (Fig. 131, c). Oval with pointed anterior end; 11-15/x by 5-7/i; stagnant water. Genus Pleuromonas Perty. Naked, somewhat amoeboid; usually attached with trailing flagellum; active cytoplasmic movement; fresh water. P. jaculans P. (Fig. 131, d). Body 6-10/i by about 5^; flagellum 2-3 times body length; 4-8 young individuals are said to emerge from a spherical cyst; stagnant water. Genus Rhynchomonas Klebs {Cruzella Faria, da Cunha and Pinto). Similar to Bodo, but there is an anterior extension of body, in which one of the flagella is embedded, while the other flagellum trails; a single nucleus; minute forms; fresh or salt water; also some- times coprozoic. R. nasuta (Stokes) (Fig. 131, e). Oval, flattened; 5-6m by 2-3/x; fresh water and coprozoic. R. marina (F., C. and P.). In salt water. Genus Proteromonas Kunstler (Prowazekella Alexeieff). Elon- gated pyriform; 2 flagella from anterior end, one directed anteriorly and the other, posteriorly; nucleus anterior; encysted stage is re- markable in that it is capable of increasing in size to a marked de- gree; exclusively parasitic; in gut of various species of lizards. P. lacertQ,Q (Grassi) (Figs. 9, 6; 131, /). Elongate, pyriform; 10- 290 PROTOZOOLOGY 30/i long, gut of lizards belonging to the genera Lacerta, Tarentola, etc. Genus Retortamonas Grassi {Emhadomonas Mackinnon). Body plastic, usually pyriform or fusiform, drawn out posteriorly; a large cytostome toward anterior end; nucleus anterior; 2 flagella; cysts pyriform or ovoid; parasitic in the intestines of various animals. Fig. 131. a, b, Bodo caudatus, X1500 (Sinton); c, B. edax, X1400 (Kiihn); d, Pleuromonas jaculans, X650 (Lemmermann) ; e, Rhin- chomonas nasuta, XlSOO (Parisi); f, Proteroynonas lacertae, X2500 (Kiihn); g, Retortamonas gryllotalpae, X2000 (Wenrich); h, R. blattae, X2000 (Wenrich); i, R. intestinalis, X2000 (Wenrich); j, Phyllomitus undulans, XlOOO (Stein); k, Col-ponema loxodes, X650 (Stein); 1, Cerco- monas longicauda, X2000 (Wenyon); m, C. crassicauda, X2000 (Dobell). R. gryllotalpae G. (Fig. 131, g). About 7-14^ (average lO^t) long; in intestine of the mole cricket, Gryllotalpa gryllotalpa. R. blattae (Bishop) (Fig. 131, h). About 6-9/x long; in colon of cockroaches. PROTOMONADINA 291 R. intestinalis (Wenyon and O'Connor) (Figs. 131, i; 132). Poly- morphic, often pyriform or ovoid with drawn-out posterior end; 4-9m by 3-4)u; cytostome large, about 1/3 the body length ; vesicular nucleus with an endosome near anterior end; anterior flagellum as long as the body; posterior flagellum shorter, but thicker, in or near cyto- stome; cysts pyriform; 4.5-7/i long; a single nucleus and an oblong area surrounded by fibril; commensal in the lumen of human intes- tine; trophozoites and also cysts occur in diarrhoeic faeces; of com- paratively rare occurrence. Genus Phyllomitus Stein. Oval; highly plastic; cytostome large and conspicuous; 2 unequal flagella, each originates in a basal gran- ule; apparently no blepharoplast; fresh water or coprozoic. r ^ % ^ 4 • • 8 Fig. 132. Retortanionas intestinalis, X1150. 1-3, living organisms; 4, 5, stained trophozoites; 6, a fresh cj^st; 7, 8, stained cysts (1-4, Wenyon and O'Connor; 5, Dobell and O'Connor; 7, Jepps; 6, 8, Kudo). P. undulans S. (Fig. 131, j). Ovoid; 21-27/x long; trailing flagel- lum much longer than anterior one; stagnant water. Genus Colponema Stein. Body small; rigid; ventral furrow con- spicuous, wide at anterior end; one flagellum arises from anterior end and the other from middle of body; fresh water. C. loxodes S. (Fig. 131, k). 18-30^t by lA/j, cytoplasm with refractile globules. Genus Cercomonas Dujardin. Biflagellate, both flagella arising from anterior end of body; one directed anteriorly and the other runs backward over body surface, becoming a trailing flagellum; plastic; pyriform nucleus connected with the basal granules of flagella; spherical cysts uninucleate; fresh water or coprozoic. C. longicauda D. (Fig. 131, I). Pyriform or ovoid; posterior end drawn out; 18-36m by 9-14//; flagella as long as body; pseudopodia; fresh water and coprozoic. 292 PROTOZOOLOGY C. crassicauda D. (Fig. 131, m). 10-16m by 7-10/x; fresh water and CO pro zoic. References Adler, S. and M. Ber 1941 The transmission of Leishmania tropica by the bite of Phlehotomus papatasii. Indian Jour. Med. Res., Vol. 29. Hardin, G. 1942 An investigation of the physiological require- ments of a pure culture of the heterotrophic flagellate, Oikomo- nas termo, Kent. Physiol. Zool., Vol. 15. Holmes, F. 0. 1925 The relation of Herpetomonas elmassiani (Migone) to its plant and insect hosts. Biol. Bull., Vol. 49. Laveran, a. and F. Mesnil 1912 Trypanosomes et Trypano- somiases. Second edition. Paris. Lemmermann, E. 1914 Protomastiginae. Siisswasserfl. Deutsch- lands, etc., H. 1. MiNCHiN, E. A. and J. D. Thomson 1915 The rat trypanosome, Trypanosoma lewisi, in its relation to the rat flea, Ceratophyllus fasciatus. Quart. Jour. Micr. Sci., Vol. 60. Nelson, R. 1922 The occurrence of Protozoa in plants affected with mosaic and related diseases. Michigan Agr. Coll. Bot. Stat., Tech. Bull. No. 58. Reynolds, B. D. 1934 Studies on monad flagellates. I, II. Arch. f. Protistenk., Vol. 81. SwAMiNATH, C. S., E. Shortt and A. P. Anderson 1942 Transmis- sion of Indian kala-azar to man by the bites of Phlebotomiis ar- gentipes. Indian Jour. Med. Res., Vol. 30. UsiNGER, R. L. 1944 The Triatominae of North and Central Amer- ica and the West Indies and their public health significance. U. S. Public Health Bull, No. 288. Wenyon, C. M. 1926 Protozoology, Vol. 1. London. Wood, F. D. and S. F. Wood 1941 Present knowledge of the dis- tribution of Trypanosoma cruzi in reservoir animals and vectors. Amer. Jour. Trop. Med., Vol. 21. Chapter 15 Order 3 Polymastigina Blochmann THE Zoomastigina placed in this group possess 3-8 (in one family up to a dozen or more) flagella and generally speaking, are minute forms with varied characters and structures. Many possess a cytostome and one to many nuclei and the body is covered by a thin pellicle which allows the organism to change form, although each species shows a typical form. The cytoplasm does not show any special cortical differentiation; in many, there is an axial structure known as axostyle or axostylar filaments (p. 61). In Trichomonadi- dae, there is usually a rod-like structure, known as costa (Kunstler), along the base of the undulating membrane and in Devescovinidae, there is a subtriangular body, the cresta, directly below the basal portion of the trailing flagellum, which in some species is very large and capable of movement. At the time of division, the old costa is retained and a new one is formed; the cresta however is resorbed and two new ones are produced (Kirby). Parabasal bodies of various form and structure occur in many species. The majority of Polymastigina inhabit the digestive tract of ani- mals and nutrition is ho lo zoic or sap ro zoic (parasitic) . Many xylopha- gous forms hold symbiotic relationship with the host termites. Asexual reproduction is by longitudinal fission, sometimes multiple. Encystment is common, and the cyst is responsible for infection of new hosts through mouth. Sexual reproduction has not been defi- nitely established. With 1 nucleus Suborder 1 Monomonadina With 2 nuclei Suborder 2 Diplomonadina (p. 311) With more than 2 nuclei Suborder 3 Polymonadina (p. 315) Suborder I Monomonadina Without axial organella With 3 flagella Family 1 Trimastigidae (p. 294) With 4 flagella None undulates on body surface Without cell-organ of attachment. . Family 2 Tetramitidae (p. 296) With rostellum Family 3 Streblomastigidae (p. 298) One undulates on body surface . . Family 4 Chilomastigidae (p. 298) With more than 4 flagella Family 5 Callimastigidae (p. 299) With axial organella Without undulating membrane Without cresta Flagella not adhering to body Without rostellum Family 6 Polymastigidae (p. 299) 293 294 PROTOZOOLOGY With rostellum Family 7 Oxymonadidae (p. 301) Flagellar cords on body surface Family 8 Dinenymphidae (p. 302) With cresta Family 9 Devescovinidae (p. 303) With undulating membrane. . . .Family 10 Trichomonadidae (p. 308) Family 1 Trimastigidae Kent Genus Trimastix Kent. Ovate or pyriform; naked; free-swimming; with a laterally produced membranous border; 3 flagella (1 anterior flagellum vibrating, 2 trailing) ; salt water. Fig. 133. a, Trimastix marina, X1250 (Kent); b, Dallingeria drysdali, X2000 (Kent); c, Macromastix lapsa, X1500 (Stokes). T. marina K. (Fig. 133, a). About 18/x long; salt water. Genus Dallingeria Kent. Free-Swimming or attached; with trail- ing flagella; body small; with drawn-out anterior end; fresh water with decomposed organic matter. D. drysdali K. (Fig. 133, 6). Small; elongate oval; less than 6m long; stagnant water. Genus Macromastix Stokes. Free-swimming, somewhat like Dallingeria, but anterior region not constricted; 3 flagella from an- terior end; one contractile vacuole; fresh water. M. lapsa S. (Fig. 133, c). Ovoid; 5.5/i long; anterior flagellum 1/2 and trailing flagella 2-3 times body length; pond water. POLYMASTIGINA 295 Genus Mixotricha Sutherland. Large; elongate; anterior tip spirally twisted and motile; posterior end probably eversible; body surface with a coat of cilia in closely packed transverse bands (in- sertion and movement entirely different from those of Trichonym- pha) except posterior end; 3 short flagella at anterior end; nucleus, o- Fig. 134. Diagram illustrating the life-cycle of Tetramitus rostratus (Bunting), a, cyst; b, vegetative amoeba; c, division; d, after division; e, f, stages in transformation to flagellate form; g, fully formed flagel- late; h, flagellate prior to division; i, flagellate after division; j-1, trans- formation stages to amoeba. 20/x by 2ju, connected with blepharoplasts by prolonged tube which encloses nucleus itself; cytoplasm with scattered wood chips; in termite gut. One species. Taxonomic position undetermined. M. paradoxa S. About 340/x long, 200)li broad and 25/x thick; in gut of Mastotermes darwiniensis; Australia. 296 PROTOZOOLOGY Family 2 Tetramitidae Blitschli Genus Tetramitus Perty. Ellipsoidal or pyriform; free-swimming; cytostome at anterior end; 4 flagella unequal in length; a contractile vacuole; ho lo zoic; fresh or salt water. T. rostratus P, (Fig. 135, a). Form variable; usually ovoid with narrow posterior region; IS-SOju by 8-1 Iju; stagnant water. Bunting (1922, 1926) observed a very interesting life-cycle of an organism which she found in culture of caecal contents of rat and which she identified as T. rostratus (Fig. 134). Fig. 135. a, Tetramitus rostratus, X620 (Lemmermann) ; b, T. pyri- formis, X670 (Klebs); c. T. salinus, X1630 (Kirby); d, Collodidijon triciliatum, X400 (Carter); e-j, Costia necatrix (e, f, X800 (Weltner); g-i, X1400 (Moroff); j, two individuals attached to host integument X500 (Kudo)); k, Enteromonas hominis, X1730 (Wenyon and O'Con- nor); 1, Copromastix prowazeki, X1070 (Aragao). T. pyriformis Klebs (Fig. 135, b). Pyriform, with pointed poste- rior end; 11-13/i by 10-12/x; stagnant water. T. salinus (Entz) (Fig. 135, c). 2 anterior flagella, 2 long trailing flagella; nucleus anterior; cytostome anterior to nucleus; a groove to posterior end; cyto pharynx temporary and length variable; 20-30)u long (Entz); 15-19^ long (Kirby), Kirby observed it in a pool with a high salinity at Marina, California. Genus Collodictyon Carter. Body highly plastic; with longitudinal POLYMASTIGINA 297 furrows; posterior end bluntly narrowed or lobed; no apparent cytostome; 4 flagella; a contractile vacuole anterior; fresh water. C. triciliatum C. (Fig. 135, d). Spherical, ovoid or heart-shaped; 27-60iu long; flagella as long as the body; pond water. Rhodes (1919) made a comprehensive cytological study of the organism. Genus Costia Leclerque. Ovoid in front view; pyriform in profile; toward right side, a funnel-like depression, at the posterior end of which are located cytostome (?) and 2 long and 2 short flagella; con- tractile vacuole in posterior half; longitudinal division; encystment; ectoparasitic in various freshwater fishes. P \f' % % % '^- "0 0 • 2 7 8 9 10 Fig. 136. Enteromonas hominis, X1150. 1, 2 (da Fonseca); 3-6, living trophozoites; 7, 8, stained trophozoites; 9, 10, stained young and mature cysts (Wen3^on and O'Connor). C. necatrix (Henneguy) (,Fig. 135, e-j). 10-20^1 by 5-10/x; compact nucleus central; a contractile vacuole; cyst uninucleate, spherical, 7-IOm in diameter; when present in large numbers, the epidermis of fish appears to be covered by a whitish coat. C. pyriformis Davis. A similar form; but smaller in size; 9-14^11 by b-Sfx. Davis (1943) observed the organism on trout [Salmo irideus and Salvelinus fontinalis) . Genus Enteromonas da Fonseca (Tricercomonas Wenyon and O'Connor). Spherical or pyriform, though plastic; 3 anterior flagella; the fourth flagellum runs along the flattened body surface and ex- tends a little freely at the posterior tip of body; nucleus anterior; no cytostome; cyst ovoid and with 4 nuclei when mature; parasitic in mammals. Da Fonseca (1915) originally observed only 3 flagella and no cysts; 4 flagella and encysted forms were noticed in Tri- cercomonas by Wenyon and O'Connor (1917); in da Fonseca's ori- ginal preparations, Dobell (1935) observed 4 flagella as well as cysts 298 PROTOZOOLOGY and concluded that Enteromonas and Tricercomonas are one and the same flagellate. E. hominis da F. {T. intestinalis W. and 0) (Figs. 135, k; 136). Trophozoites 4-lOju by 3-6ju; nucleus circular or pyriform, with a large endosome, near anterior end; 4 flagella take their origins in blepharoplasts located close to nucleus; cytoplasm vacuolated or reticulated, contains bacteria; cysts ovoid, 6-8ju by 4-6m; with 1, 2, or 4 nuclei; commensal in the lumen of human intestine; found in diarrhoeic stools. Widely distributed. Genus Copromastix Aragao. Four anterior flagella equally long; body triangular or pyramidal; coprozoic. C. prowazeki A. (Fig. 135, I). About 16-18/x long; in human and rat faeces. Fig. 137. Chilomastix mesnili, X1150 (Kudo). 1, a living trophozoite; 2-4, stained trophozoites; 5, a fresh cyst; 6, a stained cyst. Family 3 Streblomastigidae Kofoid and Swezy Genus Streblomastix K. and S. Spindle-form; with a rostellum, the anterior tip of which is enlarged into a sucker-like cup; below the cup are inserted 4 equally long flagella; extremely elongate nucleus below rostellum; body surface with 4 or more spiral ridges; in termite gut. One species. S. strix K. and S. (Fig. 138, a, h). 15-52m by 2-1 5m; 4-8 spiral ridges; blepharoplast in rostellum; in Termopsis angusticollis. Family 4 Chilomastigidae Wenyon Four flagella, one of which undulates on body surface. Genus Chilomastix Alexeieff. Pyriform; with a large cytostomal cleft at anterior end; nucleus anterior; 3 anteriorly directed flagella; short fourth flagellum undulates within the cleft; cysts common; in intestine of vertebrates. Several species. C. mesnili (Wenyon) (Fig. 137). The trophozoite is oval or pyri- form; 5-20)Lt (majority 10-15)u) long; jerky movements; a large POLYMASTIGINA 299 cytostomal cleft near anterior end; nucleus, vesicular, often without endosome; 3 anterior flagella about T-lO/x long; the fourth flagellum short, undulates in the cleft which ridge is marked by 2 fibrils. The cyst pyriform; 7-10/x long; a single nucleus; 2 cytostomal fibrils and a short flagellum; commensal in the caecum and colon (some con- sider also in small intestine) of man. Both trophozoites and cysts oc- cur in diarrhoeic faeces. It is widely distributed and very common. C. intestinalis Kuczynski. In guinea pigs. C. hettencourti da Fonseca. In rats and mice. C cuniculi da Fonseca. In rabbits. C. caprae da Fonseca. In goat. C. gallinarum Martin and Robertson. 11-20/x by 5-6^; in domes- tic fowls. Family 5 Callimastigidae da Fonseca Flagella 12 or more; in stomach of ruminants or in caecum and colon of horse. Genus Callimastix Weissenberg. Ovoid; compact nucleus central or anterior; 12-15 long flagella near anterior end, vibrate in unison. Weissenberg (1912) considered this genus to be related to Lopho- monas (p. 320), but organism lacks axial organellae; in Cyclops and alimentary canal of ruminants and horse. C. cyclopis W. In body-cavity of Cyclops sp. C. frontalis Braune (Fig. 138, c). 12 flagella; about 12/i long; fla- gella 30/x long; in cattle, sheep and goats. C. equi Hsiung (Fig. 138, d). 12-15 flagella; 12-18m by 7-10^; nucleus central; in caecum and colon of horse. Family 6 Polymastigidae Blitschli Genus Polymastix Biitschli. Pyriform; 4 flagella arise from 2 blepharoplasts located at anterior end; cytostome and axostyle in- conspicuous; ectoplasm covered by longitudinal ridges; endocom- mensal in insects. P. melolonthae (Grassi) (Fig. 138, e). 5-22^ long; in hindgut of Melolontha, Oryctes, Cetonia, Rhizotrogus, Tipula, etc. Genus Eutrichomastix Kofoid and Swezy {Trichomastix Bloch- mann). Pyriform; anterior end rounded; cytostome and nucleus anterior; 3 flagella of equal length arise from anterior end, the fourth trailing; axostyle projects beyond posterior end of body; all endo- commensals. E. serpentis (Dobell) (Fig. 138,/). About 10-25^ long; in intestine of snakes: Pituophis, Eutaenia, and Python. 300 PROTOZOOLOGY E. batrachorum (Dobell) (Fig. 138, g). Ovoid; 6-20^ long; in intestine of Rana fusca. E. axostylis Kirby (Fig. 138, h). Elongate, ellipsoid, or pyriform; axostyle projecting; 5-10.5)uby 2-3.5/x;3 anterior flagella5-10/x long; in gut of Nasutitermes kirhyi. Genus Hexamastix Alexeieff. Body similar to Eutrichomastix, but with 6 flagella, of which one trails; axostyle conspicuous; para- basal body prominent. Fig. 138. a, Streblomaslix strix, X1030; b, its anterior end, showing the rostellum, blepharoplast, sucking cup and flagella (Kidder); c, Calli- masiix frontalis, X1500 (Braune); d, C. equi, XUOO (Hsiung); e, Poly- ■mastix melolonthae, X546 (Hamburger); f, Eutrichomastix serpentis, X1450 (Kofoid and Swezy); g, E. hatracJiorum, X 1350 (Dobell); h, E. axostylis, X2000 (Kirby); i, Hexamastix termopsidis, X2670 (Kirby); j, H. batrachorum, XlOOO (Alexeieff); k, Protrichomonas legeri, XlOOO (Alexeieff); 1, Monocercomonas bufonis, X1670 (Alexeieff). H. termopsidis Kirby (Fig. 138, i). Ovoidal or pyriform; 5-1 1m long; flagella 15-25^ long; in gut of Zootermopsis angusticollis and Z. nevadensis: California. POLYMASTIGINA 301 H. hatrachorum Alexeieff (Fig. 138, j). Oval or spindle form;8-14ju by 4-8 ju; flagella about body length; in gut of Triton taeniatus. Genus Protrichomonas Alexeieff. 3 anterior flagella of equal length, arising from a blepharoplast located at anterior end; para- sitic. P. legeri A. (Fig. 138, k). In oesophagus of the marine fish. Box hoops. Fig. 139. a, motile form with rostellum of Oxymonas dimorpha, X900 (Connell); b, attached and aflagellated form of Oxymonas dimorpha, X460 (Connell); c, Proboscidiella kofoidi, X600 (Kirby). Genus Monocercomonas Grassi. Small; 4 flagella inserted in pairs in 2 places; 2 directed anteriorly and the other 2, posteriorly; axo- style filamentous; parasitic. M. hufonis Dobell (Fig. 138, I). Spindle-form; 12-15/x long; cysts spherical; in Axolotl, Triton, frogs and toads. Family 7 Oxymonadidae Kirby Genus Oxymonas Janicki. Attached phase with a conspicuous rostellum, the anterior end of which forms a sucking-cup for attach- ment; pyriform. In motile phase, rostellum is less conspicuous; 2 302 PROTOZOOLOGY blepharoplasts located near the anterior extremity of axostyle, give rise to 2 flagella each; axostyle conspicuous; xylophagous; in termite gut. 0. dimorpha Connell (Fig. 139, a, h). Subovoid; delicate pellicle; axostyle slightly protruding; a pair of long anterior flagella from 2 blepharoplasts, connected by rhizoplast; nucleus anterior. When attached to intestine, rostellum elongate, flagella disappear; 17ju by 14/i to 195/i by 165/x; in Neotermes simplicicornis; California and Arizona. Genus Proboscidiella Kofoid and Swezy {Microrhopalodina Grassi and Foa; Kirhyella Ze\iE) . Attached and motile form similar to Ox?/- monas; but multinucleate; 3(?)-4 flagella from each karyomastigont (p. 315); rostellum with filaments which extend posteriorly as axo- styles; in termite gut. P. kofoidi Kirby (Fig. 139, c). Average size 66/i by 4Qn; rostellum as long as body; karyomastigonts 2-19 or more (average 8); each mastigont with 2 blepharoplasts from which extend 4 flagella; in Cryptotermes dudleyi. Family 8 Dinenymphidae Grassi and Foa Genus Dinenympha Leidy. Medium large; spindle form; 4-8 flagellar cords adhering to body which are spirally twisted about one turn; the flagella free at the posterior end; axostyle varies from cord to band; pyriform nucleus, anterior, with a large endosome; in ter- mite gut. D. gracilis L. (Fig. 140, a). 24-50^ by 6-12/i; body flattened and twisted; ends attenuated; with adhering protophytes; in Reticuli- termes flavipes. D. fimhriata Kirby (Fig. 140, b). 52-64^ by 8-18^; 4-8 flagellar cords; with adherent protophytes; axostyle varies in width; in Reticulitermes hesperus. Genus Pyrsonympha Leidy. Large; club-shaped, the posterior end is rounded; body surface with 4-8 flagellar cords which are arranged lengthwise or slightly spirally; flagella extend freely posteriorly; blepharoplast at the anterior tip, often with a short process for at- tachment; axostyle a narrow band, may be divided into parts; in termite gut. P. vertens L. (Fig. 140, c). About 100-1 50^ long; 4-8 flagellar cords; in Reticulitermes flavipes. P. granulata Powell (Fig. 140, d). 40-120^ by 5-35m; 4-8 flagellar cords; in Reticulitermes hesperus. POLYMASTIGINA 303 Genus Saccinobaculus Cleveland. Elongate to spherical; 4, 8, or 12 flagella adhere to the body, and project out freely; axostyle is an extremely large paddle-like body and undulates, serving as cell- organ of locomotion; in wood-roach gut. S. ambloaxostylus C. (Fig. 140, e). 65-1 10/x by 18-26/x; in Cryp- tocercus punctulatus. Fig. 140. a, Dinenym-pha gracilis, X730 (Original); b, D. fimbriata, X625 (Kirby); c, Pyrsomjmyha vertens, X730 (Original); d, P. granulata, X500 (Powell); e, Saccinobaadus ambloaxostylus, X600 (Cleveland). Family 9 Devescovinidae Doflein Usually 3 anterior flagella and a trailing stout flagellum; near base of trailing flagellum an elongated cresta (becoming a large internal membrane in some species) (Fig. 141); trailing flagellum lightly adheres to body surface along edge of cresta; axostyle; para- basal body of various forms; single nucleus anterior; without undu- lating membrane; generally xylophagous. Genus Devescovina Foa. Elongate body, usually pointed poste- riorly; 3 anterior flagella about the body length; trailing flagellum, slender to band-form, about 1-1.5 times the body length; cresta; parabasal body spiraled around axostyle or nucleus; in termite in- testine. Many species (Kirby, 1941). 304 PROTOZOOLOGY B. lemniscata Kirby (Figs. 141; 142, a). 21-51^ by 9-17)u; trailing flagellum a band; cresta long, 7-9/x; in Cryptotermes hermsi and many species of the genus; species of Neotermes, Glyptotermes and Kalotermes. Genus Parajoenia Janicki. Medium large; with rounded extremi- ties; 3 anterior flagella and trailing flagellum long; cresta of moder- ate size; parabasal body well developed with its anterior end close to blepharoplast; stout axostyle expanded anteriorly into leaf like capitulum, bearing a longitudinal keel; in intestine of termites. papilla ant. flagella ant. lamella bleph. group nucL rhiz. parab. f il. parab. body cresta chrom. mass nucl. memb. chr. cone in ax. parab. spiral chromoph. element of pb. axostyle tr. flagellum Fig. 141. A diagrammatic view of the anterior part of Devescovina lem- niscata, showing the cresta and other organellae (Kirby). P. grassii J. (Fig. 142, h). 29-59m by 12-33m; trailing flagellum stout, cordlike; cresta about 9/x long; in Neotermes connexus. Genus Foaina Janicki {Janickiella Duboscq and Grasse; Para- devescovina, Crucinympha Kirby). Small to medium large; 3 anterior flagella; trailing flagellum about twice the body length; cresta slender, 2.5-17m long; parabasal body single, in some with rami; in intestine of termites. Many species (Kirby, 1942a). F. nana Kirby (Fig. 142, c). 6-18m by 4.5-8.5^*; trailing flageUum a moderately stout cord, 2-3 times the body length; cresta slender, 8.5m long; filament part of the parabasal body reaching the middle POLYMASTIGINA 305 Fig. 142. a, Devescovina lemniscata, X1600; b, Parajoenia grassii, with attached spirochaetes, X1150; c, Foaina nana, X1150; d, Macrotricho- tiwnas pulchra, X1600 (all after Kirby); e, Metadevescovina debilis, X1130 (Light, modified). 306 PROTOZOOLOGY of body; in Cryptotermes hermsi and many species of the genus; also species of Glyptotermes, Rugitermes, and Procryptotermes. Genus Macrotrichomonas Grassi. Large; 3 anterior flagella; trail- ing flagellum well developed, 1-1.5 times the body length; cresta a broad internal membrane, 21-86^ long; parabasal body coiled around the axostyle, 1-13 times; in termite gut. Several species (Kirby, 1942). M. pulchra G. (Fig. 142, d). 44-91m by 21-41/i; traihng flagellum band-form; cresta large; parabasal body coiled closely 4-10 times; in Glyptotermes parvulus, and many other species of the genus. Genus Metadevescovina Light. Moderately large; 3 anterior flagella; a short trailing flagellum; cresta small; parabasal body loosely coiled around axostyle; anterior end of axostyle in a loop;, in termite gut. M. dehilis L. (Fig. 142, e). 30-70/i by 15-30/x; in Kalotermes hub- hardi. Genus Caduceia Franga. Large; 3 long anterior flagella; trailing flagellum slender, shorter than body; cresta relatively small, l-12ju long; parabasal body coiled around axostyle 2-20 times; nucleus relatively large; in termites. Several species (Kirby, 1942). C. hugnioni Kirby (Fig. 143, a). 48-80m by 18-40/i; in Neoterrnes greeni. Genus Pseudodevescovina Sutherland. Large; 3 short anterior flagella; one short trailing flagellum; axostyle stout; cresta of moder- ate size; parabasal body large, divided into a number of attached cords; in termite gut. P. uniflagellata S. (Fig. 143, h). 52-95^ by 26-60/x; 3 delicate flagella, 30m long; trailing flagellum a little stouter; cresta 11-20^ long; main parabasal body C-shaped, with 7-19 attached cords; in Kalotermes insularis. Genus Bullanympha Kirby. Flagella and cresta similar to those in Pseudodevescovina; axostyle similar to that in Caduceia; proximal part of parabasal body bent in U-form around the nucleus and at- tached voluminous distal portion coiled around the axostyle; in termite gut. . B. silvestrii K. (Fig. 143, c). 50-138m by 35-100^; cresta about 5.8m long; distal portion of parabasal body coils around axostyle about twice ; in Neotermes erythraeus. Genus Gigantomonas Dogiel {Myxomonas D.). Medium large; 3 short anterior flagella; a long and stout trailing flagellum; cresta conspicuously large; large axostyle; in termite gut. According to POLYMASTIGINA 307 Kirby's recent work, the so-called undulating membrane is a large cresta; in aflagellate phase (Myxomonas) the nuclear division takes place. Fig. 143. a, Caduceia bugnioni, X930; b, Pseudodevescovina uniflagel- lata, X1190; c, Bullanympha silvestrii, X780 (all after Kirby); d, e, Gigantomonas hercidea (Dogiel) (d, X530; e, amoeboid phase (Myxo- monas), X400). G. herculea D. {M. polymorpha D.) (Fig. 143, d, e). 60-75/i by 30-35/x; in the intestine of Hodotermes mossambicus. 308 PROTOZOOLOGY Family 10 Trichomonadidae Wenyon Genus Trichomonas Donne (? Ditrichomonas Cutler), Pyriform; typically with 4 free anterior flagella; fifth flagellum along the outer margin of the undulating membrane; costa at the base of the mem- brane; axostyle well developed, often protruding beyond the pos- terior end of the body; cysts have been observed in forms inhabiting certain mammals such as T. caviae (Wenyon), but not in the three species living in man; all parasites. Numerous species (Wenrich, 1944). T. hominis (Davaine) (Fig. 144). Active flagellate, undergoing a jerky or spinning movement; highly plastic, but usually ovoid or \( aI r 1 t Fig. 144. TricJiomonas hominis, X1150 (Kudo). 1, living and 2, 3, stained trophozoites. pyriform; 5-20/x long; cytostome near anterior end; 4 anterior flagella equally long; fifth flagellum borders undulating membrane which is seen in life ; in degenerating individuals the membrane may undulate, even after loss of flagella, simulating amoeboid movement; axostyle straight along the median line; vacuolated cytoplasm with bacteria; commensal in the colon and ileum of man; found in diarr- hoeic stools. Wenrich (1944) states that in all 20 cases which he studied, some or most of the individuals showed five anterior flagella and two unequal blepharoplasts. Evidently the organisms belong to Pentatrichomonas. Since encysted forms have not yet been found, transmission is as- sumed to be carried on by trophozoites. According to Dobell (1934), he became infected by an intestinal Trichomonas of a monkey {Macacus nemestrinus) by swallowing "a rich two-day culture" plus bacteria which were mixed with 10 cc. of sterilized milk on an empty stomach. The presence of Trichomonas in his stools was established on the 6th day by culture and on the 13th day by microscopical examination after taking in the cultures. The infection which lasted for about four and a half years, did not cause any ill effects upon POLYMASTIGINA 309 him. This flagellate is widely distributed and of common occurrence, especially in tropical and subtropical regions. T. elongata Steinberg {T. buccalis Goodey). Similar to T. hominis; commensal in tartar and gum of human mouth. Dobell (1939) con- siders that its name should be T. tenax (O. F. Miiller). T. vaginalis Donne (Fig. 145). Similar to the above-mentioned two species; pyriform or fusiform; lO-SOju by 10-20/x; cytoplasm contains many granules and bacteria; commensal in human vagina. Hogue (1943) noticed that this flagellate produces a substance which in- jures the tissue-culture cells. Feo (1944) reported that urethral speci- mens of 144 out of 926 men were found microscopically to contain Fig. 145. Trichomonas vaginalis, X1150 (Kudo). 1, a living tro- phozoite; 2, a degenerating amoeboid trophozoite in life; 3, 4, stained trophozoites. this flagellate. Some investigators consider the organism as a cause of vaginitis. Because of the morphological similarity of these three species of human Trichomonas, a number of workers maintain that they may be one and the same species. Stabler and his co-workers (1941, 1942) obtained negative results by inoculating volunteer human subjects intravaginally with the cultures of T. hominis and T. elongata. On the other hand, Wenrich (1944) considers that there exist distinctly recognizable morphological difl*erences among the three species. Dobell inoculated a rich culture of Trichomonas obtained from his stools into the vagina of a monkey {Macacus rhesus) and obtained a positive infection which was easily proven by culture, but unsat- isfactorily by microscopical examination of smears. The infection thus produced, lasted over three years and did not bring about any ill effect on the monkey. He considers that T. vaginalis and T. hominis are synonyms and that there occur diverse strains different in minor morphological characters and physiological properties. T. macacovaginae Hegner and Ratcliffe. In the vagina of Macacus 310 PROTOZOOLOGY rhesus. Dobell (1934) holds that this is identical with T. vaginalis and T. hominis. T. linearis Kirby (Tig. 146, a). Elongate, spindle-form; 9-24)u by 3-8/i ; in gut of Orthognathotermes wheeleri; Panama. T. termitis (Cutler) (Fig. 146, b). 30-88m by 13-57^ (Imms); in gut of Archotermopsis wroughtoni; India. Fig. 146. a, Trichomonas linearis, X2000 (Kirby); b, T. termitis, X630 (Cutler); c, Tritrichomonas brevicollis, X2000 (Kirby); d, e, Tricercomittis termopsidis, X890 (Kirby); f, Pentatrichomonoides scroa, X2000 (Kirby); g, Pseudotrypanosoma giganteum, X580 (Kirby). Genus Tritrichomonas Kofoid. Similar to Trichom,onas in ap- pearance and structure; but 3 anterior flagella; parasitic. T. brevicollis Kirby (Fig. 146, c). Ovoid; undulating membrane curved around end; 10-17^ by 4-8/i; in gut of Kalotermes brevicollis; Panama. T. foetus (Riedmiiller). Pathogenic; in genitalia of cattle; simi- POLYMASTIGINA 311 lar to Trichomonas vaginalis; but 3 anterior flagella; body about 15m by 5/i; transmission by sexual act, from cow to bull or bull to cow; in infected cow conception temporarily or permanently is sus- pended or death of foetus occurs. T. fecalis Cleveland. 5m by 4m to 12m by 6m; average dimensions 8.5m by 5.7m; axostyle long, protruding 1/3-1/2 the body length from the posterior end; of 3 flagella, one is longer and less active than the other two; in the faeces of man. Its remarkable adapta- bility observed by Cleveland was noted elsewhere (p. 30). T. batrachorum (Perty). Ovoid; 14-18m by 6-10m; in frog gut. T. augusta Alexeieff. Spindle-form; 18-22m by 8-14m; in frog gut. Genus Tricercomitus Kirby. Small; 3 anterior flagella; a long trailing fiagellum, adhering to body; nucleus anterior, without endosome; blepharoplast large, with a parabasal body and an axial filament; parasitic. T. termopsidis K. (Fig. 146, d, e). 4-1 2m by 2-3m; anterior flagella 6-20m long; trailing fiagellum 19-65m long; in gut of Zoolermopsis angusticollis, Z. nevadensis and Z. laticeps; California and Arizona. Genus Pentatrichomonas Mesnil. Similar to Trichomonas, but with 5 free anterior flagella. P. hengalensis Chatterjee. 9-20m by 7-14m; in human intestine. Kirby (1943) observed that of the five flagella, four arise from the end of a columnar (1-2m long) extension, while the fifth fiagellum is a little shorter and takes its origin about 1m behind the extension. Genus Pentatrichomonoides Kirby. Five anterior flagella and the undulating membrane; axostyle very slightly developed; fusiform parabasal body; nucleus separated from the anterior blepharoplast; in termite gut. P. scroa K. (Fig. 146,/). 14-45m by 6-15m; in Cryptotermes dudleyi and Lohitermes longicollis. Genus Pseudotrypanosoma Grassi. Large, elongate; 3 anterior flagella; undulating membrane; slender axostyle; band-like structure between nucleus and blepharoplast; parabasal body long, narrow; in termite gut. P. giganteum G. (Fig. 146, g). 55-1 11m long (Grassi); 145-205m by 20-40m; anterior flagella about 30m long (Kirby); in gut of Poro- termes adamsoni and P. grandis. Suborder 2 Diplomonadina The suborder consists of a number of binucleate flagellates pos- sessing bilateral symmetry. 312 PROTOZOOLOGY Family Hexamitidae Kent Genus Hexamita Dujardin (Octomitus Prowazek). Pyriform; 2 nuclei near anterior end; 6 anterior and 2 posterior flagella; 2 axo- styles; 1-2 contractile vacuoles in free-living forms; cytostome ob- scure; endoplasm with refractile granules; encystment; in stagnant water or parasitic. Fig. 147. a, Hexamita inflata, X600 (Klebs); b, c, trophozoite and cyst oi H.intestinalis, X 1600 (Alexeieff); d, i/. saZmonts, X2100 (Davis); e,^. cryptocerci, X1600 (Cleveland); f, Trepomonas agilis, X1070 (Klebs^; g, T. rotans, X710 (Lemmermann) ; h, Gyromonas ambulans, X530 (Seligo); i, Trigonomonas compressa, X490 (Klebs); j, Urophagus rostratus, X800 (Klebs). H. inflata D. (Fig. 147, a). Broadly oval; posterior end truncate; 13-25m by 9-15^1; in stagnant water. H. intestinalis D. (Fig. 147, 6, c). 10-16^ long; in intestine of POLYMASTIGINA 313 frogs, also in midgut of Trutta fario and in rectum of Motella tricir- rata and M. mustela in European waters, H. salmonis (Moore) (Fig. 147, d). 10-12^ by 6-8^; in intestine of various species of trout and salmon; schizogony in epithelium of pyloric caeca and intestine; cysts; pathogenic to young host fish (Davis, 1925). H. periplanetae (Belaf). 5-8^ long; in intestine of cockroaches. H. cryptocerci Cleveland (Fig. 147, e). 8-13m by 4-5.5^1; in Crypto- cercus punctulatus. H. meleagridis McNiel, Hinshaw and Kofoid. Body 6-12^1 by 2-5ju. It causes a severe catarrhal enteritis in young turkeys. Experi- mentally it is transmitted to young quail, chicks, and duckling. Genus Giardia Kunstler {Lamblia Blanchard). Pyriform to ellip- soid; anterior end broadly rounded, posterior end drawn out; bi- laterally symmetrical; dorsal side convex, ventral side concave or flat, with a sucking disc in anterior half; 2 nuclei; 2 axostyles; 8 flagella in 4 pairs; cysts oval to ellipsoid; with 2 or 4 nuclei and fibrils; in the intestine of various vertebrates. Several species. G. intestinalis (Lambl) {G. lamblia Stiles) (Fig. 148). When the flagella lash actively, the organism shows a slight forward movement with a sidewise rocking motion. The trophozoite is broadly pyriform, not plastic; 9-20^ by 5-10/x; sucking disc acts as attachment organ- ella; cytoplasm hyaline; 2 needle-like axostyles; 2 vesicular nuclei near anterior margin; 8 flagella in 4 pairs; two flagella originate near the anterior end of axostyles, cross each other and follow the anterolateral margin of the disc, becoming free; two originating in anterior part of axostyles, leave the body about 1/3 from the pos- terior tip; two (ventral) which are thicker than others, originate in axostyles at nuclear level and remain free; two (caudal) flagella arise from the posterior tips of axostyles; a deeply staining body may be found in cytoplasm. The cysts are ovoid and refractile; 8-14ju by 6-10)u; cyst wall thin; contents do not fill the wall; 2 or 4 nuclei, axostyles, fibrils and fla- gella are visible in stained specimens. This flagellate inhabits the lumen of the duodenum and other parts of small intestine of man. Both trophozoites and cysts are or- dinarily found in diarrhoeic faeces. In severe cases of infection, an enormous number of the organisms attach themselves to the mucous membrane of the intestine which may result in abnormal functions of the host tissues. In some cases, the flagellate has been reported from the gall bladder. The stools often contain unusual amount of mucus. But there is no evidence that G. intestinalis attacks the in- testinal epithelium. 314 PROTOZOOLOGY G. muris (Grassi). 7-13ai by 5-1 Om; in the intestine of mice and rats. Genus Trepomonas Diijardin. Free-swimming; flattened; more or less rounded; cytostomal grooves on posterior half, one on each side; 8 flagella (one long and 3 short flagella on each side) arise from ante- rior margin of groove; near anterior margin there is a horseshoe-form structure, in which two nuclei are located; fresh water, parasitic, or coprozoic. T. agilis D. (Fig. 147, /). More or less ovoid; 7-30/x long; 1 long and 3 short flagella on each side; rotation movement; stagnant water; also reported from intestine of amphibians. Fig. 148. Giardia intestinalis, X1150 (Kudo). 1, 2, living trophozoites in front and side views; 3, 4, stained trophozoites in front and side views; 5, a fresh cyst; 6, 7, stained cysts; 8, a stained cyst in an end view. T. rotans Klebs (Fig. 147, g). Broadly oval; posterior half highly flattened; 2 long and 2 short flagella on each of 2 cytostomes; stag- nant water. Genus Gyromonas Seligo. Free-swimming; small; form constant, flattened; slightly spirally coiled; 4 flagella at anterior end; cyto- stome not observed; fresh water. G. ambulans S. (Fig. 147, h). Rounded; 8-1 5/i long; standing water. Genus Trigonomonas Klebs. Free-swimming; pyriform, plastic; cytostome on either side, from anterior margin of which arise 3 flagella; flagella 6 in all; 2 nuclei situated near anterior end; move- ment rotation; holozoic; fresh water. POLYMASTIGINA 315 T. compressa K. (Fig. 147, i). 24-33m by 10-16^; flagella of differ- ent lengths; standing water. Genus Urophagus Klebs. Somewhat similar to Hexamita; but a single cytostome; 2 moveable posterior processes; ho lo zoic; stag- nant water. U. rostratus (Stein) (Fig. 147, j). Spindle-form; 16-25ju by 6-1 2^. Suborder 3 Polymonadina This group includes forms which inhabit the intestine of various species of termites, most probably as symbionts. The majority are multinucleate. Each nucleus gives rise to a basal bod}^ (from which flagella extend), a parabasal body, and an axial filament. Janicki called this complex karyomastigont, and the complex which does not contain a nucleus akaryomastigont. Genus Calonympha Foa. Body rounded; large; numerous long flagella arise from anterior region; numerous nuclei; karyomastigonts and akaryomastigonts; axial filaments form a bundle; in termite gut. C. grassii F. (Fig. 149, a). 69-90/i long; in Cryptotermes grassii. Genus Stephanonympha Janicki. Oval, but plastic; numerous nuclei spirally arranged around anterior end; karyomastigonts; axial filaments form a bundle; in termite gut. S. nelumhium Kirby (Fig. 149, b). 45)u by 27^; in Cryptotermes hermsi. Genus Coronympha Kirby. Pyriform with 8 or 16 nuclei, arranged in a single circle in anterior region; 8 or 16 karj^omastigonts; axo- style distributed; in termite gut. C. clevelandi K. (Fig. 149, c). 25-53^ by 18-46^; in Kalotermes clevelandi. Genus Metacoronympha Kirby. Pyriform; one hundred or more karyomastigonts arranged in spiral rows meeting at the anterior end; each mastigont is composed of nucleus, blepharoplast, cresta, 3 anterior flagella, a trailing flagellum, and an axostyle; axostyle as in the last genus; in termite gut. M. senta K. (Fig. 149, d). 22-92^ by 15-67m; karyomastigonts about 66-345 (average 150) in usually 6 spiral rows; in Kalotermes emersoni and four other species of the genus. Genus Snyderella Kirby. Numerous nuclei scattered through the cytoplasm; akaryomastigonts close together and extend through the greater part of peripheral region; axial filaments in bundle; in ter- mite gut. 316 PROTOZOOLOGY S. tabogae K. (Fig. 149, e). P3^riform; rounded posteriorly; bluntly- conical anteriorly; 77-172/i by 53-97ju; in Cryptotermes longicolUs. Fig. 149. a, Calonympha grassii, X900 (Janicki); b, Stephanonympha nelumbium, X400 (Kirby); c, Coronympha clevelandi, XlOOO (Kirby); d, Metacoronympha senta, X485 (Kirby); e, Snyderella tabogae, X350 (Kirby). References Cleveland, L. R. et al. 1934 The wood-feeding roach, Cryptocer- cus, its Protozoa, and the symbiosis between Protozoa and roach. Mem. Amer. Acad. Arts and Sci., Vol. 17. Davis, H. S. 1943 A new polymastigine flagellate, Costia pyri- formis, parasitic on trout. Jour. Parasit., Vol. 29. DoBELL, C. 1934 Researches on the intestinal Protozoa of monkeys and man. VI. Parasitology, Vol. 26. POLYMASTIGINA 317 — 1935 VII. Parasitology, Vol. 27. — 1939 The common flagellate of the human mouth, Tri- chomonas tenax (O.F.M.): its discovery and its nomenclature. Ibid., Vol. 31. and F. W. O'Connor 1921 The intestinal Protozoa of man. London. Feo, L. G. 1944 The incidence and significance of Trichomonas vaginalis in the male. Amer. Jour. Trop. Med., Vol. 24. Grasse, p. p. 1926 Contribution a I'^tude des Flagelles parasites. Arch. zool. exp. g^n.. Vol. 65. HoGUE, Mary J. 1943 The effect of Trichomonas vaginalis on tissue- culture cells. Amer. Jour. Hyg., Vol. 37. KiRBY, H. 1930, 1931 Trichomonad flagellates from termites. I, II. Uni. Cal. Pub. Zool., Vols. 33, 36. 1941, 1942 Devescovinid flagellates of termites. I, II, III. Ibid., Vol. 45. 1943 Observations on a trichomonad from the intestine of man. Jour. Parasit., Vol. 29. KoFOiD, C. A. and Olive Swezy 1915 Mitosis and multiple fission in trichomonad flagellates. Proc. Amer. Acad. Arts and Sci., Vol. 51. 1920 On the morphology and mitosis of Chilomas- tix mesnili (Wenyon), a common flagellate of the human intes- tine. Uni. Cal. Pub. Zool., Vol. 20. 1922 Mitosis and fission in the active and encysted phases of Giardia enterica etc. Ibid., Vol. 20. McNeil, E., W. R. Hinshaw and C. A. Kofoid 1941 Hexamita meleagridis sp. nov. from the turkey. Amer. Jour. Hyg., Vol. 34. Rees, C. W. 1938 Observations on bovine venereal trichomoniasis. Veterin. Med., Vol. 33. Stabler, R. M., L. G. Feo and A. E. Rakoff 1941 Implantation of intestinal trichomonads {T. hominis) into the human vagina. Amer. Jour. Hyg., Vol. 34. Sutherland, J. L. 1933 Protozoa from Australian termites. Quart. Jour. Micr. Sci., Vol. 76. Wenrich, D. H. 1944 Comparative morphology of the trichomo- nad flagellates of man. Amer. Jour. Trop. Med., Vol. 24. 1944a Morphology of the intestinal trichomonad flagellates in man and of similar forms in monkeys, cats, dogs, and rats. Jour. Morph., Vol. 74. Wenyon, C. M. 1926 Protozoology, Vol. 1. London. Chapter 16 Order 4 Hypermastigina Grassi ALL members of this order are inhabitants of the aUmentary canal of termites, cockroaches, and woodroaches. The cyto- plasmic organization is of high complexity, although there is only a single nucleus. Flagella are numerous and have their origin in the blepharoplasts located in the anterior region of body. In many spe- cies, there exists a true symbiotic relationship between the host termite and the protozoans (p. 25). Method of nutrition is either holozoic or saprozoic (parasitic). Bits of wood, starch grains, and other food material are taken in by means of pseudopodia. Asexual reproduction is by longitudinal fission; multiple division has also been noted in some species under certain conditions, while sexual reproduction has not been observed. Encystment occurs in some genera of Lophomonadidae and certain species inhabiting woodroaches, in which moulting of the host insect leads to encyst- ment. Because of the peculiarity and complexity of their structures and also of their common occurrence in termites, the Hypermastigina have been frequently studied. Body without segmented appearance Flagella in spiral rows Family 1 Holomastigotidae Flagella not arranged in spiral rows Flagella in one or more anterior tufts 1 tuft of flagella Family 2 Lophomonadidae (p. 320) 2 tufts of flagella Family 3 Hoplonymphidae (p. 322) 4 tufts of flagella Family 4 Staurojoeninidae (p. 324) Several tufts (loriculae) Family 5 Kofoidiidae (p. 324) Flagella not arranged in tufts Posterior part without flagella Family 6 Trichonymphidae (p. 324) Flagella over entire body.. .Family 7 Eucomonymphidae (p. 326) Body with segmented appearance. .Family 8 Teratonymphidae (p. 326) Family 1 Holomastigotidae Janicki Genus Holomastigotes Grassi. Body small; spindle-shaped; few spiral rows reach from anterior to posterior end; nucleus anterior, surrounded by a mass of dense cytoplasm; nutrition by absorption of fluid material; in termite gut. H. elongatum G. (Fig. 150. a). In gut of Reticulitermes lucifugus, R. speratus, R. flaviceps, and Macrohodotermes massamhicus; up to 70m by 24m (Grassi). 318 HYPERMASTIGINA 319 Genus Holomastigotoides Grassi and Foa. Large; Spindle-shaped; spiral rows of flagella as in the last genus, but more numerous (12-40 rows) ; a mass of dense cytoplasm surrounds ovoid nucleus; in termite gut. Fig. 150. a, Holomastigotes elongatum, X700 (Koidzumi); b, Holo- mastigotoides hartmanni, X250 (Koidzumi); c, Spirotrichomjmpha leidyi, X400 (Koidzumi); d, S. pulchella, X900 (jBrown); e, Microspirotricho- mjmpha porteri, X250 (Koidzumi); f, M. ovalis, X600 (Brown); g, Macro- spironympha xylopletha, X300 (Cleveland et al.); h, Leptospirony mpha eupora, X1050 (Cleveland et al.). H. hartmanni Koidzumi (Fig. 150, b). 50-140^ long; in Copto- termes formosanus. Genus Spirotrichonympha Grassi. Moderately large; elongate pyriform; flagella deeply embedded in cytoplasm in anterior region, arising from 1 to several spiral bands; mass of dense cytoplasm coni- cal and its base indistinct; nucleus spherical; in termite gut. S. leidyi Koidzumi (Fig. 150, c). In Coptotermes formosanus; 15-50^ by 8-30m. S. pulchella Brown (Fig. 150, d). 36-42)u by 14-16^; in Reticu- litermes hageni. 320 PROTOZOOLOGY S. polygyra Cupp. (Fig. 61). In Kalotermes simplicicornis; 63-1 12ju by 25-60/x; four flagellar bands. Genus Spirotrichonymphella Grassi. Small; without spiral ridges; flagella longer; not wood-feeding; in termite gut. S. pudihunda G. In Porotermes adamsoni; Australia. Multiple fusion (Sutherland). Genus Microspirotrichonympha Koidzumi {Spironynipha Koid- zumi). Small, surface not ridged; spiral rows of flagella only on anterior half; a tubular structure between nucleus and anterior extremity; a mass of dense cytoplasm surrounds nucleus; with or without axial rod; in termite gut. M. porteri K. (Fig. 150, e). In Leucotermes (Reticulitermes) flaviceps; 20-55m by 20-40^. M. ovalis (Brown) (Fig. 150, /). 36-48m by about 40m; in Reticu- litermes hesperus. Genus Spire tricho soma Sutherland, Pyriform or elongate; below operculum, two deeply staining rods from which flagella arise and which extend posteriorly into 2 spiral flagellar bands; without axo- style; nucleus anterior, median; wood chips always present, but method of feeding unknown; in Stolotermes victoriensis; Australia. S. capitata S. 87ju by 38/i; flagellar bands closely spiral, reach posterior end. Genus Macrospironympha Cleveland. Broadly conical; flagella on 2 broad flagellar bands which make 10-12 spiral turns, 2 inner bands; axostyles 36-50 or more; during mitosis nucleus migrates posteriorly; encystment, in which only nucleus and centrioles are retained, takes place at each ecdysis of host; in Cryptocercus punctu- latus. M. xylopletha C. (Fig. 150, g). 112-154Mby 72-127/x. Genus Leptospironympha Cleveland. Cylindrical; small; flagella on 2 bands winding spirally along body axis; axostyle single, hya- line; nucleus does not migrate posteriorly during division; encyst- ment unknown ; in Cryptocercus punctulatus. L. eupora C. (Fig. 150, A). 30-38m by 18-21/x. Family 2 Lophomonadidae Kent Genus Lophomonas Stein. Ovoid or elongate; small: a vesicular nucleus anterior; axostyle composed of many filaments; cysts com- mon; in colon of cockroaches. L. hlatiarum S. (Figs. 23; 62; 69; 151, a-e). Small, pyriform, but plastic; bundle of axostylar filaments may project beyond posterior margin; active swimming movements; binary or multiple fission; HYPERMASTIGINA 321 25-30)u long; ho lo zoic in colon of cockroaches; widely distributed. L. striata Biitschli (Fig. 151, j-h). Elongate spindle; surface with obliquely arranged needle-like structures which some investigators believe to be a protophytan (to which Grasse gave the name, Fusi- formis lophomonadis) ; bundle of axial filaments short, never protrud- ing; movement sluggish; cyst spherical with needle-like structures; in same habitat as the last species. Fig. 151. a-e, Lophompnas blattarum (a, b, in life, X320; c, d, stained specimens; e, cyst, X1150) (Kudo); f-h, L. striata (f, in life, X320; g, h, stained individuals, X1150) (Kudo); i, Prolophomonas tocopola, X1200 (Cleveland et al.); j, Joenia annedens (Grassi and Fo^); k, Mi- crojoenia pyriformis, X920 (Brown); 1, Torqiienyrapha odoplus, X920 ("Brown). Genus Eulophomonas Grassi and Fo^. Similar to Lophomonas, but flagella vary from 5-15 or a little more in number; in termite gut. E. kalotermitis Grassi. In Kalotermes flavicollis; this flagellate has not been observed by other workers. 322 PROTOZOOLOGY Genus Prolophomonas Cleveland. Similar to Eulophoinonas ; estab- lished since Eulophomonas had not been seen by recent workers; would become synonym "if Eulophomonas can be found in K. flavicollis" (Cleveland). P, tocopola C. (Fig. 151, i). 14-19/i by 12-15iu; in Cryptocercus punctulatus. Genus Joenia Grassi. Ellipsoidal; anterior portion capable of forming pseudopodia; flagellar tufts in part directed posteriorly; surface covered by numerous immobile short filamentous processes, which some hold tobe symbiotic bacteria; nucleus spherical, anterior; posterior to it a conspicuous axostyle composed of numerous axial filaments, a parabasal apparatus surrounding it; xylophagous; in termite gut. J. annectens G. (Fig. 151, j). In Kalotermes flavicollis. Genus Joenina Grassi. More complex in structure than that of Joenia; flagella inserted at anterior end in a semi-circle; parabasal bodies 2 elongated curved rods; feeding on wood fragments. J. pulchella G. In Porotermes adamsoni. Genus Joenopsis Cutler. Oval; large; a horseshoe-shaped pillar at anterior end, flagella arising from it; some directed anteriorly, others posteriori}^; parabasal bodies long rods; a strong axostyle; feeding on bits of wood; in termite gut. J . polytricha C. In Archotermopsis wroughtoni; 95-129/i long. Genus Microjoenia Grassi. Small, pyriform; anterior end flat- tened; flagella arranged in longitudinal rows; axostyle; parabasal body simple; in termite gut. M. pyriformis Brown (Fig. 151, k). 44-52/i by 24-30^; in Reticuli- termes hageni. Genus Mesojoenia Grassi. Large ; flagellar tuft spreads over a wide area; distinct axostyle, bent at posterior end; 2 parabasal bodies; in termite gut. M. decipiens G. In Kalotermes flavicollis. Genus Torquenympha Brown. Small; pyriform or top-form; axo- style; radially symmetrical; 8 radially arranged parabasal bodies; nucleus anterior; in termite gut. T. octoplus B. (Fig. 151, I). 15-26^ by 9-13^; in Reticulitermes hesperus. Family 3 Hoplonymphidae Light Genus Hoplonympha Light. Slender fusiform, covered with thick, rigid pellicular armor; each of the two flagellar tufts arises from a plate connected with blepharoplast at anterior end; nucleus near anterior extremity, more or less triangular in form; in termite gut. HYPERMASTIGINA 323 H. natator L. (Fig. 152, a, h). 60-120m by 5-12m; in Kalotermes simplicicornis. Genus Barbulanympha Cleveland. Acorn-shaped: small, narrow, nuclear sleeve between centrioles; number of rows of flagella greater Fig. 152. a, b, Hoplonympha natator, x450 (Light); c, Barbulanympha ufalula, X210 (Cleveland et al.); d, Urinympha talea, X350 (Cleveland et al.); e, Staurojoenina assimilis, X200 (Kirby); f, Idionympha perissa, X250 (Cleveland et al.); g, Teratonympha mirabilis, X200 (Dogiel). at base; large chromatin granules; numerous (80-350) parabasals; axostylar filaments 80-350; flagella 1500-13,000; different species show different number of chromosomes during mitosis; in gut of Cryptocercus punctulatus. Four species. 324 PROTOZOOLOGY B. ufalula C. (Figs. 60; 152, c). 25(>-340m by 175-275m; 50 chromo- somes; flagellated area 36-41^ long; centriole 28-35ju long. B. laurabuda C. 180-240ai by 135-1 70m; 40 chromosomes; flagel- lated area 29-33m long; centriole 24-28^ long. Genus Rhynchonympha Cleveland. Elongate; number of flagellar rows same throughout; axial filaments somewhat larger and longer, about 30; 30 parabasals; 2400 flagella; in Cryptocercus punctulatus. R. tarda C. (Fig. 153, /). 130-215^ by 30-70^. Genus Urinympha Cleveland. Narrow, slender; flagellated area, smaller than that of the two genera mentioned above; flagella move as a unit; about 24 axial filaments; 24 parabasals; 600 flagella; in gut of Cryptocercus punctulatus. U. talea C. (Fig. 152, d). 75-300m by 15-50/i. Family 4 Staurojoeninidae Grassi Genus Staurojoenina Grassi. Pyriform to cylindrical; anterior region conical; nucleus spherical, central; 4 flagellar tufts from anter- ior end; ingest wood fragments; in termite gut. *Si. assimilis Kirby (Fig. 152, e). 105-190^ long; in Kalotermes minor. Genus Idionympha Cleveland. Acorn-shaped; axostyles 8-18; fine parabasals grouped in 4 areas; pellicle non-striated; nucleus nearer anterior end than that of Staurojoenina; flagellated areas smaller; in gut of Cryptocercus punctulatus. I. perissa C. (Fig. 152,/). 169-275^ by 98-155/^. Family 5 Kofoidiidae Light Genus Kofoidia Light. Spherical; flagellar tufts composed of 8-16 loriculae (permanently fused bundles of flagella); without either axostyle or parabasal body; between oval nucleus and bases of flagellar tufts, there occurs a chromatin collar; in termite gut. K. loriculata L. (Fig. 153, a, h). 60-140/i in diameter; in Kalotermes simplicicornis. Family 6 Trichonymphidae Kent Genus Trichonympha Leidy {Leidyonella Frenzel; Gymnonympha Dobell; ? Leidy opsis Kofoid and Swezy). Anterior portion consists of nipple and bell, both of which are composed of 2 layers; a distinct axial core; nucleus central; flagella located in longitudinal rows on bell; in termite gut. Many species. Cleveland and his associates (1934) observed that encystment takes place in species inhabiting the woodroach, Cryptocercus punctulatus and that it occurs only at the time of moulting of the host roach, namely once a year. HYPERMASTIGINA 325 T. campanula Kofoid and Swezy (Figs. 59; 153, c). 144-313;^ by 57-144/i; wood particles are taken in by posterior region of the body; in Zootermopsis angusticollis, Z. nevadensis and Z. laticeps. Fig. 153. a, b, Kofoidia loriculata, xl75, X300 (Light); c, Tricho- nympha campanula, X150 (Kofoid and Swezy); d, T. agilis, x410 (Kirby); e, Eucomonympha imla, x350 (Cleveland et al.); f, Rhyncho- nympha tarda, x350 (Cleveland et al.). T. agilis Leidy (Fig. 153, d). 55-115^ by 22-45^; in Reticulitermes flavipes, R. lucifugus, R. speratus, R.flaviceps, R. hesperus, R. tibialis. 326 PROTOZOOLOGY T. grandis Cleveland. 190-205/Lt by 79-88//; in Cryptocercus punc- tualatus. Genus Pseudotrichonympha Grassi. 2 parts in anterior end as in Trichonympha; head organ with a spherical body at its tip and surrounded by a single layer of ectoplasm ; bell covered by 2 layers of ectoplasm; nucleus lies freely; body covered by slightly oblique rows of short flagella; in termite gut. P. grassii Koidzumi. In Coptotermes formosanus; spindle-form; 200-300M by 50-120/x. Genus Deltotrichonympha Sutherland. Triangular; with a small dome-shaped "head"; composed of 2 layers; head and neck with long active flagella; body flagella short, arranged in 5 longitudinal rows; flagella absent along posterior margin; nucleus large oval, located in anterior third; cytoplasm with wood chips; in termite gut. One species. D. operculata S. Up to 230m long, 164^i wide, and about 50^i thick; in gut of Mastotermes darwiniensis; Australia. Family 7 Eucomonymphidae Cleveland Genus Eucomonympha Cleveland. Body covered with flagella arranged in 2 (longer rostral and shorter post-rostral) zones; rostral tube very broad, filled with hyaline material; nucleus at base of rostrum; in gut of Cryptocercus punctulatus. E. imla C. (Fig. 153, e). 100-165m by 48-160m; attached forms more elongate than free individuals. Family 8 Teratonymphidae Koidzumi Genus Teratonympha Koidzumi {Cyclonympha Dogiel). Large; and elongate; transversely ridged, and presents a metameric appear- ance; each ridge with a single row of flagella; anterior end complex, containing a nucleus; reproduction by longitudinal fission; in termite gut. T. mirabilis K. (Fig. 152, g). 200-300^ or longer by 40-50^; in Reticulitermes speraius. References Cleveland, L. R. 1925 The effects of oxygenation and starvation on the symbiosis between the termite, Termopsis, and its intes- tinal flagellates. Biol. Bull., Vol. 48. and others 1934 The wood-feeding roach, Cryptocercus, its Protozoa, and the symbiosis between Protozoa and roach. Mem. Amer. Acad. Arts and Sci., Vol. 17. HYPERMASTIGINA 327 DoGiEL, V. 1922 Untersuchungen an parasitischen Protozoen aus dem Darmkanal der Termiten. III. Trichonymphidae. Arch. soc. Riisse Protist., Vol. 1. Janicki, D. v. 1910, 1915 Untersuchungen an parasitischen Flagel- laten. I, II. Zeitschr. wiss. Zool, Vols. 95, 112. KiRBY, H. 1926 On Staurojoenina assimilis sp. nov., an intestinal flagellate from the termite, Kalotermes minor Hagen. Uni. Calif. Publ. Zool., Vol. 29. 1932 Flagellates of the genus Trichonympha in termites. Ibid., Vol. 37. 1944 The structural characteristics and nuclear parasites of some species of Trichonympha in termites. Ibid., Vol. 49. KoFoiD, C. A. and Olive Swezy 1919, 1926 Studies on the parasites of termites. Ibid., Vols. 20, 28. KoiDzuMi, M. 1921 Studies on the intestinal Protozoa found in the termites of Japan. Parasit., Vol. 13. Kudo, R. R. 1926 Observations on Lophomonas hlattarum, a flagel- late inhabiting the colon of the cockroach, Blatta orientalis. Arch. f. Protistenk., Vol. 53. Sutherland, J. L. 1933 Protozoa from Australian termites. Quart. Jour. Micr. Sci., Vol. 76. Chapter 17 Class 2 Sarcodina Butschli THE members of this class do not possess any definite pellicle and, therefore, are capable of forming pseudo podia (p. 41). The term 'amoeboid' is often used to describe their appearance. The pseudopodia serve ordinarily for both locomotion and food- capturing. The peripheral portion of the body shows no structural differentiation in Amoebina, Proteomyxa, and Mycetozoa. Internal and external skeletal structures are variously developed in other orders. Thus, in Testacea and Foraminifera, there is a well-devel- oped test or shell that usually has an aperture, through which the pseudopodia are extruded; in Heliozoa and Radiolaria, skeletons of various forms and materials are developed. The cytoplasm is, as a rule, differentiated into the ectoplasm and the endoplasm, but this differentiation is not constant. In Radio- laria, there is a perforated membranous central capsule which marks the border line between the two cytoplasmic regions. The endoplasm contains the nuclei, food vacuoles, various granules, and contractile vacuoles. The majority of Sarcodina are uninucleate, but numerous species of Foraminifera and Mycetozoa are multinucleate in certain phases during their development. In the family Paramoebidae, there occurs a peculiar secondary nucleus. The Sarcodina are typically holozoic. Their food organisms are Protozoa, small Metazoa and Protophyta, which present themselves conspicuously in the cytoplasm. One or more contractile vacuoles are invariably present in forms inhabiting the fresh water, but absent in parasitic forms or in those which live in the salt water. Asexual reproduction is usually by binary (or rarely multiple) fission, budding, or plasmotomy. Definite proof of sexual reproduc- tion has been noted in a comparatively smidl number of species. Encystment is common in the majority of Sarcodina, but is unknown in a few species. The life-cycle has been worked out in some forms and seems to vary among different groups. The young stages are either amoeboid or flagellate, and on this account, it is sometimes very difficult to distinguish the Sarcodina and the Mastigophora. In some forms the mature trophic stage maj^ show an amoeboid or flagellate phase, owing to differences in environmental conditions. The Sarcodina are divided into two subclasses as follows: With lobopodia, rhizopodia, or filopodia . . Subclass 1 Rhizopoda (p. 329) With axopodia Subclass 2 Actinopoda (p. 406) 328 SARCODINA, PROTEOMYXA 329 Subclass 1 Rhizopoda Siebold The name Rhizopoda has often been used to designate the entire class, but it is used here for one of the subclasses, which is further subdivided into five orders, as follows: Without test or shell With radiating pseudopodia Order 1 Proteomyxa With rhizopodia; forming Plasmodium. . .Order 2 Mycetozoa (p. 335) With lobopodia Order 3 Amoebina (p. 343) With test or shell Test single-chambered; chitinous Order 4 Testacea (p. 374) Test 1- to many-chambered; calcareous . . Order 5 Foraminifera (p. 394) Order 1 Proteomyxa Lankester A number of incompletely known Rhizopods are placed in this group. The pseudopodia are filopodia which often branch or anas- tomose with one another. In this respect the Proteomyxa show affinity to the Mycetozoa. Flagellate swarmers and encystment occur commonly. The majority of Proteomyxa lead parasitic life in algae or higher plants in fresh or salt water. Pseudoplasmodium-formation Family 1 Labyrinthulidae Solitary and Heliozoa-like With flagellate swarmers Family 2 Pseudosporidae (p. 330) Without flagellate swarmers Family 3 Vampyrellidae (p. 330) Family I Labyrinthulidae Haeckel Small fusiform protoplasmic masses are grouped in network of sparingly branched and anastomosing filopodia; individuals encyst independently; with or without flagellate stages. Genus Labyrinthula Cienkowski. Minute forms feeding on various species of algae in fresh or salt water; often brightly colored due to the chlorophyll bodies taken in as food. Young (1943) made an ex- tensive study of the genus and concluded that six known species should be grouped in three species and two varieties. L. cienkowskii Zopf (Fig. 154, a). Attacks Vaucheria in fresh water. L. macrocystis Cienkowski. Renn (1934, 1936) found a species in the diseased leaf-tissue of the 'spotting and darkening' eel-grass, Zostera marina, along the Atlantic coast of the United States. Young (1943) identified the organism which he studied as L. macrocystis, and noted that its hosts included various algae and three genera of Naiadaceae: Zostera, Ruppia and Zannichellia. The 'net-plasmodium' contains fusiform cells which average in size 18/i by 4ju and which multiply by binary fission; many cells encyst 330 PROTOZOOLOGY together within a tough, opaque membrane. The growth is the best at 14-24° C. and at 12-22 per cent chlorinity. Genus Labyrinthomyxa Duboscq. Body fusiform; amoeboid and flagellate phases, variable in size; flagellate stage penetrates the host cell membrane; in plants. L. sauvageaui D. (Fig. 154, h-e). Fusiform body 7-1 Iju long; pseu- doplasmodium-formation; amoeboid stage 2.5-14)u long; flagellate stage 7-18m long; parasitic in Laminaria lejolisii at Roscoff, France. Family 2 Pseudosporidae Berlese Genus Pseudospora Cienkowski. Body minute; parasitic in algae and Mastigophora (including Volvocidae); organism nourishes itself on host protoplasm, grows and multiplies into a number of smaller individuals, b}^ repeated division; the latter biflagellate, seek a new host, and transform themselves into amoeboid stage; encystment common. P. volvocis C. (Fig. 154, /, g). Heliozoan form about 12-30^ in diameter; pseudopodia radiating; cysts about 25)u in diameter; in species of Volvox. P. parasitica C. Attacks Spirogyra and allied algae. P. eudorini Roskin. Heliozoan forms 10-12/i in diameter; radiating pseudopodia 2-3 times longer; amoeboid within host colony; cysts 15/x in diameter; in Eudorina elegans. Genus Protomonas Cienkowski. Body irregularly rounded with radiating filopodia; food consists of starch grains; division into bi- flagellate swarmers which become amoeboid and unite to form pseudoplasmodium; fresh or salt water. P. amyli C. (Fig. 154, h-j). In fresh water. Family 3 Vampyrellidae Doflein Filopodia radiate from all sides or formed from a limited area; flagellate swarmers do not occur; the organism is able to bore through the cellulose membrane of various algae and feeds on proto- plasmic contents; body often reddish because of the presence of carotin; multinucleate; multiplication in encysted stage into uni- or multi-nucleate bodies; cysts often also reddish. Genus Vampyrella Cienkowski. Heliozoa-like; endoplasm vacuo- lated or granulated, with carotin granules; numerous vesicular nuclei and contractile vacuoles; multinucleate cysts, sometimes with stalk; 50-700^ in diameter. Several species. V. lateritia (Fresenius) (Fig. 154, k, I). Spherical; orange-red except the hyaline ectoplasm; feeds on Spirogyra and other algae SARCODINA, PROTEOMYXA 331 in fresh water. On coming in contact with an alga, it often travels along it and sometimes breaks it at joints, or pierces individual cell and extracts chlorophyll bodies by means of pseudo podia; multipli- cation in encysted condition; 30-40/x in diameter. Genus Nuclearia Cienkowski. Subspherical, with sharply pointed fine radiating pseudo podia; actively moving forms vary in shape; Fig. 154. a, Labyrinthula cienkowskii, X200 (Doflein); b-e, Laby- rinthomyxa sauvageaui (b, c, flagellate forms, XlOO; d, e, amoeboid forms, X500) (Duboscq); f, g, Pseudospora volvocis, X670 (Robert- son); h-j, Protomonas amyli (Zopf);k, 1, Vampyrella lateritia, X530 (k (Leidy), 1 (Doflein)); m, n, Nuclearia delicatula, X300 (Cash). with or without a mucous envelope; with one or many nuclei; fresh water. N. delicatula C. (Fig. 154, m, n). Multinucleate; bacteria often adhering to gelatinous envelope; up to 60^ in diameter. 332 PROTOZOOLOGY N. simplex C. Uninucleate; 30/x in diameter. Genus Arachnula Cienkowski. Body irregularly chain-form with filo podia extending from ends of branches; numerous nuclei and yhnK' Fig. 155. a, Arachnula impatiens, X670 (Dobell); b, c, Chalmydomtjxa montana: b, X270 (Cash); c, X530 (Penard); d, Rhizoplasma kaiseri, X30? (Verworn); e, Bioniyxa vagans, X200 (Cash); f, Penardia mutabilis, X200 (Cash); g, Hyalodiscus rubicundus, X370 (Penard). SARCODINA, PROTEOMYXA 333 contractile vacuoles; feeds on diatoms and other microorganisms. A. impatiens C. (Fig. 155, a). 40-350m in diameter. Genus Chlamydomy^xa Archer. Body spheroidal; ectoplasm and endoplasm well differentiated; endoplasm often green-colored due to the presence of green spherules; numerous vesicular nuclei; 1-2 contractile vacuoles; secretion of an envelope around the body is followed by multiplication into numerous secondary cysts; cyst wall cellulose; in sphagnum swamp. C. montana Lankester (Fig. 155, h, c). Rounded or ovoid; cyto- plasm colored; about 50/x in diameter; when moving, elongate with extremely fine pseudopodia which are straight or slightly curved and which are capable of movement from side to side; non-con- tractile vacuoles at bases of grouped pseudopods; in active individ- ual there is a constant movement of minute fusiform bodies (function?); when extended 100-150/i long; total length 300^ or more; fresh water among vegetation. Genus Rhizoplasma Verworn. Spherical or sausage-shaped; with anastomosing filo podia; orange-red; with a few nuclei. R. kaiseri V. (Fig. 155, d). Contracted form 0.5-1 mm. in diameter; with 1-3 nuclei; pseudopodia up to 3 cm. long; extended body up to 10 mm. long; originally described from Red Sea. Genus Chondropus Greeff. Spherical to oval; peripheral portion transparent but often yellowish; endoplasm filled with green, yellow, brown bodies; neither nucleus nor contractile vacuoles observed; pseudopods straight, fine, often branched ; small pearl-like bodies on body surface and pseudopodia. C. viridis G. Average diameter 35-45yu; fresh water among algae. Genus Biomyxa Leidy {Gymnophrys Cienkowski). Body form in- constant; initial form spherical; cytoplasm colorless, finely granu- lated, capable of expanding and extending in any direction, with many filopodia which freely branch and anastomose; cytoplasmic movement active throughout; numerous small contractile vacuoles in body and pseudopodia; with one or more nuclei. B. vagans L. (Fig. 155, e). Main part of body, of various forms; size varies greatly; in sphagnous swamps, bog-water, etc. B. cometa (C.). Subspherical or irregularly ellipsoidal; pseudopodia small in number, formed from 2 or more points; body 35-40m, or up to 80/z or more; pseudopodia 400^ long or longer. Cienkowski main- tained that this was a moneran. Genus Penardia Cash. When inactive, rounded or ovoid; at other times expanded; exceedingly mobile during progression; endoplasm chlorophyll-green with a pale marginal zone; filopodia, branching 334 PROTOZOOLOGY and anastomosing, colorless; nucleus inconspicuous; one or more contractile vacuoles, small ; fresh water. P. mutabilis C. (Fig. 155, /). Resting form 90-100ai in diameter; extended forms (including pseudopodia) 300-400jU long. Genus Hyalodiscus Hertwig and Lesser. Discoid, though outline varies; endoplasm reddish, often vacuolated and sometimes shows filamentous projections reaching body surface; a single nucleus; ectoplasmic band of varying width surrounds the body completely; . closely allied to Vampyrella ; fresh water. H. ruhicundus H. and L. (Fig. 155, g). 50-80^ by about 30^; polymorphic; when its progress during movement is interrupted by an object, the body doubles back upon itself, and moves on in some other direction; freshwater ponds among surface vegetation. References Cash, J. 1905 The British freshwater Rhizopoda and Heliozoa. Vol. 1. London. DoBELL, C. 1913 Observations on the life-history of Cienkowski's Arachnula. Arch. f. Protistenk., Vol. 31. DoFLEiN, F. and E. Reichnow 1929 Lehrbuch der Protozoenkunde. Jena. DuBOSCQ, 0. 1921 Labyrinthomyxa sauvageaui n. g., n. sp., pro- teomyxee parasite de Laminaria lejolisii Sauvageau. C. r. soc. biol., Paris. Vol. 84. KtJHN, A. 1926 Morphologie der Tiere in Bildern. H. 2; T. 2. Rhizopoden. Leidy, J. 1879 Freshwater Rhiozopods of North America. Report U. S. Geol. Survey. Vol. 12. RosKiN, G. 1927 Zur Kenntnis der Gattung Pseudospora Cienkow- ski. Arch. f. Protistenk., Vol. 59. Valkanov, a. 1940 Die Heliozoen und Proteomyxien. Ibid., Vol. 93. Young, E. L. 1943 Studies on Labyrinthula, the etiologic agent of the wasting disease of eel-grass. Amer. Jour. Bot., Vol. 30. ZoPF, W. 1887 Handhuch der Botanik (A. Schenk). Vol. 3. Chapter 18 Order 2 Mycetozoa de Bary THE Mycetozoa had been considered to be closely related to the fungi, being, known as Mj^xomycetes, or Myxogasteres, the 'slime molds.' Through extended studies of their development, de Bary showed that they are more closely related to the Protozoa than to the Protophyta, although they stand undoubtedly on the border-line between these two groups of microorganisms. The Myce- tozoa occur on dead wood or decaying vegetable matter of various kinds. The most conspicuous part of a mycetozoan is its Plasmodium which is formed by fusion of several myxamoebae, thus producing a large multinucleate body (Fig. 156, a). The greater part of the cytoplasm is granulated, although there is a thin layer of hyaline and homogeneous cytoplasm surrounding the whole body. The numerous vesicular nuclei are distributed throughout the granular cytoplasm. Many small contractile vacuoles are present in the peripheral por- tion of the Plasmodium. The nuclei increase in number by division as the body grows; the division seems to be amitotic during the growth period of the Plasmodium, but is mitotic prior to the spore- formation. The granulation of the cytoplasm is due to the presence of enormous numbers of granules which in some forms are made up of carbonate of lime. The Plasmodium is usually colorless, but some- times yellow, green, or reddish, because of the numerous droplets of fluid pigment present in the cytoplasm. The food of Mycetozoa varies among different species. The great majority feed on decaying vegetable matter, but some, such as Badhamia, devour living fungi. Thus the Mycetozoa are holozoic or saprozoic in their mode of nutrition. Pepsin has been found in the Plasmodium of Fuligo and is perhaps secreted into the food vacuoles, into which protein materials are taken. The plasmodium of Bad- hamia is said to possess the power of cellulose digestion. When exposed to unfavorable conditions, such as desiccation, the protoplasmic movement ceases gradually, foreign bodies are extruded, and the whole plasmodium becomes divided into numer- ous sclerotia or cysts, each containing 10-20 nuclei and being sur- rounded by a resistant wall (h) . These cysts may live as long as three years. Upon return of favorable conditions, the contents of the sclerotia germinate, fuse together, and thus again produce plasmodia (c-e). 335 336 PROTOZOOLOGY When lack of food material occurs, the Plasmodium undergoes changes and develops sporangia. The first indication of this process is the appearance of lobular masses of protoplasm in various parts of the body (/, g). These masses are at first connected with the stream- ing protoplasmic thickenings, but later become completely segre- gated into young sporangia. During the course of sporangium-for- mation, foreign bodies are thrown out of the body, and around each Fig. 156. The life-cycle of the endosporous mycetozoan (de Bary, Lister, and others), a, plasmodium-formation by fusion of numerous myxamoebae; b, c, formation of sclerotium; d, e, germination of sclero- tium and formation of plasmodium; f, portion of a Plasmodium showing streaming protoplasmic thickenings; g, h, formation of sporangia; i, a sporangium opened, showing capillitium; j, a spore; k, germination of spore; I, myxamoeba; m, n, myxoflagellates; o-q, multiplication of myxoflagellate; r, microcyst; s, myxamoeba. Variously magnified. sporangium there is secreted a wall which, when mature, possesses a wrinkled appearance (h). The wall continues down to the substra- tum as a slender stalk of varying length, and in many genera the end of a stalk spreads into a network over the substratum, which forms MYCETOZOA 337 the base, hypothallus, for the stalk. With these changes the interior of the sporangium becomes penetrated by an anastomosing network, capillitium, of flat bands which are continuous with the outer cover- ing (^■). Soon after the differentiation of these protective and sup- porting structures, the nuclei divide simultaneously by mitosis and the cytoplasm breaks up into many small bodies. These uninucleate bodies are the spores which measure 3-20ju in diameter and which soon become covered by a more or less thick cellulose membrane (j), variously colored in different species. The mature sporangium breaks open sooner or later and the spores are carried, and scattered, by the wind. When a spore falls in water, its membrane ruptures, and the protoplasmic contents emerge as an amoebula {k, I). The amoebula possesses a single vesic- idar nucleus and contractile vacuoles, and undergoes a typical amoe- boid movement. It presently assumes an elongate form and pro- trudes a flagellum from the nucelated end, thus developing into a myxofiagellate (zoospore or swarmer) (m, n) which undergoes a pe- culiar dancing movement and is able to form short, pointed pseudo- podia from the posterior end. It feeds on bacteria, grows and multi- plies by binary fission (o-q). After a series of division, the myxo- fiagellate may encyst and becomes a microcyst (r). Wlien the micro- cyst germinates, the content develops into a myxamoeba (s) which, through fusion with many others, produces the Plasmodium men- tioned above. This is the life-cycle of a typical endosporous myceto- zoan. In the genus Ceratiomyxa in which spores are formed on the sur- face of sporophores, the development is briefly as follows: the Plasmodium lives on or in decayed wood and presents a horn-like appearance. The body is covered by a gelatinous hyaline substance, within which the protoplasmic movements may be noted. The proto- plasm soon leaves the interior and accumulates at the surface of the mass; at first as a close-set reticulum and then into a mosaic of polygonal cells, each containing a single nucleus. Each of these cells moves outward at right angles to the surface, still enveloped by the thin hj^aline layer, which forms a stalk below. These cells are spores which become ellipsoid and covered by a membrane when fully formed. The spore is uninucleate at first, but soon becomes tetranu- cleate. When a spore reaches the water, its content emerges as an amoebula which divides three times, forming 8 small bodies, each of which develops a flagellum and becomes a myxoflagellate. The remaining part of the development is presumably similar to that of the endosporous form. 338 PROTOZOOLOGY An enormous number of mycetozoan genera and species are known. The order is divided here into two suborders. Spore develops into myxoflagellate; myxamoebae fuse completely and form Plasmodium Suborder 1 Eumycetozoa No flagellate stage; myxamoebae grouped prior to spore-formation, but do not fuse to form a true Plasmodium Suborder 2 Sorophora (p. 341) Suborder 1 Eumycetozoa Zopf Spores develop within sporangia Spores violet or violet-brown Sporangia with lime Lime in small granular form Family 1 Physaridae Fig. 157. a, b, Badhamia utricularis Berkeley (a, cluster of sporangia, X4; b, part of capillitium and spore-cluster, Xl40) (Lister); c, d, Fuligo septica Gmelin (c, a group of sporangia, X|; d, part of capillitium and two spores, Xl20) (Lister); e, f, Didyniium effusum Link (e, sporan- gium, Xl2; f, portion of capillitium and wall of sporangium showing the crystals of calcium carbonate and two spores, X200) (Lister); g, h, Stemonitis splendens Rostafinski (g, three sporangia, X2; h, col- umella and capillitium, X42) (Lister). Genus Badhamia Berkeley (Fig. 157, a, b) Capillitium, a course network with lime throughout. Genus Fuligo Haller (Fig. 157, c, d) Capillitium, a delicate network of threads with vesicular expan- sions filled with granules of lime. Lime in crystalline form Family 2 Didymiidae MYCETOZOA 339 Genus Didymium Schrader (Fig. 157, e, f) Lime crystals stellate, distributed over the wall of sporangium. Sporangia without lime Sporangia stalked Family 3 Stemonitidae Genus Stemonitis Gleditsch (Fig. 157, g, h) Sporangium-wall evanescent; capillitium arising from all parts of columella to form a network. Sporangium combined into aethalium Family 4 Amaurochaetidae Fig. 158. a, b, Amaurochaete fuliginosa MacBride (a, group of spor- angia, X|; b, capillitium, XlO) (Lister); c, empty sporangium of Cri- braria aurantiaca Schrader, X20 (Lister); d, sporangium of Orcadella operculata Wingate, X80 (Lister); e, cluster of sporangia of Tubulina jragiformis Persoon, X3 (Lister); f, aethalium of Reticularia lycoperdon Bull., XI (Lister); g, aethalium of Lycogala miniatum Persoon Xl (Lis- ter); h-j, Trichia affinis de Bary (h, group of sporangia, X2; i, elater, X250; j, spore, X400) (Lister); k, 1, Arcyria punicea Persoon (k, four sporangia, X2; 1, part of capillitium, X250 and a spore, X560) (Lister); m, n, Ceratiomyxa fruticulosa MacBride (m, sporophore, X40; n, part of mature sporophore, showing two spores, X480) (Lister). Genus Amaurochaete Rostafinski (Fig. 158, a, b) With irregularly branching thread-like capillitium. Spores variously colored, except violet Capillitium absent or not forming a system of uniform threads. Sporangium-wall membranous; with minute round granules Family 5 Cribrariidae 340 PROTOZOOLOGY Genus Cribraria Persoon (Fig. 158, c) Sporangia stalked; wall thickened and forms a delicate persistent network expanded at the nodes. Sporangia soHtary ; stalked Family 6 Liceidae Genus Orcadella Wingate (Fig. 158, d) Sporangia stalked, furnished with a lid of thinner substance. Sporangium-wall membranous without granular deposits Family 7 Tubulinidae Genus Tubulina Persoon (Fig. 158, e) Sporangia without tubular extensions. Many sporangia more or less closely fused to form large bodies (aethalia) ; sporangium-wall incomplete and perforated Family 8 Reticulariidae Genus Reticularia Bulliard (Fig. 158, /) Walls of convoluted sporangia incomplete, forming tubes and folds with numerous anastomosing threads. Sporangia forming aethalium Family 9 Lycogalidae Genus Lycogala Adanson (Fig. 158, g) Capillitium a system of uniform threads Capillitium threads with spiral or annular thickenings Family 10 Trichiidae Genus Trichia Haller (Fig. 158, h-j) Capillitium abundant, consisting of free elasters with spiral thickenings. Capillitium combined into an elastic network with thickenings in forms of cogs, half-rings, spines, or warts. Family 11 Arcyriidae Genus Arcyria Wiggers (Fig. 158, A;, I) Sporangia stalked; sporangium-wall evanescent above, persistent and membranous in the lower third. Capillitium abundant; sporangia normally sessile Family 12 Margaritidae Genus Margarita Lister CapilUtium profuse, long, coiled hair-like. Spores develop on the surface of sporophores Spores white; borne singly on filiform stalk Family 13 Ceratiomyxidae MYCETOZOA 341 Genus Ceratiomyxa Schroter (Fig. 158, m, n) Suborder 2 Sorophora Lister Pseudoplasmodium incomplete; myxamoeba of limax-form Family 1 Guttuliniidae Pseudoplasmodium complete; myxamoeba with short pointed pseudo- podia Family 2 Dictyosteliidae The Proteomyxa and the Mycetozoa as outlined above, are not distinctly defined groups. In reality, there are a number of forms which stand on the border line between them. Phytomyxinea Poche These organisms which possess a large multinucleate amoeboid body, are parasitic in various plants and also in a few animals. © ^4}^ Fig. 159. Plasmodiophora brassicae. a, root-hernia of cabbage; b, a spore, X620; c-e, stages in germination of spore, X620; f, myxamoeba, X620 (Woronin); g, a host cell with several j^oung parasites, X400; h, an older parasite, X-100 (Nawaschin). Genus Plasmodiophora Woronin. Parasitic in the roots of cabbage and other cruciferous plants. The organism produces knotty enlarge- ments, sometimes known as "root-hernia," or "fingers and toes" (Fig. 159, a). The small (haploid) spore (b) gives rise to a myxoflagel- late (c-/) which penetrates the host cell. The organism growls in size and multiplies (g, h). The Plasmodium divides into sporangia. Flagel- lated gametes that develop from them fuse in pairs, giving rise to diploid zygotes. These zygotes develop further into plasmodia in which haploid spores are produced. P. brassicae W. (Fig. 159). In Brassica spp. Genus Sorosphaera Schroter. Parasitic in Veronica spp. Genus Tetramyxa Goebel. In Ruppia, Zannichellia, etc. Genus Octomyxa Couch, Leitner and Whiff en. In Achlya glomerata. Genus Sorodiscus Lagerheim and Winge. In Chara, Callitriche, etc. 342 PROTOZOOLOGY Genus Polymyxa Ledingham. In Triticum, etc. Genus Membranosorus Ostenfeld and Petersen. In Heterahthera duhia. Genus Spongospora Brunchorst. Parasitic in Solanum; the dis- eased condition of potatoes is known as powdery or corky scab. Genus Ligniera Maire and Tison. In Alisma, Juncus, etc. References DE Bary 1864 Die Mycetozoa. Leipzig. Hagelstein, R. 1944 The Mycetoza of North America. New York. Jahn, E. 1901-1920 Myxomycetenstudien. I to X. Ber. Deutsch. Bot. Ges., Vols. 19, 20, 22-26, 29, 36 and 37. Jones, P. M. 1928 Morphology and cultural study of Plasmodio- phora brassicae. Arch. f. Protistenk., Vol. 62. Karling, J. S. 1942 The Plasmodiophorales. New York. Lister, A. 1925 A monograph on the Mycetozoa. 3rd ed. London. MacBride, T. H. 1922 North American slime molds. 2nd ed. New York. and G. H. Martin 1934 The Myxomycetes. New York. Chapter 19 Order 3 Amoebina Ehrenberg THE Amoebina show a very little cortical differentiation. There is no pellicle or test, surrounding the body, although in some a delicate pellicle occurs. The cytoplasm is more or less distinctly dif- ferentiated into the ectoplasm and the endoplasm. The ectoplasm is hyaline and homogeneous, and appears tougher than the endoplasm. In the endoplasm, which is granulated or vacuolated, are found one or more nuclei, various food vacuoles, crystals, and other inclusions. In the freshwater forms, there is at least one distinctly visible contractile vacuole. The pseudopodia are lobopodia, and ordinarily both the ectoplasm and endoplasm are found in them. They are formed by streaming or fountain movements of the cytoplasm. In some members of this order, the formation of pseudopodia is erup- tive or explosive, since the granules present in the endoplasm break through the border line between the two cytoplasmic laj^ers and suddenly flow into the pseudopodia. Asexual reproduction is ordi- narily by binary fission, although multiple fission may occasionally take place. Encystment is of common occurrence. Sexual reproduc- tion, which has been reported in a few species, has not been con- firmed. The Amoebina inhabit all sorts of fresh, brackish, and salt waters. They are also found in moist soil and on ground covered with decay- ing leaves. Many are inhabitants of the digestive tract of various animals, and some are pathogenic to the hosts. The taxonomic status of the group is highly uncertain and con- fusing, since their life-histories are mostly unknown and since numer- ous protozoans other than the members of this group often possess amoeboid stages. Forms such as Rhizomastigina (p. 263) may be considered as belonging to either the Sarcodina or the Mastigophora. The order is subdivided into four families as follows: With amoeboid and flagellate stages Family 1 Dimastigamoebidae (p. 344) Amoeboid stage only With one or more nuclei of one kind Free-living Family 2 Amoebidae (p. 345) Parasitic. Family 3 Endamoebidae (p. 351) With a secondary nucleus Family 4 Paramoebidae (p. 371) 343 344 PROTOZOOLOGY Family 1 Dimastigamoebidae Wenyon The members of the two genera placed in this family possess both amoeboid and flagellate phases {diphasic). In the former, the organ- ism undergoes amoeboid movement by means of lobopodia and in the latter the body is more or less elongated. Binary fission seems to take place during the amoeboid phase only. Thus these are diphasic protozoans, in which the amoeboid stage predominates over the flagellate. The amoeboid phase resembles a 'limax' amoeba; under natural circumstances, it is often exceedingly difficult by observing the amoeboid stage only, to determine whether they belong to this family or the family Amoebidae. Fig. 160. a-c, trophozoite, flagellate phase and cj^st (all stained) of Dimastig amoeba gruberi, x750 (Alexeieff); d-f, similar stages of D. bistadialis, X750 (Kiihn); g-j, trophozoite, flagellate phase, cyst and excystation of Trimastigamoeba philippi7iensis X950 (Whitemore). Genus Dimastigamoeba Blochmann ( Nacgleria Alexeieff). Minute; flagellate stage with 2 flagella; amoeboid stage resembles Vahlkamp- fia (p. 350), with lobopodia; cytoplasm differentiated; vesicular nucleus with a large endosome; contractile vacuole conspicuous; food vacuoles contain bacteria; cysts uninucleate; free-living in stagnant water and often coprozoic. D. gruberi (Schardinger) (Fig. 160, a-c). Amoeboid stage 10-50)u long; cyst wall with several openings; flagellate stage 10-30/i long; stagnant freshwater and often coprozoic. D. bistadialis (Puschkarew) (Fig. 160, d-f). Similar in size; but cyst with a smoother wall. Genus Trimastigamoeba Wliitmore. Flagellate stage bears 3 flagella of nearlj- equal length ; vesicular nucleus with a large endo- some; amoeboid stage small, less than 20m in diameter; uninucleate cysts with smooth wall; stagnant water. One species. AMOEBINA 345 T. philippinensis W. (Fig. 160, g-j). Amoeboid stage 16-18ju in diameter; oval cysts 13-14ju by 8-12)u; flagellate stage 16-22/i by Family 2 Amoebidae Bronn These amoebae do not have flagellate stage and are exclusively amoeboid (monophasic) . They are free-living in fresh or salt water, in damp soil, moss, etc., and a few parasitic; 1, 2, or many nuclei; contractile vacuoles in freshwater forms; multiplication by binary or multiple fission or plasmotomy; encystment common. Genus Amoeba Ehrenberg (Proteus Miiller; Amiba Bory). Amoe- boid; naked, in a few species there are indications that a delicate pellicle occurs; a single nucleus, vesicular or somewhat compact; contractile vacuoles; pseudopodia mainly lobopodia, never anas- tomosing with one another; some students have used the nuclear structure for specific differentiation, but unfortunately not always clear; holozoic; fresh, brackish or salt water. Numerous species. A. proteus (Pallas) (Figs. 25; 32, h, c; 41,/; 43-45; 161, a, h). Up to 600;u or longer in largest diameter; creeping with a few large lobopo- dia, showing longitudinal ridges; ectoplasm and endoplasm usually distinctly differentiated; typically uninucleate; nucleus disco idal but polymorphic; endoplasmic crystals truncate bipyramid, up to 4.5^1 long (Schaeffer); nuclear and cytosomic divisions show a dis- tinct correlation (p. 143) ; fresh water. A. discoides Schaeffer (Figs, 41, g; 161, c). About 400^ long during locomotion; a few blunt, smooth pseudopodia; crystals abundant, truncate bipyramidal, about 2.5;u long (Schaeffer); endoplasm with numerous coarse granules; fresh water. A. dubia S. (Figs. 41, h-l; 161, d). About 400m long; numerous pseudopodia flattened and with smooth surface; crystals, few, large, up to 30^ long and of various forms among which at least 4 types are said to be distinct (Schaeffer); contractile vacuole one or more; fresh water. Angerer (1942) studied the action of cupric chlo- ride on the protoplasmic viscosity of this amoeba. A. verrucosa Ehrenberg (Figs. 32, a, d-h; 42, a; 161, e). Ovoid in general outline with wart-like expansions; body surface usually wrinkled, with a definite pellicle; pseudopodia short, broad and blunt; nucleus ovoid, vesicular, with a large endosome; contractile vacuole; up to 200m in diameter; fresh water among algae. A. striata Penard (Fig. 161,/). Somewhat similar to A. verrucosa, but small; body flattened; ovoid, narrowed and rounded posteriorly; nucleus vesicular; contractile vacuole comparatively large and often 346 PROTOZOOLOGY not spherical; extremely delicate pellicle shows 3 or 4 fine longitud- inal lines which appear and disappear with the movement of the body; 25-45ju by 20-35^; fresh water among vegetation. A. guttula Dujardin (Fig. 161, g). Ovoid during locomotion, nar- rowed behind; often with a few minute, nipple-like dentations at Fig. 161. a, b, Amoeba proteus (a, X130 (Schaeffer), b, cyst (Doflein)); c, A. discoides, X130 (Schaeffer); d, A. dubia, X130 (Schaeffer); e, A. verrucosa, X200 (Cash); f, A. striata, X400 (Penard); g, A. guttula, X800 (Penard); h, A. liviicola, X530 (Penard). the temporary posterior end; movement by wave-like expansions of ectoplasm; endoplasm granulated, with crystals; nucleus vesicular; a single contractile vacuole; 30-35/i by 20-25/i; fresh water in vege- tation. AMOEBINA 347 A. limicola Rhumbler (Fig. 161, h). Somewhat similar to A. gut- tula; body more rounded; locomotion by eruption of cytoplasm through the body surface; 45-55^ by 35m; nucleus vesicular; fresh water among vegetation. Fig. 162. a, Amoeba spumosa, x400 (Penard); b, c, A. vespertilio X300 (Penard); d-f, A. gorgonia, X400 (Penard); g, A. radiosa, X500 (Penard); h, Dinamoeba mirabilis, X250 (Leidy). A. spumosa Gruber (Fig. 162, a). Somewhat fan-shaped; flat- tened; during locomotion broad pseudopodia with pointed end at 348 PROTOZOOLOGY temporary anterior region; posterior reigon with nipple-like projec- tions; a small number of striae become visible during movement, showing there is a very thin pellicle; endoplasm always vacuolated, the vacuoles varying in size (up to 30m in diameter) ; vesicular nucleus with an endosome; 50-125^ long during locomotion; fresh w^ater. A. vespertilio Penard (Fig. 162, b, c.) Pseudo podia conical, com- paratively short, connected at base by web-like expansions of ecto- plasm; endoplasm colorless, with numerous granules and food par- ticles; a single vesicular nucleus with a large endosome; contractile vacuoles; 60-100)u long; fresh water. A. gorgonia P. (Fig. 162, d-f). Body globular when inactive with a variable number of radiating 'arms,' formed on all sides; locomotion by forming elongate pseudopodia, composed of both ectoplasm and endoplasm; nucleus, vesicular, with a large endosome; 40-50/i in diameter; extended forms about 100^ long; fresh water among vegetation. A. radiosa Ehrenberg (Fig. 162, g). Small, usually inactive; globular or oval in outline; with 3-10 radiating slender pseudopodia which vary in length and degree of rigidity; when pseudopods are withdrawn, the organism may be similar to A. proteus in general ap- pearance; pseudopods straight, curved or spirally coiled; size varies, usually about 30m in diameter, up to 120)U or more; fresh water. Genus Dinamoeba Leidy. Essentially Amoeba, but the temporary posterior region of body with retractile papillae; body surface includ- ing pseudopods and papillae, bristling with minute spicules or mo- tionless cils; often surrounded by a thick layer of delicate hyaline jelly, even during locomotion; fresh water. D. mirahilis L. (Fig. 162, h). Oval to limaciform; spheroid when floating; pseudopodia numerous, conical; ectoplasm clear, usually with cils; endoplasm with food vacuoles, oil (?) spherules and large clear globules; nucleus and contractile vacuole obscure; spherical forms 64-160/i in diameter; creeping forms 152-340)uby 60-220^; in sphagnous swamp. Genus Pelomyxa Greeff. Large amoeboid organisms, ranging from 0.5 to 4 or 5 mm. in length when clavate and moving progressively; nuclei numerous, 100 to 1000 or more; many small contractile vacu- oles; refringent bodies ("Glanzkorper") of various dimension and amount; wdth or without bacterial inclusions (which Penard and others consider as symbiotic) ; holozoic on plant or animal organisms; plasmotomy into 2 or more individuals; all in fresh water. Several species. P. palustris G. (Fig. 163, a). Large; 2-3 mm. or larger in diameter; AMOEBINA 349 with one broad pseiidopodium by which the organism undergoes rolling movement; cytoplasm undifferentiated; numerous vacuoles and nuclei; various inclusions often color the body brown to black and make it appear opaque; symbiotic protophytan, Cladoihrix pelomyxae Veley, occurs regularly; cysts with 2-3 envelopes (Stole); feeds on plant matter; polysaprobic, in still stagnant water, creeping on the muddy bottom. Central Europe, Great Britain, North America. Ms. Fig. 163. a, Pelomyxa palustris, Xl30 (Kiihn); b, P. villosa, X420 (Leidy); c, Vahlkampfia Umax, X830 (Kudo); d, V. patuxent, X830 (Hogue); e, f, Acanthamoeba hyalina, X1170 (Dobell); g, h, A. castel- lanii, X1590 (Hewitt). P. villosa (Leidy) (Fig. 163, h). Similar to the last-named species, but somewhat smaller; with numerous short and papillary villi at posterior extremity; during locomotion, 120ju-1.25 mm. long; in the ooze of freshwater bodies. Europe, North America. P. carolinensis Wilson, Monopodia! forms 1-5 mm. long; polypo- dial (feeding) forms 1-2 mm, in diameter; ectoplasm near the tips of expanding pseudopods; endoplasm contains up to 1000 or more nuclei which are circular in front view, 20/i in diameter, and ellipsoid in profile; fluid and food vacuoles, crystals, many contractile vacu- 350 PROTOZOOLOGY oles; feeds on various Protozoa and also small invertebrates; may- take 20 Paramecium within one food-cup; plasmotomy into 2-6 smaller individuals. North America (North Carolina (Wilson); Vir- ginia (Kepner and Edwards) ; Tennessee and New Jersey (Schaeff er) ; Illinois (Kudo)) and Great Britain (McGuire). Genus Vahlkampfia Chatton and Lalung-Bonnaire. Small amoe- bae; vesicular nucleus with a large endosome and peripheral chro- matin; with polar caps during nuclear division; snail-like movement, with one broad pseudo podium; cysts with a perforated wall; fresh water or parasitic. V. Umax (Dujardin) (Fig. 163, c). 30-40^1 long; fresh water. V. patuxent Hogue (Fig. 163, d). In the alimentary canal of the oyster; about 20^ long during the first few days of artificial culti- vation, but later reaching as long as 140/i in diameter; ordinarily one large broad fan-shaped pseudopodium composed of the ecto- plasm; in culture, pseudopodium-formation eruptive; ho lo zoic on bacteria; multiplication by fission or budding; encystment rare; cysts uninucleate. Genus Hartmannella Alexeieff. Small amoebae, with moderately or well-developed ectoplasm; vesicular nucleus with a large endo- some; mitotic figure ellipsoidal or cylindrical, without polar caps. Cysts rounded; wall smooth or slightly wrinkled in one species. Several species. Volkonsky (1933) distinguishes four groups. H. hyalina (Dangeard). 20-25)u in diameter; ectoplasm well developed; endoplasm vacuolated; slender pseudo podia extend in different directions; Hartmann and Chagas observed a centriole in the endosome. Genus Acanthamoeba Volkonsky. Small amoebae similar to Hart- mannella; ectoplasm is not well developed; mitotic figure at the end of metaphase, a straight or concave spindle with sharply pointed poles. Cysts enveloped by two membranes, the outer envelope being highly wrinkled and mammillated. Several species. A. castellanii (Douglas) (Fig. 163, g, h). In association with fungi and certain bacteria; Hewitt obtained the organism from agar cul- tures of sample soil taken from among the roots of white clover; co- existing with yeast-like fungi, Flavohacterium trifolium and Rhizo- bium sp.; 12-30/1 in diameter; some cysts are said to remain viable at 37°C. for 6 days. A. hyalina (Dobell and O'Connor) (Fig. 163, e, /). According to Volkonsky, the organism described by Dobell and O'Connor as Hartmannella hyalina, is transferred to this genus. Small amoeba; 9-1 7)u in diameter when rounded; a single contractile vacuole; binary AMOEBINA 351 fission; mitotic figure a sharply pointed spindle. Cysts spherical; 10-15ju in diameter; with a smooth inner and a much wrinkled outer wall; easily cultivated from old faeces of man and animals; also in soil and fresh water. Genus Sappinia Dangeard. With two closely associated nuclei. S. diploidea (Hartmann and Nagler). Coprozoic in the faeces of different animals; pseudopodia short, broad, and few; highly vacu- olated endoplasm with 2 nuclei, food vacuoles, and a contractile vacuole; surface sometimes wrinkled; the nuclei divide simultane- ously; during encystment, two individuals come together and secrete a common cyst wall; 2 nuclei fuse so that each individual possesses a single nucleus; finally cytoplasmic masses unite into one; each nucleus gives off reduction bodies (?) which degenerate; 2 nuclei now come in contact without fusion, thus producing a binucleate cyst (Hartmann and Nagler). Family 3 Endamoebidae Calkins Exclusively parasitic amoebae; the vegetative form is relatively small and occurs mostly in the alimentary canal of the hosts; con- «) Fig. 164. Diagrams showing the nuclei of the trophozoites of 5 genera of parasitic amoebae, a, Endamoeba; b, Entamoeba; c, lodamoeba; d, Endolimax; e, Dientamoeba. tractile vacuoles absent, except in Hydramoeba; multiplication by binary fission; encystment common. The generic differentiation is based upon the morphological characteristics of the nucleus. Sum- mary No. 99 of 'Opinions Rendered' by the International Commis- sion of Zoological Nomenclature (1928) holds that Entamoeba is a synonym of Endamoeba; in the present work, however, Endamoeba and Entamoeba are separated, since the two groups of species placed under them possess different nuclear characteristics (Fig. 164) and since it is not advisable to establish another generic name in place of Entamoeba which has been so frequently and widely used through- out the world. Genus Endamoeba Leidy (1879). Nucleus spheroidal to ovoid; 352 PROTOZOOLOGY membrane thick; in life, filled with numerous granules of uniform di- mensions along its peripheral region; upon fixation, a fine chro- matic network becomes noticeable in their stead; central portion coarsely reticulated; with several endosomes between the two zones (Fig. 164, a); in some, cytoplasm becomes prominently striated dur- ing locomotion; in the intestine of invertebrates. Fig. 165. Endamoeba blattae. a-c, trophozoites in fife, X530; d, a stained binucleate amoeba; e, f, stained and fresh cysts, X700 (Kudo). E. hlattae (Biitschli) (Figs. 51; 165). In the colon of cockroaches; 10-150/x in diameter; rounded individuals with broad pseudopodia, show a distinct differentiation of cytoplasm; elongated forms with a few pseudopodia, show ectoplasm only at the extremities of the pseudopods; endoplasm of actively motile trophozoites shows a distinct striation, a condition not seen in other amoebae; fluid-filled vacuoles occur in large numbers; amoebae feed on starch grains, yeast cells, bacteria and protozoans, all of which coexist in the host organ; cysts, 20-50/x in diameter, commonly seen in the colon con- tents, with often more than 60 nuclei. The life-cycle cf this amoeba AMOEBINA 353 is still unknown. Mercier (1909) held that when the multinucleate cysts gain entrance to the host intestine through its mouth, each of the C3^st-nuclei becomes the center of a gamete; when the cyst- membrane ruptures, the gametes are set free and anisogamj^ takes place, resulting in formation of numerous zygotes which develop into the hal)itual trophozoites. Among the more recent investigators, Morris (1936) is inclined to think that sexual reproduction brings about 'zygotic adults.' Meglitsch (1940) made an extensive cyto- logical study of this amoeba. Fig. 166. a, Endamoeba majestus, X420 (Kirby); b, E. simulans, X420 (Kirby); c, Entamoeba brasiliensis in Zelleriella, X290 (Stabler and Chen). E. thomsoni Lucas. In colon of the cockroaches; 7-30^ in diameter; very adhesive; 1-3 chromatin blocks on the nuclear membrane; cysts 8-16m in diameter, with 1-4 nuclei. E. disparata Kirby. In colon of Microtermes hispaniolae ; 20-40/x long; active; xylophagous. E. majestas K. (Fig. 166, a). In the same habitat; 65-165^ in diameter; many short pseudopodia; cytoplasm filled with food particles. E. simulans K. (Fig. 166, 6). In the gut of Microtermes pana- maensis; 50-1 50/u in diameter. E. sahidosa K. In the same habitat; small 19-35iu in diameter. Four additional species have recently been described by Hender- son from the colon of Cubitermes sp. of Africa. They are E. pellucida, E. granosa, E. lutea, and E. suggrandis. Genus Entamoeba Casagrandi and Barbagallo (1895). Nucleus vesicular, with a comparatively small endosome, located in or near the center and with varying number of peripheral chromatin 354 PROTOZOOLOGY granules attached to the nuclear membrane (Fig. 164, h). It was es- tablished by the two Italian authors who were unaware of the exist- ence of the genus Endamoeba (p. 351). Numerous species in vertebrates and invertebrates. E. histolytica Schaudinn (Figs. 167; 168). The trophozoite is a very active amoeba and measures about 15-35jLi in diameter; cytoplasm /- -. :. V ®€! « a.- 6^ o ■xmi '^''' R <:> Fig. 167. Entamoeba histolytica, X1150 (Kudo). 1, a living trophozoite; 2-4, stained trophozoites; 5, a fresh cyst; 6-9, stained cysts. usually well dijEferentiated ; eruptive formation of large lobopodia, composed largely of ectoplasm; when fresh, active monopodial progressive movement; the vesicular nucleus appears in life as a ring, difficult to recognize; food vacuoles contain erythrocytes, tissue cell fragments, leucocj^es, etc.; stained nucleus shows a membrane, peripheral chromatin granules, a centrally located small endosome, and an indistinct network with a few scattered chromatin granules. The trophozoite multiplies by binary fission. The amoeba lives normally in the tissues of the intestinal wall of man and brings about characteristic ulceration of the colon which is often accom- panied by symptoms of amoebic dysentery. Through the portal vein, AMOEBINA 355 the amoeba may invade the liver in which it produces abscess, or other organs such as lung, brain, testis, etc. The infection in these organs is referred to as amoehiasis. Under certain circumstances not well understood, the amoebae remain small after division. Such amoebae are sluggish and known as the precystic forms. The precystic amoeba secretes presently a resistant wall and becomes encysted. The highly refractile cyst is spherical and measures 5-20(j, in diameter. At first it contains a single nucleus which divides twice. The mature cyst contains four nuclei. In addition the cyst contains diffused glycogen and elongated refrac- tile rod-like bodies with rounded extremities which stain deeply with haematoxylin (hence called chromatoid bodies). These inclusions are absorbed and disappear as the cyst matures. No further changes take place in the cyst as long as it remains outside the host's intes- tine. The trophozoites are found in dysenteric or diarrhoeic faeces, but formed faeces usually contain cysts only. The life-cycle of Entamoeba histolytica in human host is unknown. The amoeba has, however, been cultivated in vitro by numerous investigators since the first successful cultivation by Boeck and Drbohlav (1924) (p. 717). The excystment of cysts and metacystic development have also been observed and studied especiallj'- by Dobell (1928) and Cleveland and Sanders (1930) in cultures, Snyder and Meleney (1941) found that bacteria-free cysts usually excyst when suspended in various media with living bacteria and in the absence of bacteria, excystment was observed onl}^ in the presence of the reducing agents, cysteine or neutralized thioglycoUic acid or under conditions of reduced oxygen tension. According to Dobell, in the process of excystation, a single tetranucleate amoeba emerges from a cyst through a minute pore in the cyst wall. The tetranucleate metacystic amoeba produces a new generation of trophozoites by a complicated series of nuclear and cytoplasmic divisions (Fig. 168) which result in production of eight uninucleate amoebulae. These amoebulae are young trophozoites which grow into larger ones. No sexual phenomena have been observed during these changes. It is supposed that when viable cysts reach the lower portion of the small intestine or the colon, the changes stated above take place in the lumen and the young uninucleate amoebulae enter the intestinal wall, bringing about an infection. While the description of Entamoeba histolytica given above apply in general, diversities in dimensions of trophozoites and cysts, and in pathogenicity in human host as well as in experimental animals have been reported. A number of observers are inclined to think 356 PROTOZOOLOGY that there are several varieties or races of this amoeba, as has already been mentioned (p. 179). Entamoeba histolytica, commonly known as "the dysentery amoeba," was first definitely recognized by Losch in Russia in 1875. It is now known to be widely distributed in tropical, subtropical and temperate regions alike, although it is more prevalent in warmer regions. The incidence of infection depends mainly on the sanitary Fig. 168. Diagram showing excystment and a common way by which a metacystic amoeba of Entamoeba histolytica divides into 8 uninucleate amoebulae (Dobell). conditions of the community, since the organism is voided from host in faeces. Faecal examinations which have been carried on by nu- merous investigators in different countries of the world, reveal that the incidence of infection is as high as over 50 per cent in some areas. According to Craig (1934), 49,336 examinations made by many observers in various parts of the United States show that the infec- AMOEBINA 357 tion rate varied from 0.2 to 53 per cent, averaging 11.6 per cent, which justifies Craig's (1926) earlier estimate that about 10 per cent of the general population harbor this protozoan. An acute infection by E. histolytica is accompanied by dysenterj^, while in chronic cases or in convalescence, the host may void infectious cysts without suffering from the infection himself. Such a person is known as a cyst-carrier or -passer. The trophozoite if voided in faeces perish in a comparatively short time. The dissemination of infection is exclusively carried on by the cyst. Viable cysts may be transmitted (1) by contamination of food through contact with contaminated water or through unsanitary habit of food handlers who are cyst-carriers; (2) by droppings of flies and cockroaches which, as noted below, contain viable cysts for a comparatively long time after feeding on faeces containing cysts and by soiled appendages of these insects which may directly trans- fer the cysts to food by walking on it; (3) by contaminated Avater in which the cysts live considerably longer than in faeces (p. 358) ; and (4) by cysts originating in faeces voided by animals such as dogs (in which spontaneous infections by apparently this amoeba have been reported to occur), rats, monkeys, etc. The seriousness of water-borne infection in crowded areas is easily realized when one recalls the outbreak (some 1400 cases) of amoebic dysentery and amoebiasis which originated in Chicago in 1933, where defective plumbing in certain establishments contaminated the wa- ter system with the cysts of Entamoeba histolytica (Bundesen et al., 1936) and the development of some 100 cases of amoebic dysentery among firemen who drank the water contaminated bj^ cyst-contain- ing faeces in connection wdth the 1934 fire of the Union Stockyards in Chicago (Hardy and Spector). The cysts remain viable for a considerable length of time outside the human intestine, if environmental conditions are favorable. Since information regarding the viability and longevity of the cyst is highly important from the epidemiological standpoint, many papers have dealt with it. In testing the viability of the cyst, the following two tests have been used by the majority of investigators. (a) Eo sin-staining test. Kuenen and Swellengrebel (1913) first used a dilute solution of eosin (1:1000). It has since been used by Wenyon and O'Connor, Root, Boeck, and many others. Solutions used vary from 1:10,000 (Root) to 1:100 (Boeck). A small amount of fresh cyst-containing material and a drop of eosin solution are mixed on a slide, then dead cysts will appear stained reddish under the microscope, while living cysts remain unstained. Whether or not 358 PROTOZOOLOGY unstained cysts might be dead or uninfectious is unknown. But as Wenyon and O'Connor wrote, "if we accept the eosin test as a criterion and regard all unstained cysts as living, the error in judg- ment will be on the safe side." Root found neutral red in 1:10,000 dilution to give a slightly larger proportion of stained cysts than eosin. Frye and Meleney's (1936) comparative study leads one to look upon this method as a fairly dependable one. (b) Cultivation test. Improved cultural technique now brings about easily excystment of viable cysts in a proper culture medium. For example, Yorke and Adams (1926) obtained in 24 hours "a plentiful growth of vegetative forms" from cysts in Locke-egg-serum medium (p. 717). Snyder and Meleney (1941) note recently that the excystation does not take place in various culture media unless liv- ing bacteria were added or oxygen concentration of the media was decreased. Animal infection method has not been used much, as experimental animals (cats) show individual difference in suscepti- bility. Some of the published results are summarized below. The testing method used is indicated by: a for eosin test or h for cultiva- tion test and is given after the name of the investigators. 1. Cysts in faeces kept in a covered container. All cysts disap- peared in 3 days at 37°C.; at 27-30°C. half of the cysts found dead by the 4th and all dead by the 9th day (Kuenen and Swellengrebel ; a). Alive for 3 weeks (Thomson and Thomson; a). Remain un- changed for several weeks if kept "cool and moist" (Dobell). All dead within 10 days at 16-20° or 0°C. (Yorke and Adams; b). 2. Cysts kept in water emulsion. All alive on the 9th, but almost all dead on the 13th day (Kuenen and Swellengrebel; a). Viable for 25 days (Thomson and Thomson; a). Cysts in running water for 15 days, excysted in pancreatic juice (Penfield, Woodcock and Drew). Viable for 30 days (Wenyon and O'Connor; a) ; for 5 weeks (Dobell) ; for 153 days (Boeck; a). Alive for 10 and 17 days at 16-20° and 0°C. respectively (Yorke and Adams; 6); for 3. 10, 30, and 90 days at 30°, 20°, 10° and 0°C. respectively (Chang and Fair; b). 3. Cysts in relation to high temperatures. Cysts are killed at 68°C. in 5 minutes (Boeck; a); at 50°C. in 5 minutes (Yorke and Adams; 6). Dipping in boiling water for 5-10 seconds kills the cysts (Kessel; a). 4. Cysts in relation to desiccation. Desiccation kills cysts instantly (Kuenen and Swellengrebel; Wenyon and O'Connor, Dobell, etc.). Therefore, the cysts carried in dust are most probably not viable under ordinary circumstances. AMOEBINA 359 5. Cysts in relation to chemicals. Hg2Cl. 0.1% solution kills cysts in 4 hours (Kuenen and Swellengrebel; a); kills readily (Lin; b). 1 : 2500 solution kills cysts in 30 minutes at 20-25°C. (Yorke and Adams; h). Creolin. 1 :250 solution kills cysts in 5-10 minutes (Kuenen and Swellengrebel; a). Alcohol. 50% alcohol kills cysts immediately (Kuenen and Swellengrebel; a); in one hour (Kessel; a). Formaldehyde. Cysts treated in 1% solution for 4 hours were apparently dead, though not stained with eosin (Wenyon and O'Connor). 0.5% solution kills cysts in 30 minutes at 20-25° or 37°C. (Yorke and Adams; h). Cresol. 1:20, 1:30, and 1:100, killed the cysts immediately, in one minute and in 30 minutes respectively (Wenyon and O'Connor; a). Phenol. 1 :40 and 1 : 100 killed cysts in 15 minutes and 7 hours respectively (Wenyon and O'Connor; a). 1% solution of phenol or lysol kills cysts in 30 minutes at 20-25° or 37°C. (Yorke and Adams; h). HCl. 7.5% solution at 20-25°C. and 5% at 37°C. kill the cysts in 30 minutes (Yorke and Adams; b). NaOH. 2.5% solution kills cysts in 30 minutes at 20-25° or 37°C. (Yorke and Adams; b). Chlorine. 1:10,000 solution did not have any effect on cysts after several hours (Wenyon and O'Connor; a). 0.2% and 0.5% solutions kill the cysts in 7 days and 72 hours respec- tively (Kessel; a). 0.5% and 1% solutions kill the cysts in 36-48 and 12-24 hours respectively (Lin; 6). 1/64 of a saturated solution of chlorine (about 0.7 weight %) at 20-25°C. and 1/320 solution at 37°C. killed the cysts in 30 minutes (Yorke and Adams; b). Thus the cysts of E. histoly- tica are resistant to chlorinated water far above the concen- tration which is used ordinarily in water treatment. Potassium permanganate. 2% solution kills the cysts in 3 days (Kessel; a). 1 :500 solution kills cysts in 24-48 hours (Lin; b). 1% solution does not kill cysts at 20-25° or 37°C. in 30 minutes (Yorke and Adams; 6). Emetin hydrochloride and yatren. 5% solutions of the two drugs did not have any effects upon cysts at 20-25° or 37°C, in 30 minutes (Yorke and Adams; b). 360 PROTOZOOLOGY 1. 7 > 1 a! 1 a 1 K > c •3 S3 CO a 1 1 1 1 a. 2 a > •i 1 bb E 1 3 1 2 > 0 c 0 ^=} s III m li 3 oil ^-5 ft 1 :2 i Ji •c ]l ol 1 >> 1 1 1 0 3 .2 > 0 3. 85 1! lit 111 1^ 1 1 :2 1 a Ji .2-- || ill III 6 II 2 1 8 bl i .2 -g 1 .2" M 0 a "o S 0 1 lis JJll 0 3'S diss's 1 11 el .i! T CD 0 g Wo 3 0 a 1 II s o5 Is i Ji o n 3 1 S If a •i 1 S Is 1-° 3 d" 1 Q xi il g a ■3 1 1 '3 03 AMOEBINA 561 6. Cysts in relation to passage through the intestine of insects. Wenyon and O'Connor found that the cysts of E. histolytica sur- vived as long as 24 hours in the intestines of flies, Musca domestica, Calliphora, and Lucilia, and living cysts were voided for 16 hours after feeding on faecal material containing cysts. Roubaud using Musca domestica, found also unaltered cysts for over 24 hours (but rarely after 40 hours) after taking the cysts in its gut, and if a fly drowned in water, the cysts remained viable for about a week. Root (1921) using Musca domestica, Calliphora erythrocephala (and Fannia canicularis, Lucilia caesar, and Chrysomyia macellaria) found that about half the cysts were dead after 15 hours and last living cysts were found after 49 hours in the intestines of these flies after feeding on cyst-containing material, and that when the flies which ingested cysts were drowned in water, about half the cysts were found dead in 3 days and last living cysts were noticed on the 7th day. Frye and Meleney (1932) found C3^sts in the intestines of flies which were caught in 4 of 12 houses where infected subjects lived. Macfie (1922) reported that the cysts of Entamoeba histolytica he observed in the intestine of Periplaneta americana appeared un- harmed. Tejera (1926) reports successful experimental infection in two kittens that were fed on the droppings of cockroaches (sp.?) caught in a kitchen, which contained cysts resembling those of E. histolytica. Frye and Meleney (1936) observed that the cysts passed through the intestine of Periplaneta americana in as early as 10-12 hours and remained in the intestine for as long as 72 hours, after feeding on experimental material. Cysts which stayed in the cockroach intestine for 48 hours gave good cultures of trophozoites in egg-horse-serum-Ringer medium. In addition to E. histolytica, there are now known four other intestinal amoebae living in man. They are E. coli, Endolimax nana, lodamoeba biitschlii and Dientamoeha fragilis. In Table 8 are given the characteristics necessary for distinguishing E. histolytica from the other four amoebae. E. coli (Grassi) (Fig. 169). The trophozoite measures 15-40/i in diameter; average individuals 20-35iu; cytoplasm not well differenti- ated; movement sluggish; endoplasm granulated, contains micro- organisms and faecal debris of various sizes in food vacuoles; erythro- cytes are not ingested, though in a few cases (Tyzzer and Geiman) and in culture (Dobell, etc.), they may be taken in as food particles; nucleus, 5-8)u in diameter, seen in vivo ; compared with E. histolytica, the endosome is somewhat large (about 1^ in diameter) and located eccentrically; peripheral chromatin granules more conspicuous. The 362 PROTOZOOLOGY precystic form, 8-20/i in diameter, resembles that of E. histolytica. Separation of the two species of amoebae by this stage is ordinarily impossible. The cyst is spherical or often ovoid, highly refractile; 10-30^ in diameter; immature cyst contains 1, 2 or 4 nuclei, one or more large glycogen bodies with distinct outlines, but comparatively small number of acicular, filamentous or irregular chromatoid bodies with ■-0, ,© X 0 Fig. 169. Entamoeba coli, X1150 (Kudo). 1, a living amoeba; 2-5, stained trophozoites; 3, an amoeba infected by Sphaerita; 6, a precystic amoeba; 7, a fresh cyst; 8, a stained young cyst with a large glycogen vacuole; 9, a stained mature cyst. sharply pointed extremities; when mature the cyst contains 8 nuclei and a few or no chromatoid bodies. The trophozoites and small number of cysts occur in diarrhoeic or semiformed faeces and the formed faeces contain cysts only. This amoeba lives in the lumen of the colon and does not enter the tissues of the wall. As noted above, it has been observed in a few instances to ingest erythrocytes, but there is no evidence to show that it takes them in from living tissues. This amoeba is therefore considered as a commensal. The abundant occurrence of the tro- phozoite in diarrhoeic faeces is to be looked upon as a result and not the cause of the intestinal disturbance. This amoeba is of common occurrence and widely distributed throughout the world. AMOEBINA 363 Nothing is known about its life-cycle in the human intestine. Cultivation of cysts in vitro indicates, according to Dobell (1938), the following changes : The cyst content usually emerges as a single multinucleate amoeba through a large opening in the cyst wall. Prior to or during the emergence, the amoeba may divide. Normal mature cysts ''frequently lose" 1-4 of their original 8 nuclei before germination, thus becoming "infranucleate" (with 4-7 nuclei). Un- like in E. histolytica, there is no nuclear division in the metacystic stages. By a series of binary divisions with random nuclear distribu- m.' :^ .o^ 0 Fig. 170. Entamoeba gingivalis, X1150 (Kudo). 1, 2, living amoebae; 3-7 stained amoebae. tion, uninucleate amoebulae are finally produced. These are young amoebae which develop into large trophozoites. Here also, there is no sexual phenomenon in the life-cycle. E. gingivalis (Gros) (E. buccalis Prowazek) (Fig. 170). This amoeba lives in carious teeth, in tartar and debris accumulated around the roots of teeth, and in abscesses of gums, tonsils, etc. The trophozoite is as active as that of E. histolytica; 8-30^ (average 10-20/x) in diameter; cytoplasm well differentiated; monopodial progressive movement in some individuals; endoplasm hyaline, but vacuolated, and contains ordinarily a large number of pale greenish bodies (which are probably nuclei of leucocytes, pus cells or other degenerating host cells) and bacteria in food vacuoles; nucleus, 2-4/x in diameter, appears as a ring ; when stained it shows a small central endosome and small peripheral chromatin granules closely attached to the membrane. Stabler (1940) observed 5 chromosomes during 364 PROTOZOOLOGY binary division. Encysted forms have not been observed in this amoeba. E. gingivalis is the very first parasitic amoeba that has become known to man. Gros (1849) found it in Russia in the tartar on the surface of the teeth. Some observers maintain that this amoeba is the cause of pyorrhoea alveolaris, but evidence for such an assumption seems to be still tacking. It has been found in the healthy gums and even' in false teeth (Lynch). Therefore, it is generally considered as a commensal. It is widely distributed and of common occurrence. In the absence of the encysted stage, it is supposed that the organism is transmitted in trophic forms. According to Koch (1927) who studied the effects of desiccation and temperatures upon the amoeba in culture, the amoeba is killed at 0°C. in 18 hours, at 5°C. in 24 hours, at 10°C. in 48 hours, at 45°C. in 20 minutes, at 50°C. in 15 minutes, and at 55°C. in 2 minutes. At 40°C., the survival is said to be for an indefinite length of time. Complete desiccation of the culture medium or immersion in water at 60°C. kills the amoeba. She considered that E. gingivalis may be disseminated both by direct contact and by intermediate contaminated articles. E. gedoelsti Hsiung {E. intestinalis (Gedoelst)). In colon and caecum of horse; 6-13/x by 6-1 l/x; endosome eccentric; bacteria- feeder. E. equi Fantham. 40-50ju by 23-29/i; nucleus oval; cysts tetra- nucleate, 15-24/i in diameter; seen in the faeces of horse; Fantham reports that the endoplasm contained erythrocytes. E. hovis Liebetanz. 5-20m in diameter; in stomach of cattle. E. ovis Swellengrebel. Cyst uninucleate; in intestine of sheep. E. caprae Fantham. In goat intestine. E. polecki (Prowazek). In colon of pigs; 10-12iu in diameter; cyst uninucleate. E. dehliecki Nieschulz. 5-10/i in diameter; cyst uninucleate; in the intestine of pig. Hoare (1940) found it in goat also. E. venaticum Darling. In colon of dog; similar to E. histolytica; since the dog is experimentally infected with the latter, this amoeba discovered from spontaneous amoebic dysentery cases cf dogs, in one of which were noted abscesses of liver, is probably E. histolytica. E. cuniculi Brug. Similar to E. coli in both trophic and encysted stages; in intestine of rabbits. E. cobayae Walker (E. caviae Chattcn). Similar to E. coli; in intestine of guinea-pigs. E. muris (Grassi). Similar to E. coli; in intestine of rats and mice. E. gallinarum Tyzzer. In fowl's intestine; cysts octo nucleate. AMOEBINA 365 E. testudinis Hartmann. In intestine of turtles, Testudo graeca, T. argentina, T. calcarata and Terrapene Carolina. E. harreti Taliaferro and Holmes. In colon of snapping turtle, Chelydra serpentina. E. terrapinae Sanders and Cleveland. Trophozoites 10-15/i long; cysts 8-14m in diameter, tetranucleate when mature; in colon of Chrysemys elegans. E. invadens Rodhain. Resembles E. histolytica. Trophozoites measure 15.9ju in average diameter (9. 2-38. 6^ by 9-30/x); active loco- motion; feed on leucocytes, liver cells, epithelial cell debris, bacteria, etc.; nucleus similar to that of E. histolytica. Cysts 13.9/i (11-20/x) in diameter; 1-4 nuclei; glycogen vacuole; chromatoid bodies acicular, rod-like or cylindrical. Hosts include various reptiles: Varanus salvator, V. varius, Tiliqua scincoides, Pseudohoa clelia, Lampropeltis getulus, Ancis- trodon mokasen, Matrix rhomhifcr, N. sipedon, N. sipedon sipedon, N. cyclopion, Python sebae, Rachidelus brazili, etc. Zoological Gar- dens in Philadelphia (Geiman and Ratcliffe) and Antwerp (Rodhain). The amoeba produces lesions in the stomach, duodenum, ileum, colon and liver in host animals. Time for excystation in host's intes- tine 5-14 hours; time for metacystic development in host's intestine 7-24 hours; optimum temperature for cultural growth 20-30°C. (Geiman and Ratcliffe, 1936). Ratcliffe and Geiman (1938) observed spontaneous and experimental amoebiasis in 32 reptiles. E. ranarum (Grassi). In colon of various species of frogs; re- sembles E. histolytica; 10-50/i in diameter; cysts are usually tetranu- cleate, but some contain as many as 16 nuclei; amoebic abscess of the liver was reported in one frog. E. minchini Mackinnon. In gut of tipulid larvae; 5-30/x in diam- eter; cyst nuclei up to 10 in number. E. apis Fantham and Porter. In Apis mellifica; similar to E. coli. E. hrasiliensis (Carini) {Brumptina brasiliensis C.) (Fig. 166, c). In the cytoplasm of many species of Protociliata; trophozoites 5.3- 14.3m in diameter; cysts about 9.4/^ in diameter, uninucleate; no effect upon host ciliates even in case of heavy infection (Stabler and Chen, 1936). Carini and Reichenow (1935): trophozoites 8-14ju in diameter; cysts 8-1 2;u; either identical with E. ranarum or a race derived from it. Genus lodamoeba Dobell. Vesicular nucleus, with a large en- dosome rich in chromatin, a layer of globules which surrounds the endosome and do not stain deeply, and achromatic strands between the endosome and membrane (Fig. 164, c); cysts ordinarily uninu- 366 PROTOZOOLOGY cleate, contain a large glycogenous vacuole which stains conspicu- ously with iodine; in intestine of man or mammals. I. biitschlii (Prowazek) (7. williamsi P.) (Fig. 171). The tropho- zoite is 6-25ju (average 8-1 5/x) in diameter; fairly active with pro- gressive movement, when fresh; cytoplasm not well differentiated; endoplasm granulated, contains bacteria and yeasts in food vacu- oles ; the nucleus (3-4ju in diameter) visible in vivo ; the large endo- some about ^ the diameter of nucleus, surrounded by small spherules. §> « jrf' © w ■''-^ m u: © Fig. 171. lodamoeba butschlii, X1150 (Kudo). 1, a living amoeba; 2-5, stained trophozoites; 4, 5, somewhat degenerating trophozoites; 6, a fresh cyst; 7-10, stained cysts. The cysts are spherical, ovoid, ellipsoid, triangular, pyriform or square; rounded cysts measure about 6-1 5/i in the largest diameter; a large glycogen body which becomes conspicuously stained with Lugol's solution (hence formerly called "iodine cysts") persists; nucleus with a large, usually eccentric endosome. The trophozoites and cysts are ordinarily present in diarrhoeic faeces, while the formed faeces contain cysts only. This amoeba ap- parently lives in the lumen of the colon and does not seem to attack host's tissues. It is recognized as a commensal. It does not appear to be as common as the other intestinal amoebae that have already been described above. I. suis O'Connor. In colon of pig; widely distributed; indis- tinguishable from I. biitschln; it is considered by some that pigs are probably reservoir host of I. butschlii. Genus Endolimax Kuenen and Swellengrebel. Small; vesicular AMOEBINA 367 nucleus with a comparatively large irregularly shaped endosome, composed of chromatin granules embedded in an achromatic ground mass and several achromatic threads connecting the endosome with membrane (Fig. 164, d) ; commensal in hindgut in man and animals. Several species. E. nana (Wenyon and O'Connor) (Fig. 172). The trophozoite measures 6-15jli in diameter; fairly active monopodial movement by forming a broad pseudo podium; when stationary pseudo podia are formed at different points; endoplasm is granulated and contains bacteria as food particles; the vesicular nucleus, 1.5-3)u in diameter, is composed of a delicate membrane with a few chromatin granules, and a large irregularly shaped endosome. Fig. 172. Endolimax nana, X1150 (Kudo). 1, a living amoeba; 2-4, stained amoebae; 5, a fresh cyst; 6, a stained cyst. The cyst is usually ovoid; young cyst contains 1 or 2 nuclei; mature cyst with 4 nuclei; indistinctly outlined glycogen body may be present while immature; dimensions 5-12/x (majority 7-10/i) in diameter. The trophozoites are found in diarrhoeic or semifluid faeces to- gether with the cysts, and formed faeces contain cysts only. This amoeba is coelozoic in the lumen of the upper portion of colon and is considered as a commensal. E. gregariniformis (Tyzzer). In caecum of fowls; 4-12)u in diam- eter; cysts uninucleate. E. ranarum Epstein and Ilovaisky. In colon of frogs; cyst octo nu- cleate, up to 25ju in diameter. E. blattae Lucas. In colon of cockroaches; 3-15^ long; cyst with more than one nucleus. Genus Dientamoeba Jepps and Dobell. Small amoeba; number of binucleate trophozoites often greater than that of uninucleate forms; nuclear membrane delicate; endosome consists of several chromatin granules embedded in plasmosomic substances and connected with the membrane by delicate strands (Fig, 164, e); in colon of man. 368 PROTOZOOLOGY D. fragilis J. and D. (Fig. 173). The trophczoite is actively amoe- boid; i-18fx (average 5-12/i) in diameter; progressive movement; cj^toplasm well differentiated; endoplasm granulated contains bac- teria in food vacuoles; nucleus onty faintly visible; 1 or 2 nuclei, the ratio is variable; in some material binucleate forms may be 80% or more, while in others uninucleate forms may predominate; nucleus is made up of a delicate membrane and a large endosome (more than one-half the diameter of nucleus) in which are embedded 4-8 chro- matin granules along the periphery. According to Dobell (1940), the binucleate condition represents an arrested telophase stage of mitosis and the chromatin granules are in reality chromosomes, probably 6 in number. Comparison with Histomonas meleagridis (p. 266) led this author to think that this amoeba may be an aberrant flagellate closely related to Histomonas. 12 3 4 5 Fig. 173. Dientamoeba fragilis, X1150 (Kudo). 1, 2, living trophozoites; 3, a stained uninucleate amoeba; 4, 5, stained binucleate individuals. Encysted stage has not been observed. Degenerating trophozoites often develop vacuoles which coalesce into a large one and the or- ganisms may then resemble Blastocystis hominis (p. 721) w^hich is very common in faeces. Transmission may be carried on by tropho- zoites. According ot Wenrich (1940), this amoeba if left in the faeces remains alive up to 48 hours at room temperature, but disappears probably by disintegration in 2 hours at 3.5°C. Since all attempts to bring about experimental infection by mouth or by rectum failed, Dobell considered that the amoeba may be transmitted from host to host in the eggs of nematodes such as Trichuris or Ascaris, as in the case of Histomonas (p. 266). The amoeba inhabits the lumen of the colon. There is no indica- tion that it is histozoic or cytozoic. Some workers attribute certain intestinal disturbances to this amoeba, but no definite evidence for its pathogenicity is available at present. It seems to be widely dis- tributed, but not as common as the other intestinal amoebae men- tioned above, although in some areas it appears to be common. Genus Dobellina Bishop and Tate. Trophozoite: small amoeba; ectoplasm and endoplasm differentiated; usually monopodial; AMOEBINA 369 nucleus one to many ; nucleus with a large central endosome and an achromatic nuclear membrane; nuclear divisions mitotic and simul- taneous; no solid food vacuoles; no contractile vacuole; with refrin- gent granules. Cysts: spherical; thin-walled; devoid of glycogen and of chromatoid bodies; 2 or more nuclei; parasitic. One species. Fig. 174. a-f, Dobellina viesnili (Bishop and Tate): a, b, uni- and multi- nucleated stained amoebae, X2200; c, a trinucleate (stained) amoeba in which the nuclei are dividing, X1760; d-f, stained cysts with 2, 4, and 6 nuclei, X1760 (Bishop and Tate); g, h, stained trophozoite and cyst of Schizamoeba salmonis, X1070 (Davis); i, j, Hydramoeha hydroxena (Rey- nolds and Looper): i, a heavily infected Hydra oligadis, X95; j, part of a section of an infected host hydra, showing a trophozoite feeding on ecto- dermal cells, X470; k, a stained individual of Paramoeba -pigmentifera, with its nucleus in the center, X800 (Janicki). D. mesnili (Keilin) (Fig. 174, a-j). Uninucleate amoebae as small as 3.6ju in diameter; multinucleate forms 20-25/x by 10-1 5yu; cysts 370 PROTOZOOLOGY 8-1 1/i in diameter; in the space between the peritrophic membrane and the epithehum of the gut in the larvae of Trichocera hiemalis, T. annulata, and T. regelationis (winter gnats). Genus Schizamoeba Davis. Nucleus vesicular, without endosome, but with chromatin granules arranged along nuclear membrane; 1 to many nuclei; cyst-nuclei formed by fragmentation of those of the trophozoite and possess a large rounded chromatic endosome, connected at one side with the nuclear membrane by achromatic strands to which chromatin granules are attached; in stomach of salmonoid fish. One species. S. salmonis D. (Fig. 174, g, h). Sluggish amoeba; 10-25/i in di- ameter; 1 to several nuclei; multiplication by binary fission; nuclear division amitotic. Cysts are said to be more abundant than tropho- zoites and their appearance seems to be correlated with the amount of available food; cysts spherical, 15-35;u in diameter; cyst-mem- brane thin and nuclei vary from 3 to many; during encystment, chromatin bodies of trophozoite become collected in several masses which then break up and each chromatin grain becomes the endo- some of newly formed nucleus; cyst contents divide sooner or later into 4-11 multinucleate bodies and the whole increases in size; finally cyst-membrane disintegrates and the multinucleate bodies become set free. Trophozoites are said to occur in the mucous covering of stomach of host fish; cysts occur in both stomach and intestine. Aside from the loss of certain amount of available food, no pathogenic effect of the amoeba upon the host fish was noticed by Davis. Genus Hydramoeba Reynolds and Looper. Nucleus vesicular with a large central endosome composed of a centriole (?) and chromatin granules embedded in an achromatic mass, achromatic strands radiating from endosome to membrane; a ring made up of numerous rod-shaped chromatin bodies in the nuclear-sap zone; 1 or more contractile vacuoles; apparently the most primitive para- sitic amoeba; parasitic on Hydra. H. hydroxena (Entz) (Fig. 174, i, j). Parasitic in various species of Hydra; first observed by Entz; Wermel found 90 per cent of Hydra he studied in Russia were infected by the amoeba; Reynolds and Looper stated that infected Hydra die on an average in 6.8 days and that the amoebae disappear in 4-10 days if removed from a host Hydra. More or less spheroidal, with blunt pseudopods; 60-380/i in diameter; nucleus shows some 20 refractile peripheral granules in life; contractile vacuoles; food vacuoles contain host cells; multipli- cation by binary fission; encystment has not been observed. AMOEBINA 371 Family 4 Paramoebidae Poche Genus Paramoeba Schaudinn. The amoeba possesses a nucleus and nucleus-like secondary cytoplasmic structure, both of which mul- tiply by division simultaneously; free-living or parasitic. P. pigmentifera (Grassi) (Fig. 174, k). About SO^u long; sluggish; cytoplasm distinctly differentiated; secondary body larger than the nucleus; flagellated swarmers are said to occur; parasitic in coelom of Chaetognatha such as Sagitta daparedei, Spadella bipiinctata, S. inflata, and *S. serratodentata. P. schaudinni Faria, da Cunha and Pinto. About 7-22/i in diame- ter; in salt water; Rio de Janeiro, Brazil. References Angerer, C. a. 1942 The action of cupric chloride on the proto- plasmic viscosity of Amoeba dubia. Physiol. Zool., Vol. 15. Bishop, A. and P. Tate 1939 The morphology and systematic posi- tion of DohelUna mesnili nov. gen. {Entamoeba mesnili Keilin, 1917). Parasitology, Vol. 31. Boeck, W. C. and C. W. Stiles 1923 Studies on various intestinal parasites (especiallv amoebae) of man. U. S. Public Health Service, Hyg. Lab. Bull., No. 133. BuNDESEN, H. N. et al. 1936 Epidemic amebic dysentery: the Chi- cago outbreak of 1933. Nat. Inst. Health Bull, No. 166. CarinIj a. 1943 Novas observagoes em batraquios e ofidios, de Zelleriellas hiperparasitadas por entamebas. Arqu. de Biolog., Vol. 27. Cash, J. 1905 The British freshwater Rhizopoda and Heliozoa. Vol. 1. Chalkley, H. W. and G. E. Daniel 1933 The relation between the form of the living cell and the nuclear phases of division in Amoeba proteus (Leidy). Physiol. Zool., Vol. 6. Cleveland, L. R. and E. P. Sanders 1930 Encystation, multiple fission without encystment, excystation, metacystic develop- ment, and variation in a pure line and nine strains of Entamoeba histolytica. Arch. f. Protistenk., Vol. 30. Craig, C. F. 1934 Amebiasis and amebic dysentery. Springfield, 111. Dangeard, p. a. 1900 fitude de la karyokinese chez V Amoeba hyalina sp. nov. Le Botaniste, Ser. 7. DoBELL, C. 1928 Researches on the intestinal Protozoa of monkeys and man. I and II. Parasitology, Vol. 20. 1938 IX. Ibid., Vol. 30. 1940 X. Ibid., Vol. 32. and F. W. O'Connor 1921 The intestinal Protozoa of man. London. Geiman, Q. M. and H. L. Ratcliffe 1936 Morphology and life- cycle of an amoeba producing amoebiasis in reptiles. Parasit., Vol. 28. 372 PROTOZOOLOGY Hartmann, M. and C. Chagas 1910 Ueber die Kernteilung von Amoeba hyalina Dang. Mem. Inst. Oswaldo Cruz, Vol. 2. Henderson, J. C. 1941 Studies of some amoebae from a termite of the genus Cubitermes. Uni. Calif. Publ. ZooL, Vol. 43. KiRBY, H., Jr. 1927 Studies on some amoebae from the termite Microtermes, with notes on some other Protozoa from the Termitidae. Quart. Jour. Micr. Sci., Vol. 71. Koch, D. A. 1927 Relation of moisture and temperature to the via- bility of Endamoeba gingivalis (Gros) in vitro. Uni. Calif. Publ. ZooL, Vol. 31. Kudo, R. R. 1926 Observations on Endamoeba blattae. Amer. Jour. Hyg., Vol. 6. 1926a Observations on Dientamoeba fragilis. Amer. Jour. Trop. Med., Vol. 6. Leidy, J. 1879 Freshwater Rhizopods of North America. Report U. S. Geol. Surv. Terr., Vol. 12. Mast, S. O., 1938 Amoeba and Pelomyxa vs Chaos. Turtox News, Vol. 16. and P. L. Johnson 1931 Concerning the scientific name of the common large amoeba, usually designated Amoeba proteus (Leidy). Arch. f. Protistenk., Vol. 75. Meglitsch, p. a. 1940 Cytological observations on Endamoeba blattae. 111. Biol. Monogr., Vol. 17. Mercier, L. 1909 Le cycle evolutif d' Amoeba blattae Biitschli. Arch. f. Protistenk., Vol. 16. Morris, S. 1935 Studies of Endamoeba blattae (Biitschli). Jour. Morph., Vol. 59. Penard, E. 1890 Etudes sur les rhizopodes d'eau douce. Mem. soc. phys. et rhist. nat. Geneva, Vol. 31. 1902 Faune rhizopodique du Bassin du Leman. Geneva. Ratcliffe, H. L. and Q. M. Geiman 1938 Spontaneous and ex- perimental amebic infection in reptiles. Arch. Path., Vol. 25. Root, F. M. 1921 Experiments on the carriage of intestinal Pro- tozoa of man by flies. Amer. Jour. Hyg., Vol. 1. ScHAEFFER, A. A. 1917 Notes on the specific and other character- istics of Amoeba proteus Pallas (Leidy), A. discoides spec, nov., and A. dubia spec. nov. Arch. f. Protistenk., Vol. 37. 1926 Taxonomy of the amebas. Papers Dep't Mar. Biol. Carnegie Inst. Washington, Vol. 24. 1937, 1938 Turtox News, Vols. 15, 16. Snyder, T. L. and H. E, Meleney 1941 The excystation of Enda- fnoeba histolytica in bacteriologically sterile media. Amer. Jour. Trop. Med., Vol. 21. Stabler, R. M.. 1940 Binary fission in Entamoeba gingivalis. Jour. Morph,, Vol. 66. Volkonsky, M. 1931 Hartmannella castellanii Douglas et classifi- cation des Hartmannelles. Arch. zool. exp. et gen.. Vol. 72. Wenrich, D. H. 1936, 1937 Studies on Dientamoeba fragilis (Pro- Jour. Parasit., Vols. 22, 23. AMOEBINA 373 1937a Studies on lodamoeba hutschlii (Protozoa) with spe- cial reference to nuclear structure. Proc. Amer. Phil. Soc, Vol. 77. Wenyon, C. M. 1926 Protozoology. Vol. 1. London. Wilson, H. V. 1900 Notes on a species of Pelomyxa. Amer. Nat., Vol. 34. YoRKE, W. and A. R. D. Adams 1926 Observations on Entamoeba histolytica. Ann. Trop. Med. Paras., Vol. 20. Chapter 20 Order 4 Testacea Schultze THE Testacea or Thecamoeba comprise those amoeboid organ- isms which are enveloped by a simple shell or test, within which the body can completely be withdrawn. The shell has usually a single aperture through which pseudopodia protrude, and varies in shape and structure, although a chitinous or pseudochitinous membrane forms the basis of all. It may be thickened, as in Arcella and others, or composed of foreign bodies cemented together as in Difflugia, while in Euglypha siliceous platelets or scales are formed in the endoplasm and deposited in the shell. The cytoplasm is ordinarily differentiated into the ectoplasm and endoplasm. The ectoplasm is conspicuously observable at the aper- ture of the shell where filopodia or slender ectoplasmic lobopodia are produced. The endoplasm is granulated or vacuolated and con- tains food vacuoles, contractile vacuoles and nuclei. In some forms there are present regularly in the cytoplasm numerous basophilic granules which are known as 'chromidia' (p. 37). Asexual reproduction is either by longitudinal fission in the forms with soft tests, or by transverse division or budding, while in others multiple division occurs. Encystment is common. Sexual reproduc- tion b}^ amoeboid or flagellate gametes has been reported in some species. The testaceans are mostly inhabitants of fresh water, but some live in salt water and others are semi-terrestrial, being found in moss or moist soil, especiallj^ peaty soil. Shell simple and membranous Filopodia, in some anastomosing Family 1 Gromiidae Pseudopodia filose, simplj^ branched Family 2 Arcellidae (p. 378) Shell with foreign bodies, platelets, or scales With foreign bodies Family 3 Difflugiidae (p. 384) With platelets or scales Family 4 Euglyphidae (p. 389) Family 1 Gromiidae Eimer and Fickert These forms are frequently included in the Foraminifera by other authors. Genus Gromia Dujardin {Allogromia, Rhyiichogromia, Diplo- gromia Rhumbler). Thin test rigid or flexible, smooth or slightly coated with foreign bodies; spherical to elongate ellipsoid; aperture terminal; 1 or more nuclei; contractile vacuoles; many filopodia, 374 TESTACEA 375 branching and anastomosing; cytoplasm with numerous motile granules; fresh or salt water. Man}^ species. mm Fig. 175. a, Gromia jiuvialis, X120 (Dujardin); b, G. ovoidea, X50 (Schultze); c, G. nigricans, x200 (Cash and Wailes); d, Microgromia sociahs, X170 (Cash); e, Microcometes paludosa, X670? (Penard)- f, Artodiscus saltans, X670 (Penard); g, Schultzella diffluens, Xl2() (Rhumbler). 376 PROTOZOOLOGY G.fluvialis D. (Fig. 175, a). Test spherical to subspherical ; smooth or sparsely covered with siliceous particles; yellowish cytoplasm fills the test; aperture not seen; a large nucleus and numerous con- tractile vacuoles; filopodia long, often enveloping test; 90-250/i long; on aquatic plants, in moss or soil. G. ovoidea (Rhumbler) (Fig. 175, 6). In salt water. G. nigricans (Penard) (Fig. 175, c). Test large, circular in cross- section; a single nucleus; 220-400)U long; in pond water among vege- tation. Genus Microgromia Hertwig and Lesser, Test small, hyaline, spherical or pyriform, not compressed; aperture terminal, circular; filopodia long straight or anastomosing, arising from a peduncle; a single nucleus and contractile vacuole; solitary or grouped. M. socialis (Archer) (Fig. 175, d). Cytoplasm bluish; contractile vacuole near aperture; filopodia arise from a peduncle, attenuate, branching, anastomosing; often numerous individuals are grouped; multiplication by fission and also by swarmers; 25-35^ in diameter; among vegetation in fresh water. Genus Microcometes Cienkowski. Body globular, enclosed within a transparent, deUcate, light yellowish and pliable envelope with 3-5 apertures, through which long branching filopodia extend; body protoplasm occupies about 1/2 the space of envelope; 1-2 contrac- tile vacuoles; fresh water. M. paludosa C. (Fig. 175, e). About lQ-17f^ in diameter; fresh water among algae. Genus Artodiscus Penard. Body globular, plastic; covered by envelope containing small grains of various kinds; nucleus eccentric; a few pseudopodia extend through pores of the envelope; movement very rapid ; fresh water. A. saltans P. (Fig. 175,/). 18-23/1 in diameter; fresh water. Genus Lieberkiihnia Claparede and Lachmann. Test ovoidal or spherical, with or without attached foreign particles; aperture usually single, lateral or subterminal; one or more nuclei; many con- tractile vacuoles; pseudopodia formed from a long peduncle, reticu- late, often enveloping test; fresh or salt water. L. wagneri C. and L. (Fig. 176, a). Spheroidal; aperture subtermi- nal, oblique, flexible; cytoplasm slightly yellowish, fills the test; 80-150 vesicular nuclei; many contractile vacuoles; pseudopodia long, anastomosing; 60-160/x long; nuclei Q/j, in diameter; among algae in fresh and salt water. TESTACEA 377 Genus Diplophrys Barker, Test thin, spherical; 2 apertures, one at each pole; cytoplasm colorless; a single nucleus; several contrac- tile vacuoles; filo podia radiating. One species. D. archeri B. (Fig. 176, h). With 1-3 colored oil droplets; pseu- dopodia highly attenuate, radiating, straight or branched; multi- plication into 2 or 4 daughter individuals; solitary or in groups; diameter 8-20;u ; on submerged plants in fresh water. Fig. 176. a, Lieberkuhnia wagneri, Xl60 (Verworn); b, Diplophrys archeri, X930 (Hertwig and Lesser); c, Lecythium hyalinum, X330 (Cash and Wailes); d, Myxotheca arenilega, X70 (Schaudinn); e, Dac- tylosaccus vermiformis, Xl5 (Rhumbler); f, Boderia turneri (Wright). Genus Lecythium Hertwig and Lesser. Test thin, flexible, color- less; aperture elastic, terminal; colorless cytoplasm fills the test; large nucleus posterior; numerous filo podia long, branching, not anastomosing; fresh water. L. hyalinum (Ehrenberg) (Fig. 176, c). Spheroidal; aperture cir- cular with a short flexible neck; a single contractile vacuole; diame- ter 20-45/i; in submerged vegetation. 378 PROTOZOOLOGY Genus Schultzella Rhumbler. Test thin, delicate, difficult to recognize in life, easily broken at any point for formation of pseudo- podia which branch and anastomose; irregularly rounded; without foreign material; salt water. S. diffluens (Grubler) (Fig. 175, g). Cytoplasm finel}^ granulated; opaque, colorless; with oil droplets, vacuoles and numerous small nuclei; up to 220^ in diameter. Genus Myxotheca Schaudinn. Amoeboid; spherical or hemi- spherical, being flattened on the attached surface; a thin pseudo- chitinous test with foreign bodies, especially sand grains; pseudo- podia anastomosing; salt water. M. arenilega S. (Fig. 176, d). Test yellow, with loosely attached foreign bodies; cytoplasm bright red due to the presence of highly refractile granules; 1-2 nuclei, 39-75/n in diameter; body diameter 160-560/i. Genus Dactylosaccus Rhumbler. Test sausage-shape and vari- ously twisted; pseudo podia filiform, anastomosing; salt water. D. vermiformis R. (Fig. 176, e). Test smooth; pseudo podia rise from small finger-like projections; 1-2 nuclei; body 4 mm. by 340/^; salt water. Genus Boderia Wright. Body form changeable; often spherical, but usually flattened and angular; filopodia long; test extremely delicate, colorless; salt water. B. turneri W. (Fig. 176, /). Body brown to orange; active cyto- plasmic movement; 1-10 nuclei; multiple division(?); 1.56-6.25 mm. in diameter; in shallow water. Family 2 Arcellidae Schultze Genus Arcella Ehrenberg. Test transparent, chitinous, densely punctated; colorless to brown (when old); in front view circular, angular, or stellate; in profile plano-convex or semicircular; vari- ously ornamented; aperture circular, central, inverted like a funnel; protoplasmic body does not fill the test and connected with the latter by many ectoplasmic strands; slender lobopodia, few, digitate, sim- ple or branched; 2 nuclei; several contractile vacuoles; fresh water. Numerous species. A. vulgaris E. (Fig. 177, a, h). Height of test about 1/2 the diame- ter; dome of hemispherical test evenly convex; aperture circular, central; colorless, yellow, or brown; protoplasmic body conforms with the shape of, but does not fill, the test; lobopodia hyaline; 2 vesicular nuclei; several contractile vacuoles; test 30-lOO^t in dia- meter; in the ooze and vegetation in stagnant water and also in soil. TESTACEA 379 Of several varieties, two may here be mentioned; var. angulosa (Perty), test smaller, 30-40/x in diameter, faceted, forming a 5- to 8-sided figure, with obtuse angles; var. gibbosa (Penard), test gib- bous, surface pitted with circular depressions of uniform dimensions; 45-50/x up to 100/x in diameter. A. discoides E. (Fig. 177, c). Test circular in front view, plano- convex in profile; diameter about 3-4 times the height; test color- ation and body structure similar to those of A. vulgaris; test 70- 260^ in diameter; in fresh w^ater. Fig. 177. a, b, Arcella vidgaris, Xl70; X230 (Leidy); c, A. discoides, X170 (Leidy); d, A. mitrata, Xl40 (Leidy); e, f, A. catinus. X 170 (Cash); g-i, A. dentata, Xl70 (Leidy); j, k, A. artocrea, Xl70 (Leidy). A. mitrata Leidy (Fig. 177, d). Test balloon-shaped or polyhedral; height exceeds diameter of base; aperture circular, crenulated and usually evarted within inverted funnel; protoplasmic body sphe- roidal, wdth 'neck' to aperture and cj^toplasmic strands to test; 6 or more slender lobopodia; test 100-145;u high, 100-152/i in diameter; in fresh water among vegetation. A. catinus Penard (Fig. 177, e, /). Test oval or quadrate, not circular, in front view; aperture oval; dome compressed; lateral margin with 6 or 8 facets; test 100-120^ in diameter and about 45/i high; fresh water among vegetation. A. dentata Ehrenberg (Fig. 177, g-i). Test circular and dentate 380 PROTOZOOLOGY in front view, crown-like in profile; diameter more than twice the height; aperture circular, large; colorless to brown; about 95/i in diameter, aperture SO/z in diameter; 15-17 spines; in the ooze of freshwater ponds. A. artocrea Leidy (Fig. 177, j, k). Height of test 1/4-1/2 the diame- ter; dome convex; surface mammillated or pitted; border of test everted and rising 1/4-1/2 the height of test; about 175ju in diame- ter; fresh water. Fig. 178, a, b, Pyxidicula operculata, X800 (Penard); c, Pseudochlaniys patella, X330 (Cash); d, e, Diflugiella apiculata, X270 (Cash); f, Crypto- difflugia oviformis, X320 (Cash); g, Lesquereusia spiralis, X270 (West); h, Hyalosphenia papilio, X330 (Leidy); i, Corycia coronata, Xl70 (Penard); j, Pamphagus mutahilis, X330 (Leidy); k, Plagiophrys parvi- punctata, X330 (Penard). Genus Pyxidicula Ehrenberg. Test patelliform; rigid, transparent, punctate; aperture circular, almost the entire diameter of test; cytoplasm similar to that of Arcella; a single nucleus; 1 or more contractile vacuoles; fresh water. P. operculata (Agardh) (Fig. 178, o, b). Test smooth, colorless to TESTACEA 381 brown; a single vesicular nucleus; pseudopodia short, lobose or digitate; 20^* in diameter; on vegetation. Genus Pseudochlamys Clapar^de and Lachmann. Test discoid, flexible when young; body with a central nucleus and several con- tractile vacuoles. P. patella C. and L. (Fig. 178, c). Young test hyaline, older one rigid and brown; often rolled up like a scroll; a short finger-like pseudopodium between folds; 40-45/1 in diameter; in fresh water among vegetation, in moss and soil. Genus Difflugiella Cash. Test ovoid, not compressed, flexible and transparent membrane; colorless cytoplasm fills the test, usually with chlorophyllous food material; median pseudopodia lobate or digitate with aciculate ends, while lateral pseudopods long, straight, and fine, tapering to a point; fresh water. One species. D. apiculata C. (Fig. 178, d, e). About 40/i by 28m ; among vege- tation. Genus Cryptodifflugia Penard, Small test yellowish to brownish; Difflugia-like in general appearance, compressed; with or without foreign bodies; pseudopodia long, acutely pointed; fresh water. C. oviformis P. (Fig. 178,/). Test ovoid; without foreign bodies; crown hemispherical; aperture truncate; cytoplasm with chloro- phyllous food particles; 16-20iu by 12-15/1 ; in marshy soil. Genus Lesquereusia Schlumberger. Test compressed, oval or globular in profile, narrowed at bent back; semispiral in appearance; with curved or comma-shaped rods or with sand-grains (in one species); body does not fill up the test; pseudopodia simple or branched ; fresh water. L. spiralis (Ehrenberg) (Fig. 178, g). Aperture circular; border distinct; cytoplasm appears pale yellow; a single nucleus; 96-188/i by 68-1 14/1 ; in marsh water. Genus Hyalosphenia Stein. Test ovoid or pyriform; aperture end convex; homogeneous and hyaline, mostly compressed; crown uni- formly arched; protoplasm partly filling the test; several blunt pseudopodia simple or digitate. Several species. H. papilio Leidy (Fig. 178, h). Test yellowish; transparent; pyriform or oblong in front view; a minute pore on each side of crown and sometimes one also in center; aperture convex; in narrow lateral view, elongate pyriform, aperture a shallow notch; with chloro- phyllous particles and oil globules; llO-140/i long; in fresh water among vegetation. Genus Corycia Dujardin. Envelope extremely pliable, open at base, but when closed, sack-like; envelope changes its shape with 382 PROTOZOOLOGY movement and contraction of body; with or without spinous pro- jections. C. coronata Penard (Fig. 178, i). 6-12 spines; 140^ in diameter; in moss. Genus Pamphagus Bailey. Test hyaline membranous, flexible; aperture small; body fills the envelope completely; spherical nuc- leus large; contractile vacuoles; filopodia long, delicate, branching, but not anastomosing; fresh water. P. mutabilis B. (Fig. 178, j). Envelope 40-100^ by 28-68/1. Genus Plagiophrys Claparede and Lachmann. Envelope thin, hyaline, changeable with body form; usually elongate-oval with rounded posterior end; narrowed at other half; envelope finely punctated with a few small plates; aperture round; cytoplasm clear; nucleus large; pseudopods straight filopodia, sometimes branching ; fresh water. P. parvipunctata Penard (Fig. 178, A;). Envelope 50/i long. Genus Leptochlamys West. Test ovoid, thin transparent chitinous membrane, circular in optical section; aperture end slightly ex- panded with a short neck; aperture circular, often oblique; body fills test; without vacuoles; pseudopodium short, broadly expanded and sometimes cordate; fresh water. L. ampullacea W. (Fig. 179, a). Nucleus large, posterior; with green or brown food particles; test 45-55/i by 36-40/* in diameter; aperture 15-17/i; among algae. Genus Chlamydophrys Cienkowski. Test rigid, circular in cross- section; aperture often on drawn-out neck; body fills the test; zonal differentiation of cytoplasm distinct; nucleus vesicular; refractile waste granules; pseudo podia branching; fresh water or coprozoic. C. stercorea C. (Fig. 179, k). Test 18-20/i by 12-15/1 ; mature cysts yellowish brown, 12-15/i in diameter; multiplication by budding; coprozoic and fresh water. Genus Cochliopodium Hertwig and Lesser. Test thin, flexible, expansible and contractile; with or without extremely fine hair-like processes; pseudo podia blunt or pointed, but not acicular. Several species. C. bilimhosum (Auerbach) (Fig. 179, 6). Test hemispherical; pseu- dopodia conical with pointed ends; test 24-56/i in diameter; fresh water among algae. Genus Amphizonella Greeff. Test membranous with a double marginal contour; inner membrane smooth, well-defined; outer serrulate; aperture inverted; a single nucleus; pseudo podia blunt, digitate, and divergent. TESTACEA 383 A. violacea G. (Fig. 179, c). Test patelliform, violet-tinted; with chlorophyllous corpuscles and grains; sluggish; 'average diameter 160m ; fresh water. Genus Zonomyxa Niisslin. Test rounded pyriform, flexible, chitinous, violet-colored; endoplasm vacuolated, with chlorophyl- lous particles; several nuclei; pseudo podia simple, not digitate; fresh water. Fig. 179. a, Leptochlamys ampidlacea,. X330 (West); b, Cochliopodium bilimbosum, X670 (Leidy); c, Amphizonella violacea, X270 (Greeff); d, Zonomyxa violacea, X200 (Penard); e, f, Microcorycia flava, X240 (Wailes); g, h, Parmulina cyathus, X500 (Penard); i, Diplochlamys leidyi X270 (Brown); j, Capsellina timida, X270 (Wailes); k, Chlamydophrys stercorea, X670 (Wenyon). Z. violacea N. (Fig. 179, d). A single lobular pseudopodium with acuminate end; 4 nuclei; diameter 140-160/^; actively motile forms 250m or longer; among sphagnum. 384 PROTOZOOLOGY Genus Microcorycia Cockerell. Test discoidal or hemispherical, flexible, with a diaphanous continuation or fringe around periphery, being folded together or completely closed; crown of test with cir- cular or radial ridges; body does not fill the test; 1-2 nuclei; pseu- dopodia lobular or digitate; fresh water. A few species. M. flava (Greeff) (Fig. 179, e, /). Test yellowish brown; crown with few small foreign bodies; endoplasm with yellowish brown granules; 2 nuclei; contractile vacuoles; diameter 80-1 00/^; young individuals as small as 20^; in moss. Genus Parmulina Penard. Test ovoid, chitinoid with foreign bodies; aperture may be closed; a single nucleus; 1 or more contrac- tile vacuoles; fresh water. A few species. P. cyathus P. (Fig. 179, g, h). Test small, flexible; ovoid in aper- ture view, semicircular in profile; aperture a long, narrow slit when test is closed, but circular or elliptical when opened; 40-55/1 long; in moss. Genus Capsellina Penard. Test hyaline, ovoid, membranous; with or without a second outer covering; aperture long slit; a single nucleus; 1 or more contractile vacuoles; filose pseudopodia; fresh water. C. timida Brown (Fig. 179, j). Small, ovoid; elliptical in cross- section; with many oil (?) globules; filo podium; 34/^ by 25/^; in moss. Genus Diplochlamys Greeff. Test hemispherical or cup-shaped, flexible with a double envelope; inner envelope a membranous sack with an elastic aperture; outer envelope with loosely attached for- eign bodies; aperture large; nuclei up to 100; pseudopodia few, short, digitate or pointed; fresh water. Several species. D. leidyi G. (Fig. 179, i). Test dark gray; inner envelope project- ing beyond outer aperture; nuclei up to 20 in number; diameter 80-100^. Family 3 Difflugiidae Taranek Genus Difflugia Leclerc. Test variable in shape, but generally circular in cross-section; composed of cemented quartz-sand, di- atoms, and other foreign bodies; aperture terminal; often with zoochlorellae; cytoplasmic body almost fills the test; a single nu- cleus; many contractile vacuoles; pseudopodia cylindrical, simple or branching; end rounded or pointed; fresh water, woodland soil, etc. D. oblonga Ehrenberg (D. pyriformis Perty) (Fig. 180, a). Test pyriform, flask-shaped, or ovoid; neck variable in length; fundus rounded, with occasionally 1-3 conical processes; aperture terminal, TESTACEA 385 typically circular; test composed of angular sand-grains, diatoms; bright green with chlorophyllous bodies; 60-580ju by 40-240^; in the ooze of fresh water ponds, ditches and bogs; also in moist soil. Several varieties. D. urceolata Carter ^Fig. 180, b). A large ovoid, rotund test, with a short neck and a rim around aperture; 200-230/i by 1 50-200/1 ; in ditches, ponds, sphagnous swamps, etc. Fig. 180. a, Difflugia oblonga, Xl30 (Cash); b, D. urceolata, Xl30 (Leidy); c, d, D. arcula, Xl70 (Leidy); e, D. lohostoma, Xl30 (Leidy); f, D. constrida, X200 (Cash); g, Centropyxis aculeata, X200 (Cash); h, Campuscus cornutus, Xl70 (Leidy); i, Cucurhitella mespiliformis, X200 (Wailes). D. arcula Leidy (Fig. 180, c, d). Test hemispherical, base slightly concave, but not invaginated; aperture triangular, central, trilobed; test yellowish with scattered sand-grains or diatoms; diameter 100-140/i; in sphagnous swamp, moss, soil, etc. D. lohostoma L. (Fig. 180, e). Test ovoid to subspherical; aperture terminal; with 3-6 lobes; test usually composed of sand-grains, rarely with diatoms; endoplasm colorless or greenish; diameter 80-1 20)u; in fresh water. D. constrida (Ehrenberg) (Fig. 180, /). Test laterally ovoid, fundus more cr less prclonged obliquely upward, rounded, and sim- ple or provided with spines; soil forms generally spineless; aperture antero-inferior, large, circular or oval and its edge inverted; test 386 PROTOZOOLOGY composed of quartz grains; colorless to brown; cytoplasm colorless; 80-340;u long; in the ooze of ponds and in soil. D. corona Wallich. Test ovoid to spheroid, circular in cress- section; crown broadly rounded, with a variable number of spines, aperture more or less convex in profile, central and its border mul- tidentate or multilobate; test with fine sand-grains, opaque; cyto- plasm colorless; pseudopodia numerous, long, branching or bifur- cating; 180-230^4 by about 150/1 ; in fresh water. Genus Centropyxis Stein. Test circular, ovoid, or discoid; aper- ture eccentric, circular or ovoidal, often with a lobate border; with or without spines; cytoplasm colorless; pseudopodia digitate; fresh water. C. aculeata S. (Fig. 180, g). Test variable in contour and size; with 4-6 spines; opaque or semitransparent ; with fine sand-grains or diatom shells; pseudopodia sometimes knotted or branching; when encysted, the body assumes a spherical form in wider part of test; granulated, colorless or with green globules; diameter lOO-lSOju; aperture 50-60^ in diameter. Genus Campascus Leidy. Test retort-shaped with curved neck, rounded triangular in cross-section; aperture circular, oblique, with a thin transparent discoid collar; nucleus large; 1 or more contrac- tile vacuoles; body does not fill the test; fresh water. C. cornutus L. (Fig. 180, h). Test pale-yellow, retort-form; with a covering of small sand particles; triangular in cross-section; a single nucleus and contractile vacuole; filopodia straight; 110-140/i long; aperture 24-28/; in diameter; in the ooze of mountain lakes. Genus Cucurbitella Penard. Test ovoid with sand-grains, not compressed; aperture terminal, circular, surrounded by a 4-lobed annular collar; cytoplasm grayish, with zoochlorellae; nucleus large; 1 to many contractile vacuoles; pseudopodia numerous, digitate ; fresh water. C. mespiliformis P. (Fig. 180, i). 115-140/x long; diameter 80- 105/1 ; in the ooze or on vegetaiton in ponds and ditches. Genus Plagiopyxis Penard. Test subcircular in front view; ovoid in profile; aperture linear or lunate; cytoplasm gray, with a single nucleus and a contractile vacuole; fresh water. P. callida P. (Fig. 181, a). Test gray, yellowish, or brown; large nucleus vesicular; pseudopodia numerous, radiating, short, pointed or palmate; diameter 55-135/i; in vegetation. Genus Pontigulasia Rhumbler. Test similar to that of Difflugia, but with a constriction of neck and internally a diaphragm made of the same substances as those of the test. TESTACEA 387 P. vas (Leidy) (Fig. 181, h). Round or ovoid test; constriction deep and well-marked; with sand-grains and other particles; aper- ture terminal; 125-170/i long; fresh water ponds. Stump (1943) made a study of the nuclear division of the organism. During meta- phase 8-12 "chromosomes" form a well-defined equatorial plate; average time for completion of the division was found to be 80 min- utes. Fig. 181. a, Plagiojnjxis callida, X200 (Wailes); b, Pontigulasia vas X200 (Cash); c, Phryganella acropodia, Xl90 (Cash); d, Bullinula indica, Xl30 (Wailes); e, f, Heleopera petricola, Xl90 (Cash); g, Nadi- nella tenella, X400 (Penard); h, Frenzelina reniformis, X600 (Penard); i, Amphitreyna flavum, X360 (Cash and Wailes); j, Pseudodifflugia gracilis, X330 (Cash); k, Diaphoropodon mobile, X270 (Cash and Wailes); 1, m, Clypeolina niarginata, x330 (Cash and Wailes). Genus Phryganella Penard. Test spheroidal or ovoid, with sand- grains and minute diatom shells; aperture terminal, round; pseudo- podia drawn out to a point; fresh water. 388 PROTOZOOLOGY P. acropodia (Hertwig and Lesser) (Fig. 181, c). Test circular in aperture view; hemispherical in profile; yellowish or brownish, semi-transparent, and covered with sand-grains and scales; in front view sharply pointed pseudopodia radiating; colorless endoplasm usually with chlorophyllous bodies; 30-50/i in diameter. Genus Bullinula Penard. Test ellipsoidal, flattened on one face, with silicious plates; on the flattened surface, co -shaped aperture; a single nucleus; pseudopodia digitate or spatulate, simple or branched ; fresh water. B. indica P. (Fig. 181, d). Test dark brown; 120-250/1 in diameter. Genus Heleopera Leidy. Test variously colored; fundus hemi- spherical, with sand-grains; surface covered with amorphous scales, often overlapping; aperture truncate, narrow, elliptic notched in narrow lateral view; a single nucleus; pseudopodia variable in num- ber, thin digitate or branching; fresh water. Several species. H. petricola L. (Fig. 181, e, /). Test variable in size and color, strongly compressed; fundus rough with sand-grains of various sizes; aperture linear or elliptic, convex in front view; pseudopodia slender, branching; 80-100^1 long; in boggy places. Genus Averintzia Schouteden. Test similar to that of Heleopera, but small aperture elliptical; test thickened around aperture; fresh water. A. cyclostoma (Penard). Test dark violet, with sand-grains of dif- ferent sizes; elliptical in cross-section; pseudopodia unobserved; 135- 180/1 long; in sphagnum and aquatic plants. Genus Nadinella Penard. Test chitinous, thin, hyaline, with for- eign bodies and collar around aperture; filo podia; fresh water. N. tenella P. (Fig. 181, g^). 50-55/1 long; fresh water lakes. Genus Frenzelina Penard. Two envelopes, outer envelope hemi- spherical, thin, rigid, covered with siliceous particles; inner envelope round or ovoid, drawn out at aperture, thin, hyaline and covering the body closely; aperture round, through which a part of body with its often branching straight filopods extends; cytoplasm with dia- toms, etc.; a nucleus and a contractile vacuole; fresh water. F. reniformis P. (Fig. 181, h). Outer envelope 26-30/t in diameter; fresh water lakes. Genus Amphitrema Archer. Test ovoid, symmetrical, compressed; composed of a transparent membrane, with or without adherent foreign bodies; 2 apertures at opposite poles; with zoochlorellae; nucleus central; 1 to several contractile vacuoles; straight filo podia, sparsely branched, radiating; fresh water. Several species. A. flavum A. (Fig, 181, i). Test brown, cylindrical with equally TESTACEA 389 rounded ends in front view; elliptical in profile; ovoid with a small central oval aperture in end view; 45-77)u by 23-45/i; in sphagnum. Genus Pseudodifflugia Schlumberger. Test ovoid, usually rigid, with foreign bodies; circular or elliptical in cross-section; aperture terminal; granulated cytoplasm colorless or greyish; nucleus poster- ior; a contractile vacuole; filopodialong, straight or branching; fresh water. Several species. P. gracilis S. (Fig. 181, j). Test yellowish or brownish; subspheri- cal, with sand-grains; aperture without neck; 20-65/1 long. Genus Diaphoropodon Archer. Test ovoid, flexible, with minute foreign bodies and a thick covering of hyaline hair-like projections; pseudopodia long, filose, branching; fresh water. D. mobile A. (Fig. 181, k). Test brown; of various shapes; aperture terminal; body does not fill the test; nucleus large; 1-2 contractile vacuoles; 60-120/x long; projections 8-10ai long; in vegetation. Genus Clypeolina Penard. Test ovoid, compressed, formed of a double envelope; outer envelope composed of 2 valves with scales and particles; inner envelope a membranous sack; Icng filo podia, often branching; fresh water. C. marginata P. (Fig. 181, I, m). Outer test-valves yellow to dark brown; lenticular in cross-section; wide terminal aperture; endo- plasm with many small globules; a single nucleus and contractile vacuole; 80-150/x long. Family 4 Euglyphidae Wallich Genus Euglypha Dujardin ( Parevglypha Penard). Test hyaline, ovoid, composed of circular, oval, or scutiform siliceous imbricated scales, arranged in longitudinal rows; aperture bordered with regu- larly arranged denticulate scales; usually with spines; 1-2 nuclei large, placed centrally; filopodia dichotomously branched; contrac- tile vacuoles; fresh water. Numerous species. E. acanthophora (Ehrenberg) (E. alveolata D.) (Fig. 70). Test ovoid, or slightly elongate; 3-7 scales protruding around the circular aperture; scales elliptical; body almost fills the test; 50-100/i long. E. cristata Leidy (Fig. 182, a). Test small, elongate with a long neck, fundus with 3-8 spines; scales oval; aperture circular, bordered by a single row of 5-6 denticulate scales; cytoplasm colorless; nucleus posterior; reserve scales are said to be collected around the exterior of aperture, unlike other species in which they are kept within the cytoplasm; SO-lO/j. long; 12-23/i in diameter; aperture 6-12^; scales 4.5-9.5/i by 2.5-6. 5)u; spines 10-15/i long. E. mucronata L. (Fig. 182, h). Test large; fundus conical, with 390 PROTOZOOLOGY 1-2 terminal spines (12-44;u long); aperture circular, bordered by a single row of 6-8 denticulate scales; 100-1 50yu long, diameter 30-60/^; aperture 15-20yu in diameter. Genus Paulinella Lauterborn. Test small ovoid, not compressed; with siliceous scales in alternating transverse rows; aperture ter- minal; bodj^ does not fill the test completely ; nucleus posterior; among vegetation in fresh or brackish water. Fig. 182. a, Eughjpha cristata, X330 (Wailes); b, E. mucronata, X330 (Wailes); c, Paulinella chromatophora, XlOOO (Wailes); d, Cyphoderia ampulla, X200 (Cash); e, f, Corythion pulchellum, X350 (Wailes). P. chromatophora L. (Fig. 182, c). Scales arranged in 11-12 rows; with 1-2 curved algal symbionts; no food particles; a single con- tractile vacuole; 20-32^ long; 14-23^ in diameter. Genus Cyphoderia Schlumberger. Test retort-shaped; colorless to yellow; made up of a thin chitinous membrane, covered with discs or scales; aperture terminal, oblique, circular; body does not fill the test completely; nucleus large, posterior; pseudo podia, few, long filose, simple or branched; fresh water. C. ampulla (Ehrenberg) (Fig. 182, d). Test usually yellow, trans- lucent, composed of discs, arranged in diagonal rows; circular in cross-section; aperture circular; cytoplasm gray, with many granules TESTACEA 391 and food particles; 2 contractile vacuoles; 60-200/x long; diameter 30-70/x. Several varieties. Genus Trinema Dujardin. Test small, hyaline, ovoid, compressed anteriorly, with circular siliceous scales; aperture circular, oblique, invaginate; nucleus posterior; filopodia not branched; fresh water in vegetation. T. enchelys (Ehrenberg) (Fig. 183, a). 1-2 contractile vacuoles; pseudopodia attenuate, radiating; 30-100)u long; IS-GOju wide; scales 4-12;u in diameter. Genus Corythion Taranek. Test small, hyaline, composed of small oval siliceous plates; compressed; elliptical in cross-section; aperture subterminal, ventral or oblique, and circular or oval; numerous filopodia; fresh water. C. pulchellum Penard (Fig. 182, e, /). Aperture lenticular; cyto- plasm colorless; 2-3 contractile vacuoles; 25-35/x by 15-20ju; aper- ture 7-1 0/x by 3-4/x. Genus Placocista Leidy. Test ovoid, hyaline, compressed; len- ticular in cross-section; with oval or subcircular siliceous scales; aperture wide, linear, with flexible undulate borders; nucleus large, posterior; often with zoochlorellae; filopodia branching and many, generally arising from a protruded portion of cytoplasm; fresh water. P. spinosa (Carter) (Fig. 183, h). Margin of test with spines, either singly or in pairs; 116-174)u by 70-100^; in sphagnum. Genus Assulina Ehrenberg. Test colorless or brown; ovoid; with elliptical scales, arranged in diagonal rows; aperture oval, terminal bordered by a thin chitinous dentate membrane; nucleus posterior; contractile vacuoles; filopodia divergent, sometimes branching; fresh water. A. seminulum (E.) (Fig. 183, c). Body does not fill the test; with numerous food particles; pseudopodia few, straight, divergent, slender, seldom branched; 60-150/^ by 50-75/^; in sphagnum. Genus Nebela Leidy. Test thin, ovate or pyriform; with circular or oval platelets of uniform or various sizes; highly irregular; endo- plasm with oil globules; nucleus posterior; body does not fill the test, and is connected with the latter by many ectoplasmic strands at fundus end; pseudopodia blunt, rarely branched; fresh water. Numerous species. N. collaris (Ehrenberg) (Fig. 183, d). Test pyriform, fundus obtuse in profile; aperture without any notch; endoplasm with chlorophyl- lous food particles; pseudopodia digitate, short, usually 3-6 in num- ber; about 130)u by 85-90yu; in marshes among sphagnum. 392 PROTOZOOLOGY Genus Quadrula Schulze. Test pyriform, hemispherical, or dis- coidal; with quadrangular siliceous or calcareous platelets, arranged generally in oblique series, not overlapping; a single nucleus; body and pseudopodia similar to those of Difflugia; fresh water. Q. symmetrica (Wallich) (Fig, 183, e). Compressed, smaller plate- lets near aperture; cytoplasm very clear, with chlorophyllous gran- ules; 3-5 pseudopodia digitate; nucleus posterior; 80-140^1 by 40- 96/i; in sphagnum. Fig. 183. a, Trinema enchelys, X330 (Wailes); b, Placocista spinosa, X200 (Wailes); c, Assulina seminulum, X400 (Wailes); d, Nebela collaris, X200 (Cash); e, Quadrula symmetrica, X200 (Cash); f, Sphenoderia lenta, X330 (Leidy). Genus Sphenoderia Schlumberger. Test globular or oval, some- times slightly compressed; hyaline, membranous, with a short broad neck, and a wide elliptical aperture; scales circular, oval, or hexag- onal, arranged in alternating series; cytoplasm colorless; 1-2 con- tractile vacuoles; filo podia, fine, branching; fresh water. S. lenta S. (Fig. 183, /). Hyaline test ovoid or globular; scales cir- cular or broadly oval; aperture terminal, surrounded by a thin chi- tinous collar, one side inclined inwards; nucleus large; cytoplasm colorless; 2 contractile vacuoles; 30-64/x by 20^6/i; aperture 10-22/x in diameter. References Cash, J. 1905, 1909 The British freshwater Rhizopoda and Heliozoa. Vols. 1, 2. and G. H. Wailes 1915, 1918 The British freshwater Rhizo- poda and Heliozoa. Vols. 3, 4. TESTACEA 393 Deflandre. G. 1928 Le genre Arcella Ehrenberg. Arch. f. Protis- tenk., Vol. 64. Hegner, R. W. 1920 The relation between nuclear number, chro- matin mass, cytoplasmic mass, and shell characteristics in four species of the genus Arcella. Jour. Exp. Zool., Vol. 30. Leidy, J. 1879 Freshwater Rhizopods of North America. Rep. U. S. Geol. Surv., Vol. 12. Penard, E. 1890 Etudes sur les rhizopodes d'eau douce. Mem. soc. phys. et d'hist. nat. Geneva, Vol. 31. — 1902 Faune rhizopodique du hassin du Leman. Geneva. Stump, A. B. 1943 Mitosis and cell division in Pontigulasia vas (Leidy) Schouteden. Jour. Elisha Mitchell Sci. Soc, Vol. 59. Chapter 21 Order 5 Foraminifera d'Orbigny THE Foraminifera are comparatively large Protozoa, living al- most exclusively in the sea. They were very abundant in geo- logic times and the fossil forms are important in applied geology (p. 10). The majority live on ocean bottom, moving about slug- gishly over the mud and ooze by means of their pseudo podia. Some are attached to various objects on the ocean floor, while others are pelagic. The cytoplasm is ordinarily not differentiated into the two zones and streams out through the apertures, and in perforated forms through the numerous pores, of the shell, forming rhizopodia which are fine and often very long and which anastomose with one another to present a characteristic appearance (Fig. 5). The streaming move- ment of the cytoplasm in the pseudopodia are quite striking; the granules move toward the end of a pseudopodium and stream back along its periphery. The body cytoplasm is often loaded with brown granules which are apparently waste matter and in some forms such as Peneroplis pertusus these masses are extruded from the body from time to time, especially prior to the formation of a new cham- ber. Contractile vacuoles are usually not found in the Foraminifera. The test of the Foraminifera varies greatly in form and structure. It may show various colorations — orange, red, brown, etc. The ma- jority measure less than one millimeter, although larger forms may frequently reach several millimeters. The test may be siliceous or calcareous and in some forms, various foreign materials, such as sand-grains, sponge-spicules, etc. which are more or less abundantly found where these organisms live, are loosely or compactly cemented together by pseudochitinous or gelatinous substances. Certain forms show a specific tendency in the selection of foreign materials for the test (p. 40). Siliceous tests are comparatively rare, being found in some species of Miliolidae inhabiting either the brackish water or deep sea. Calcareous tests are sometimes imperforated, but even in such cases those of the young are always perforated. By far the ma- jority of the Foraminifera possess perforated calcareous tests. The thickness of the shell varies considerably, as do also the size and number of apertures, among different species. Frequently the per- forations are very small in the young and later become large and coarse, while in others the reverse may be the case. 394 FORAMINIFERA 395 The form of the shell varies greatly. In some there is only one chamber composed of a central body and radiating arms which repre- sent the material collected around the pseudopodia, as in Rhabdam- mina (Fig. 185, a) , or of a tubular body alone, as in Hyperammina (Fig. 185, d). The polythalamous forms possess shells of various spirals. The first chamber is called the proloculum which may be formed either by the union of two swarmers or by asexual reproduction. The former is ordinarily small and known as the microspheric proloculum, while the latter, which is usually large, is called the megalospheric proloculum. To the proloculum are added many chambers which may be closely or loosely coiled or not coiled at all. These chambers are ordinarily undivided, but in many higher forms they are divided into chamberlets. The chambers are delimited by the suture on the exterior of the shell. The septa which divide the chambers are per- forated by one or more foramina known as stolon canals, through which the protoplasm extends throughout the chambers. The last chamber has one or more apertures of variable sizes, through which the cytoplasm extends to the exterior as pseudopodia. The food of Foraminifera consists mostly of diatoms and algae, though pelagic forms are known to capture other Protozoa and micro crustaceans. All species of Foraminifera manifest a more or less distinct tend- ency toward a dimorphism : the megalospheric form has a large pro- loculum, is uninucleate and is relatively small in size ; while the micro- spheric form possesses a small proloculum, is multinucleate, and is large. In addition, there is a difference in the direction of rotation of spiral chambers of tests in some species (Myers). For example, in Discorhis opercularis, the microspheric form has clockwise rotation of the chambers, and the megalospheric form shows counterclock- wise rotation. The megalospheric forms are said to be much more numerous than the microspheric forms, especially in pelagic species. It is possible that, as Myers (1938) pointed out, the flagellate gam- etes are set free in open water and have a minimum of opportunity for syngamy. Lister (1895) observed the development of the megalospheric form in Elphidium by asexual reproduction from the microspheric form. He noticed flagellated swarmers in megalospheric tests and considered them as gametes which through syngamy gave rise to microspheric individuals. Recent studies by Myers (1935-1940) confirm the correctness of this view, except that in some species the gametes are amoeboid. In Spirillina vivipara (Fig. 184, A, 1-5) the mature microspheric form (1) which measures 125-1 52/i in diameter, becomes surrounded by an envelope composed of substrate debris 396 PROTOZOOLOGY and viscous substance. Within the "multiple fission cyst," nuclear and cytoplasmic fissions form numerous small uninucleate megalo- spheric individuals which produce tests and emerge from the cyst A B r Fig. 184. Developmental cycles of Foraminifera (Myers). A, Spirillina vivipara; B, Discorbis petalliformis; C Elphidium crispa. 1, microspheric forms; 2, megalospheric forms, a-c, enlarged views of young megalo- spheric forms; 3, beginning of sexual reproduction; 4, gamete and zygote formation, a-c, gametes; 5, young microspheric forms, a-c, enlarged views of one in each species. FORAMINIFERA 397 {2). They grow into mature megalo spheric forms which measure 60-72)U in diameter. Two to four such individuals become associated and transform into "fertilization cyst." (S). The nucleus in each individual divides twice or occasionally three times and thus formed multinucleate bodies escape from the tests within the cyst envelope where many gametocytes are produced by multiple fissions. Each gametocyte which contains 12 chromosomes divides into two amoe- boid haploid gametes by meiosis. Gametes developed from different parents presumably undergo fusion in pairs and zygotes are pro- FiG. 185. a, Rhabdammina abyssorum, X5 (Kiihn); b, Rhizammina algaeformis, fragment of, Xl4 (Cushman); c, Saccammina sphaerica, X8 (Rhumbler); d, Hyperammina subnodosa, X4 (Brady); e, Ainmo- discus incertus, X20 (Ktihn); f, Silicina limitata, Xl3 (Cushman); g, Reophax nodulosus, X3 (Brady). duced (4)- Each zygote becomes proloculum in which the nucleus divides twice and when the coiled tubular chamber of test grows to about three-quarters of a whorl, young microspheric individuals escape from the cyst and lead independent existence (5). Myers re- ports the development of PatelUna corrugata is similar to that of Spirillina, except the amoeboid gametes possess 12 haploid number of chromosomes. In Discorbis patelliformis (Fig. 184, B, 1-5), the same investigator noticed no fertilization cyst during the sexual reproduction, but two megalospheric individuals come in contact and flagellate gametes are produced in them. The zygotes develop within the space formed by the dissolution of septa between chambers and tests; the zygote nucleus divides repeatedly within each zygote and forms about 40 nuclei before a test is secreted. In Elphidium crispa (Fig. 184, C, 1-5), there is no direct association of megalospheric individuals dur- 398 PROTOZOOLOGY ing sexual reproduction. The flagellated gametes produced in each, are set free in the water and the fusion of the gametes depends en- tirely upon the chance meeting. More than 300 genera of extinct and living Foraminifera are now known. Cushman distinguished 45 families. The present work fol- lows Cushman in recognizing and differentiating 44 families, and lists one genus as an example for each, but places Gromia and allied genera in the order Testacea (p. 374). Test entirely or in part arenaceous Test single-chambered or rarely an irregular group of similar chambers loosely attached Test with a central chamber, 2 or more arms; fossil and recent. . . . Family 1 Astrorhizidae Genus Rhabdammina Sars (Fig. 185, a) Test without a central chamber, elongate, open at both ends; fossil and recent Family 2 Rhizamminidae Genus Rhizammina Brady (Fig. 185, b) Test a chamber or rarely series of similar chambers loosely attached, with normally a single opening; fossil and recent Family 3 Saccamminidae Genus Saccammina Sars (Fig. 185, c) Test 2-chambered, a proloculum and long undivided tubular second chamber Test with the second chamber, simple or branching, not coiled; mostly recent and also fossil Family 4 Hyperamminidae Genus Hyperammina Brady (Fig. 185, d) Test with the second chamber usually coiled at least in young Test of arenaceous material with much cement, usually yellowish or reddish brown; fossil and recent. Family 5 Ammodiscidae Genus Ammodiscus Reuss (Fig. 185, e) Test of siliceous material, second chamber partially divided; fossils only Family 6 Silicinidae Genus Silicina Bornemann (Fig. 185, /) Test typically many-chambered Test with all chambers in a rectilinear series; fossil and recent Family 7 Reophacidae Genus Reophax Montfort (Fig. 185, g) Test planispirally coiled at least in young Axis of coil, short; many uncoiled forms; fossil and recent Family 8 Lituolidae FORAMINIFERA 399 Genus Lituola Lamarck (Fig. 186, a) Axis of coil usually long, all close-coiled Interior not labyrinthic; fossil only Family 9 Fusulinidae Genus Fusulina Fisher (Fig. 186, b) Interior labyrinthic; fossil only Family 10 Loftusiidae Genus Loftusia Brady Test typically biserial at least in young of microspheric form; fossil and recent Family 11 Textulariidae Fig. 186. a, Lituola nautiloidea (Cushman); b, section through a Fusulina (Carpenter); c. Textularia agglutinans, X90 (Rhumbler); d. Verneuilina propinqua, X8 (Brady); e, Valvulina triangularis, (d'Or- bigny); f, Trochammina inflata, X32 (Brady); g, Placopsilina cenomana (Reuss); h, Tetrataxis palaeotrochus, Xl5 (Brady); i, Spirolocvlina limbata, X20 (Brady); j, Triloculina trigonula, X 15 (Brady); k, Fischer- ina helix, X32 (Heron-Allen and Earland); 1, Vertebralina striata, X40 (Kiihn); m, Alveolinella mello, X35 (Brady). Genus Textularia Def ranee (Fig. 186, c) Test typically triserial at least in young of microspheric form Aperture usually without a tooth, test becoming simpler in higher forms; fossil and recent Family 12 Verneuilinidae Genus Verneuilina d'Orbigny (Fig. 186, d) Aperture typically with a tooth, test becoming conical in higher forms; fossil and recent Family 13 Valvulinidae 400 PROTOZOOLOGY Genus Valvulina d'Orbigny (Fig. 186, e) Test with whole body labyrinthic, large, flattened, or cylindrical; recent Family 14 Neusinidae Genus Neusina Goes Test trochoid at least while young Mostly free, typically trochoid throughout; fossil and recent. . Family 15 Trochamminidae Genus Trochammina Parker and Jones (Fig. 186, /) Attached; young trochoid, later stages variously formed; fossil and recent Family 16 Placopsilinidae Genus Placopsilina d'Orbigny (Fig. 186, g) Free; conical, mostly of large size; fossil only Family 17 Orbitolinidae Genus Tetrataxis Ehrenberg (Fig. 186, h) Test coiled in varying planes, wall imperforate, with arenaceous portion only on the exterior; fossil and recent Family 18 Miliolidae (in part) Genus Spiroloculina d'Orbigny (Fig. 186, i) Test calcareous, imperforate, porcellaneous Test with chambers coiled in varying planes, at least in young; aperture large, toothed; fossil and recent. .Family 18 Miliolidae (in part) Genus Triloculina d'Orbigny (Fig. 186, j) Test trochoid; fossil and recent Family 19 Fischerinidae Genus Fischerina Terquem (Fig. 186, k) Test planispiral at least in young Axis very short, chambers usually simple; fossil and recent Family 20 Ophthalmidiidae Genus Vertebralina d'Orbigny (Fig. 186, I) Axis short, test typically compressed and often discoid, chambers mostly with many chamberlets; fossil and recent Family 21 Peneroplidae Genus Peneroplis Montfort (Figs. 4; 187) Axis typically elongate, chamberlets developed; mainly fossil Family 22 Alveolinellidae Genus Alveolinella DouvilI6 (Fig, 186, m) Test globular, aperture small, not toothed; recent only Family 23 Keramosphaeridae FORAMINIFERA 401 Bj% a ^" k J 1 d ...;;: # @ Fig. 187. Diagram illustrating the life-cycle of Peneroj)lis pertusus (Winter), a-f, megalospheric generation; g, gamete formation; h-k, isogamy; 1-n, microspheric generation; o, multiple division. Genus Keramosphaera Brady Test calcareous, perforate Test vitreous with a glassy lustre, aperture typically radiate, not trochoid Test planispirally coiled or becoming straight, or single-chambered; fossil and recent Family 24 Lagenidae 402 PROTOZOOLOGY Genus Lagena Walker and Jacob (Fig. 188, a) Test biserial or elongate spiral; fossil and recent Family 25 Polymorphinidae Genus Pol3anorphina d'Orbigny Test not vitreous; aperture not radiating Test planispiral, occasionally trochoid, then usually with processes along the suture lines, septa single, no canal system ; fossil and recent Family 26 Nonionidae Fig. 188. a, Lagena striata, X50 (Rhumbler); b, Elphidium strigilata, X40 (Kiihn); c, Opercidina amynonoides, X50 (Kiihn); d, Pavonina flabelliformis, X30 (Brady); e, Hantkenina alabamensis, X40 (Cushman); f, Bolivina ■punctata, XlOO (Kiihn); g, Rotalia beccarii, x40 (Kiihn); h, Asterigerina carinata, X30 (d'Orbigny from Kiihn). Genus Elphidium Montfort (Figs. 5; 184, C; 188, h) {Polysiomella Lamarck) Test planispiral, at least in young, generally lenticular, septa double, canal system in higher forms; fossil and recent Family 27 Camerinidae Genus Operculina d'Orbigny (Fig. 188, c) Test generally biserial in at least microspheric form, aperture usually large, without teeth; fossil and recent Family 28 Heterohelicidae FORAMINIFERA 403 Genus Pavonina d'Orbigny (Fig. 188, d) Test planispiral, bi- or tri-serial with elongate spines and lobed aperture; fossil and recent Family 29 Hantkeninidae Genus Hantkenina Cushman (Fig. 188, e) Test typically with an internal tube, elongate Aperture generally loop-shaped or cribrate; fossil and recent. . . Family 30 Buliminidae Genus Bolivina d'Orbigny (Fig. 188, /) Aperture narrow, curved, with an overhanging portion; mostly fossil, also recent Family 31 Ellipsoidinidae Genus Ellipsoidina Seguenza Test trochoid, at least in young of microspheric form, usually coarsely perforate; when lenticular, with equatorial and lateral chambers Test trochoid throughout, simple; aperture ventral No alternating supplementary chambers on ventral side; fossil and recent Family 32 Rotaliidae Genus Rotalia Lamarck (Fig. 188, g) Genus Spirillina Ehrenberg (Fig. 184, A) Genus Patellina Williamson. Genus Discorbis Lamarck (Fig. 184, B) Alternating supplementary chambers on ventral side; fossil and recent Family 33 Amphisteginidae Genus Asterigerina d'Orbigny (Fig. 188, h) Test trochoid and aperture ventral in young With supplementary material and large spines, independent of chambers; fossil and recent Family 34 Calcarinidae Genus Calcarina d'Orbigny (Fig. 189, a) With later chambers in annular series or globose with multiple apertures, but not covering earlier ones; fossil and recent. . . . Family 35 Halkyardiidae Genus Halkyardia Heron-Allen and Earland (Fig. 189, h) With later chambers somewhat biserial; aperture elongate in the axis of coil; fossil and recent. .Family 36 Cassidulinidae 404 PROTOZOOLOGY Genus Cassidulina d'Orbigny (Fig. 189, c) With later chambers becoming involute, very few making up the exterior in adult; aperture typically elongate, semicircular; in a few species circular; fossil and recent Family 37 Chilostomellidae Genus Allomorphina Reuss (Fig. 189, d) With chambers mostly finely spinose and wall cancellated, adapted, for pelagic life, globular forms with the last chamber com- pletely involute; aperture umbilicate or along the suture; fossil and recent Family 38 Globigerinidae Fig. 189. a, Calcarina defrancei, X25 (Brady); b, Halkyardia radiata, Xl5 (Cushman); c, Cassidulina laevigata, X25 (Brady); d, Allomorphina Irigona, X40 (Btady); e, Globigerina bulloides, X30 (Kiihn); f, Anomalinp, pundulata (d'Orbigny); g, Rupertia stabilis, X50 (Brady). Genus Globigerina d'Orbigny (Fig. 189, e) Early chambers globigerine, later ones spreading and compressed; fossil and recent Family 39 GloJ:)orotaliidae Genus Globorotalia Cushman Test trochoid at least in young, aperture peripheral or becoming dorsal Mostly attached, dorsal side usually flattened; fossil and recent Family 40 Anomalinidae Genus Anomalina d'Orbigny (Fig. 189, /) Later chambers in annular series; fossil and recent Family 41 Planorbulinidae FORAMINIFERA 405 Genus Planorbulina d'Orbigny Test trochoid in very young, later growing upward Later chambers in loose spiral; fossil and recent Family 42 Rupertiidae Genus Rupertia Wallich (Fig. 189, g) Later chambers in masses or branching, highly colored; mostly recent, also fossil Family 43 Homotremidae Genus Homotrema Hickson Test trochoid in the very young of microspheric form, chambers becoming annular later, with definite equatorial and lateral chambers, often with pillars; fossil only Family 44 Orbitoididae Genus Orbitoides d'Orbigny References Brady, B. H. 1884 Report on the Foraminifera dredged by H.M.S. Challenger, during the years 1873 to 1876. Rep. Voy. Challenger, Vol. 9. CusHMAN, J. A. 1940 Foraminifera: their classification and economic use. Third edition. Cambridge, Mass. Myers, E. H. 1935 The life history of Patellina corrugata William- son, a foraminifer. Bull. Scripps Inst. Oceanogr. Uni. Calif., Tech. Ser., Vol. 3. 1936 The life-cycle of Spirillina vivipara Ehrenberg, with notes on morphogenesis, systematics and distribution of the Foraminifera. Jour. Roy. Micr. Soc, Vol. 56. 1938 The present state of our knowledge concerning the life cycle of the Foraminifera. Proc. Nat. Acad. Sci., Vol. 24. 1940 Observations on the origin and fate of flagellated gametes in multiple tests of Discorbis (Foraminifera). Jour. Ma- rine Biol. Ass. United Kingdom, Vol. 24. Rhumbler, L. 1904 Systematische Zusammenstellung der rezenten Reticulosa (Nuda u. Foraminifera). Arch. f. Protistenk., Vol. 3. Chapter 22 Subclass 2 Actinopoda Calkins THE Actinopoda are divided into two orders as follows: Without central capsule Order 1 Heliozoa With central capsule Order 2 Radiolaria (p. 417) Order 1 Heliozoa Haeckel The Heliozoa are, as a rule, spherical in form with many radi- ating axopodia. The cytoplasm is differentiated, distinctly in Ac- tinosphaerium, or indistinctly in other species, into the coarsely vacuolated ectoplasm and the less transparent and vacuolated endoplasm. The food of Heliozoa consists of living Protozoa or Protophyta; thus their mode of obtaining nourishment is holozoic. A large organism may sometimes be captured by a group of Heliozoa which gather around the prey. When an active ciliate or a small roti- fer comes in contact with an axopodium, it seems to become suddenly paralyzed and, therefore, it has been suggested that the pseudopodia contain some poisonous substances. The axial filaments of the axo- podia disappear and the pseudopodia become enlarged and surround the food completely. Then the food matter is carried into the main part of the body and is digested. The ectoplasm contains several contractile vacuoles and numerous refractile granules which are scattered throughout. The endoplasm is denser and usually devoid of granules. In the axopodium, the cytoplasm undergoes streaming movements. The hyaline and homogeneous axial filament runs straight through both the ectoplasm and the endoplasm, and ter- minates in a point just outside the nuclear membrane. When the pseudopodium is withdrawn, its axial filament disappears com- pletely, though the latter sometimes disappears without the with- drawal of the pseudopodium itself. In Acanthocystis the nucleus is eccentric (Fig. 192, b), but there is a central granule, or centroplast, in the center of the body from which radiate the axial filaments of the axopodia. In multinucleate Actinosphaerium, the axilia filaments terminate at the periphery of the endoplasm. In Camptonema, an axial filament arises from each of the nuclei (Fig. 190, d). The skeletal structure of the Heliozoa varies among different species. The body may be naked, covered by a gelatinous mantle, or provided with a lattice-test with or without spicules. The spicules are variable in form and location and may be used for specific dif- 406 ACTINOPODA, HELIOZOA 407 ferentiation. In some forms there occur colored bodies bearing chromatophores, which are considered as holophytic Mastigophora (p. 25) living in the heliozoans as symbionts. The Heliozoa multiply by binary fission or budding. Incomplete division may result in the formation of colonies, as in Rhaphidi- ophrys. In Actinosphaerium, nuclear phenomena have been studied by several investigators (p. 164), In Acanthocystis and Oxnerella (Fig, 58), the central granule behaves somewhat like the centriole in a metazoan mitosis. Budding has been known in numerous species. In Acanthocystis the nucleus undergoes amitosis several times, thus forming several nuclei, one of which remains in place while the other migrates toward the body surface. Each peripheral nucleus becomes surrounded by a protruding cytoplasmic body which becomes cov- ered by spicules and which is set free in the water as a bud. These small individuals are supposed to grow into larger forms, the central granules being produced from the nucleus during the growth. For- mation of swarmers is known in a few genera and sexual reproduc- tion occurs in some forms. The Heliozoa live chiefly in fresh w^ater, although some inhabit the sea. Without gelatinuous envelope Without flagella Pseudopodia arise from thick basal parts, branching Family 1 Actinocomidae Pseudopodia not branching, cytoplasm highly vacuolated Family 2 Actinophryidae (p. 408) With 1-2 flagella Family 3 Ciliophryidae (p. 409) With gelatinous envelope; with or without skeleton Without flagella Without chitinous capsule Without definite skeleton Family 4 Lithocollidae (p. 409) With chitinous or siliceous spicules or scales With chitinous spicules. . . .Family 5 Heterophryidae (p. 410) With siliceous skeleton Cup-like plates over body; 2-3 pseudopodia often grouped Family 6 Clathrellidae (p. 412) Scales flattened, not cup-like. Family 7 Acanthocystidae (p. 412) With chitinous retiform capsule Family 8 Clathulinidae (p. 414) With numerous flagella, among axopodia; siliceous scales Family 9 Myriophryidae (p. 414) Family 1 Actinocomidae Poche Genus Actinocoma Penard. Body spherical; one or more contrac- tile vacuoles; nucleus with a thick membrane, central; filopodia, not axopodia, simple or in brush-like groups; fresh water. 408 PROTOZOOLOGY A. ramosa P. (Fig. 190, a). Average diameter 14-26^. Family 2 Actinophyxidae Claus Genus Actinophyrs Ehrenberg. Spheroidal; cytoplasm highly vac- uolated, especially ectoplasm; with often symbiotic zoochlorellae; nucleus central; 1 to many contractile vacuoles; axopodia straight, Fig. 190. a, Actinocoma ramosa, X630 (Penard); b, Actinophyrs sol, X400 (Kudo); c, Actinosphaerium eichhorni, X45 (Kudo); d, Catnp- tonema nutans, X350 (Schaudinn). numerous, axial filaments terminate at surface of the nucleus; "sun animalcules"; fresh water. A. sol E. (Figs. 82; 190, h). Spherical; ectoplasm vacuolated; endo- plasm granulated with numerous small vacuoles; a large central nucleus; solitary but may be colonial when young; diameter variable, average being 40-50^; among plants in still fresh water. Reproduc- ACTINOPODA, HELIOZOA 409 tion studied by Belaf (p. 164); Looper (1928) studied its food re- actions. A. vesiculata Penard. Ectoplasm with saccate secondary vesicles, extending out of body surface between axo podia; nucleus central, with many endosomes; 25-30/1 in average diameter; fresh water. Genus Actinosphaerium Stein. Spherical; ectoplasm consists al- most entirely of large vacuoles in one or several layers; endoplasm with numerous small vacuoles; numerous nuclei; axial filaments end in the inner zone of ectoplasm. 2 species. A. eichhorni Ehrenberg (Figs. 6; 190, c). Numerous nuclei scattered in the periphery of endoplasm; 2 or more contractile vacuoles, large; axial filaments arise from a narrow zone of dense cytoplasm at the border line between endoplasm and ectoplasm; body large, diameter 200-300/i, sometimes up to 1 mm.; nuclei 12-20/z in diameter; among vegetation in freshwater bodies. A. arachnoideum Penard. Ectoplasm irregularly vacuolated; no distinct endoplasmic differentiation; nuclei smaller in number; pseu- dopodia of 2 kinds; one straight, very long and the other filiform, and anastomosing; 70-80/x in diameter; fresh water. Genus Camptonema Schaudinn. Spheroidal; axial filaments of axopodia end in nuclei about 50 in number; vacuoles numerous and small in size; salt water. C. nutans S. (Fig. 190, d). About ISOyu in diameter. Genus Oxnerella Dobell. Spherical; cytoplasm indistinctly dif- ferentiated; eccentric nucleus with a large endosome; axial filaments take their origin in the central granule; no contractile vacuole; nuclear division typical mitosis (Fig. 58). 0. maritima D. (Fig. 58). Small, 10-22/i in diameter; solitary, floating or creeping; salt water. Family 3 Ciliophryidae Poche Genus Ciliophrys Cienkowski. Spherical with extremely fine radiating filopodia, giving the appearance of a typical heliozoan, with a single flagellum which is difficult to distinguish from the nu- merous filopodia, but which becomes conspicuous when the pseudo- podia are withdrawn; fresh or salt water. C. infusionum C. (Fig. 191, a). 25-30/x long; freshwater infusion. C. marina Caullery. About 10/x in diameter; salt water. Family 4 Lithocollidae Poche Genus LithocoUa Schulze. Spherical body; outer envelope with usually one layer of sand-grains, diatoms, etc. ; nucleus eccentric. 410 PROTOZOOLOGY L. glohosa S. (Fig. 191, h). Body reddish with numerous small colored granules; nucleus large; central granule unknown; envelope 35-50/1 in diameter; in lakes, ponds, and rivers; also in brackish water. Genus Astrodisculus Greeff. Spherical with gelatinous envelope, free from inclusions, sometimes absent; no demarcation between 2 regions of the cytoplasm; pseudopodia fine without granules; fresh water. A. radians G. (Fig. 191, c). Outer surface usually with adherent foreign bodies and bacteria; cytoplasm often loaded with green, yellow, or brown granules; nucleus eccentric; a contractile vacuole; diameter 25-30/x including envelope; in pools and ditches. Genus Actinolophus Schulze. Body pyriform, enveloped in a gelatinous mantle; stalked; stalk apparently hollow; axopodia long, numerous; nucleus eccentric; salt water. A. pedunculatus S. (Fig. 191, d). Diameter about BO/x; stalk about lOOyu long. Genus Elaeorhanis Greeff. Spherical; mucilaginous envelope with sand-grains and diatoms; cytoplasm with a large oil globule; nu- cleus eccentric; 1 or more contractile vacuoles; pseudopodia not granulated, sometimes forked; fresh water. E. cincta G. (Fig. 191. e). Bluish with a large yellow oil globule; without any food particles; no central granule; pseudopodia rigid, but apparently without axial filaments, sometimes forked; young forms colonial; solitary when mature; outer diameter 50-60^; body itself 25-30yu; in lakes and pools. Genus Sphaerastrum Greeff. Somewhat flattened; greater part of axopodia and body covered by a thick gelatinous mantle; a cen- tral granule and an eccentric nucleus; fresh water. S. fockei G. (Fig. 191, /). Diameter about 30/t; often colonial; in swamps. Family 5 Heterophryidae Poche Genus Heterophrys Archer. Spherical; mucilaginous envelope thick, with numerous radial, chitinous spicules which project beyond periphery; nucleus eccentric; axial filaments originate in a central granule; fresh or salt water, H. myriopoda A. (Fig. 191, g). Nucleus eccentric; cytoplasm loaded with spherical algae, living probably as symbionts; contractile vacuoles indistinct; 50-80yu in diameter; in pools and marshes; and also among marine algae. ACTINOPODA, HELIOZOA 411 H. glahrescens Penard. Spherical; gelatinous envelope poorly de- veloped; chitinous needles indistinct; pseudopodia very long; 11-15/i in diameter; fresh water. Fig. 191. a, Ciliophrys infusionum, X400 (Butschli); b, Lithocolla glohosa, X250 (Penard); c, Astrodisculus radians, X600 (Penard); d, Adinolophus pedunculatus, X400 (Schultze); e, Elaeorhanis dncta, X300 (Penard); f, Sphaerastrurnfockei, X300 (Stubenrauch); g, Hetero- phrys myriopoda, x270 (Penard)'. 412 PROTOZOOLOGY Family 6 Clathrellidae Poche Genus Clathrella Penard. Envelope distinct, polygonal; surface with uniform alveoli with interalveolar portion extending out; en- velope appears to be continuous, but in reality formed by a series of cup-like bodies; contractile vacuole large; voluminous nucleus eccentric; filopodia straight, some bifurcated, arising between "cups." C. foreli P. (Fig. 192, a). Envelope about 40-55^ in diameter; fresh water. Family 7 Acanthocystidae Glaus Genus Acanthocystis Garter. Spherical; siliceous scales, arranged tangentially and radiating siliceous spines with pointed or bifur- cated ends; nucleus and endoplasm eccentric; a distinct central granule in which the axial filaments terminate. Several species. A. aculeata Hertwig and Lesser (Fig. 192, h). Tangential scales stout and pointed; spines curved and nail-headed; cytoplasm grey- ish; a single contractile vacuole; diameter 35-40/*; spines about 1/3 the body diameter; in fresh water. Genus Pompholjrxophrys Archer. Spherical; outer mucilaginous envelope with minute colorless spherical granules arranged in con- centric layers; nucleus eccentric; contractile vacuoles; pseudopodia long, straight, acicular; fresh water. P. punicea A. (Fig. 192, c). Body colorless or reddish, with usually many colored granules and green or brown food particles; nucleus large, eccentric; solitary, active; diameter 25-35/1; outer envelope 5-10/1 larger; in pools. Genus Raphidiophrys Archer. Spherical; mucilaginous envelope with spindle-shaped or discoidal spicules which extend normally outwards along pseudopodia; nucleus and endoplasm eccentric; solitary or colonial; fresh water. Several species. R. pallida Schulze (Fig. 192, d). Outer gelatinous envelope crowded with curved lenticular spicules, forming accumulations around pseudopodia; ectoplasm granulated; nucleus eccentric; con- tractile vacuoles; axial filaments arise from the central granule; solitary; diameter 50-60/i; nucleus 12-15/t in diameter; spicules 20/i long; among vegetation in still fresh water. Genus Raphidocystis Penard. Spicules of various forms, but un- like those found in the last genus. R. tuhifera P. (Fig. 192, e). Spicules tubular with enlarged extrem- ity; diameter about 18/t; envelope 25/t; fresh water. Genus Wagnerella Mereschkowsky. Spherical, supported by a ACTINOPODA, HELIOZOA 413 cylindrical stalk with an enlarged base; small siliceous spicules; nucleus in the base of stalk; multiplication by budding. Fig. 192. a, Clathrella foreli, X250 (Penard); b, Acanthocyshs aculeata, X300 (Stern); c, Pompholyxophrys punicea, X260 (West); d, Raphidio- phrys pallida, X300 (Penard); e, Raphidocystis tubifera, X500 (Penard); f, Wagnerella borealis, X75 (Kiihn); g, Pinaciophora fluviatilis, X250 (Penard). W. horealis M. (Fig. 192,/). About 180^ in diameter; stalk often up to 1.1 mm. long; salt water. 414 PROTOZOOLOGY Genus Pinaciophora Greeff. Spherical; outer envelope composed of circular discs, each being perforated with 19 minute pores; cyto- plasm reddish ; fresh water. P. fluviatilis G. (Fig. 192, g). Diameter 45-50/i, but somewhat variable; in freshwater ponds. Family 8 Clathrulinidae Glaus Genus Clathrulina Cienkowski. Envelope spherical, homogeneous, with numerous regularly arranged openings; with a stalk; proto- plasm central, not filling the capsule; nucleus central; pseudo podia numerous, straight or forked, granulated; fresh water. C. elegans C. (Fig. 193, a). Envelope colorless to brown, perforated by numerous comparatively large circular or polygonal openings; 1 or more contractile vacuoles; nucleus central; diameter 60-90/i, openings 6-10)u; length of stalk 2-4 times the diameter of envelope, 3-4)u wide; solitary or colonial; among vegetation in ponds. Genus Hedriocystis Hertwig and Lesser. Envelope spherical, openings minute, surrounded by polyhedral facets or ridges; with stalk; solitary or colonial; fresh water. H. reticulata Penard (Fig. 193, 6). Envelope colorless or pale yellow, facets regularly polygonal with raised borders; stalk solid, straight; nucleus central; 1 contractile vacuole; each pseudo- podium arises from a pore located in the center of a facet; solitary; capsule about 25;u in diameter; body about I2fj. in diameter; stalk about 70/1 by l.S/t; in marshy pools. Genus Blaster Grimm. Envelope spherical, delicate, penetrated by numerous more or less large pores; without stalk; pseudopodia many, straight filose. E. greeffi G. (Fig. 193, c). Diameter of envelope 20/1; envelope delicate, colorless; many pseudopodia; in peaty soil. Genus Choanocystis Penard. Spherical envelope with perforations which possess conical borders; openings of cones provided with funnel-like expansions, edges of which nearly touch one another; fresh water. C. lepidula P. (Fig. 193, d). Diameter 10-13/i; envelope delicate; 1 or more contractile vacuoles; pseudopodia very long. Family 9 Myriophryidae Poche Genus Myriophrys Penard. Spherical or ovoid, covered with a protoplasmic envelope containing scales (?), surrounded by numer- ous fine processes; endoplasm vesicular; a large nucleus eccentric; a ACTINOPODA, HELIOZOA 415 large contractile vacuole; long pseudopodia granulated and attenu- ated toward ends. M. paradoxa P. (Fig. 193, e). Average diameter 40^; in fresh-water swamps. Fig. 193. a, Clathrulina elegans, X250 (Leidy); b, Hedriocystis reticu- lata, X500 (Brown); c, Blaster greeffi,, X6S0 (Penard); d, Choanocystis lepidula, X690 (Penard); e, Myriophrys paradoxa, X300 (Penard). 416 PROTOZOOLOGY References Belar, K. 1922 Untersuchungen an Actinophyrs sol Ehrenberg. I, II. Arch. f. Protistenk., Vols. 46, 48. Cash, J. and G. H. Wailes 1921 The British freshwater Rhizopoda and Heliozoa. Vol. 5. Leidy, J. 1879 Freshwater Rhizopods of North America. Rep. U. S. Geol. Survey. Vol. 12. Penard, E. 1904 Les Heliozoaires d'eau douce. Geneva. ■ — - — ■ 1904 Les Sarcodines des Grands Lacs. Geneva. Valkanov, a. 1940 Die Heliozoen und Proteomyxien. Arch. f. Protistenk.. Vol. 93. Chapter 23 Order 2 Radiolaria Mtiller THE Radiolaria are pelagic in various oceans. A vast area of the ocean floor is known to be covered with the ooze made up chiefly of radiolarian skeletons. They seem to have been equally abundant during former geologic ages, since rocks composed of their skeletons occur in various geological formations. Thus this group is the second group of Protozoa important to geologists. The body is generally spherical, although radially or bilaterally symmetrical forms are also encountered. The cytoplasm is divided distinctly into two regions which are sharply delimited by a mem- branous structure known as the central capsule. This is a single or double perforated membrane of pseudochitinous or mucinoid nature. Although its thickness varies a great deal, the capsule is ordinarily very thin and only made visible after addition of reagents. Its shape varies according to the form of the organism; thus in spherical forms it is spherical, in discoidal or lenticular forms it is more or less ellips- oidal, while in a few cases it shows a number of protruding processes. The capsule is capable of extension as the organism grows and of dissolution at the time of multiplication. The cytoplasm on either side of the capsule communicates with the other side through pores which may be large and few or small and numerous. The intracap- sular portion of the body is the seat of reproduction, while the extra- capsular region is nutritive and hydrostatic in function. The intra- capsular cytoplasm is granulated, often greatly vacuolated, and is stratified either radially or concentrically. It contains one or more nuclei, pigments, oil droplets, fat globules, and crystals. The nucleus is usually of vesidular type, but its form, size, and structure, vary among different species and also at different stages of development even in one and the same species. A thin assimilative layer, or matrix, surrounds the central capsule. In Tripylea, waste material forms a brownish mass known as phaeo- dium, around the chief aperture (astropyle) of the capsule. Then there is a highly alveolated region, termed calymma, in which the alveoli are apparently filled with a mucilaginous secretion of the cy- toplasm. Brandt showed that the vertical movement of some Radio- laria is due to the formation and expulsion of a fluid which consists of water saturated with carbon dioxide. Under ordinary weather and temperature conditions, the interchange between the alveoli 417 418 PROTOZOOLOGY and the exterior is gradual and there is a balance of loss and gain of the fluid, so that the organisms float on the surface of the sea. Under rough weather conditions or at extraordinary high temperatures, the pseudopodia are withdrawn, the alveoli burst, and the organisms descend into deeper water, where the alveoli are reformed. The Radiolaria feed on microplankton such as copepods, dia- toms, and various Protozoa. The food is taken in through pseudo- podia and passed down into the deeper region of calymma where it is digested in food vacuoles. The Radiolaria can, however, live under experimental conditions without solid food if kept under light. This is ordinarily attributed to the action of the yellow corpuscles which are present in various parts of the body, although they are, as a rule, located in the calymma. In Actipylea they are found only in intracapsular cytoplasm, and in Tripylea they are absent alto- gether. They are spherical bodies, about 15/i in diameter, with a cellulose wall, 2 chromatophores, a pyrenoid, starch, and a single nucleus. They appear to multiply by fission. These bodies are con- sidered as zooxanthellae (p. 215). In the absence of organic food material, the Radiolaria live probably by utilizing the products of holophytic nutrition of these symbiotic organisms. The axopodia arise from either the extracapsular or the intra- capsular portion and radiate in spherical forms in all directions, as in Heliozoa. In Actipylea, myonemes are present in certain pseudo- podia and produce circular groups of short, rod-like bodies clustered around each of the radial spines (Fig. 195, c). They connect the pe- ripheral portion of the body with the pseudopodial covering of the spicule and possess a great contractile power, supposedly with hy- drostatic function (p. 54). The skeletal structure of Radiolaria varies considerably from sim- ple to complex and has a taxonomic value. The chemical nature of the skeleton is used in distinguishing the major subdivisions of the order. In the Actipylea it seems to be made up of strontium sul- phate, while in the three other groups, Peripylea, Monopylea, and Tripylea, it consists fundamentally of siliceous substances. The skeleton of the Actipylea is sharply marked from others in form and structure. The majority of this group possess 20 rods radiating from center. The rod-shaped skeletons emerge from the body in most cases along five circles, which are comparable to the equatorial, two tropical and two circumpolar circles of the globe, which arrangement is known as Miiller's law, since J. Miiller first noticed it in 1858. The life-cyle of the Radiolaria is very incompletely known (Fig. 194). Binary or multiple fission or budding has been seen in some RADIOLARIA 419 Peripylea, Actipylea, and Tripylea. Multiple division is also known to occur in Thalassophysidae in which it is the sole known means of reproduction. The central capsule becomes very irregular in its out- hne and the nucleus breaks up into numerous chromatin globules. Finally the capsule and the intracapsular cytoplasm become trans- FiG. 194. Diagram illustrating the life-cycle of Actipylea (Kiihn). a, mature individual; b, c, binary fission; d, e, multiplication by budding; f, mature individual similar to a; g, formation of swarmers; h-j, supposed, but not observed, union of two swarmers producing a zygote; k, 1, young individuals. formed into numerous small bodies, each containing several nuclei. Further changes are unknown. Swarmer-formation is known in some forms. In Thalassicolla, the central capsule becomes separated from the remaining part of the body and the nuclei divide into a number of small nuclei, around each of which condenses a small avoidal mass 420 PROTOZOOLOGY of cytoplasm. They soon develop flagella. In the meantime the cap- sule descends to a depth of several hundred meters, where its wall bursts and the flagellate swarmers are liberated (g). Both isoswarm- ers and anisoswarmers occur. The former often contain a crystal and a few fat globules. Of the latter, the macroswarmers possess a nucleus and refringent spherules in the cytoplasm. Some forms possess 2 flagella, one of which is coiled around the groove of the body, which makes them resemble certain dinoflagellates. Further development is unknown; it is supposed that the anisoswarmers are sexual and isoswarmers asexual generations. Enormous numbers of species of Radiolaria are known. An out- line of the classification is given below,, together with a few examples, of the genera. Skeleton composed of strontium sulphate Suborder 1 Actipylea Skeleton composed of other substances Central capsule uniformly perforated, skeleton either tangential to the capsule or radiating without reaching the intracapsular region. . Suborder 2 Peripylea (p. 421) Central capsule not uniformly perforated Capsule monaxonic, bears at one pole a perforated plate forming the base of an inward-directed cone Suborder 3 Monopylea (p. 423) Capsule with 3 openings: 1 astro pyle and 2 parapyles Suborder 4 Tripylea (p. 424) Suborder 1 Actipylea Hertwig Radial spines, 10-200, not arranged according to Miiller's law. Spines radiate from a common center, ancestral forms (Haeckel). . . . Family 1 Actineliidae Genus Actinelius (Fig. 195, a) 10-16 spines irregularly set Family 2 Acanthociasmidae Genus Acanthociasma (Fig. 195, h) Radial spines, few, arranged according to Miiller's law Without tangential skeletons Spines more or less uniform in size Spicules circular in cross-section Family 3 Acanthometridae Genus Acanthometron (Fig. 195, c) Spicules cruciform in cross-section Family 4 Acanthoniidae Genus Acanthoma (Fig. 195, d) 2 opposite spines much larger Family 5 Amphilonchidae RADIOLARIA 421 Genus Amphilonche (Fig. 195, e) With tangential skeletons 20 radial spines of equal size, shell composed of small plates, each with one pore Family 6 Sphaerocapsidae Genus Sphaerocapsa 2 or 6 larger spines 2 enormously large conical sheathed spines , , Family 7 Diploconidae Fig. 195. a, Adinelius primordialis, X25 (Haeckel); b, Acanthociasma planum, X65 (Mielck); c, Acanthometron elasticum (Hertwig); d. Acan- thoma tetracopa, X40 (Schewiakoff ) ; e, Amphilonche hydrometrica, Xl30 (Haeckel); f, Hexaconus serratus, XlOO (Haeckel). Genus Diploconus 6 large spines Family 8 Hexalaspidae Genus Hexaconus (Fig. 195, /) Suborder 2 Peripylea Hertwig Solitary, skeleton wanting or simple spicules; mostly spherical Nucleus spherical with smooth membrane Vacuoles intracapsular Family 1 Physematiidae Genus Lampoxanthium (Fig. 196, a) Vacuoles extracapsular Family 2 Thalassicollidae Genus Thalassicolla (Fig. 196, h) Nuclear membrane not smoothly contoured Nuclear wall branching out into pouches, structure similar to the last Family 3 Thalassophysidae 422 PROTOZOOLOGY Genus Thalassophysa Fig. 196 a, Lampoxanthium pandora, X20 (Haeckel); b, Thalassicolla nucleata, Xl5 (Huth). Nuclear wall crenate Huge double spicule Family 4 Thalassothamnidae Genus Thalassothamnus A latticed skeleton, with branching and thorny spines Family 5 Orosphaeridae Genus Orosphaera Solitary, skeleton complex, often concentric Central capsule and skeleton spherical Family 6 Sphaeroidae Genus Hexacontium (Fig. 197, a) Central capsule and skeleton elliptical or cylindrical Family 7 Prunoidae Fig. 197. a, Hexacontium aster acanthion, Xl30; b, Pipetta tuba, XlOO; c, Staurocyclia phacostaurus, Xl30; d, Cenolarus primordialis, XlOO; e, Sphaerozoum ovodimare, X30 (Haeckel). RADIOLARIA 423 Genus Pipetta (Fig. 197, h) Central capsule and skeleton discoidal or lenticular Family 8 Discoidae Genus Staurocyclia (Fig. 197, c) Similar to the above, but flattened Family 9 Larcoidae Genus Cenolarus (Fig. 197, d) Colonial, individuals with anastomosing extracapsular cytoplasm, em- bedded in a jelly mass Without latticed skeleton, but with siliceous spicules arranged tan- gentially to central capsule Family 10 Sphaerozoidae Genus Sphaerozoum (Fig. 197, e) Central capsule of each individual enclosed in a latticed skeleton Family 11 CoUosphaeridae Genus Collosphaera " - -. '« -^e^vii 'jm^d%'} w ©1 1 ' \ \ Fig. 198. a, Cystidium princeps, Xl20; b, Triplagia primordialis, X25; c, Lithocircus magnificus, XlOO; d, Dictyophimus hertwigi, X80 (Haeckel). Suborder 3 Monopylea Hertwig Without any skeleton Family 1 Nassoidae Genus Cystidium (Fig. 198, a) With skeleton Without a complete latticed skeleton Skeleton a basal tripod Family 2 Plectoidae Genus Triplagia (Fig. 198, h) Skeleton a simple or multiple sagittal ring. . . Family 3 Stephoidae Genus Lithocircus (Fig. 198, c) With a complete latticed skeleton Lattice skeleton single, without constriction. . . Family 4 Cyrtoidae 424 PROTOZOOLOGY Genus Dictyophimus (Fig. 198, d) Lattice skeleton multiple Family 5 Botryoidae Genus Phormobothrys Suborder 4 Triplylea Hertwig Without skeleton; with isolated spicules Skeleton consists of radial hollow rods and fine tangential needles Family 1 Aulacanthidae Genus Aulacantha (Fig. 199, a) With foreign skeletons covering body surface Family 2 Caementellidae Fig. 199. a, Aulacantha scolymantha, X30 (Kiihn); b, Caementella stapedia, X65 (Haeckel); c, Aidosphaera labradoriensis, XlO (Haecker). Genus Caementella (Fig. 199, b) With skeleton 1-2 (concentric) usually spherical skeletons Outer lattice skeleton with triangular or areolar meshes Family 3 Sagosphaeridae Genus Sagenoscene One lattice skeleton with hollow radial bars Family 4 Aulosphaeridae Genus Aulosphaera (Fig. 199, c) 2 concentric lattice skeletons connected by radial bars Family 5 Cannosphaeridae Genus Cannosphaera One skeleton, simple, but variable in shape; bilaterally symmetrical Skeleton with fine diatomaceous graining . . Family 6 Challengeridae RADIOLARIA 425 Genus ChaUengeron (Fig. 200, a) Skeleton smooth or with small spines Family 7 Medusettidae Genus Medusetta (Fig. 200, b) One skeleton; spherical or polyhedral, with an opening and with radiat- ing spines Skeleton spherical or polyhedral, with uniformly large round pores Family 8 Castanellidae Fig. 200. a, ChaUengeron mjvillei, Xl05 (Haeckel); b, Medusetta ansata, X230 (Borgert); c, Castanidiimi murrayi, X25 (Haecker); d, Circoporus octahedrus, X65 (Haeckel); e, Tuscarora murrayi, X7 (Haeckel); i,Coelo- dendrum ramosissimum, XlO (Haecker). •Genus Castanidium (Fig. 200, c) Skeleton similar to the last, but the base of each radial spine sur- rounded by pores Family 9 Circoporidae Genus Circoporus (Fig. 200, d) Skeleton flask-shaped with 1-2 groups of spines Family 10 Tuscaroridae Genus Tuscarora (Fig. 200, e) Central portion of skeleton consists of 2 valves Valves thin, each with a conical process which divides into branched tubes Family 11 Coelodendridae Genus Coelodendrum (Fig. 200, /) 426 PROTOZOOLOGY References Brandt, K. 1905 Zur Systematik der koloniebildenden Radio- larien. Zool. Jahrb. Suppl., Vol. 8. BoRGERT, A. 1905-1913 Mehrere Arbeiten ueber Familien der Tripyleen. Ergebn. d. Planktonex'pedition. Vol. 3 . Haeckel, E. 1862-1887 Die Radiolarien. Eine Monographic. I, II. 1887 Rep. on the Radiolaria collected by H.M.S. Challenger. Challenger Rep. Zool. Vol. 18. Haecker, V. 1908 Tiefseeradiolarien. Wiss. Ergebn. Deutsch. Tiefsee-Exp. a.d. Dampfer "Valdivia." Vol. 14. Hertwig, R. 1879 Der Organismus der Radiolarien. Jena. Chapter 24 Class 3 Sporozoa Leuckart THE Sporozoa are without exception parasitic and bear spores. Their hosts are distributed in every animal phylum, from Protozoa to Chordata. As a rule, they are incapable of locomo- tion, but some when immature may move about by means of pseudopodia. They possess neither cilia nor flagella, except as gametes. In the forms that are conjfined to one host, the spore is usually enveloped by a resistant membrane which would enable it to withstand unfavorable conditions while outside of the host body, but in those having two host animals, as in Plasmodium, the sporozoite is naked. The method of nutrition is saprozoic or parasitic, the food being dissolved cytoplasm, tissue fluid, body fluid, or dis- solved food material of the host. Both asexual and sexual reproductions are well known in many species. Asexual reproduction by repeated binary or multiple fission or budding of intracellular trophozoites or schizonts produces far greater number of individuals than that of protozoans belonging to other classes and often is referred to as schizogony. The sexual re- production is by isogamous or anisogamous fusion or autogamy and marks in many cases the beginning of sporogony or spore-formation. Schaudinn divided the Sporozoa into two groups, Telosporidia and Neosporidia, and this scheme has been followed by several authors. Some recent writers consider these two groups as separate classes. This, however, seems to be improper, as the basis of dis- tinction between them is entirely different from that which is used for distinguishing the other four classes: Sarcodina, Mastigophora, Ciliata, and Suctoria. For this reason, the Sporozoa are placed in a single class and divided into three subclasses as follows : Spore simple; without polar filament Spore with or without membrane; with 1-many sporozoites Subclass 1 Telosporidia Spore with membrane; with one sporozoite Subclass 2 Acnidosporidia (p. 507) Spore with polar filament Subclass 3 Cnidosporidia (p. 515) Subclass 1 Telosporidia Schaudinn The spore which contains neither a polar capsule nor a polar fila- ment possesses one to several sporozoites and is formed at the end of the trophic life of the individual. In the forms which invade two host 427 428 PROTOZOOLOGY animals to complete their development, there occur naked sporo- zoites instead of spores. The infection of a new host begins with the entrance of mature spores through mouth, or with the introduction of the sporozoites by blood-sucking invertebrates directly into the blood stream. The sporozoites enter specific host cells and there grow at the expense of the latter. In the Coccidia and the Haemosporidia, the trophozoite continues its intracellular existence, but in the Gregarinida it leaves the host cell and grows in an organ cavity. Except Eugregarinina, the vegetative form undergoes schizogony and produces a large number of daughter individuals which invade new host cells, thus spreading the infection within the host body. The trophozoites fi- nally develop into gametocytes. In the Coccidia and the Haemospo- ridia, anisogametes are, as a rule, produced. Each macrogametocyte develops into a single macrogamete and each microgametocyte, into several microgametes. Fusion of the gametes in pairs results in formation of a large number of zygotes, each of which develops either into one to many spores or into a number of naked sporozoites. In the Gregarinida, two fully mature trophozoites (or gametocytes) encyst together and the nucleus in each multiplies repeatedly to form numerous gametes, which fuse in pairs with those produced in the other individual within the common envelope. The zygotes de- velop into spores, each containing variable number of sporozoites. When these spores enter a new host, the changes outlined above are repeated. The Telosporidia are parasitic in vertebrates and higher invertebrates. Three orders are distinguished in this subclass : Mature trophozoite extracellular, large; zygote not motile; sporozoites enveloped Order 1 Gregarinida Mature trophozoite intracellular, small Zygote not motile; sporozoites enveloped. . .Order 2 Coccidia (p. 464) Zygote motile; sporozoites naked. . . .Order 3 Haemosphoridia (p. 484) Order 1 Gregarinida Lankester The gregarines are chiefly coelozoic parasites in invertebrates, especially arthropods and annelids. They obtain their nourishment from the host organ-cavity through osmosis. The vast majority of gregarines do not undergo schizogony and an increase in number is carried on solely by sporogony. In a small group, however, schizog- ony takes place and this is used as the basis for grouping these protozoans into two suborders as follows: No schizogony Suborder 1 Eugregarinina (p. 429) Schizogony occurs Suborder 2 Schizogregarinaria (p. 457) SPOROZOA, GREGARINIDA 429 Suborder 1 Eugregarinina Doflein This suborder includes the majority of the so-called gregarines which are common parasites of arthropods. When the spore gains en- trance into a suitable host, it germinates and the sporozoites emerge and enter the epithelial cells of the digestive tract. There they grow at the expense of the host cells which they leave soon and to which they become attached by various organellae of attachment (Fig, 208). These trophozoites become detached later from the host cells and move about in the lumen of the gut. This stage, sporadin, is ordi- narily most frequently recognized. It is usually large and vermiform. Fig. 201. The life-cycle of Lankesteria culicis, X about 500 (Wen- yon), a, entrance of sporozoites into the epithelial cell and growth stages of trophozoite; b, mature trophozoite; c, association of two trophozoites; d-f, gamete-formation; g, zygote-formation; h, development of spores from zygotes; i, a spore; j, germination of spore in host gut. The body is covered by a definite pellicle and its cytoplasm is clearly differentiated into the ectoplasm and endoplasm. The former con- tains myonemes (p. 54) which enable the organisms to undergo glid- ing movements. In one group, Acephalina, the body is of a single compartment, but in the other group, Cephalina, the body is divided into two com- partments by an ectoplasmic septum. The smaller anterior part is the protomerite and the larger posterior part, the deutomerite, contains a single nucleus. In Pileocephalus the nucleus is said to be located in the protomerite and according to Goodrich (1938) both the protomerite and deutomerite of Nina gracilis contain 430- PROTOZOOLOGY a nucleus. The endoplasm contains numerous spherical or ovoidal bodies which are called zooamylon or paraglycogen grains and which are apparently reserve food material (p. 99). The proto- merite may possess an attaching process with hooks or other structures at its anterior border; this is called the epimerite. The epi- merite is usually not found on detached sporadins. Goodrich ob- served recently that in Nina the protomerite is a knob-like part of the gregarine when contracted, but expands freely and used as a mobile sucker for attachment to the gut epithelium of the host Scolo- pendra. Presently multiple filiform epimerite grows at the free edge of the sucker and penetrates between the host cells. Epimerite bear- ing trophozoites are called cephalins. Many gregarines are solitary, others are often found in an endwise association of two or more sporadins. This association is called syzygy. The anterior individual is known as the primite and the pos- terior, the satellite. Sporadins usually encyst in pairs and become gametocytes. Within the cyst-membrane, the nucleus in each indi- vidual undergoes repeated division, forming a large number of small nuclei which by a process of budding transform themselves into numerous gametes. The gametes may be isogamous or anisogamous. Each of the gametes in one gametocyte appears to unite with one formed in the other, so that a large number of zygotes are produced. In some species such as Nina gracilis the microgametes enter the individual in which macrogametes develop, and the development of zygotes takes place, thus producing the so-called pseudocyst. The zygote becomes surrounded by a resistant membrane and its content develops into the sporozoites, thus developing into a spore. The spores germinate when taken into the alimentary canal of a host animal and the life-cycle is repeated. According to Wenyon, in a typical Eugregarinina, Lankesteria culicis (Fig. 201) of Aedes aegypti, the development in a new host begins when a larva of the latter ingests the spores which had been set free by infected adult mosquitoes in the water. From each spore are liberated 8 sporozoites (j), which enter the epithelial cells of the stomach and grow (a). These vegetative forms leave the host cells later and become mingled with the food material present in the stomach lumen of the host (6). When the larva pupates, the sporad- ins enter the Malpighian tubules, where they encyst (c). The re- peated nuclear division is followed by formation of large numbers of gametes (d-f) which unite in pairs (g). The zygotes thus formed develop into spores, each possessing 8 sporozoites (A). Meanwhile the host pupa emerges as an adult mosquito, and the spores which SPOROZOA, GREGARINIDA 431 become set free in the lumen of the tubules pass into the intestine, from which they are discharged into water. Larvae swallow the spores and acquire infection. Eugregarinina are divided into 2 tribes : Trophozoite not septate Tribe 1 Acephalina Trophozoite septate Tribe 2 Cephalina (p. 440) Tribe 1 Acephalina Kolliker The acephalines are mainly found in the body cavity and organs associated with it. The infection begins by the ingestion of mature spores by a host, in the digestive tract of which the sporozoites are set free and undergo development or make their way through the gut wall and reach the coelom or various organs such as seminal vesicles. Young trophozoites are intracellular, while more mature forms are either intracellular or extracellular. Spores with similar extremities Spores biconical Sporadins solitary Anterior end not differentiated Family 1 Monocystidae Anterior end conical or cylindro-conical Family 2 Rhynchocystidae (p. 433) Sporadins in syzygy Spores with thickenings at ends. .Family 3 Zygocystidae (p. 434) Spores without thickenings. .Family 4 Aikinetocystidae (p. 434) Spores not biconical Spores navicular Family 5 Stomatophoridae (p. 434) Spores round or oval No encystment Family 6 Schaudinnellidae (p. 436) 2 sporadins encyst together Family 7 Diplocystidae (p. 437) Spores with dissimilar ends Spores with epispore Family 8 Urosporidae (p. 438) Spores without epispore Family 9 Allantocystidae (p. 440) Spores unobserved; grown trophozoites with cup-like depression at posterior end for syzygy Family 10 Ganymedidae (p. 440) Family 1 Monocystidae Blitschli Trophozoites spheroidal to cylindrical; anterior end not differ- entiated; solitary; spores biconical, without any spines, with 8 spo- rozoites. Genus Monocystis Stein. Trophozoites variable in form; motile; incomplete sporulation in cyst; spore biconical, symmetrical; in coelom or seminal vesicles of oligochaetes. Numerous species. M. ventrosa Berlin (Fig. 202, a-c). Sporadins 109-183^ by 72- 135m; nucleus up to 43m by 20/x; cysts 185-223^ by 154-182/x; 432 PROTOZOOLOGY spores 17-25/x by 8-19/i; in Lumbricus ruhellus, L. castaneus and Helodrilus foetidus. M. lumbrici Henle (Fig. 202, d, e). Sporadins about 200^ by 60-70m; cysts about 162/i in diameter; in Lumbricus terrestris, L. ruhellus, and L. castaneus. Genus Apolocystis Cognetti. Trophozoites spherical; without principal axis marked by presence of any special peripheral organ; solitary; spore biconical; in seminal vesicles or coelom of various oligochaetes. Many species. A. gigantea Troisi (Fig. 202, /). In seminal vesicles of Helodrilus foetidus and Lumbricus rubellus; late October to March only; fully grown trophozoites 250-800/i in diameter; whitish to naked eyes; pellicle thickly covered by 10-15/x long 'hairs'; endoplasm packed with spherical paraglycogen grains (3/^ in diameter); nucleus 35- 43/1 in diameter; cysts 40O-800yu in diameter; spores 19/1 by 8.6/1. A. minuta Troisi (Fig. 202, g). In seminal vesicles of Lumbricus terrestris, L. castaneus and L. rubellus; mature trophozoites 40- 46/i in diameter; endoplasm yellowish brown, packed with spherical paraglycogen grains (5.3-7/x in diameter); nucleus 10/t in diameter; cysts 68-74/t by 55-65/i; spores of 3 sizes, 11/i by 5.5/i, 18.8/t by 7n and 21.6/1 by 9.8/1. Genus Nematocystis Hesse. Trophozoites elongate, cylindrical and shaped like a nematode; solitary. Many species. N. vermicularis H. (Fig. 202, h). In seminal vesicles of Lumbricus terrestris, L. rubellus, Helodrilus longus, Pheretima barbadensis; trophozoites 1 mm, by lOO/i; cylindrical, both ends with projections; nucleus oval; endoplasm alveolated, with paraglycogen grains; sporadins become paired lengthwise; cysts and spores unknown. Genus Rhabdocystis Boldt. Trophozoites elongate, gently curved; anterior end swollen, club-shaped; posterior end attenuated; spores with sharply pointed ends. One species. R. claviformis B. (Fig. 202, i, j). In seminal vesicles of Octolasium complanatum; sporadins extended, up to 300/t by 30/t; pellicle dis- tinctly longitudinally striated; zooamylon bodies 2-4/t in diameter; cysts biscuit-form, 110/t by 70/i; spores 16/i by 8/i. Genus Enterocystis Zwetkow. Early stages of trophozoites in syzygy; sporadins in association ensiform; cysts spherical without ducts; spores elongate ovoid, with 8 sporozoites; in gut of ephemerid larvae. E. ensis Z. (Fig. 202, k, I). Sporadins in syzygy 200-510/t long; cysts 200-350/£ in diameter; spores elongate ovoid; in gut of larvae of Caenis sp. SPOROZOA, GREGARINIDA 433 Family 2 Rhynchocystidae Bhatia Trophozoites ovoid, spherical or elongate, with a conical or cy- lindro-conical trunk at anterior end; solitary; spore biconical, with 8 sporozoites. Fig. 202. a-c, Monocystis ventrosa (a, X260; b, Xl50; c, XS30) (Berlin); d, e, M. lumhrici, X280 (Berlin); f. Apolocystis gigantea, X90 (Troisi); g, A. minuta, with attached phagocytes, X770 (Troisi); h, Nematocystis vermicularis, X80 (Hesse); i, j, Rhabdocystis claviformis (i, X220; j, X270) (Boldt); k, 1, Enterocystis ensis (k, Xl40) (Zwetkow). Genus Rhjmchocystis Hesse. Trophozoites ovoid or cylindrical; plastic epimerite, conical or cylindro-conical trunk; in seminal vesi- cles of oligochaetes. Many species. R. pilosa Cuenot (Fig. 203, a). In seminal vesicles of Lumbricus terrestris, L. castaneus and Helodrilus foetidus; 217/x by 25.5^; pel- licle with close, longitudinal ridges from which arise 'hairs' up to 40/i in length; endopl^asm viscous, packed with oval (Sn by 2n) 434 PROTOZOOLOGY zooamylon bodies; cysts ovoid, 95/i by 84^1; spores 13.3/i by 5^. R. porrecta Schmidt (Fig. 203, 6, c). In seminal vesicles of Lum- hricus ruhellus and Helodrilus foetidus; extremely long with an en- larged head; up to 2.5 mm. by 32-36m; sluggish; endoplasm granu- lated, filled with oval {4n by 2-3/x) paraglycogen grains; nucleus 17- 25)u in diameter; spores 27.7-28/x by 12iu; sporozoites 13-18/x by 3-5/i. Family 3 Zygocystidae Bhatia Trophozoites in association; spores biconical, with peculiar thick- enings at extremities; with 8 sporozoites; in seminal vesicles or coe- lom of oligochaetes. Genus Zygocystis Stein. Sporadins pyriform, 2-3 in syzygy; in seminal vesicles or coelom of oligochaetes. Several species. Z. wenrichi Troisi (Fig. 203, d, e). In seminal vesicles of Lumbricus ruhellus and Helodrilus foetidus; sporadins up to 1.5 mm, by 250/i in diameter; pellicle with longitudinal ridges which become free and form a 'tuft of hairs' at the posterior end; cysts 500-800/x by 300- 500//; spores 28m by 13m. Genus Pleurocystis Hesse. Trophozoites in longitudinal or lateral association; spores biconical. One species. P. cuenoti H. (Fig. 203, /). In the ciliated seminal horn of Helo- drilus longus and H. caliginosus; 2 mm. by 300m ; pellicle striated longitudinally, oblique near the posterior end; cysts 1.5-2 mm. in diameter; spores 28.5m by 12m. Family 4 Aikinetocystidae Bhatia Trophozoites solitary or in syzygy; branching dichotomously, branches with sucker-like organellae of attachment; spores biconical. Genus Aikinetocystis Gates. Trophozoites cylindrical or columnar, with a characteristic, regular dichotomous branching at attached end, with sucker-like bodies borne on ultimate branches; solitary or 2 (3-8) individuals in association; spores biconical. A. singularis G. (Fig. 203, g, h). In coelom of Eutyphoeus foveatus. E. rarus, E. peguanus and E. spinulosus (of Burma) ; trophozoites up to 4 mm. long; number of branches 8 or 16, each with an irregular sucker; ovoid nucleus near rounded end; spores of two sizes, 20-23m long and 7-8m long; a few cysts found, ovoid and about 600m long. Family 5 Stomatophoridae Bhatia Trophozoites spherical to cylindrical or cup-shaped; with a sucker- like epimerite; solitary; spores navicular, ends truncate; 8 sporo- zoites; in seminal vesicles of Pheretima (Oligochaeta) . SPOROZOA, GREGARINIDA 435 Genus Stomatophora Drzewecki. Trophozoites spherical or ovoid; anterior end with a sucker-Hke epimeritic organella with a central mucron; spores navicular. Several species. Fig. 203. a, Rhynchocystis pilosa, X200 (Hesse); b, c, R. porrecta: b, Xl70 (Hesse); c, spore, X1330 (Troisi); d, e, Zygocystis wenrichi (d, X45; e, X450) (Troisi); f, Pleurocystis cuenoti, Xl90 (Hesse); g, h, Aikinetocystis singularis (h, X320) (Gates); i-k, Stomatophora coronata (i, j, X430; k, X870) (Hesse); 1, Astrocystella lobosa, Xl20 (Cognetti); m, Craterocystis papua, X65 (Cognetti); n, Choanocystella tentaculata, X570 (Cognetti); o, Choanocystoides costaricensis, X470 (Cognetti). S. coronata (Hesse) (Fig. 203, i-k). In seminal vesicles of Phere- tima rodericensis, P. hawayana and P. barhadensis; trophozoites spherical, ovoid or elliptical, about 180/x by 130^; endoplasm with ovoid zooamylon grains; cysts ellipsoid or fusiform, 7O-80/i by 436 PROTOZOOLOGY 50-60/x; spores in 2 sizes, 1 1/x by 6m and Tju by 3/i and in chain. Genus Astrocystella Cognetti. Trophozoites sohtary; stellate with 5-9 lobes radiating from central part containing nucleus; anterior surface with a depression. One species. A. lobosa C. (Fig. 203, I). In seminal vesicles of Pheretima heau- fortii (New Guinea) ; diameter about 200^; spores fusiform. Genus Craterocystis Cognetti. Trophozoites solitary; rounded; a sucker-like depression on anterior end; myonemes well developed, running from concave to convex side. One species. C. papua C. (Fig. 203, m). In prostate and lymphatic glands of Pheretima wendessiana (New Guinea); trophozoites about 360- 390/i in diameter. Genus Choanocystella Cognetti (Choanocystis C). Trophozoites solitary; rounded or ovate; anterior end with a mobile sucker and a tentacle bearing cytoplasmic hairs; myonemes. One species. C. tentaculata C. (Fig. 203, n). In seminal vesicles of Pheretima beaufortii (New Guinea) ; trophozoites 50At by 36^. Genus Choanocystoides Cognetti. Trophozoites solitary, rounded or cup-shaped ; anterior end with a mobile sucker, bordered by cyto- plasmic filaments. One species. C. costaricensis C. (Fig. 203, o). In seminal vesicles of Pheretima heterochaeta (Costa Rica); trophozoites 40-45^ in diameter; nucleus ovoid, large, 12/i in diameter. Genus Beccaricystis Cognetti. Mature trophozoites elongate, cylindrical, with a sucker-like depression at anterior end; nucleus at its bottom. One species. B. loriai C. (Fig. 204, a). In seminal vesicles of Pheretima ser- mowaiana; trophozoites cylindrical, with wart-like growths, myo- nemes run lengthwise with radially arranged transverse fibrils ; about 100m long. Genus Albertisella Cognetti. Mature trophozoites cup-shaped, with anterior sucker with a smooth wall; nucleus at its bottom. One species. A. crater C. In seminal vesicles of Pheretima sermowaiana. Family 6 Schaudinnellidae Poche Parasitic in the digestive system of oligochaetes; spores spherical; trophozoites do not encyst; male trophozoites producing microgam- etes and female, macrogametes ; zygotes or amphionts (spores) rounded. Genus Schaudinnella Nusbaum. Trophozoites elongate spindle, free in lumen or attached to gut wall; sporadins male or female; SPOROZOA, GREGARINIDA 437 spherical macrogametes and fusiform microgametes; zygotes or amphionts encapsulated, passed out of host or enter gut epithelium, dividing to produce many sporozoites (autoinfection). S. henleae N. (Fig. 204, b, c). In gut of Henlea leptodera; mature trophozoites about 70/i by 9/x; attached trophozoite with a clear wart-like epimerite; female and male sporadins; macrogametes, Fig. 204. a, Beccaricystis loriai, X570 (Cognetti); b, c, Schaudinnella henleae (b, X885; c, XlOOO) (Nusbaum); d, e, Diplocystis schneideri (d, Xl4;e, spore, X2000) (Kunstler) ; f , Urospora chiridotae, X200 (Pix- ell-Goodrich); g-i, Gonospora minchini (g, a young trophozoite in host egg; h, a mature trophozoite, X330; i, sporadins in association, X80) (Goodrich and Pixell-Goodrich). 5-7. 5ju in diameter; microgametes, spindle-form, 1-1. 25^ long; sporozoites rounded oval, 2.5-3/x in diameter. Family 7 Diplocystidae Bhatia Coelomic or gut parasites of insects; trophozoites solitary or asso- ciated early in pairs; spores round or oval, with 8 sporozoites. Genus Diplocystis Kunstler. Trophozoites spherical to oval; asso- ciation of 2 individuals begin early in spherical form; spores round or oval, with 8 sporozoites; in coelom of insects. 438 PROTOZOOLOGY D. schneideri K. (Fig. 204, d, e). In general body cavity of Peri- planeta americana; young stages in gut epithelium; cysts up to 2 mm, in diameter; spores l-Sfx in diameter; sporozoites 16/1 long. Genus Lankesteria Mingazzini. Trophozoites more or less spatu- late; spherical cyst formed by 2 laterally associated sporadins in rotation; spores oval, with flattened ends, with 8 sporozoites; in gut of tunicates, flatworms and insects. Several species. L. culicis (Ross) (Fig. 201). In gut and Malpighian tubules of Aedes aegypti and A. albopicius; mature trophozoites about 150- 200/4 by 31-41/i; cysts spherical, in Malpighian tubules of host, about 30/z in diameter; spores lOyu by 6/x. Family 8 Urosporidae Woodcock Coelomic parasites in various invertebrates; sporadins associative; spores with unequal ends; with or without epispores of various forms, with 8 sporozoites. Genus Urospora Schneider. Large; frequently in lengthwise asso- ciation of 2 individuals of unequal sizes; spores oval, with a long filamentous process at one end; in body cavity or blood vessel of Tubifex, Nemertinea, Sipunculus, Synapta, and Chiridota. Several species. U. chiridotae (Dogiel) (Fig. 204, /). In blood vessel of Chiridota laevis (in Canada); paired trophozoites up to about 1 mm. long; with stiff 'hairs.' Genus Gonospora Schneider. Trophozoites polymorphic, oval, pyriform or vermiform; cysts spherical; spore with a funnel at one end, rounded at the other; in gut, coelom or ova of polychaetes. G. minchini Goodrich and Pixell-Goodrich (Figs. 204, g-i; 205, g). In coelom of Arenicola ecaudata; young trophozoites live in host eggs which float in the coelomic fluid; fully grown trophozoites leave eggs in which they grow up to 200/i long, and encyst together in pairs; spores without well-developed funnel, 8-10/i long. Genus Lithocystis Giard. Trophozoites large, ovoid or cylindrical; attached for a long period to host tissue; pellicle with hairlike pro- cesses; endoplasm with calcium oxalate cystals; spores ovoid, with a long process at one end; in coelom of echinids. L. brachycercus Pixell-Goodrich (Fig. 205, a, b). In coelom of Chiridota laevis (Canada); fully grown spherical trophozoites up to 200)u in diameter; spore with a short projection at one end. Genus Pterospora Racovitza and Labbe. Sporadins associative or solitary; free end drawn out into 4 bifurcated processes; cysts SPOROZOA, GREGARINIDA 439 spherical or oval; spores with epispore drawn out into 3 lateral processes; in coelom of polychaetes. P. maldaneorum R. and L. (Fig. 205, c, d). In coelom of Liocepha- lus liopygue; trophozoites about 140^ long; cysts 288yu, by 214//; epispore 24ju in diameter; endospore 10-14/x by 3-4/i. Genus Ceratospora Ldger, Sporadins elongate conical, head to Fig. 205. a, b, Lithocystis brachycercus, X1330 (Pixell-Goodrich); c, d, Pterospora maldaneorum (c, X40; d, X530) (Labb^); e, f, Ceratospora mirabilis (e, X45; f, X670) (L^ger); g, Gonospora minchini, X2000 (Goodrich); h, i, Cystobia irregularis (h, X65; i, X770) (Minchin); j-m, Allantocystis dasyhelei (j-1, X500; m, X560) (Keilin); n, Ganymedes anaspides, X570 (Huxley). head association; without encystment; spores oval with a small collar at one end and 2 divergent elongate filaments at other. One species. C. mirabilis L, (Fig. 205, e, /). Sporadins 500-600^ long; spore 12)Li by 8/i, filaments 34ju long; in general body cavity of Glycera sp. 440 PROTOZOOLOGY Genus Cystobia Mingazzini. Trophozoites, large, irregular; fully grown forms always with 2 nuclei, due to early union of 2 individ- uals; spores oval, membrane drawn out and truncate at one end; in blood vessels and coelom of Holothuria. C. irregularis (Minchin) (Fig. 205, h, i). Trophozoites irregular in form; up to 500^ long; endoplasm opaque, granulated; cysts in connective tissue of vessels; spore ovoid, epispore bottle-like, 25/i long; in blood vessel of Holothuria nigra. Family 9 Allantocystidae Bhatia Trophozoites elongate cylindrical; cysts elongate, sausage-like; spores fusiform, sides slightly dissimilar. Genus Allantocystis Keilin. Sporadins, head to head association; cysts sausage-like; in dipterous insect. One species. A. dasyhelei K. (Fig. 205, j-m). In gut of larval Dasyhelea obscura; full-grown sporadins 65-7 5ai by 20-22^; cysts 140-150/z by 20;u; spores 18/i by 6.5/i. Family 10 Ganymedidae Huxley Trophozoites only known; mature individuals biassociative; pos- terior end of primite with a cup-like depression to which the epi- meritic organella of satellite fits; cysts spherical; spores unknown. Genus Ganjonedes Huxley. Characters of the family; Huxley considers it as an intermediate form between Acephalina and Cephalina. G. anaspides H. (Fig. 205, n). In gut and liver-tube of the crus- tacean, Anaspides tasmaniae (of Tasmania); trophozoites in associa- tion. 70-300^ by 60-130^; cysts 85-115m in diameter. Tribe 2 Cephalina Delage The body of a trophozoite is divided into the protomerite and deutomerite by an ectoplasmic septum; inhabitants of the ali- mentary canal of invertebrates, especially arthropods. One host species involved None-septate; epimerite a knob Family 1 Lecudinidae (p. 441) Septate Development intracellular Sporadins associative Family 2 Cephaloidophoridae (p. 442) Sporadins solitary Family 3 Stenophoridae (p. 442) Development extracellular Sporadins associative Satellite non-septate Family 4 Didymophyidae (p. 442) Satellite septate Family 5 Gregarinidae (p. 443) SPOROZOA, GREGARINIDA 441 Sporadins solitary Epimerite simple knob-like Cysts with several ducts Family 6 Leidyanidae (p. 445) Cysts without or with one duct Family 7 Monoductidae (p. 445) Epimerite not simple knob-like Epimerite cup-shaped or digitate Epimerite cup-shaped . . . Family 8 Menosporidae (p. 448) Epimerite digitate. . . .Family 9 Dactylophoridae (p. 448) Epimerite otherwise Spore hat-shaped Family 10 Stylocephalidae (p. 450) Spore of other shapes Spore with spines. .Family 11 Acanthosporidae (p. 451) Spore without spines Family 12 Actinocephalidae (p. 452) Two host species involved Family 13 Porosporidae (p. 455) Family 1 Lecudinidae Kamm Epimerite simple, symmetrical; non-septate; spores ovoidal, thickened at one pole; solitary; in gut of polychaetes and termites. Undoubtedly intermediate forms between Acephalina and Cepha- lina. Genus Lecudina Mingazzini. Epimerite simple, knob-like; in polychaetes. L. pellucida (Kolliker) (Fig. 206, a). In Nereis cuUrifera and N. heaucourdrayi; trophozoites ellipsoid; spores 7/z by 5/i. Genus Polyrhabdina Mingazzini. Trophozoites flattened, ovoidal; epimerite with a corona of processes with split ends, deeply stain- able; in polychaetes (Spionidae). P. spionis (Kolliker) (Fig. 206, b). In Scololepis fuligionosa; 100/i by 35/i; epimerite with a corona of 8-10 processes; cysts (?). Genus Kofoidina Henry. Epimerite rudimentary; development intracellular; 2-14 sporadins in association; cysts and spores un- known. K. ovata H. In midgut of Zootermopsis angusticollis and Z. neva- densis; syzygy 153-672^ long; sporadins 41-105/i long. Genus Sycia Leger. Epimerite knobbed, bordered by a thick ring; protomerite subspherical; deutomerite conical, with navicular in- clusions; in marine annelids. S. inspinata L. (Fig. 206, c). In Audouinia lamarcki. Genus Zygosoma Labbe, Trophozoites with wart-like projections; epimerite a simple knob; spores oval; in gut of marine annelids. Z. globosum Noble (Fig. 206, d, e). Trophozoites 250-500/1 by 200-380/x; epimerite a large globule; cysts 400/i by 360^, without 442 PROTOZOOLOGY ducts; spores oval, with 4 sporozoites, 9/i by 7ju; reduction zygotic, 6 chromosomes; in gut of Urechis cawpo in California. Genus Ulivina Mingazzini. Elongate ellipsoid; epimerite simple; spores unknown; in gut of polychaetes. U. rhynchoboli (Crawley). Sporadins up to 700/i long; in Rhyncho- bolus americanus. Family 2 Cephaloidophoridae Kamm Development intracellular; early association; cysts without spo- roducts; spores ovoidal, with equatorial line; in gut of Crustacea. Genus Cephaloidophora Mawrodiadi. Sporadins biassociative, early; epimerite rudimentary; cysts without sporoducts; spores in chain, ovoidal. C. olivia (Watson) (Fig. 206,/). Biassociated sporadins up to 218^ long; individuals up to 118/i by 36/i; cysts spheroidal, 60/z in diame- ter; spores (?) ; in gut of Libinia dubia; Long Island. C. nigrofusca (Watson). Sporadins, ovoid to rectangular, up to 125/i by 75/i; cysts and spores (?); in gut of Uca pugnax and U. pugilator. Family 3 Stenophoridae Leger and Duboscq Development intracellular; sporadins solitary; with a simple epimerite or none; cysts open by rupture; spores ovoid, with or without equatorial line, not extruded in chain; in Diplopoda. Genus Stenophora Labbe. With or without simple epimerite; spores ovoid with equatorial line, not in chain. S. larvata (Leidy) (Fig. 206, g). Sporadins up to 800^ by 23^; protomerite small; in gut of Spirobolus spinigerus at Philadelphia. S. robusta Ellis (Fig. 206, h). Sporadins 140-180m by 67/^; cysts and spores both unobserved; in gut of Parajulus venustus, Orihomorpha gracilis and 0. sp.; Colorado. Genus Fonsecaia Pinto. Spores elongate ovoid; without equa- torial line; without endospore. F. polymorpha Pinto (Fig. 206, i, j). Sporadins 170/1 long; spores 18/i by Sjjl; in gut of Orihomorpha gracilis; Brazil. Family 4 Didymophyidae Leger Two to three sporadins in association; satellite without septum. Genus Didymophyes Stein. Epimerite a small pointed papilla; cysts spherical, open by rupture; spores ellipsoidal. D. gigantea S. Sporadins slender, 1 cm. by 80-100//; 2 deuto- merites; cysts spherical, 600-700/i in diameter; spores oval, 6.5/: by SPOROZOA, GREGARINIDA 443 6/z; in gut of larvae of Orydes nasicornis, 0. sp., and Phyllognathus sp. Family 5 Gregarinidae Labb6 Sporadins in association; epimerite simple, symmetrical; cysts with or without ducts; spores symmetrical. Fig. 206. a, Lecudina pellucida (Kolliker); b, Polyrhabdina spionis, X800 (Reichenow); c, Sycia inspinata (L^ger); d, e, Zygosoma glohosum (d, X60; e, X1260) (Noble); f, Cephaloidophora olivia, Xl90 (Kamm); g, Stenophora larvata, X50 (Leidy); h, S. robusta, Xl30 (Ellis); i, j, Fonsecaia polymorpha (i, X220; j, X430) (Pinto); k, Gregarina blattarum, X55 (Kudo); 1, G. locustae, X65 (Leidy); m, G. oviceps, X30 (Crawley); n, Protomagalhaesia serpentiila, X35 (Finto); o, Gamocystis tenax (Schnei- der). Genus Gregarina Dufour. Sporadins biassociative; epimerite small, globular or cylindrical; spores dolioform to cylindrical; cysts 444 PROTOZOOLOGY open by sporoducts; in gut of arthropods. Numerous species. G. hlattarum Siebold (Fig. 206, k). Sporadins in syzygy, 500-1 100m by 160-400At; cysts spherical or ovoidal; 8-10 sporoducts; spores cylindrical to dolioform, truncate at ends, 8-8. 5^ by 3.5-4/z; in gut of the cockroach. Sprague (1941) made an excellent study of this gregarine. G. locustae Lankester (Fig. 206, I). Sporadins 150-350^ long; syzygy; in Dissosteria Carolina. G. oviceps Diesing (Fig. 206, m). Sporadins up to SOO/x by 225iu; in syzygy; spherical cysts 250ai in diameter; 2-5 sporoducts up to 1 mm. long; spores dolioform. 4.5/i by 2.25^; in Gryllus ahhreviatus and G. americanus. Genus Protomagalhaesia Pinto. Sporadins cylindrical; in syzygy, protomerite of satellite draws in the posterior end of primite; cysts without ducts; spores dolioform, with spines at ends. P. serpentula (Magalhaes) (Fig. 206, n). Sporadins up to 1.2 mm. by 180/i; in gut and coelom of Blatta orientalis. Genus Gamocystis Schneider, Septate only in trophozoites; spo- radins non-septate; in syzygy; spore formation partial; with sporo- ducts; spores cylindrical. A few species. G. tenax S. (Fig. 206, o). Association head to head; spherical cysts with 15 or more ducts; spore cylindrical, with rounded ends; in gut of Blattella lapponica. Genus Hyalospora Schneider. Sporadins in syzygy; cytoplasm yellowish orange; epimerite a simple knob; cysts open by rupture; spores fusiform. H. affinis S. Trophozoites SOO/z long; cysts, yellow, 60^ in diame- ter; spores 8.7/1 by Qn; in gut of Machilis cylindrica. Genus Hirmocystis Labb6. Sporadins associative, 2-12 or more; with a small cylindrical papilla-like epimerite; cysts without ducts; spores ovoidal. H. harpali Watson (Fig. 207, a). Total length of association up to 1060/1; sporadins up to 560/i by SO/i; cysts unknown; in gut of Harpalus pennsylvanicus erythropus. H. termitis (Leidy) (Fig. 207, 6). Associtation 614-803/x long; epimerite simple sphere; cysts rare; spores (?); in Zootermopsis angusticollis, Z. nevadensis, etc. Genus Uradiophora Mercier. Sporadins in syzygy; deutomerite with small process; epimerite an elongate papilla; cysts oval without ducts; spores spherical, in chains. U. cuenoti M. 2-4 sporadins in syzygy; individuals up to 700m long; cysts ovoid, 44/t long; spores 4/i in diameter; in gut of Aiyae- phrya desmaresii. SPOROZOA, GREGARINIDA 445 Genus Pjrxinoides Tregouboff. Sporadins biassociative; epimerite with 16 longitudinal furrows, small cone at end. P. halani (Kolliker). Primite up to 130m; satellite 60/i long; in gut of Balanus amphitrite and B. eburneus. Genus Anisolobus Vincent. Sporadins in syzygy; epimerite lack- ing; protomerite of primite expanded to form sucker-like organella; cysts ellipsoid, with thick envelope; with 6-8 sporoducts; spores barrel-shaped. One species. A. dacnecola V. (Fig. 207, c). In midgut of Dacne rufifrons; 2 sporadins in syzygy 100-300/i by 20-50/x; cysts without envelope, 130-150^1 by 80-90)u; sporoducts 40-50/i long; spores in chain, dolio- form, 6^1 by 4/x. Genus Carcinoectes Ball. Sporadins in syzygy of 2 or more individ- uals; epimerite rudimentary; cysts without sporoducts; spores round to ovoidal, not in chain; in gut of Crustacea. C. hesperus B. (Fig. 207, d, e). 2-6 sporadins in association; sporad- ins up to 320/x by 9m; cysts about 140/x by 123m, attached to the wall of hindgut; spores 8.6m by 7.7m, with 8 radially arranged sporozoites; in gut of Pachygrapsus crassipes in California. Family 6 Leidyanidae Similar to the last two families; but sporadins are solitary and epimerite simple knob-like; cysts with several sporoducts. Genus Leidyana Watson. Solitary; epimerite a simple globular sessile knob; cysts with ducts; spores dolioform. L. erratica (Crawley) (Fig. 207,/). Sporadins up to 500m by 160m; cysts about 350m in diameter; membrane about 30m thick; 1-12 sporoducts; spores extruded in chains, 6m by 3m; in gut of Gryllus ahhreviatus and G. pennsylvanicus. Family 7 Monoductidae Ray and Chakravatry As in the last family solitary; but cyst with a single sporoduct or none; spore with 8 sporozoites. Genus Monoductus R. and C. Sporadins solitary; epimerite a small elevation with prongs attached to its base; anisogamy; cyst with a single sporoduct; spores flattened fusiform, with dissimilar ends, each with 8 sporozoites. One species. M. lunatus R. and C. (Fig. 207, m-o). Cephalins 225-445m by 33-4 7m; epimerite with about 16 prongs; nucleus parachute-shaped, with myonemes attached at posterior margin; sporadins develop posterior pseudopodial processes before association; cysts spherical, 225-230m in diameter, voided by host; development completed in 3-4 days outside the host body, with one duct; spores 10.25m by 4m, 446 PROTOZOOLOGY truncate at one end, attenuated at other and discharged in a single chain; in gut of Diplopoda sp. Genus Sphaerocystis Leger. Sporadins solitary; without protomer- rite; spherical. Fig. 207. a, Hirmocystis harpali, X50 (Watson); b, H. termitis, X85 (Henry); c, Anisolobus dacnecola, X270 (Vincent); d, e, Carcinoedes hesperus (d, X200; e, X780) (Ball); f, Leydiana erratica, Xl70 (Wat- son); g-i, Lepismatophila ther7nobiae {g,h, X 85 ; i, spores, X200) (Adams and Travis); j-1, Colepismatophila watsonae (j, k, X85; 1, spores, X200) (Adams and Travis); m-o, Monodudus lunatus (m, cephalin, X240; n, cyst, Xl20; o, two views of spore, X2330) (Ray and Chakravatry). S. simplex L. Sporadins 100-140)u in diameter; protomerite in young trophozoites; spherical cysts in which individuals are not associative, lOO/x in diameter; spores ovoid, 10. 5^ by 7.5/i; in gut of Cyphon pallidulus. Genus Lepismatophila Adams and Travis. Epimerite a simple knob; cysts without ducts; spores ellipsoidal, smooth, in chain. One species. SPOROZOA, GREGARINIDA 447 L. ihermobiae A. and T. (Fig. 207, g-^). Sporadins 67-390^ by 30-174m; cysts white to black, ellipsoidal to subspherical, 244-378/i by 171-262yu; spores brown, 13.6ai by 6.8^; in ventriculus of Ther- mobia domestica. Genus Colepismatophila Adams and Travis. Similar to the last genus; but larger; spores in wavy chains, hat-shaped, with 2 curved filamentous processes attached at opposite ends. One species. C. watsonae A. and T. (Fig. 207, j-l). Sporadins 92-562^ by 55- 189/i; cysts 226-464/1 by 158-336^; spores 16.5/1 by 9.7/1, processes 21/i long; in ventriculus of Thermohia domestica. Family 8 Menosporidae Leger Sporadins soHtary; epimerite a large cup, bordered with hooks, with a long neck; cysts without sporoducts; spores crescentic, smooth. Genus Menospora Leger. With the characters of the family. M. polyacantha L. (Fig. 208, a, b). Sporadins 600-700/t long; cysts 200/t in diameter; spores 15/i by 4/i; in gut of Agrion puella. Family 9 Dactylophoridae Leger Sporadins solitary; epimerite complex, digitate; cysts dehiscence by pseudocyst; spores cylindrical; in gut of chilopods. Genus Dactylophorus Balbiani. Protomerite wide, bordered by digitiform processes; spores cylindrical. D. robustus Leger (Fig. 208, c, d). Sporadins 700-800/: long; cysts spherical, 200/t in diameter; spores ll/i by 4.3/i; in gut of Cryptops hortensis. Genus Echinomera Labbe. Epimerite an eccentric cone with 8 or more digitiform processes; cysts without sporoducts; spores cylin- drical. E. magalhaesi (Pinto) ("Fig. 208, e). Sporadins up to 300/i by IO/j.; in gut of Scolopendra sp. Genus Rhopalonia Leger. Epimerite spherical, with 10 or more digitiform processes; pseudocysts; spores cylindrical. R. hispida (Schneider) (Fig. 208, /, g). Endoplasm yellowish orange; cysts 200-250/t in diameter; spores 16/x by 6.5/t; in gut of Geophiles sp. and Stigmatogaster gracilis. Genus Dendrorhynchus Keilin. Elongate; epimerite a disc, sur- rounded by numerous ramified papillae; transverse fibrils conspicu- ous; cysts elliptical; spores fusiform. D. system K. (Fig. 208, h). Sporadins 255/x by 18.5-20/t; spores 448 PROTOZOOLOGY 18-1 9m by 7fjL; in midgut of larvae of Systenus sp., a dolichopodid fly, found in decomposed sap of elm tree. Genus Trichorhynchus Schneider. Protomerite prolonged ante- riorly into a long neck, dilated at tip; pseudocyst; spores cylindrical to ellipsoidal. Fig. 208. a, b, Menospora polyacantha (L^ger); c, d, Dadylophorus robustus (c, Xl30; d, X900) (L6ger); e, Echinomera magalhaesi, Xl30 (Pinto); f, g, Rhopalonia hispida (g, X830) (L6ger); h, Dendrorhynchus system, X770 (Keilin); i, Trichorhynchus pidcher (Schneider); j, k, Nina gracilis (j, XlO) (Schneider); 1, Seticephalus elegans, X450 (Pinto); m, Acutispora macrocephala, X65 (Crawley); n, Metamera schubergi, X270 (Duke); o, p, Hentschelia thalassemae (o, X230; p, X620) (Mackin- nona,ndRa,y);q,v, Lecythionthalassemaeiq, X270;r, X930) (Mackinnon and Ray). SPOROZOA, GREGARINIDA 449 T. pulcher S. (Fig. 208, i). Cysts 303-3 16m in diameter; spores 9.7/1 by S.Sfi; in gut of Scutigera sp. Genus Nina Grebnecki {Pterocephalus Schneider). Protomerite made up of 2 long narrow horizontal lobes fused and upturned spirally at one end, peripheral portion with many teeth, from which project long filaments; spores in chain; in gut of myriapods. N. gracilis G. (Fig. 208, j, k). 1.5-5 mm. long; cyst spherical; spores ellipsoidal; in the gut of Scolopendra cingulata and S. suhspini- pes. Goodrich (1938) studied the organism recently. Genus Setic^phalus Kamm. Protomerite with closely set brush- like bristles. S. elegans (Pinto) (Fig. 208, I). Sporadins up to 75m by 35/x; cysts and spores unknown ; in gut of Scolopendra sp. Genus Acutispora Crawley. Solitary; pseudocyst; spore biconical, with a thick blunt endosporal rod at each end. One species. A. macrocephala C. (Fig. 208, m). Sporadins up to 600m long; cysts spherical, 410m in diameter; spores navicular, slightly curved, 19m by 4m; in gut of Lithohius forficatus. Genus Metamera Duke. Epimerite eccentric, bordered with many branched digitiform processes; cysts without ducts; spores biconical. M. schuhergi D. (Fig. 208, n). Sporadins 150m by 45m; spores 9m by 7m; in gut of Glossosiphonia complanata and Placobdella margi- nata. M. reynoldsi Jones. Sporadins with epimerite measure 280m by 50m; cysts spherical; dehiscence by rupture; spore biconical, 5m by 3m, with 8 sporozoites; in the stomach diverticula and intestine of Glossosiphonia complanata. Genus Hentschelia Mackinnon and Ray. Epimerite with a short neck, umbrella-like with its margin divided into 4-5 lobes, each fluted on anterior surface; 2 sporadins encyst together; gametes anisogamous; flagellate and non-flagellate; zygote gives rise to a spherical spore with 8 sporozoites. One species. H. thalassemae M. and R. (Fig. 208, o, p). Cephalins 75-98m by 30-45m ; in gut of Thalassema neptuni. Genus Lecythion Mackinnon and Ray. Epimerite a low cone, sur- rounded by 14-15 petal-shaped lobes, with a neck; cysts and spores unknown. L. thalassemae M. and R. (Fig. 208, q. r). Cephalins 135m by 52m; epimerite about 27m long; in gut of Thalassema neptuni. 450 PROTOZOOLOGY Family 10 Stylocephalidae Ellis Sporadins solitary; epimerite varied; pseudocysts; hat-shaped spores in chains. Genus Stylocephalus Ellis. Epimerite nipple-like; cysts covered with papillae; in arthropods and molluscs. Fig. 209. a, Stylocephahis giganteus, X65 (Ellis); b, Bulbocephalus elongatus, Xl5 (Watson); c, d, Cystocephalus algerianus (c, X6; d, X930) (Schneider) ; e, Lophocephalus insignis (Schneider) ; f, Acanthospora poly- morpha, X1670 (Leger); g, h, Corycella armata (h, X860) (L6ger); i, Prismatospora evansi, X50 (Ellis); j, k, Ancyrophora gracilis (k, X1250) (Leger); 1, m, Cometoides capitatus (m, X1330) (Leger); n, o, Actino- cephahis acutispora (L^ger); p. Amphoroides calverti, Xl30 (Watson); q, Asterophora philica, X65 (Leidy); r, Steinina rotunda, Xl30 (Watson); s, Pileocephalus striatus, X 180 (L6ger and Duboscq) ; t, Stylocystis praecox, XSO (L6ger). S. giganteus E. (Fig. 209, a). Sporadins L2-1.8 mm. long; cysts spherical, 450/^ in diameter; spores subspherical black, llfi by 7^; in Eleodes sp., Asida opaca, A. sp., and Eusattus sp. (Coleoptera). Genus Bulbocephalus Watson. Epimerite a dilated papilla located in middle of a long neck. SPOROZOA, GREGARINIDA 451 B. elongatus W. (Fig. 209, b). Sporadins up to 1.6 mm. by 50ai; micleus diagonal; cysts and spores unknown; in gut of Cucujus larva (a coleopteran). Genus Sphaerorhynchus Labbe. Epimerite a small sphere at end of a long neck. S. ophioides (Schneider). Cephalins 1.3 mm. long; epimerite 220m long; terminal part 8.5^; sporadins 3-4 mm. long; in gut of Ads sp. Genus Cystocephalus Schneider. Epimerite a large lance-shaped papilla with a short neck; spore hat-shaped. C. algerianus S. (Fig. 209, c, d). Sporadins 3-4 mm. long; spores 10-10.5m long; in gut of Pimelia sp. Genus Lophocephalus Labbe. Epimerite sessile crateriform disc with crenulate periphery, surrounded by digitiform processes. L. insignis (Schneider) (Fig. 209, e). Sporadins 1 mm. long; cysts rounded; 430^ by 330^; pseudocysts; spores 10m long; in gut of Helops striatus. Family 11 Acanthosporidae Leger Sporadins solitary; epimerite complex; cysts without sporoducts; spores with equatorial and polar spines. Genus Acanthospora Leger. Epimerite simple conical knob; spores with spines. A. polymorpha L. (Fig. 209, /). Sporadins polymorphic; up to 1 mm. long; protomerite cylindro-conical ; deutomerite ovoidal; endo- plasm yellowish brown; cyst 500-700m in diameter; spore with 6 spines at each pole and at equatorial plane, 8m by 4.4m; in gut of Hydrous cerahoides. Genus Corycella Leger. Epimerite globular, with 8 hooks; spores biconical, with one row of polar spines. C. armata L. (Fig. 209, g, h). Sporadins 280-300m long; cysts spherical, 250m in diameter; spores 13m by 6.5m; in gut of larva of Gyrinus natator. Genus Prismatospora Ellis. Epimerite subglobular with 8 lateral hooks; spores hexagonal, with one row of spines at each pole. P. evansi E. CFig. 209, i). Sporadins broadly conical, 400m long; cysts 370m in diameter; without sporoducts; spores with 6 long spines at each pole, 11m by 5.8m; in gut of Tramea lacerta and Sym- petrum ruhicundulum; Michigan. Genus Ancyrophora L^ger. Epimerite globular with 5-10 digiti- form processes directed posteriorly; spores biconical, with spines. A. gracilis L. (Fig. 209, j, k). Sporadins 200m-2 mm. long; cysts spherical, 200m in diameter; spores hexagonal in optical section, 452 PROTOZOOLOGY with 4 polar and 6 equatorial spines, 8.5^ by 5n; in gut of larvae and adults of Carahus auratus, C. violaceus, C. sp., and of larvae of Silpha thoracica (Coleoptera), Genus Cometoides Labb6. Epimerite globular with 6-15 long filaments; spores with polar spines and 2 rows of equatorial spines. C. capitatus (L^ger) (Fig. 209, I, m). Sporadins up to 2 mm. long, active; epimerite with 12-15 filaments, 32-35/i long; cysts 300/x in diameter; spores 5,1^ by 2.5^^; in gut of larvae of Hydrous sp. (Coleop- tera). Family 12 Actinocephalidae L^ger Sporadins solitary; epimerite variously formed; cysts without sporoducts; spores irregular, biconical or cylindro-biconical; in gut of insects. Genus Actinocephalus Stein. Epimerite sessile or with a short neck, with 8-10 simple digitiform processes at its apex; spores bi- conical. A. acutispora Leger (Fig. 209, n, o). Sporadins 1-1.5 mm. long; cysts ovoid, 550-600^ by 280/i; spores, acutely pointed, of 2 sizes, 4.5^4 by 2.8iu and 6.4/i by S.Qfj.; in gut of the coleopteran Silpha laevigata. A. parvus Wellmer. Sporadins 180/x by 50fx; cysts rounded, 62- 112)U in diameter; spores spindle-form, 6-7.5ju by 3-3. 8^; 8 diploid chromosomes; the first division in the zygote is meiotic; in the gut of larvae of dog-flea, Ctenocephalus canis. Genus Amphoroides Labbe. Epimerite a globular sessile papilla; protomerite cup-shaped; spores curved; in myriapods. A. calverti (Crawley) (Fig. 209, p). Sporadins up to 1670m by 120^; cysts spherical, 380/i in diameter; spores unknown; in gut of Callipus lactarius. Genus Asterophora Leger. Epimerite a thick horizontal disc with a milled border and a stout style projecting from center; spore cylin- drobiconical; in Neuroptera and Coleoptera. A. philica (Leidy) (Fig. 209, g). Sporadins 300^-2 mm. long; cysts and spores unknown; in gut of Nyctohates pennsylvanica. Genus Steinina Leger and Duboscq. Solitary; epimerite a short motile digitiform process, changing into a flattened structure; spore biconical ; in Coleoptera. S. rotunda Watson (Fig. 209, r). Sporadins 180-250/i long; in gut of Amara augustaia (Coleoptera). Genus Pileocephalus Schneider. Epimerite lance-shaped, with a short neck. SPOROZOA, GREGARINIDA 453 P. striatus Leger and Duboscq (Fig. 209, s). Sporadins 150^ long; nucleus in protomerite; cysts spherical; in gut of larvae of Ptychop- tera contaminata. Genus Stylocystis Leger. Epimerite a sharply pointed, curved process; spores biconical. S. praecox L. (Fig. 209, t). Sporadins up to SOOyulong; cysts ovoidal, 200ju long; spores Sju by 5^ in gut of larval Tanypus sp. Fig. 210. a, b, Discorhynchus truncatus (a, Xl30) (L^ger); c, d, An- thorhynchus sophiae (c, Xl5; d, X1330) (Schneider); e-g, Sciadiophora phalangii (g, spore, X1040) (L^ger); h, Aniphorocephalus amphorellus (Ellis); i, Pyxinia bulbifera (Watson); j, Schneideria miicronata, X75 (L^ger); k, Beloides firmus (L6ger); 1, Taeniocystis niira, X85 (L^ger); m, n, Stictospora provincialis (L6ger); o, Bothriopsis histrio (L^ger); p-r, Coleorhynchus heros (p, X 14) (Schneider) ; s, Legeria agilis (Schnei- der); t-v, Phialoides ornata (t, X45; v, X930) (L^ger); w, Geneiorhynchus aeschnae, X60 (Crawley). Genus Discorhynchus Labbe. Epimerite a large spheroidal papilla with collar and short neck; spores biconical, slightly curved. D. truncatus (Leger) (Fig. 210, a, b). Sporadins 300^ long; cysts spherical, 140;u in diameter; in gut of larvae of Sericostoma sp. 454 PROTOZOOLOGY Genus Anthorh3aichus Labbe. Epimerite a large flattened fluted disc; spores biconical, chained laterally. A. sophiae (Schneider) (Fig. 210, c,d). Cephalins up to 2 mm. long, with 200/x long epimerite; protomerite 150^ long; endoplasm opaque; spores 7ju by 5/i ; in gut of Phalangium opilio. Genus Sciadiophora Labbe. Epimerite a large sessile disc with crenulate border; protomerite with numerous vertical laminations; spores biconical. S. phalangii (Leger) (Fig. 210, e-g). Sporadins 2-2.5 mm. long; protomerite with 15-16 plates; cysts 500/x in diameter; spores 9/x by 5yu; in gut of Phalangium crassum and P. cornutum (Arachnida). Genus Amphorocephalus Ellis. Epimerite a sessile peripherally fluted disc set upon a short neck; protomerite constricted super- ficially; spores unknown. A. amphorellus E. (Fig. 210, h). Sporadins 500-970^ long; in gut of Scolopendra heros. Genus Pyxinia Hammerschmidt. Epimerite flat crenulate cra- teriform disc; with a style in center; spores biconical. P. bulbifera Watson (Fig. 210, i). Sporadins up to 850/i long; in gut of Dermestes lardarius. Genus Schneideria Leger. Epimerite sessile, a thick horizontal disc with milled border; a style arising from center; sporadins with- out protomerite; spores biconical. S. mucronata L. (Fig. 210, j). Sporadins 700-800^ long; agile; polymorphic; cysts 270m by 190^; spores fusiform, 15m by 9)u; in intestinal caeca of larvae of Bihio marci. Genus Beloides Labbe. Epimerite bordered by pointed lateral processes and apical style; spores biconical. B. firmus (Leger) (Fig. 210, k). Style SO/x long; cysts 180-200^ in diameter; spores 14.5)U by Qfx; in gut of larvae of Dermestes lar- darius. Genus Taeniocystis Leger. Epimerite sessile or with a short neck; 8-10 digitiform processes at its apex; deutomerite divided by septa into many chambers; spores biconical. T. mira L. (Fig. 210, I). Sporadins tapeworm-hke; 400-500^ long; epimerite with 6-8 curved hooks; cysts spherical, 130m in diameter; spores 7)u by 3m; in gut of larval Ceratopogon solstitialis. Genus Stictospora Leger. Epimerite with a short neck, a spher- ical crateriform ball with 12 posteriorly-directed laminations set close to neck; cysts with a gelatinous envelope; without ducts; spores biconical, slightly curved. SPOROZOA, GREGARINIDA 455 S. provincialis L. (Fig. 210, m, n). Sporadins 1-2 mm. long; cysts 800m in diameter; in gut of larvae of Melolontha sp. and Rhizotrogus sp. Genus Bothriopsis Schneider. Epimerite sessile, small, oval, with 6 or more filamentous processes directed upward; spores biconical; cysts spherical. B. histrio S. (Fig. 210, o). Epimerite with 6 filaments, 80-90m long; cysts 400-500^ long; spores 7.2/i by 5m; in gut of Hydaticus sp. Genus Coleorhjmchus Labbe. Epimerite discoid, lower border over deutomerite; spores biconical. C. heros (Schneider) (Fig. 210, p-r). Sporadins 2-3 mm. long; in gut of Nepa cinerea. Genus Legeria Labb6. Protomerite wider than deutomerite; epimerite unknown; cysts without duct; spores cylindro-biconical. L. agilis (Schneider) (Fig. 210, s). In gut of the larvae of Colym- betes sp. Genus Phialoides Labbe. Epimerite a cushion set peripherally with stout teeth, surrounded by a wider collar; with a long neck; cysts spherical, without ducts; spores biconical. P. ornata (Leger) (Fig. 210, t-v). Sporadins 500/x long; cysts 300-400m in diameter; spores 10.5/i by 6.7m; in gut of larvae of Hydrophilus piceus. Genus Geneiorh3nichus Schneider. Epimerite a tuft of short bristles at end of neck; spores cylindrical. G. aeschnae Crawley (Fig. 210, w). Sporadins 420m long; cysts and spores unknown; in Aeschna constricta. Family 13 Porosporidae Leger When naked or well-protected sporozoites enter the stomach and midgut of a specific crustacean host, they develop into typi- cal cephaline gregarines; 1, 2, or more sporadins become associat- ed and encyst. Repeated nuclear and cytoplasmic division re- sults in formation of an enormous number of gymnospores in hind- gut. Some observers consider this change as schizogony, and hence include the family in the suborder Schizogregarinaria. When the gymnospores are voided in the faeces of crustaceans and come in contact with moUuscan host, they enter, or are taken in by phago- cytosis of, the epithelial cells of the gills, mantle or digestive system. These gymnospores are especially found in abundance in the lacunae of the gills. Presently they become paired and fuse (Hatt) ; 456 PROTOZOOLOGY the zygotes develop into naked or encapsulated sporozoites within the phagocytes of the molluscan host, which when taken in by a crustacean host, develop into cephaline gregarines. Genus Porospora Schneider. Sporozoites formed in molluscan phagocytes without any protective envelope (Hatt). Fig. 211. a-f, Porospora gigantea (Hatt). a, a cephalin attached to Homarus gut, X1250; b, gymnospores; c, d, developing sporozoites in mollusc; e, sporozoites enveloped by phagocyte; f, a sporozoite, X2250. g-n, Nematopsis legeri (Hatt). g, h, trophozoites in Eriphia; i, associated trophozoites attached to gut-epithelium, X1250; j, gym- nospores; k, gymnospores after entering molluscan body; 1, a young sporo- zoite, X2250; m, cyst in mollusc with six spores; n, germination of a spore in Eriphia gut, X1250. SPOROZOA, GREGARINIDA 457 P. gigantea (van Beneden) (Fig. 211, a-f). Sporadins in Ho- marus gammarus, up to 10 mm. long; cysts 3-4 mm. in diameter; gymnospores spherical, 8/x in diameter (Hatt), containing some 1500 merozoites; in molluscan hosts, Mytilus minimus and Tro- chocochlea mutahilis, they develop into naked sporozoites (17/i long) which are usually grouped within phagocytes. Genus Nematopsis Schneider. Development similar to that of Porospora (Hatt) ; but each sporozoite in a double envelope. N. legeri (de Beauchamp) {Porospora galloprovincialis Leger and Duboscq; N. ostrearum Prytherch) (Fig. 211, g-n). Hatt (1931) carried on a very careful study of its development. Sporadins in a crustacean, Eriphia spiniffons, in linear or bifurcated syzygy 75-750/x long; cysts about 80/x in diameter; gymnospores 7m in diameter, composed of fewer, but larger merozoites; permanent spores with a distinct one-piece shell (endospore) and a less con- spicuous epispore, about 14-15)U long and circular in cross-section, develop in numerous species of molluscan hosts: Mytilus gallo- provincialis, M. minimus, Lasea rubra, Cardita calyculata, Chiton caprearum, Trochocochlea turbinata, T. articulata, T. mutabilis, Phorcus richardi, Gibbula divaricata, G. rarilineata, G. adamsoni, Pisania maculosa, Cerithium rupestre, Columbella rustica, and Conus mediterraneus in European waters. The author found in Oslrea virginica and other molluscs in North Carolina, Virginia, and Maryland, this gregarine and was the first to demonstrate on this continent the germination of the spores taken from the infected oysters in the stomach and midgut of Panopeus herbsti and Eurypanopeus depressus at the Bureau of Fisheries Biological Laboratory at Beaufort, N. C, in July, 1936. The vermiform sporozoites emerge from the spores in the pyloric chamber of the stomach and more abundantly in the mid- gut of the mud crabs as early as thirty minutes after introduction of the infected tissues of the oyster into their mouths. In the brack- ish water of the middle Chesapeake Bay region of Maryland, the oyster and other molluscs are only slightly infected. The presence of the characteristic spores in oyster tissues is easily demonstrated by addition of 10 per cent sodium hydroxide solution to the mate- rial on slides. Suborder 2 Schizogregarinaria Leger The schizogregarines are intestinal parasites of arthropods, an- nelids, and tunicates. When the spore gains entrance to the di- 458 PROTOZOOLOGY gestive tract of a specific host through mouth, it germinates and the sporozoites are set free (Fig. 212). These sporozoites develop into trophozoites either in the gut-lumen or within the host cells, and undergo schizogony (c), which may be binary or multiple fis- sion or budding. The fully grown trophozoites become paired as in Eugregarinina and encyst, in which condition they undergo sexual reproduction. Each individual which is now a gametocyte Fig. 212. The life-cycle of Schizocystis gregarinoides, XlOOO (L^ger). a, germinating spore; b, growth of schizonts; c, schizogony; d, two gametocytes and their association; e, stages in gamete formation, f, zygote formation, g, cyst containing zygotes, each of which develops into a spore shown in a. produces gametes (d-e). Fusion of two gametes follows (/). The zygote develops into a spore containing 1-8 sporozoites (g, a). One spore from 2 gametocytes Family 1 Ophryocystidae (p. 459) Two or more spores from 2 gametocytes Family 2 Schizocystidae (p. 460) SPOROZOA. GREGARINIDA 459 Family 1 Ophryocystidae L^ger and Duboscq Two gametocytes produce one spore; in Malpighian tubules of Coleoptera, gut of Aseidia and coelom of Oligochaeta. Genus Ophryocystis Schneider. Schizogony by binary or mul- tiple division; extracellular; schizonts conical, attached to host cells by pseudopods; a single spore in a pair of spheroidal gameto- cytes; spore with 8 sporozoites; in Malpighian tubules of Coleop- tera. Several species, 0. mesnili Leger (Fig. 213, a-e). In Tenebrio molitor; schizonts 1-4 nuclei; gametocytes 11/x in diameter; pairs 16-17)u by ll/x; spores biconical, 1 1)U by T/x, Fig. 213. a-e, Ophryocystis mesnili (a, trophozoite attached to Mal- pighian tubule; b-e, sporogony), X1330 (L^ger); f, g, Merogregarina amaroucii, XlOOO (Porter); h, i, Spirocystis nidiila (h, X770; i, X500) (L6ger and Duboscq); j, k, Caulleryella pipientis (j, gut of Culex pipiens with trophozoites, X 200 ; k, a spore, X1200) (Buschkiel). Genus Merogregarina Porter. Schizogony intracellular; tropho- zoites attached to gut epithelium by a proboscidiform organel- la; resembles somewhat Selenidium, but 2 gametocytes giving rise to one spore containing 8 sporozoites. M. amaroucii P. (Fig. 213, /, g). In gut of the ascidian, Ama- roucium sp.; extracellular; trophozoites with epimerite, 27-3lAt long; spore about 14/i long. Genus Spirocystis Leger and Duboscq. Schizogony intracellular; schizonts curved, one end highly narrowed; mature schizonts 460 PROTOZOOLOGY snail-like, with numerous nuclei; repeated schizogony (?); gametes in chloragogen cells, somatic and visceral peritonium; association of 2 gametes produces a spore. One species. S. nidula L. and D. (Fig. 213, h, i). In coelom and gut epithelium of Lumbricus variegatus; multinucleate schizont about 35)U long; microgametes fusiform or ovoid, 7/i by B^i; macrogametes ovoid or spherical, 11/x in diameter; fusion of 2 gametes produces one spore which is thick-walled, 35^1 long and contains one sporozoite, up to 40m long. Family 2 Schizocystidae Leger and Duboscq Two or more spores are produced in a pair of gametocytes. Genus Schizocystis Leger. Mature trophozoite multinucleate; ovoid or cylindrical with differentiated anterior end; schizogony by multiple division; trophozoites become associated, encyst, and produce numerous (up to 30) spores, each with 8 sporozoites; in Diptera, Annelida, and Sipunculoida. S. gregarinoides L. (Fig. 212). In gut of larvae of Ceratopogon solstitialis; mature schizonts up to 400iU by IS/x; curved or spirally coiled; gametocytes 30-50^ long; cysts ovoid, 16-32^ long; spores biconical, 8/x by 4/u. Genus Syncystis Schneider. Schizogony and sporogony extra- cellular; young trophozoites elongate, amoeboid; mature schizonts more or less spheroidal, producing some 150 merozoites; cysts spherical, producing about 150 spores. One species. S. mirabilis S. (Fig. 214, k, I). In coelomic fluid and fat bodies of Nepa cinerea; merozoites, 7m long; cysts spherical; spores navicu- lar, 3-4 spines at ends, 10m by 6m, with 8 sporozoites. Genus Mattesia Naville. Schizogony in the adipose tissue cell; 2 spores produced by a pair of gametocytes. One species. M. dispora N. (Fig. 214, m). In adipose tissue cells of larvae of the flour moth, Ephestia kuhniella and Plodia interpunctella (pupa and adult also); schizonts 2.5-12m long; cyst 8-12m in diameter, with 2 spores, each with 8 sporozoites; spores 14m by 7.5m (Na- ville); Um by 6m (maximum 13.5m by 8m) (Musgrave and Mackin- non). Highly pathogenic according to Musgrave and Mackinnon. Genus Caulleryella Keilin. Schizogony extracellular; each game- tocyte gives rise to 8 gametes, a pair forming 8 zygotes or spores; spore with 8 sporozoites; in gut of dipterous larvae. Several species. C. pipientis Buschkiel (Fig. 213, j, k). Average trophozoites SPOROZOA, GREGARINIDA 461 50-60^ by 23-26m; with paraglycogen grains; schizogony produces 30-38 merozoites; in gut of larvae of Culex pipiens. Genus Lipotropha Keilin. Schizogony and sporogony intracel- lular; cyst contains 16 spores, each with 8 sporozoites; in fat body of Systenus larvae. One species. L. macrospora K. (Fig. 214, n). Spores about 13.5/x by 3ju. Fig. 214. a-c, Selenidium potainillae (a, X420; b, cyst with spores, X330; c, spore) (Mackinnon and Ray); d-f, Meroselenidium keilini (d, sporadin, X670; e, f, different views of spore, X930) (Mackinnon and Ray); g-j, Machadoella triatomae (g, a schizont, X1420; h, i, a single and associated sporadins, X710; j, spore, X1920) (Reichenow); k, 1, Syncystis ynirabilis: k, a cyst, X470 (Steopoe); 1, spore (Schneider); m, Mattesia dispora, X1480 (Naville); n, Lipotropha macrospora, X800 (Keilin). Genus Selenidium Giard. Schizogony intracellular; many spores produced by a pair of extracellular gametocytes; spore with 4 or more sporozoites; in gut of annelids. S. potamillae Mackinnon and Ray (Fig. 214, a-c). Trophozoites euglenoid, average size 40ai by 15/i; longitudinal striae; cysts ob- long, producing many spores; spore, spherical with 4 (up to 10) sporozoites; in gut of the polychaete, Poiamilla reniformis. 462 PROTOZOOLOGY Genus Meroselenidium Mackinnon and Ray. Schizogony intra- cellular, initiated by formation of small masses which give rise to merozoites; about 20 spores from a pair of gametocytes; spores with numerous sporozoites. One species. M. keilini M. and R. (Fig. 214, d-f). Large schizonts about 150m by 30/x; sporadins free in gut 200-300m by 40-70/i; paired gameto- cytes 85/1 by 40m; spores 26-28m by 14- 16m, bivalve (?), trans- verse ridges, with many sporozoites; in gut of Potomilla reniformis. Genus Machadoella Reichenow. Nematode-like, rigid; simple rounded anterior end; thick pellicle, longitudinally striated; schi- zogony in vermiform stage; head to head association of gameto- cytes; cysts with 3-6 spores, each with 8 sporozoites. M. triatomae R. (Fig. 214, g-j). Schizonts about 55m long; game- tocytes 100-120m long; schizogony into 6-8 merozoites; cysts with 3-6 spores; spore 10-1 1m by 7-7. 5m; in Malpighian tubules of Triatoma dimidiata (of Guatemala) . References DoFLEiN, F. and E. Reichenow 1929 Lehrbuch der Proiozoen- kunde. 5th edition. Jena. Labbe, a. 1899 Sporozoa. In Das Tierreich. Part 5. Naville, a. 1931 Les Sporozoaires. Mem. d'hist. nat. de Geneve, Vol. 41. Wenyon, C. M. 1926 Protozoology. Vols. 1, 2. Bhatia, B. L. 1930 Synopsis of the genera and classification of haplocyte gregarines. Parasitology. Vol. 22. Goodrich, H. P. 1938 Nina: a remarkable gregarine. Quart. Jour. Micr. Sci. (N.S.), Vol. 81. Hatt, p. 1931 L'evolution des Porosporides chez les mollusques. Arch. zool. exp., Vol. 72. Hesse, E. 1909 Contribution a I'etude des Monocystidees des Oligochetes, Ibjd., Vol. 3. Jones, A. W. 1943 Metamera reynoldsi n. sp., a cephaline gregarine from the leech, Glossosiphonia complanata. Trans. Amer. Micr. Soc, Vol. 62. Kamm, Ninnie Watson 1922 Studies on gregarines. II. Illinois Biol. Monogr., Vol. 7. 1922 A list of the new gregarines described from 1911 to 1920. Trans. Amer. Micr. Soc, Vol. 41. Leger, L. 1907, 1909 Les schizogregarines des tracheates. I, II. Arch. f. Protistenk., Vols. 8, 18. and 0. DuBOSCQ 1915 Etude sur Spirocystis nidula L. et D., schizogregarine du Lumbricus variegatus Miill. Ibid., Vol. 35. Noble, E. R. 1938 The life-cycle of Zygosoma glohosum sp. nov., a gregarine parasite of Urechis caupo. Univ. Calif. Publ. Zool., Vol. 43. SPOROZOA, GREGARINIDA 463 Sprague, V. 1941 Studies on Gregarina hlattarum with particular reference to the chromosome cycle. Illinois Biol. Monogr., Vol. 18. Troisi, R. a. 1933 Studies on the acephaline gregarines of some oligochaete annelids. Trans. Amer. Micr. Soc, Vol. 52. Watson, Minnie 1916 Studies on Gregarines. I. Illinois Biol. Mongr., Vol. 2. Weschenfelder, R. 1938 Die Entwicklung von Actinocephalus parvus Wellmer. Arch. f. Protistenk., Vol. 91. Chapter 25 Order 2 Coccidia Leuckart THE Coccidia show a wide zoological distribution, attacking all vertebrates and higher invertebrates alike. The majority are parasites of the epithelium of the digestive tract and its asso- ciated glands. Asexual reproduction is by schizogony and sexual reproduction by anisogamy in the majority of species. Both kinds of reproduction take place in one and the same host body, with the exception of such forms as Aggregata in which alternation of generations and of hosts occurs. Gametocytes similar; independent; a microgametocyte developing into many microgametes Suborder 1 Eimeridea Gametocytes dissimilar; association begins during the late trophic life; a few microgametes Suborder 2 Adeleidea (p. 477) Suborder 1 Eimeridia L^ger These coccidians are, as a rule, intracellular parasites of the gut epithelium. Both asexual (schizogonic) and sexual (sporogonic) generations occur in one host, although in some there is also alter- nation of hosts. The life-cycle of Eimeria schuhergi, a gut parasite of the centipede, Lithobius forficatus, as observed by Schaudinn, is as follows (Fig. 215). The infection begins when the mature oocysts of the coccidian gain entrance into the host through the mouth. The sporozoites escape from the spores and make their way through the micropyle of the oocyst into the gut lumen (p). By active movement they reach and enter the epithelial cells (a). These schizonts grow into large rounded bodies and their nuclei multiply in number. The newly formed nuclei move to the body surface, and each becomes surrounded by a small mass of cyto- plasm, forming a merozoite. When the host cells rupture, the mero- zoites are set free in the gut lumen, make their way into new host cells and repeat the development (6). Instead of growing into schizonts, some merozoites transform themselves into macro- or micro-gametocytes (c). Each macrogametocyte contains refrac- tile bodies, and becomes a mature macrogamete, after extruding a part of its nuclear material {d, e). In the microgametocyte, the nucleus divides several times and each division-product assumes a compact appearance (f-h). The biflagellate comma-shaped mi- crogametes thus produced, show activity when freed from the host cells (i). A microgamete and a macrogamete unite to form a zygote which secretes a membrane around itself (j). This stage is known as the oocyst. The nucleus divides twice and produces four 464 COCCIDIA 465 nuclei {k-m). Each of the four nuclei becomes the center of a spo- roblast which secretes a membrane and transforms itself into a spore (r?). Its nucleus, in the meantime, undergoes a division, and Fig. 215. The life-cycle of Eimeria schubergi, X400 (Schaudinn). a, entrance of a sporozoite in the gut epithelial cell of host and growth of schizont; b, schizogony; c, macro- and micro-gametocyte; d, e, for- mation of macrogamete; f-h, formation of microgametes; i, mature gametes prior to fusion, j, k, fertilization; 1-n, spore-formation; o, oocyst containing four mature spores, each with two sporozoites; p, germination of spores in host's gut. two sporozoites develop in the spore (o). Oocysts leave the host in the faecal matter and become the source of infection. Body vermiform; schizogony in motile stage Family 1 Selenococcidiidae (p. 466) Body not vermiform Alternation of generations and of hosts . . Family 2 Aggregatidae (p. 466) Only one host Gametocytes become associated early; many microgametes Family 3 Dobelliidae (p. 469) Gametocytes independent Family 4 Eimeriidae (p. 470) 466 PROTOZOOLOGY Family 1 Selenococcidiidae Poche Vermiform body and gametic differentiation place this family on the borderline between the Coccidia and Gregarinida. Genus Selenococcidium Leger and Duboscq. Nucleus of vermi- form trophozoite divides 3 times, producing 8 nuclei; trophozoite becomes rounded after entering gut-epithelium and divides into 8 schizonts; this is apparently repeated; schizonts develop into gametocytes; microgametocyte produces numerous microgametes; gametic union and sporogony (?). One species. Fig. 216. Selenococciduim intermedium, X550 (L^ger and Duboscq). a, schizont in host gut; b, c, schizogony; d, microgametocyte; e, micro- gametes; f, macrogametocyte; g, macrogamete; h, zygote (oocyst). S. intermedium L. and D. (Fig. 216). Octonucleate vermiform schizont 60-IOOm long, and divides into vermicular merozoites in gut cells; parasitic in gut lumen of European lobster. Family 2 Aggregatidae Labbe Anisogamy results in production of zygotes which become trans- formed into many spores, each with 2-30 sporozoites; in schizogony cytomeres first appear and then merozoites; alternation of genera- tions and of hosts which are marine annelids, molluscs and crus- taceans. Genus Aggregata Frenzel. Schizogony in a crustacean and sporo- gony in a cephalopod; zygote produces many spores, each with 3 sporozoites. Many species. A. eherthi (Labbe) (Fig. 217). Schizogony in Portunus depura- tor and sporogony in Sepia officinalis. Spores (a) germinate in the crab gut, each liberating 3 sporozoites (6) which grow and produce merozoites (lO/x by 2^) by schizogony in peri-intestinal connec- tive tissue cells (6 chromosomes) (c-/) ; when host crab is eaten by COCCIDIA 467 a cuttlefish, merozoites penetrate gut wall and develop into mi- cro- and macro-gametocytes (h, k), and further into gametes (j-l); anisogamy (m) produces zygotes; zygote nucleus contains 12 chromosomes which become divided into 2 groups of 6 in the first Fig. 217. The life-cycle of Aggregata eberthi (Dobell). a, a mature spore; b, germination of spore; c-f, schizogony; g, a merozoite, swal- lowed by Sepia; h-j, development of microgametes; k-1, development of macrogamete; m, fertilization; n, o, first zygotic division, chromosomes reduced in number from 12 to 6; p, q, development of sporoblasts, each of which develops into a spore with three sporozoites. division (n, o); repeated nuclear division (p) forms many sporo- blasts (q), each transforms itself into a spherical spore wdth 3 sporo- zoites (Dobell; Naville; Belaf). 468 PROTOZOOLOGY Genus Merocystis Dakin. Spoiogony in the kidney of the whelk, Buccinum; schizogon}- unknown, in another host (possibh- a crab); microgametocj^tes produce first cytomeres which in turn form microgametes ; anisogamy gives rise to zygotes, zygote forms many sporoblasts, each developing into a spore; spore spherical, with 2 sporozoites. One species. M. kathae D. (Fig. 218, a, h). In the kidney of Buccinum un- datum; spores spherical, about 14/i in diameter. Patten (1935) studied its life cycle and found that during microgametogenesis and sporogony, 6 chromovsomes occur. She added that meiosis occurs in the zygote which is the only diploid stage as in Aggregata eberthi. Genus Pseudoklossia Leger and Duboscq. Anisogamy and spo- rogony in the kidney of marine mussels; oocyst or zygote produces numerous spores; spore with 2 sporozoites; no residual body; schi- zogony unknown, in another host. P. pectinis L. and D. (Fig. 218, c). In kidney of Pecten maximus in France; association of 2 sporozoites which are 3.5m in diameter. Genus Caryotropha Siedlecki. Both schizogony and sporogony take place in a host. One species. C. mesnili S. In coelom (in floating bundles of spermatogonia) of the polychaete, Polymnia nebulosa; schizogony in bundle of sper- matogonia, in which cytomeres with 10-16 nuclei and then mero- zoites are formed; schizogony repeated; gametocytes undergo de- velopment also in the same host cells; microgametes become set free in coelom, where union with macrogametes takes place; each oocyst forms about 16 spores; spore with usually 12 sporozoites; cysts are extruded with the reproductive cells of the host worm. Genus Myriospora Lermantoff. Anisogamy and sporogony in marine snails; schizogony unknown; oocyst forms numerous spores each with 2 sporozoites. One species. M. trophoniae L. In the polychaete, Trophonia plufnosa; macro- gametes, vermiform, up to 800/x long, later ovoid; microgameto- cyte forms first about 100 cytomeres, each with some 20 nuclei; microgametes comma-shaped; anisogamy; ooc3^st with several hun- dred spores, each with about 24 sporozoites. Genus Hyaloklossia Labbe. Schizogony unknown; sporogony in the kidne.v of marine mussels; oocyst in the organ-cavity; spherical spores of 2 kinds: smaller one with 2 spirally coiled sporozoites and the other with 4-6 sporozoites. One species. H. pelsenecri Leger. Spherical oocysts 75-80/^ in diameter; spores 8m and 11-12^ in diameter; in kidney of Tellina sp. and Donax sp. COCCIDIA 469 Genus Angeiocystis Brasil. Schizogori}' unknown; sporogony in polychaetes; oocyst forms 4 spores; spore oval, with about 30 sporozoites and residual body at a pole. One species. .4. audouiniae B. In the cardiac bod}- of Audouinia tenlaculata; macro gametes vermiform, up to 65/u long. Fig. 218. a, b, Merocystis kathae, XlOOO (Foulon); c, Pseudoklossia ])ectinis, two sporozoites of a spore, X1470 (Leger and Duboscq); d-k, Eimeria stiedae: d, a trophozoite; e, host cell with three trophozoites; f, g, schizogony; h, macrogametocyte, X1270 (Hartmann); i-k, oocysts, XS30 (Wasilewski); 1, m. E. perforans, X750 (Perard); n, E. faurei, X800 (Wenyon). Family 3 Dobelliidae Ikeda Numerous microgametes develop from each microgametocyte; the union of gametocytes begins early. Genus Dobellia Ikeda. Schizonts sexually differentiated : micro- sc.hizonts and macroschizonts; young schizonts binucleate; associa- tion of 2 gametocytes begins early as in Adeleidea (p. 477), but many microgametes are formed in each microgametocyte. One species. 7). linuclcata I. In the gul of Pcialostoma mtnuium; mature oocyst 20-25/i in diameter, with a thin wall, contains some 100 sporozoites without any spore membrane around them. 470 PROTOZOOLOGY Family 4 Eimeriidae Leger Macro- and micro-gametocytes develop independently; micro- gametocyte produces many gametes; an oocyst from a pair of anisogametes ; oocyst with variable number of spores containing 1-many sporozoites, which condition is used as basis of generic differentiation. Oocysts found in the faeces of hosts are usually im- mature; time needed for completion of spore formation depends upon the species, temperature, moisture, etc. Becker (1934) recom- mends the following bactericidal solutions in which oocysts may develop to maturity: 1% formaldehyde, 1% chromic acid or 2-4% potassium dichromate. Genus Eimeria Schneider (Coccidium Leuckart). Zygote or oocyst develops 4 spores, each with 2 sporozoites. Numerous species. A check list of known species has been prepared bj^ Hardcastle (1943). E. schuhergi (Schaudinn) (Fig. 215). In the gut of Lithohius forfi- catus; oocysts spherical, 22-25iu in diameter. E. stiedae (Lindemann) {Coccidium oviforme Leuckart) (Fig. 218, d-k). In the epithelium cf the bile-duct and liver (with white nodules) of rabbits; heavy infection is believed to be the cause of death of young animals, which may occur in an epidemic form; schi- zonts ovoid or spherical, 15-18/^i in diameter; merozoite S-lOju long; oocysts ovoid to ellipsoid, often yellowish, micropjdar end flattened; mature oocysts 28-40^ by 16-25m; sporulation in 60-70 hours. E. perforans (Leuckart) (Fig. 218, I, m). In the gut of rabbits; pathogenic to host; oocysts with equally rounded ends, 24-30iu by 14-20ju; sporulation in 30-48 hours. E. zurni (Rivolta). In the gut of cattle; said to be the cause of diarrhoea; oocysts spherical to ellipsoidal, 12-28/Lt by 10-20ju; sporu- lation in 48-72 hours. E. sniithi Yakimoff and Galouzo. In the gut of cattle; oocysts 25- 32/i by 20-29m; sporulation in 3-5 da3\s in shallow dishes, and 2 weeks in deep dishes (Becker). E. ellipsoidalis Becker and Frye. In the faeces of healthy calf; oocysts ellipsoidal, 20-26/i by 13-17iu; sporulation in 18 days. E. cylindrica Wilson. In the faeces of cattle; oocysts cylindrical, 19-27iLi by 12-15/i; sporulation in 2-10 days. E. faurei Moussu and Morotel (Fig. 218, n). In the gut of sheep and goat; oocysts ovoid, 20-40/i by 17-26^; sporulation in 24-48 hours. Christensen (1938) recognized 7 species of Eimeria in the faeces of 96 of 100 North American sheep. E. arloingi Marotel. In the gut of sheep and goat; oocysts with a cap, ovoid, 25-35/x by 18-25/i; sporulation in 3 days. COCCIDIA 471 E. intricala Spiegel. In gut of sheep and goat; oocysts with thick wall, with or without cap, ellipsoidal, 42-60)u by 30-36^; sporula- tion in about 9 days. E. debliecki Douwes (Fig. 219, a). In the gut of pigs; 30-82 per cent infection in California (Henry); oocysts 12-29ju by 12-20^; sporula- tion in 7-9 days. Fig. 219. a, Eimeria debliecki, X1070 (Wenyon); b, E. canis, X650 (Wenyon); c, E. falciformis, X730 (Wenyon); d, E. tenella, X600 (Tyzzer); e, E. mitis, X430 (Tyzzer); f, E. acervulina, X430 (Tyzzer); g, E. maxima, X470 (Tyzzer); h, E. ranarum, X670 (Laveran and Mesnil); i, E. prevoti, X670 (Laveran and Mesnil); j, E. ranae, X670 (Dobell); k, E. sardinae, X600 (Thomson and Robertson); 1, E. clupe- arutn, X600 (Thomson and Robertson); m, n, Jarrina paludosa, X800 (L6ger and Hesse); o, p, Wenyonella africana, X1330 (Hoare); q, r, Isospora hominis, X1400 (Dobell); s, /. higemina, X930 (Wenyon); t, /. rivolta, X930 (Wenyon). E. scahra Henry. In the caecal contents of pigs; oocysts, brown, el- lipsoidal, 22-36/x by 16-26m. Henry (1931) recognized 2 other .species in California swine. 472 PROTOZOOLOGY E. caviae Sheather. In the gut of guinea pigs; oocysts subspherical to ellipsoid, 13-26m by 13-22m. E. canis Wenj^on (Fig. 219, h). In the gut of dogs; oocj^sts, ellip- soidal, 18-45ju by 11-28^; spores 9.5^ by 2.5^; sporulation in 24 hours. E.felina Nieschulz. In the gut of cat; oocysts 21-26m b}^ 13-17/x. E. falciformis (Eimer) (Fig. 219, c). In the gut of mice; oocysts spherical to ovoid, 16-21^ by ll-17)u; sporulation in 3 days. E. nieschulzi Dieben. In the small intestine of rat; oocj^sts 16- 26.4iu by 13-21/x; sporulation in 65-72 hours. E. separata Becker and Hall. In the caecum and colon of rat; oocysts 13-19. 5/x by 11-17/x; sporulation in 27-36 hours. E. miyairii Ohira. In the small intestine of rat; oocysts 16.5-29^ by 16-26m; sporulation in 96-120 hours. E. tcnella (Railliet and Lucet) (Fig. 219, d). In the caecum, colon and lower small intestine tf chicken; cause of acute coccidiosis (Tyz- zer); in caecal contents of California quail (Henry); schizogony in caecum; oocysts 19.5-26/i b}^ 16.5-23iu; sporulation in 48 hours; heavily infected caecum highly haemorrhagic. E. mitis Tj^zzer (Fig. 219, e). In anterior region of small intestine of chicken; oocysts subspherical, 16.2/i by 15.5^; sporulation in 48 hours. E. acervulina T. (Fig. 219, /). In anterior region of small intes- tine of chicken; also in California quail (Henry); oocysts oval, 17.7-20.2^ by 13. 7-16. 3m; sporulation in 20 hours; associated with serious chronic coccidiosis (Tyzzer). E. maxima T. (Fig. 219, g). In the mid-gut of chicken; ooc3'sts oval, 21.5-42.5m by 16.5-29.8m. E. necatrix Johnson. In the small intestine (schizonts) and caecum (oocysts) of chicken; a cause of chronic coccidiosis; oocysts obo- vate, 13-23m by 11-18m; sporulation in 48 hours. E. praecox J. In the vipper third of small intestine of chicken; oocysts ovoid, 20-25m by 15.5-20m; sporulation in 48 hours. E. meleagridis Tj^zzer. In the caecum of turkey; apparenth' ncn- pathogenic; oocysts, ellipsoidal, 19-30m by 14.5-23m. E. meleagrimitis T. In the lower small intestine in turkey; some- what similar to E. mitis; oocysts, 16.5-20.5m bj^ 13. 2-17. 2m. E. truncata (Railliet and Lucet). In the kidney of geese; oocysts truncate at one pole, ovoid, 14-23m by 13-18m; some observers find that this coccidian is fatal to young geese. E. anseris Kotlan. In the gut of geese; ooc3'sts spherical or pyri- form, 11-16m in diameter. COCCIDIA 473 E. labbeana Pinto. In the gut of domef^tir ])igeon; oocysts some- times light brown, 15-26ju by 14-24^. E. dispersa Tyzzer. In the small intestine of bob-white quail and pheasant; oocysts ovate, 18.8-22.8/x (quail), smaller in pheasant, without polar inclusion; sporulation in about 24 hours. E. ranarum (Labbe) (Fig. 219, /?). In the gut epithelium (nuclei) of frogs; oocysts about 17)u b}^ 12^. E. prevoti (Laveran and Mesnil) (Fig. 219, /). In the gut epithelium of frogs; oocysts about IT/x by 12/x; when sporozoites are fully formed, the spore membranes dissolve. E. ranae Dobell (Fig. 219, j). In gut of frogs; oocysts 22jix bj'^ ISfx. E. sardinae (Thelohan) (E. oxyspora Dobell) (Fig. 219, k). In the testis of sardine; oocysts spherical 30-50^. E. dupearum (Thelohan) {E. wenyoni Dobell) (Fig. 219, I). In the hver of herrings, mackerels, and sprats; oocysts, spherical, 18- 33)U in diameter. E. gadi Fiebiger. In the s\vhn-l)ladder cf (kulus I'irens, G. morrhua, and 0. aeglefinus; schizogony and sporogony; germination of spores takes place in the bladder of the same host individual, bringing about a very heavy infection; ooc3^sts 26-28^; pathogenic (Fiebiger). Genus Jarfina Leger and Hesse. Oocysts ovoid, one end rounded and the other drawn out into a shoit neck; 4 spores, each with 2 sporozoites. /. paludom L. and H. (P ig. 219, m, n). In the gut cf Fulica atra and Gallinula chloropus; ooc3'sts 15/i by llfx; sporulation in 15 days. Genus Wenyonella Hoare. Oocj'sts with 4 spores, each with 4 sporozoites. Three species. W. africana H. (Fig. 219, o, p). In the small intestine cf Boaedon lineatus ("brown snake") in Uganda; oocysts ovoid or subspherical, 18.5-19.2/x by 16-17.6^; spores ovoid, 9.6/i by 8m; sporulation in 5-6 days. Genus Isospora Schneider. Oocyst produces 2 spores, each con- taining 4 sporozoites. 7. hominis (Rivolta) (Figs. 219, q, r; 220). This is the sole coccidian parasite of man known up to the present time. Its life cycle is un- known, but most probably the schizogony, gametogenesis and sexual fusion occur in the intestinal epithelium. Oocysts have only been seen in the stools of infected persons. The oocyst is asymmetrically' fusiform; 20-33^ by 10-16^; wall is made up of two membranes which are highly resistant to chemicals; when voided in faeces, the contents either fill up the oocyst or appear as a spherical mass, composed of refractile granules of various sizes; 474 PROTOZOOLOGY nucleus appears as a clear circular area; when the faecal specimen is kept in a covered container at the room temperature, the proto- plasmic mass divides into 2 spherical sporo blasts in about 24 hours (Fig. 220, 3) each sporoblast develops in another 24 hours into a spore (10-16m by T-lO/z) containing 4 sporozoites (4). Further changes take place when the oocyst finds its way into the human in- testine in contaminated food or water. /. hominis has been observed in widely separated regions, but appears not to be of common occurrence. Magath (1935) reviewed the reported cases up to 1935. As to its effect on the human host, very little is known. Connal (1922) described the course of an acci- dental oral infection by viable mature oocysts, as follows: The Fig. 220. Isospora hominis, X1150 (Kudo). 1, a young oocyst; 2, an oocyst in which the protoplasmic mass has contracted; 3, an oocyst with 2 sporoblasts, one of which shows the division of content; 4, a mature oocyst with 2 tetrazoic spores. incubation period was about six daA-s, the onset sudden, and the duration over a month. The cure was spontaneous. The symptoms were diarrhoea, abdominal discomfort, flatulence, lassitude, and loss of weight. During the first three weeks of the illness no oocysts were found, but then oocysts appeared in the stools for nine days. On the 10th day they were not seen, but reappeared on the 11th and 12th days, after which the}' were not found again. The acute signs of ill- ness abated within one week of the finding of the oocysts. The faeces contained a large amount of undigested material, particularly fat which gave it a thick oily consistency, showing signs of slow gaseous formation. 7. hominis is to be considered as pathogenic to man (coccidiosis) ; but although it gives rise to illness in some cases, the coccidian causes no serious disturbances in most instances. /. higemina (Stiles) (Fig. 219, .s). In the gut of cat and dog; oocysts 10-14m by 7-9fi. COCCIDIA 475 /. rivolta (Grassi) (Fig. 219, t). In the gut of cat and dogs; oocysts 20-25m by 15-20^. I. felis Wenyon (Fig. 221, a). In cat and dog; oocysts 39-48^ by 26-37m. I. suis Biester. In swine faeces; oocysts siibspherical, about 22.5/i by 19.4^t; sporulation in 4 days. I. lacazei Labbe. In small intestine of passerine birds (sparrows, blackbirds, finches, etc.); oocysts subspherical, 18.5-30^ by 18- 29.2)u; heavily infected sparrow shows definite symptoms; sporula- tion in 4-5 days. /. lieberkuhni (Labbe) (Fig. 221, h). Oocyst about 40m long; in the kidney of frogs. Genus Cyclospora Schneider. Development similar to that of Eimeria; oocyst with 2 spores, each with 2 sporozoites and covM'ed by a bi-valve shell. C. caryolyfica Schaudinn (Fig. 221, c). In the gut of mole; sporo- zoites enter and develop in the nuclei of gut epithelial cells; oocyst oval, about 15m by 11.5^l. Genus Dorisiella Ray. Zygote develops (without becoming oocyst) into 2 spores, each with 8 sporozoites; macrogametocytes migratory. D. scolelepidis R. (Fig. 221, ci). In the gut of Scolelepis fuUginosa; zygote contents divide into 2 oval spores, 12-16m by 6-10^; spore with 8 sporozoites. Genus Caryospora Leger. Oocyst develops into a single spore with 8 sporozoites and a residual mass; membrane thick and yellow. One species. C. simplex L. (Fig. 221, e,f). In the gut-epithelium of Vipera aspis; < cyst thick-walled, 10-15^ in diameter. Genus Cryptosporidium Tyzzer. Lumen-dwelling minute organ- ms; oocyst with 4 sporozoites. C. muris T. (Fig. 221, g, i). In the peptic glands of the mouse; both schizogony and sporogony in the mucoid material on surface of the epithelium; oocysts 7m by 5m; 4 sporozoites, 12-14m long. C. parvum T. In the glands of small intestine of the mouse; oocysts with 4 sporozoites, 4.5m in diameter. Genus Pfeififerinella Wasielewski. Macrogamete with a "recep- tion tubule" by which microgamete enters; oocyst produces directly 8 sporozoites. P. ellipsoides W. (Fig. 221, j). In the liver of Planorhis corneus; oocysts oval, 13-15m long. P. impudica Leger and Hollande (Fig. 221, k). In the liver of Limax marginafiis; oocysts ovoid, 20m by 10m. 476 PROTOZOOLOGY Genus Lankesterella Labbe. Oocyst produces 32 or more sporo- zoites directly without spore-formation; in endothelial cells of cold- Ijlooded vertebrates; mature sporozoites enter erythrocytes in which they are transmitted to a new host individual by bloodsucking in- vertebrates. L. minima (Chaussat) (Fig. 221, /). In frogs; transmitted by the leech (Placobdella marginata); frog acquires infection through introduction of sporozoites by a leech; sporozoites make their way Fig. 221. a, Isospora felis, X930 (Wenyon); b, /. lieberkuhni, X660 (Laveran and Mesnil); c, Cyclosporn caryolytica, X1330 (Schaudinn); d, Dorisiella scolelepidis, oocyst with two spores, X1400 (Ray); e, f, Caryospora simplex, X800 (Leger); g-i, Cryptosporidium maris (g, h, oocysts; i, emergence of four sporozoites), XlOBO (Tyzzer); j, Pfeif- ferinella ellipsoides, X1330 (Wasielewski) ; k, P. impudica, X800 (Leger and Hollande); 1, Lankesterella minima, a mature cyst in endothelial cell, XlOOO (Xoller); m, Barrouxia ornata, X1330 (Schneider); n. Echinospora labbei, XlOOO (L^ger). into the blood capillaries of various organs; there they enter endo- thelial cells; schizogony produces numerous merozoites which bring about infection of many host cells; finally macro- and micro-gameto- C3^tes are formed; anisogamy produces zygotes which transform into oocysts, in which a number of sporozoites develop; these sporozoites COCCIDIA 477 are set free upon disintegration of cyst wall in the blood plasma and enter erythrocytes (Xoller) ; oocyst oval, about 33^1 by 23^. Genus Schellackia Reichenow. Oocyst spherical with 8 sporo- zoites, without spore membrane; in gut of lizards. S. holivari R. In mid-gut of Acanthodadylus vulgaris and Psam- modromus hispanicus; development similar to Eimeria schubergi (Fig. 215); oocysts, spherical, 15-19/i in diameter, with 8 sporozoites. Genus Barrouxia Schneider. Oocyst wdth numerous spores, each with a single sporozoite; spore membrane uni- or bi-valve, w^th or without caudal prolongation. B. ornata S. (Fig, 221, m). In gut of Nepa cinerea; oocysts spheri- cal, 34-37m in diameter, with many spores; spore with one sporozoite and bivalve shell, 17-20m by 7-10m. Genus Echinospora Leger. Oocyst with 4-8 spores, each with a sporozoite; endospore with many small spinous projections. E. lahbei L. (Fig. 221, n). In the gut of Lithohius mutabilis; oocyst spherical, 30-40)u in diameter; spores, 11/x by 9.4^:, with bi-valve shell; sporulation completed in about 20 days. Suborder 2 Adeleidea Leger The Adeleidea are on the whole similar to Eimeridea in their habitat and development, but the micro- and macro-gametocytes become attached to each other in pairs during the course of develop- ment into gametes (Fig. 222), and each microgametocyte produces a few microgametes. The zygote becomes oocyst which produces numerous sporoblasts, each of which develops into a spore with 2 or 4 sporozoites. In epithelium of gut and its appended glands of chiefly invertebrates. . . Family 1 Adeleidae In cells of circulatory system of vertebrates Family 2 Haemogregarinidae (p. 480) Family 1 Adeleidae Leger Genus Adelea Schneider. Zygote develops into a thinly walled oocyst with numerous flattened spores, each with 2 sporozoites; in arthropods. A. ovata S. (Fig. 222). In the gut of Lithohius for ficatus; merozoites 17-22/i long; spores 11-14/z in diameter by 6^ thick; sporozoites 20m by 4m. Genus Adelina Hesse. Oocyst thick-walled; spores spherical, com- paratively small in number; in the gut or coelom of arthropods and oligochaetes. 478 PROTOZOOLOGY Fig. 222. The life-cycle of Adelea ovafa, X600 (Schellack and Reiche- now). a, schizont entering the gut epithelium of the host centipede; b-d, schizogony; e, larger form of merozoite; f, microgametocyte (left) and macrogametocyte (right); g, association of gametocytes; h, i, fertilization; j, zygote; k, nuclear division in zygote; 1, mature oocyst with many spores. A. dimidiata (Schneider) (Fig. 223, a). In the gut of Scolopendra cingulata and other myriapods; oocysts with 3-17 spores. A. octospora H. (Fig. 223, b). Spherical oocyst contains spores; in the coelom of Slavina appendiculata. COCCIDIA 479 A. deronis Hauschka and Pennypacker. In peritoneum of Dero limosa; oocyst contains 12 ( 10-14) spores; meiosis at the first zygotic nuclear division; haploid chromosome number 10; the life cycle is completed in 18 days at room temperature (Hauschka, 1943). Genus Klossia Schneider. Oocyst with numerous spherical spores, each with 3-10 sporozoites. Several species. K. helicina S. In the kidneys of various land-snails, belonging to genera Helix, Succinea, and Vitrina; ooc3^st with a double envelope 120-180/i in diameter; spores 12/i in diameter, with 5-6 sporozoites. Fig. 223. a, Adelina dimidiata, spore, XlOOO (Schellack); b, A. odo- spora, oocyst, XlOOO (Hesse); c, Orcheobius herpobdellae, X550 (Kunze); d, e, Klossiella muris (d, renal cell of host with 14 sporoblasts; e, spore), X280 (Smith and Johnson); f, Legerella hydropori, oocyst, XlOOO (Vincent); g, h, Haemogregarina of frog, X1400 (Kudo); i-m, H. simondi, in the blood of the sole, Solea vulgaris, X1300 (Laveran and Mesnil); n, Hepatozoon muris, spore, X420 (Miller); o, Karyolysus lacertarum, X700 (Reichenow). Genus Orcheobius Schuberg and Kunze. Macrogametes vermi- form; oocyst with 25-30 spores, each with 4 (or 6) sporozoites. 0. herpobdellae S. and K. (Fig. 223, c). In the testis of Herpobdella atomaria; mature macrogametes 180;^ by 30//; microgametes 50/i by 12^; schizogony in April and May; sporogony in June and July. 480 PROTOZOOLOGY Genus Klossiella Smith and Johnson. Microgametocyte produces 2 microgametes; oocyst with many spores, each with numerous sporozoites; in the kidney of mammals. K. muris S. and J. (Fig. 223, d, e). Oocyst with 12-16 spores; spore with about 25 sporozoites, discharged in the host's urine; in the kidney of mouse. K. cobayae Seidelin. Oocyst with 8-20 spores; spore with about 30 sporozoites; in the kidney of guinea pig. Genus Legerella Mesnil. Oocyst contains numerous sporozoites; spores entirely lacking; in arthropods. L. hydropori Vincent (Fig. 223,/). In the epithelium of Malpighian tubules of Hydroporus palustris; oocysts ovoid, 20-25/x long, with 16 sporozoites which measure IT^t by 3/i. Genus Chagasella Machado. Oocyst with 3 spores, each with 4 or 6 (or more) sporozoites; in hemipterous insects. C. hartmanni (Chagas). In the gut of Dysdercus ruficollis; oocysts with 3 spores about 45/i in diameter; spore with 4 sporozoites, about 35m by 15m. Family 2 Haemogregarinidae Leger With 2 hosts: vertebrates (circulatory system) and invertebrates (digestive system) . Genus Haemogregarina Danilewsky. Schizogony takes place in blood cells of vertebrates; merozoites develop into gametocytes; when taken into gut of leech or other blood-sucking invertebrates, sexual reproduction takes place; microgametocyte develops 2 or 4 microgametes; sporozoites formed without production of spores. H. stepanowi D. (Fig. 224). Schizogony in Emys orbicularis and sexual reproduction in Placobdella catenigera; sporozoites introduced into blood of the chelonian host by leech (a), and enter erythrocytes in which they grow (d-g) ; schizogony in bone-marrow, each schizont producing 12-24 merozoites (h); schizogony repeated (i); some merozoites produce only 6 merozoites (j, k) which become gameto- cytes (l-o); gametogony occurs in leech; 4 microgametes formed from each microgametocyte and become associated with macro- gametocytes in gut of leech (p-r) ; zygote (s) divides three times, and develops into 8 sporozoites (t-w). Haemogregarines are found commonly in various frogs (Fig. 223, g, h) and less commonly in fishes (Fig. 223, i-m). Genus Hepatozoon Miller, Schizogony in the cells of liver, spleen, and other organs of vertebrates; merozoites enter erythrocytes or leucocytes and develop into gametocytes; in blood-sucking arthro- COCCIDIA 481 Fig. 224. The life-cycle of Haemogregarina stepanowi, X1200 (Reich- enow), a, sporozoite; b-i, schizogony; j-k, gametocyte-formation, 1, m, microganietocytes; n, o, macrogametocytes; p, q, association of gameto- cytes; r, fertilization; s-w, division of the zygote nucleus to form eight sporozoites. 482 PROTOZOOLOGY pods (ticks, mites), micro- and macro-gametes develop and unite in pairs; zygotes become oocysts which increase in size and produce sporoblasts, spores, and sporozoites. H. muris (Balfour) (Fig. 223, n). In various species of rat; several specific names were proposed on the basis of difference in host, locality, and effect on the host, but they are so indistinctly defined that specific separation appears to be impossible. Schizogony in the liver of rat; young gametocytes invade mononuclear leucocytes and appear as haemogregarines ; when blood is taken in by the mite, Laelaps echidninus, union of 2 gametes produces vermicular body which penetrates gut-epithelium and reaches peri-intestinal tissues and grows; becoming surrounded by a cyst-membrane, cyst content breaks up into a number of sporoblasts and then into spores, each of which contains a number of sporozoites; when a rat devours infected mites, it becomes infected. Genus Karyolysus Labbe. Sporoblasts formed in the oocysts in gut- epithelium of a mite, vermiform sporokinetes, enter host ova and become mature; when young mites hatch, spores in gut-epithelium are cast off and discharged in faeces; a lizard swallows spores; liber- ated sporozoites enter endothelial cells in which schizogony takes place; merozoites enter erythrocytes as gametocytes which when taken in by .a mite complete development in its gut. K. lacertarum (Danilewsk}^) (Fig. 223, o). In Lacerta muralis; sexual reproduction in Liponyssus saurarum; sporokinetes 40-50/z long; spores 20-25^ in diameter. References Becker, E. R. 1934 Coccidia and coccidiosis. Ames, Iowa. BouGHTON, Ruth B. and J. Volk 1938 Avian hosts of the genus Isospora (Coccidiida). Ohio. Jour. Sci., Vol. 38. Christensen, J. F. 1938 Species differentiation in the coccidia from the domestic sheep. Jour. Parasit., Vol. 24. CoNNAL, A. 1922 Observations on the pathogenicity of Isospora hominis, Rivolta^ emend. Dobell, based on a second case of hu- man coccidiosis in Nigeria, with remarks on the significance of the Charcot-Leyden crystals in the faeces. Trans. Roy. Soc. Trop. Med. Hyg., Vol. 16. Dobell, C. 1925 The life-history and chromosome cycle of Aggre- gata eherthi. Parasitology, Vol. 17. Hardcastle, a. B. 1943 A check list and host index of the species of the protozoan genus Eimeria. Proc. Helm. Soc. Washington, Vol. 10. Hauschka, T. S. 1943 Life history and chromosome cycle of the coccidian Adelina deronis. Jour. Morph., Vol. 73. COCCIDIA 483 Henry, Dora P. 1931 Species of Coccidia in chickens and quail in California. Uni. Cal. Publ. Zool., Vol. 36. Levine, H. D. and E. R. Becker 1933 A catalog and host index of the species of the coccidian genus Eimeria. Iowa State Coll. Jour. Sci., Vol. 8. Miller, W. W. 1908 Hepatozoon perniciosum. U. S. Publ. Health Service, Hyg. Lab. Bull, No. 46. Patten, R. 1935 The life history of Merocystis kathae in the whelk, Buccinum undatum. Parasitology, Vol. 27. ScHAUDiNN, F. 1900 Untersuchujigen liber den Generationswechsel bei Coccidien. Zool. Jahrb. Abt. Morph., Vol. 13. Tyzzer, E. E. 1929 Coccidiosis in gallinaceous birds. Amer. Jour. Hyg., Vol. 10. Wenyon, C. M. 1926 Protozoology. Vol. 2. London. Chapter 26 Order 3 Haemosporidia Danilewsky THE development of the Haemosporidia is, on the whole, similar to that of the Coccidia in that they undergo asexual reproduction or schizogony, and also sexual reproduction or sporozoite-formation; but the former takes place in the blood of vertebrates and the latter in the alimentary canal of some blood-sucking invertebrates. Thus one sees that the Haemosporidia remain always within the body of one of the two hosts; hence, the sporozoites do not possess any pro- tective envelope. The Haemosporidia are minute intracorpuscular parasites of ver- tebrates. The malarial parasites of man are typical members of this order. The development of Plasmodium vivax is briefly as follows (Fig. 225). An infected female anopheline moscjuito introduces sporo- zoites into human blood when it feeds on it through skin {1). The sporozoites are fusiform and 6-15m long. They are capable of slight vibratory and gliding movement when seen under the microscope after removal from mosquitoes. After about 7-10 days the organisms are found in erythrocytes {2, 3) and are called schizonts. At the be- ginning the schizonts are small rings. They grow and finally divide into 12-24 or more merozoites (4, 5) which are presently set free in the blood plasma {6). This schizogony requires 48 hours. The freed merozoites will, if not ingested by leucocytes, enter and repeat schizogony in the erythrocytes. After repeated and simultaneous schizogony in geometric progression, large numbers of infected eryth- rocytes will be destroyed at intervals of 48 hours, setting free ever- increasing amounts of toxic substances into the blood. This is the cause of the regular occurrence of a characteristic paroxysm on every third day. In the mean while, .some of the merozoites develop into gameto- cytes instead of undergoing schizogony (7-10). When fully formed they are differentiated into macro- and micro-gametocytes, but re- main as such while in the human blood. When a female anopheline mosquito takes in the blood containing gametocytes, the microgame- tocyte develops into 4-8 microgametes (10, 11), and the macroga- metocyte into a macrogamete (5, 12) in its stomach. An ookinete (zygote) is formed when a microgamete fuses with a macrogamete {12, 13). The ookinetes are motile. As they come in contact with the stomach epithelium, they enter it and become rounded into oocysts which lie between the base of the epithelium and the outer membrane 484 HAEMOSPORIDIA 485 of the stomach (14)- Within the oocysts, repeated nuclear division produces numerous sporozoites (15). When fully mature, the oocyst ruptures and the sporozoites are set free in the haemolymph through which they migrate to the salivary glands (16, 17). The sporozoites make their way through the gland epitheliimi and finally to the duct Fig. 225. The life-cycle of Plasmodium vivax (Kudo). 1, sporozoite en- tering human blood; 2, an organism entering an erythrocyte; 3, young schizont ("ring form"); 4-6, schizogony; 7, 8, macrogametocytes; 9, 10, microgametocytes; 11, microgamete-formation in the stomach of a mos- quito; 12, union of gametes; 13, zygote or ookinete; 14, rounding up of an ookinete in the stomach wall; 15, oocyst in which sporozoites are developing; 16, mature ooc^yst ruptured and sporozoites are set free in the liaemolymph; 17, sporozoites entering the salivary gland cells. 486 PROTOZOOLOGY of hypopharynx. They are ready to infect a human victim when the mosquito pierces with its proboscis the skin for another blood meal. Thus the sexual reproduction occurs in the mosquito (primary host) and the asexual reproduction, in man (secondary host). The Haemosporidia are divided into three families: With pigment granules Schizogony in peripheral blood of vertebrates . . Family 1 Plasmodiidae Gametocytes in peripheral blood; schizogony elsewhere Family 2 Haemoproteidae (p. 499) Without pigment granules; minute parasites of erythrocytes Family 3 Babesiidae (p. 502) Family 1 Plasmodiidae Mesnil Genus Plasmodium Marchiafava and Celli. Schizogony in erythro- cytes and also probably in endothelial cells of man, mammals, birds, and reptiles; sexual reproduction in blood-sucking insects; widely distributed. Numerous species. Until recent years it had been generally believed that the sporo- zoites upon entering the blood vessel, penetrate and enter immedi- ately the erythrocyte and begin intracorpuscular development, which process Schaudinn (1902-1903) reported to have seen in life. Although some authors still follow this view, thei'e are increasing numbers of others who doubt Schaudinn's observation, since no one has up to the present time been able to duplicate the observation. James (1931) noticed the ineffectiveness of quinine as a causal pro- phylactic in malaria infection, and suggested the possibility that the sporozoites are carried away immediately from peripheral to visceral circulation and develop in the cells of reticulo-endothelial system. Boyd and Stratman-Thomas (1934) found that the peripheral blood of a person who had been subjected to the bites of 15 anophe- line mosquitoes infected by Plasmodium vivax, did not become in- fectious to other per.sons by subinoculation until the 9th day and that the parasites were not observed before the 11th day in the stained films of the peripheral blood. Warren and Coggeshall (1937) observed that when suspensions of the sporozoites of P. cathemerium ob- tained from infected Culex pipiens, were inoculated into canaries, the blood was not infectious for 72 hours, but emulsions made from the spleen, liver and bone marrow contained infectious parasites which brought about infection by subinoculations in other birds. These and many similar observations cannot be satisfactorily ex- plained if one follows Schaudinn's view. The fact that P. elongatum is capable of undergoing schizogony in the leucocytes and reticulo- HAEMOSPORIDIA 487 endothelial cells in addition to erythrocytes of host birds had been observed by Raffaele (1934) and Huff and Bloom (1935). As to the nature of development of Plasmodium during the pre- patent period, James and Tate (1938) showed that there occur schiz- onts and schizogonic stages in the endothelial cells of the spleen, heart, liver, lung, and brain of the birds infected b}^ P. gallinaceum (Fig. 226). They suggested the term exo erythrocytic to this schizog- ony in contrast to the well known erythrocytic schizogony. Similar schizogony has further been observed by several investigators in P. g h Fig. 226. Exoerythrocytic schizogony in avian Plasmodium, a-f, P. gallinaceum in smears from chicks (James and Tate), a, monocyte from lung, infected by 2 young schizonts; b, monocyte from liver, with a grow- ing trinucleate schizont; c, monocyte from lung, with a large multi- nucleate schizont; d, large mature schizont containing many mature mero- zoites, free in lung; e, portion of broken schizont from lung, showing the attached developing merozoites. ( X1660). f, a capillary of brain blocked by 3 large schizonts ( X740). g, h, P. cathemerium in sections of organs of canaries (Porter; X 1900). g, capillary in the brain, showing an endothelial cell infected with a uninucleate and a multinucleate schizont; h, a multi- nucleate schizont and a group of merozoites found in a capillary of heart muscle. cathemerium, P. circumflexum, P. nucleophilum and P. relictum. However, these reported exoerythrocytic stages are of varied ap- pearances and their relation to erythrocytic schizogony is still un- 488 PROTOZOOLOGY known. In addition, some authors are inclined to think that experi- mental birds may have been infected not only by Plasmodium, but also by other organisms such as Haemoproteus, Leucocytozoon or Toxoplasma and that consequently the developmental stages of the latter might have been confused with those of the former. Positive proof that the reported exoerythrocytic schizogony pertains to Plasmodium and further details of this change, depend upon future investigations (Fig. 227). mosquito Fig. 227. Diagrammatical life-cycle of an avian Plasmodium (Several authors). Well established phases are connected by solid lines, while undetermined and recently suggested phases are indicated by broken lines, a, sporozoite injected into host bird by a mosquito; b-e, exoerythro- cytic schizonts and schizogony in monocytes; f-i, commonly seen schi- zogony in erythrocytes; j, macrogametocyte; k, microgametocyte. The incubation period of Plasmodium infections in man varies due to various factors such as the strain, vitality and number of the spo- rozoites injected by the mosquitoes, the varied susceptibility on the part of host, etc. Boyd and co-workers found that the incubation periods for the three species of human Plasmodium which they stud- ied were, as follows: In P. vivax. 8-21 days (the majority 11-14 days) after the bites of infected mosquitoes, but in one case as long as 304 HAEMOSPORIDIA 489 days; in P. malariae, 4-5 weeks, with the onset of fever lagging 3-12 days behind; and in two strains of P. falciparum, one, 6-25 days and the other, 9-13 days; in another observation, P. falciparum was observable in the peripheral blood in 5-9 days and the onset of fever in 7-12 days. The paroxysm of malaria is usually divisible into three stages: chill or rigor stage, high temperature or febrile stage (104° F. or over) and sweating or defervescent stage. The time of paroxysm corre- sponds, as was stated already, with the time of liberation of mero- zoites from erythrocytes, and is believed to be due to extrusion of a toxic substance into the blood plasma. The nature of this toxic ma- terial is however unknown at present. In the grown schizonts as well as in gametocytes of Plasmodium, are found invariably yellowish brown to l)lack pigment granules which vary in foi-m, size and num- ber among different species. They are usually called haemozoin gran- ules and are apparently the catabolic products formed within the parasites. They possess certain taxonomic significance. The infected erythrocytes, if stained more or less deeply, may show a punctate appearance. These dots may be small and numerous in the erythro- cytes infected by P. vivax or P. ovale {Schilffner^ s dots) or few and coarse in those infected by P. falciparum, {Maurer's dots). The condition w^hich brings about the formation of gametocytes is not known at present. The gametocytes appear in the peripheral blood at various intervals after onset of fever, and remain inactive while in the human blood. The assumption that the macrogameto- cytes undergo parthenogenesis under certain conditions and develop into schizonts as advocated by Grassi, Schaudinn and others, does not seem to be supported by factual evidence. The initiation of further development appears to be correlated with a lower tempera- ture. If living mature microgametocytes of human Plasmodium taken from an infected person are examined microscopically under a sealed cover glass at room temperature (18-22° C), development takes place in a few hours and motile microgametes are produced ("exflagellation"). Similar changes take place W'hen the gameto- cytes are taken into the stomach of mosquitoes belonging to gen- era other than Anopheles, but no sexual fusion l^etween gametes occurs in them and all degenerate sooner or later. In the stomach of an anopheline mosquito, however, the sexual reproduction of human Plasmodium continues, as has been stated before. All species are transmitted by adult female mosquitoes. The males are not concerned, since they do not take blood meal. The species of Plasmodium which attack man are transmitted only by the mosqui- 490 PROTOZOOLOGY toes placed in genus Anopheles, while avian species of Plasmodium are transmitted by those which belong to genera Culex, Aedes, and Theobaldia. The chief vectors of the human malarial parasites in North America are A. quadrimaculatus (eastern, southern and mid- dle-western States), A. punctipennis (widely distributed), A. cru- cians (southern and south-eastern coastal area), A. walkeri (eastern area), and A macM/^pewn^s (Pacific coast). Boyd and coworkers ob- served that (1) A. quadrimaculatus and A. punctipennis were about equally susceptible to Plasmodium vivax; (2) A. qaudrimaculatus was susceptible to several strains of P. falciparum, while A . puncti- pennis varied from highly susceptible to refractory to the same strains ; (3) A. quadrimaculatus was more susceptible to all three species of Plasmodium than coastal or inland A. crucians. Thus A. quadri- maculatus is the most dangerous malaria vector in the United States as it shows high susceptibility to all human Plasmodium, it possesses house-frequenting habits and furthermore it prefers human blood to those of animals. A. pseud op unctipennis distributed from southwestern United States to Argentina, A. albimanus occurring in Central America, and A. gambiae, an African species, which sud- denly appeared some ten years ago in the vicinity of Natal, Brazil, and which now seems to be under control, are but one or two out of many anopheline vectors of human Plasmodium in the areas indi- cated. The time required for completion of sexual reproduction of Plas- modium in mosquitoes varies according to various conditions such as species and strain differences in both Plasmodium and Anopheles, temperature, etc. Boyd and co-workers showed that when the ano- phelines which fed on patients infected by P. vivax were allowed to feed on other persons, their infectivity was as follows: 1-10 days after infective feeding, 87.2%; 11-20 days, 93.8%; 21-30 days, 78%; 31-40 days, 66%; 41-50 days, 20%; and over 50 days, none. In a similar experiment with P. falciparum, during the first 10 days the infection rate was 84%, but thereafter the infectivity rapidly dim- inished until there was no infection after 40 days. It is generally known that the development of the parasites in mosquitoes depends a great deal on temperature. Although the organisms may survive freezing temperature in mosquitoes (Coggeshall), sporozoite-for- mation is said not to take place at temperatures below 16° C. or above 35° C. (James). According to Stratman-Thomas (1940), the development of Plasmodium vivax in Anopheles quadrimaculatus is completed within the temperature range of 15-17° to 30° C. It varies from 8 to 38 days after infective feeding. The optimum tem- HAEMOSPORIDIA 491 ])eratiire is said to l^e 28° C. at which the development is com- pleted in the shortest time. A period of 24 hours at 37.5° C. will sterilize all but a ver\^ small per cent of Anopheles quadrimaculatus of their Plasmodium vivax infection. This has a bearing on the trans- mission of Plasmodium vivax in summer months. In certain localities (;ocysts may survive the winter and complete their development in the following spring. There are three long-recognized species of human Plasmodium. They are P. vivax, P. falciparum and P. malariae. To these P. ovale is here added. Each species appears to be represented by numerous strains or races as judged by the differences in virulence, immuno- logical responses, incubation period, susceptibility to quinine, etc. Malaria has been, and still is, perhaps the most important proto- zoan disease of man. In India alone, malaria fever is held to be the direct cause of over a million deaths annually among nearly 100 million persons who suffer from it (Sinton, 1936). In the United States, the disease had been prevalent in places in south-eastern States. In malarious countries, the disease is a serious economic and social problem, since it affects the majority of population and brings about an immense number of persistent sickness, the loss of man ])0wer, and retardation of both mental and ])hysical develo])ments among children. It must be added here that human ingenuity has been of late util- izing the malarial organism in combatting another disease; namely, naturally induced malaria (P. vivax) therapy has been successfully used in the treatment of patients suffering from general paresis and other forms of neuro-syphilis (Boyd and Stratman-Thomas, 1933). P. vivax (Grassi and Feletti) (Fig. 228). The benign tertian malaria parasite; schizogony completed in 48 hours and paroxysm every third day. Ring forms: About 1/4-1/3 the diameter of erythrocytes; unevenly narrow cytoplasmic ring is stained light blue (in Giemsa) and encloses a vacuole; nucleus stained dark-red, conspicuous. Growth period: Irregular amoeboid forms; host cell slightly' enlarged; Schiiffner's dots begin to appear. Grown schizonts : In about 26 hours after paroxysm; occupy- about 2/3 of the enlarged erythrocytes, up to 12/z in diameter, which are distinctly paler than uninfected ones; Schiiffner's dots more numerous; brownish haemozoin granules; a large nucleus. Schizogonic stages: Repeated nuclear division produces 12-24 or more merozoites; multinucleate schizonts about 8-9m in diameter; haemozoin granules in loose masses; merozoites about 1.5,u long. Gamctocytes: Time recjuired for development of ringform into a 492 PROTOZOOLOGY mature gametocyte is estimated to be about four days; smoothly rounded body, occupying almost whole of the enlarged erythrocytes; brown haemozoin granules numerous. Macrogametocytes are about 9-lOju in diameter, stain more deeply and contain a small compact nucleus; microgametocytes are a little smaller (7-8jU in diameter), stain less deeply and contain a less deeply staining large nucleus. The benign malaria fever is the commonest and the most widel}" distributed species in the tropical and subtropical regions as well as in the temperate zone. It has been reported as far north as the Great a ry^ x^t- V C ^.- c d g h ^, I ) k I Fig. 228. Plasmodium vivax, X1535 (Original), a, young ring-form b, c, growing schizonts; d, two schizonts in an erythrocyte; e, f, large schizonts; g-i, schizogonic stages; j, fully developed nierozoites; k, macro- gametocyte; 1. microgametocyte. Lakes region in North America; England, southern Sweden and northern Russia in Europe; and as far south as Argentina, Australia, and Natal in the southern hemisphere. Generally speaking this spe- cies predominates in the spring and early summer over the other species. P. falciparum (Welch) {Laverania malariae Grassi and Feletti; P. icnue Stepens) (Fig. 229). The subtertian, malignant tertian or aesti- vo-autumnal fever parasite; schizogonic cycle is somewhat irregular, though generally 36-48 hours. Ring forms: Much smaller than those of P. vivax; about 1m in diameter; marginal forms and multiple (2-6) infection common; nucleus often rod-form or divided into two granules; in about 12 hours after paroxj^sm, all schizonts disappear from the pei-ipheral blood. Growth and schizogonic stages: These are HAEMOSPORIDIA 493 almost exclusively found in the capillaries of internal organs; as schizonts mature Maurer's dots appear in the infected erythrocytes; when about Sju in diameter, nucleus divides repeatedly and 8-24 or more small merozoites are produced ; haemozoin granules dark brown or black and usuall}^ in a compact mass; infected erythrocytes are not enlarged. Gametocytes: Mature forms sausage-shaped ("crescent"), about 10-12 fjL by 2-3iu; appear in the peripheral blood. Macro gameto- cytes stain blue and contain a compact nucleus and coarser granules, grouped around nucleus; microgametccj'tes stain less deeply blue or reddish, and contain a large lightly staining nucleus and scattered smaller haemozoin granules. # ^ f g h J Fig. 229. Plasmodium falciparum, X 153.3 (Original), a, three ring-forms in an erythrocyte; b, a somewhat grown schizont in an erythrocyte with Maurer's dotes; c-f, growng and schizogonic stages, g, h; merozoite for- mation; i, macrogametocyte; j, microgametocyte. The subtertian fever is widely- distributed in the tropics. In the subtropical region, it is more prevalent in late summer or early autumn. It is relativel}^ uncommon in the temperate zone. The malignancy of the fever brought about by this parasite is attributed in ]3art to decreased elasticity of the infected erythrocytes which be- (•( me clumped together into masses and which adhere to the walls of the capillaries of internal organs especially brain, thus preventing the circulation of blood through these capillaries. P. malariae (Laveran) (Fig. 230). The ciuartan malaria parasite; schizogony in 72 hours and paroxysm every fourth day. Ring forms: Similar to those of P. vivax. Growth -period: Less amoeboid, rounded; in about 6-10 hours haemozoin granules begin to appear; granules are dark brown; in 24 hours, schizonts are about 1/2 the diameter of erythrocytes Avhich remain normal in size; schizonts often stretched into "band-form" across the erythrocytes; no dots com- parable with Schiiffner's or Maurer's dots. Mature and segmenting 494 PROTOZOOLOGY schizonts: In about 48 hours, sehizonts nearly fill the ho.st cells; rounded; haemozom granules begin to collect into a mass; nuclear divisions produce 6-12 merozoites which are the largest of the three species and may often be arranged in a circle around a haemozoin mass. Gametocytes : Circular; with haemozoin granules. Macrogame- tocytes stain more deeph' and contain a small, more deeply staining " ^m V^Ek JHp^ ^mmam mmBBs ^w ^"W^ ^w ^P^ i i k I Fig. 230. Plasmodium malariae, X1535 (Original), a, ring-form; b-e, band-form schizonts; f-i, schizogonic stages; j, merozoite formation; k. macrogametocyte, 1, microgametocyte. nucleus and coarser granules; microgametocytes stain less deeply and contain a larger lightly stained nucleus and finer and numerous granules. The quartan fever is distributed in the tropics and subtropics. though it is the rarest of the three species. As a rule, in an area where the three species of Plasmodium occur, this seems to appear later in the year than the other two. P. ovale Stevens (Fig. 231). The Ovale or mild tertian fever para- site; schizogon}^ in about 48 hours; its morphological characters re- semble both P. vivax and P. malariae. Ring forms: Similar to those of the two species just mentioned; Schiiffner's dots appear early. Growth -period: Infected erythrocytes are more or less oval with irregular fimbriated margin; slightly enlarged; not activel}' amoeboid, sometimes in band-form; with dark brown haemozoin granules; Schiiffner's dots abundant. Schizogonic stages: 6-12 mero- HAEMOSPORIDIA 495 zoites. Gamctocytes: Resemble closely those of P. malariac; host cells with Schiiffner's dots and slightly enlarged. This organism appears to be confined to Africa and Asia (Philip- pine Islands and India). Several malariologists doubt the validit}^ of the species. The malarial parasites are ordinarily studied in stained blood films (p. 727). Table 9 will serve for differential diagnosis. Several species of Plasmodium have been observed in primates and monkeys, some of which resemble the human species. Species are known to occur in various other mammals. W' ^^- i # e f g h Fig. 231. Plasmodium ovale, X1535 (Original), a, ring-form; b, c, growing schizonts; d-f, schizogonic stages; g, macroganietocyte; h. micro- gametoeyte. Man}^ species of Plasmodium have been reported from numerous species of birds in w^hich are observed clinical symptoms and path- logical changes similar to those which exist in man with malaria infection. In recent ^^ears the exoerythrocytic stages have been in- tensively studied in these forms. According to Hegner and co- workers the erythrocytes into which merozoites enter are often the most immature erythrocytes (polychromatophilic erythroblasts). Hewitt (1940) gave an excellent digest of available information on avian Plasmodium. The species of avian Plasmodium are transmit- ted by adult female mosquitoes belonging to Culex, Aedes or Theo- baldia. More or less distinct species are here briefly described. P. relictmn Grassi and Feletti (P. praccox G. and F.; P. inconslans Hartman) (Fig. 232, a). In English sparrow {Passer domesticus) and other passerine birds; schizogony varies in different strains, in 12, 24, 30 or 36 hours; 8-15 or 16-32 merozoites from a schizont; game- tocytes rounded, with small pigment granules; host-cell nucleus dis- placed; canaries (Serinus canaria) susceptible; many strains; transmitted by Culex, Aedes and Theobaldia; widely distributed. 496 PROTOZOOLOGY Table 9. — Differential diagnosis of three species of human Plasmodium P. vivax P. falciparum P. malariae Ring forms About l-l the diam- eter of erythrocytes; a single granular nu- cleus. About \-\ the diam- eter of erythrocytes; marginal forms and multiple (2-6) infec- tion common. Similar to those of P. vivax: cytoplasm slightly denser. Infected erythro- cytes Much enlarged, up to 12ju in diameter, paler than normal (7.5/i in diameter) erythrocytes ; Schiiff- ner's dots. Normal; some are distorted or con- tracted in later schiz- ogonic period ; Maur- er's dots. Not enlarged: some- times slightly smaller than uninfected ones; no dots. Growing schizonts Irregularly amoe- boid; vacuolated; paler; small yellow- ish brown haemozoin granules. Partly grown ring forms often with rod- shaped or 2 granular nuclei; further devel- opment not seen in peripheral blood. Not amoeboid: oval, rounded, band-form, rarely irregular; less vacuolated cyto- plasm deeper blue; dark brown gran- ules. Fully grown schizonts Irregular in form ; about 1 the enlarged erythrocytes; vacuo- lated; brown haemo- zoin granules. Only in internal or- gans; i-f of erythro- cytes; dark haemo- zoin in compact mass. Nearly filling eryth- rocytes ; rounded : cy- toplasm deeper blue; dark brown jjigment granules. Schizogonic stages 12-24 or more mero- zoites; irregularly ar- ranged in much en- larged host cells. Only in internal or- gans; 8-24 or more small merozoites; ir- regularly arranged ; dark pigment. 6-12 merozoites which are the larges- of all, typically ar- ranged in a circle. Gameto- cytes Almost filling en- larged erythrocytes ; rounded or oval ; with brown pigment granules. Sausage-shaped; hae- mozoin dark brown; in the peripheral blood. Filling normal-sized erythrocytes ; round or ovoid, much smaller than those of P. vivax: dark brown pigment. P. vaughani Novy and McNeal (Fig. 232, 6). In robin {Turdus m. migraiorius) and starling (Sturnus v. vulgaris) ; 4-8 (usually 4) merozoites from a schizont, ordinarily with 2 pigment granules; schizogony in about 24 hours; gametocytes elongate; host-cell nu- cleus not displaced. HAEMOSPORIDIA 497 P. cathetnerium Hartman (Fig. 232, c). In English sparrow, cow- bird, red-winged blackbird, and other birds; schizogony in 24 hours, segmentation occurs at 6-10 p.m.; 6-24 merozoites from a schizont; mature schizonts and gametocytes about 7-8/x in diameter; gameto- cytes rounded ; haemozoin granules in microgametocytes longer and more pointed than those present in macrogametocytes; canaries susceptible; numerous strains; common; transmitted by manj' spec- ies of Culex and Aedes. P. rouxi Sergent, Sergent and Catanei (Fig. 232, (]). In English sparrow in Algeria; similar to P. vaughani; schizogony in 24 hours; 4 merozoites from a schizont; transmitted by Culex. P. elongatum Huff (Fig. 232, e). In English sparrow; schizogon,y occurs mainly in the bone marrow, and completed in 24 hours; 8-12 merozoites from a schizont; gametocytes elongate, found in periph- eral blood; transmitted by Culex. Chen (1944) made a study of its nucleus. P. circumflexum Kikuth (Fig. 232, /). In red-winged blackbird, cowbird and several other birds; growing schizonts and gametocytes form broken rings around the host-cell nucleus; schizogony com- pleted in 48 hours; 13-30 merozoites from a schizont; gametocytes elongate, with a few haemozoin granules; transmitted by Culex and Theobaldia. P. polare Man well (Fig. 232, g). In cliff swallow {Petrochelidon I. lunifrons); grown schizonts at one of the poles of host erythrocytes; 8-14 merozoites from a schizont; few in peripheral blood; gameto- cytes elongate. P. nudeophilum AI. (Fig. 232, h). In catbird (Dumatella carolin- ensis)\ schizogony in 24 hours; 3-10 merozoites from a schizont; mature schizonts usually not seen in the peripheral blood; gameto- cytes elongate, often seen closely applied to the host-cell nucleus; haemozoin granules at one end. P. gallinaceum Brumpt (Fig. 232, i). In domestic fowl {Gallus domesticus) in India; schizogony in 36 hours; 20-36 merozoites from a schizont; gametocytes round, with few haemozoin granules; host-cell nucleus displaced; pheasants, geese, partridges and peacocks are susceptible, but canaries, ducks, guinea fowls, etc., are refractory; transmitted by Aedes. P. hexamerium^ Huff (Fig. 232, j). In bluebird {Sialias. sialis) and ^Maryland yellow-throats; schizogony in 48 or 72 hours; grown schi- zonts often elongate; 6 merozoites from a schizont; gametocytes elongate. P. oti Wolf son (Fig. 232, k). In eastern screech owl {Otus asio 498 PROTOZOOLOGY naevius) ; 8 merozoites from a schizont ; body outlines irregular, rough ; gametocj'tes elongate. P. lophurae Coggeshall (Fig. 232, l). In fire-back pheasant (Loph- ura i. igniti) from Borneo, examined at New York Zoological Park; 8-18 merozoites from a schizont; gametoc^-tes large, elongate; host- ®®®( Fig. 232. a, Plasmodium relictum; h, P. vaughani; c, P. cathemerium; d, P. rouxi; e, P. elongatum; f, P. circumflexum; g, P. polare; h, P. mccleophilum ; i, P. gallinaceum; j, P. hexamerium ; k, P. oti; 1, P. lophurae. Columns 1, ring-forms; 2, growing schizonts; 3, segmenting schizonts; 4, macrogametocytes; and 5, microgametocytes. X about 1400 (Several au- thors; from Hewitt, modified). HAEMOSPORIDIA 499 cell nucleus not displaced; chicks are susceptible, but canaries re- fractory. Experimentally it developed up to the oo cyst-stage in Anopheles quadrimaculatus, though the sporozoites did not develop (Coggeshall, 1941). Family 2 Haemoproteidae Doflein Schizogony occurs in the endothelial cells of vertebrates; mero- zoites penetrate into circulating blood cells and develop into game- tocytes; if blood is taken up by specific blood-sucking insects, gametocytes develop into gametes which unite to form zygotes that undergo changes similar to those stated above for the family Plas- modiidae. Fig. 233. The life-cycle of Haemoproteus columhae. (Several authors), a, a sporozoite entering an endothelial cell of the pigeon; b, growth of a schizont; c, segmentation of multinucleate schizont into uninucleate cytomeres; d-i, development of cytomeres to produce merozoites; j-m, development of microgametes; n-p, development of macrogamete; q, fertilization; r, s, ookinetes; t, a young oocyst in the stomach wall of a fly; u, a ruptured mature oocyst with sporozoites. a-k, n, o, in the pigeon, I, m, p-u, in Pseudolynchia maura. 500 PROTOZOOLOGY Genus Haemoproteus Kruse. Gametocytes in erythrocytes, with pigment granules, halter-shaped when fully formed (hence Halter- idium Labbe) ; schizogony in endothelial cells of viscera of vertebrate hosts; sexual reproduction in blood-sucking insects; in birds and reptiles. H. columhae Celli and Sanfelice (Fig. 233). In pigeons (Columha livia), etc.; widely distributed; young schizonts, minute and uninu- cleate, are in the endothelial cells of lungs and other organs, grow into large multinucleate bodies which divide into 15 or more uninu- cleate cytomeres (Aragao). Each cytomere now grows and its nucleus divides repeatedly. The host cell in which many cytomeres undergo enlargement, becomes highly hypertrophied and finally ruptures. The multinucleate cytomeres break up into numerous merozoites, some of which possibly repeat the schizogony by invading endothe- lial cells, while others enter erythrocytes and develop into gameto cytes which are seen in the peripheral blood; sexual reproduction in, and transmitted by, the flies: Lynchia hrunea, L. lividicolor, L. capensis, Pseudolynchia maura, and Microlynchia fusilla. H. lophoriyx O'Roke. In California valley quail, Gambel quail, and Catalina Island quail (Lophortyx) ; gametocytes in erythrocytes, also occasionally in leucocytes; young gametocytes, spherical to elongate, about 1m long; more developed forms, cylindrical, about 8/x by 2ju, with 2-10 pigment granules; mature gametocytes, halter- shaped, encircling the nucleus of the host erj^throcyte, 18/i by 1.5- 2.5/i; numerous pigment granules; 4-8 microgametes, about 13.5/x long, from each microgametocyte; on slide in one instance, gamete- formation, fertilization and ookinete formation, completed in 52 minutes at room temperature; in nature sexual reproduction takes place in the fly, Lynchia hirsuta; sporozoites enter salivary glands and fill central tubules; schizonts present in lungs, liver and spleen of quail after infected flies sucked blood from the bird; mero- zoites found in endothelial cells of capillaries of lungs, in epithelial cells of liver and rarely in peripheral blood cells; how merozoites enter blood cells is unknown; schizonts seldom seen in circulating blood; infected birds show pigment deposits in spleen and lungs (O'Roke). Several species of Haemoproteus have been described by Coatney and Roudabush (1937). Genus Leucocytozoon Danilewsky. Schizogony in the endothelial cells as well as visceral cells of vertebrates; sexual reproduction in blood-sucking insects; gametocytes in spindle-shaped host cells. Several species. L. simondi Mathis and Leger (L. anatis Wickware) (Fig. 234). HAEMOSPORIDIA 501 Mathis and Leger (1910) described this species from the teal duck (Querquedula crecca) in Tonkin, China. Wick ware (1915) saw L. anatis in ducks in Canada. O'Roke (1934) carried on experimental studies on the developmental cycle with the form which he found in wild and domestic ducks in Michigan. Herman (1938) observed the Fig. 234. The life-cycle of Leucocytozoon simondi (Brumpt, modified), a-c, development of macrogamete; d-f, development of microgametes; g, fertilization; h, ookinete; i, j, ookinete piercing through the stomach wall; k-m, development of sporozoites; n, sporozoites entering endo- thelial cells; o-r, schizogony. organism in common black ducks {Anas ruhripes /mits) , red-breasted merganser (Mergus serrator), and blue-winged teal (Querquedula discors) and considered L. anatis as identical with L. simondi. Huff (1942) also maintained the species he studied in mallard ducks {Anas p. platyrhynchos) and domestic ducks from Wisconsin to be L. sim- ondi. 502 PROTOZOOLOGY According to O'Roke, the vector is a black fly, Simulium venustum, in which the sexual reproduction takes place. Gametocytes develop into mature gametes in 1-2 minutes after blood is obtained from an infected duck; macrogametes about 8m in diameter; 4-8 micro- gametes, 15.7-24. 1/i long, from a single microgametocyte; zygotes are found in stomach contents of fly in 10-20 minutes after sucking in the infected blood cf bird; motile ookinetes abundant after 5 hours, measure 33.3)u by 3-4. 6m; 22 hours after sucking duck blood, oocysts are found on outer wall of stcmach; sporozoites mature probably in 24-48 hours; 5 days after a duck has been bitten by infected black flies, schizogonic stages are noticed in endothelial cells of capillaries of lungs, liver, spleen; on about 7th day gametocytes appear in blood ; liver and spleen become hypertrophied; the infection among duck- lings is said to be highly fatal and appears often suddenly. Mathis and Leger: Macrogametocytes, oval; 14-15m by 4.5-5.5m; several vacuoles in darkly stained cytoplasm. Microgametocytes, oval; slightly smaller; cytoplasm stains less deeply. Infected host cells about 48m long; nucleus elongate. Huff found that (1) young schizonts are in macrophages of, and also extracellularly in, the spleen and hver; (2) two types of schi- zonts occur: one, "hepatic schizonts" in hepatic cells which cause no distortion or alteration of the host cell, and the other, "megalo- schizonts" in the blood vessels of, or extravascularly in, the heart, spleen, hver and intestine; (3) megaloschizonts become divided into many cytomeres which give rise to numerous merozoites; (4) young gametocytes occur in lymphocytes, monocytes, myelocytes and late polychromatophile erythrc blasts; (5) the cells in which fully grown gametocytes occur, appear to be macrophages. Family 3 Babesiidae Poche Minute non-pigmented parasites of the erythrocytes of various mammals; transmission by ticks. Genus Babesia Starcovici {Piroplasma Patton). In erythrocytes of cattle; pear-shaped, arranged in couples; sexual reproduction in fe- male ticks in which developing ova, hence young ticks, become in- fected with ookinetes, producing sporozoites which enter salivary glands (Dennis). B. higemina (Smith and Kilbourne) (Figs. 235; 236, a-d). The causative organism of the haemoglobinuric fever, Texas fever or red-water fever of cattle; the very first demonstration that an ar- thropod plays an important role in the transmission of a protozoan parasite; the infected cattle contain in their erythrocytes oval or HAEMOSPORIDIA 503 pyriform bodies with a compact nucleus and vacuolated cytoplasm; the division is peculiar in that it appears as a budding process at the beginning. We owe Dennis (1932) for our knowledge of the develop- ment of the organism. Fig. 235. The life-cycle of Babesia bigemina (Dennis), a-f, division in erythrocytes of cattle; g, h, gametocytes; i, isogametes; j, fertilization; k, zygote; 1, ookinete penetrating through the gut wall; m, ookinete in host egg; n-p, sporoblast-formation; q, sporokinetes in a large em- bryonic cell; r, sporozoites in salivary gland. Sexual reproduction followed by sporozoite formation occurs in the tick, Boophilus (Margaropus) annulatus; when a tick takes in 504 PROTOZOOLOGY injected blood into gut lumen, isogametes, 5.5-6/i long, are produced; isogamy results in motile club-shaped ookinetes, 7-12m long, which pass through gut wall and invade larger ova (1-2, in one case about 50, ookinetes per egg) ; each ookinete rounds itself up into a sporont 7.5-12/x in diameter, which grows in size and whose nucleus divides repeatedly; thus are produced multinucleated (4-32 nuclei) amoe- boid sporokinetes, up to 15m long, which now migrate throughout embryonic tissue cells of tick, many of which cells develop into Fig. 236. a-d, Babesia bigemina, X3000 (Nuttall); e-h, B. bovis, X3000 (Nuttall); i-1, Theileria parva, XBOOO (Nuttall); m-s, Dactylo- soma ranarum (m-q, schizogony; r, s, gametocytes), X2700 (Noller). salivary gland cells; sporokinetes develop into sporozoites before or after hatching of host tick; sporozoites bring about an infection to cattle when they are inoculated by tick at the time of feeding. Texas fever once caused a considerable amount of damage to the cattle industry in the southern United States to which region the distribu- tion of the tick is limited. B. bovis Starcovici (Fig. 236, e-h). In European cattle; amoeboid form usually rounded, though sometimes stretched; 1-1. 5^ in dia- meter; paired pyriform bodies make a larger angle, 1.5-2/x long; transmitted by Ixodes ricinus. HAEMOSPORIDIA 505 Babesia occur also in sheep, goats, pigs and horses. B. canis (Piana and Galli-Valerio), Pyriform bodies 4.5-5m long; the organism causes malignant jaundice in dogs; widely distributed; transmitted by the ticks: Hacmaphysalis leachi, Rhipicephalus san- guineus, and Dermacentor reticulatus. Genus Theileria Bettencourt, Franga and Borges. Schizogony takes place in endothelial cells of capillaries of viscera of mammals; certain forms thus produced enter erythrocytes and appear in the peripheral circulation. T. parva (Theiler) (Fig. 236, i-l). In the cattle in Africa, cause of African coast fever; intracorpuscular forms 1-2/x in diameter; trans- mitted by the tick, Rhipicephalus evertsi. ^ %^ ^ ^ Fig. 237. Toxoplasma gondii. X about 1750. (Chatton and Blanc) a, isolated organisms; b, 2 trophozoites; c, organisms undergoing binary fission; d, a host cell with many organisms which developed by repeated binary fission. Genus Dactylosoma Labbe. In blood of reptiles and amphibians; schizogony and gametocytes in erythrocytes; invertebrate hosts unknown. D. ranarum (Kruse) (Fig. 236, m-s). In European frogs; schizonts 4-9m in diameter; 4-16 merozoites, 2-3m by 1-1. 5m; gametocytes 5-8Mby 1.5-3/i. Genus Toxoplasma NicoUe and Manceaux. Minute intracellular parasites in leucocytes and endothelial cells of various mammals, birds and reptiles; round or ovoid; ordinarily not common in periph- eral blood; often abundant in the liver, spleen, bone marrow, lung, brain, etc.; reproduction by binary fission. The genus has been often mentioned in connection with exo erythrocytic schizogony of Plas- modium. Many "species" have been designated by various observers on the basis of the difference in host species. T. gondii N. and M. (Fig. 237). In Ctenodaclylus gundi, a rodent in North Africa; a variety of experimental animals susceptible to it; crescentic; 4-6m by 2-3m; division occurs intra- or extra-cellularly. 506 PROTOZOOLOGY Toxoplasma appears to be common in birds. For example, in a survey on the blood parasites of birds on Cape Cod, Herman (1938) found the organism in 11 species of birds examined by him. In the past ten years a considerable amount of information has accumu- lated on the organisms which attack and produce a disease (toxoplas- mosis) in man. Sabin (1942) gives an excellent digest on it. References Boyd, M. F. 1930 An introduction to malariology. Cambridge. 1940 On strains or races of the malaria parasites. Amer. Jour. Trop. Med., Vol. 20. and W. K. Stratman-Thomas 1933 A controlled technique for the employment of naturally induced malaria in the therapy of paresis. Amer. Jour. Hyg., Vol. 17. Chen, T. T. 1944 The nuclei in avian malaria parasites. I. The structure of nuclei in Plasmodium elongatum, with some con- siderations on technique. Amer. Jour. Hyg., Vol. 40. CoATNEY, G. R. and R. L. Roudabush 1937 Some blood parasites from Nebraska birds. Amer. Midi. Nat., Vol. 18. Dennis, E. W. 1932 The life-cycle of Babesia higemina (Smith and Kilbourne) of Texas cattle-fever in the tick, Margaropus an- nulatus (Say). Uni. Calif. Publ. Zool., Vol. 36. Hartman, E. 1927 Three species of bird malaria. Arch. f. Pro- tistenk., Vol. 60. Hewitt, R. 1940 Bird malaria. Amer. Jour. Hyg., Monogr. Ser., No. 15. Huff, C. G. 1942 Schizogony and gametocyte development in Leucocytozoon simondi, and comparison with Plasmodium and Haemoproteus. Jour. Infect. Dis., Vol. 71. James, S. P. and P. Tate 1938 Exo-erythrocytic schizogony in Plasmodium gallinaceum Brumpt, 1935. Parasitology, Vol. 30. O'RoKE, E. C. 1934 A malaria-like disease of ducks caused by Leucocytozoon anatis Wickware. Uni. Michigan Sch. Forest and Conservation, Bui., No. 4. Porter, R. J. and C. G. Huff 1940 Review of the literature on exo-erythrocytic schizogony in certain malarial parasites and its relation to the schizogonic cycle in Plasmodium elongatum. Amer. Jour. Trop. Med., Vol. 20. Ross, R. 1928 Studies on malaria. London. Sabin, A. B. Toxoplasmosis. A recently recognized disease of hu- man beings. In: Advances in pediatrics, edited by A. G. De Sanc- tis. Vol. 1. Simmons, J. S. et al. 1939 Malaria in Panama. Amer. Jour. Hyg., Monogr. Ser. No. 13. Stratman-Thomas, W. K. 1940 The influence of temperature on Plasmodium vivax. Amer. Jour. Trop. Med., Vol. 20. Wenyon, C. M. 1926 Protozoology. Vol. 2. London and Baltimore. Chapter 27 Subclass 2 Acnidosporidia Cepede THE sporozoa which are provisionally grouped here are mostly incompletely known, although some of them are widely dis- tributed among the higher vertebrates. They possess spores which are quite simple in their structure, while their development is so far as is known wholly different from that of the Telosporidia. Muscle parasites of higher vertebrates Order 1 Sarcosporidia Parasites of invertebrates and fish Order 2 Haplosporidia (p. 510) Order 1 Sarcosporidia Balbiani These sporozoans are characteristic muscle parasites of mammals, although reptiles and birds have also been found to harbor them. Fig. 238. a, Sarcocystis tenella in the oesophagus of sheep; b, S.miescheri- ana in the muscle of pig; Xl (Schneidemiihl from Doflein). The spore which has been known as Rainey's corpuscle, is crescent- shaped (Fig. 239). One end is rounded and the other end is bluntly pointed. There is a single nucleus and the cytoplasm contains numer- ous granules. Infection of a new host begins with the entrance of spores into the digestive tract of a specific animal through mouth. The delicate spore membrane ruptures and the sporozoite is liber- ated, which enters the gut-epithelium. After undergoing certain de- velopment which is still unknown, the organism makes its way through blood stream (?) into the muscular tissue. At the beginning the trophozoite is a small uninucleate body, but develops, by divi- sion and growth, into an elongated multinucleate body which then ordinarily divide into many uninucleate bodies. These become the centers of infection in other muscle fibers. Some trophozoites grow in size and the body becomes divided into parts, in each of which spores are formed. Some authors believe that the spores themselves are capable of fission. The host muscle fiber harboring the trophozoite 607 508 PROTOZOOLOGY may vary in size from microscopic to as large as 5 centimeters. They are cylindrical with more or less pointed extremities and with a some- what lobulated surface, and appear opaque whitish. They were for- merly called Miescher's tubes (Fig. 238). The envelope around the parasitic mass appears to rupture sooner or later and the spores are set free in the blood stream and into the alimentary canal. The spores find finally their way out of the host intestine and become the source of infection (Scott). Muscle layer ■^ Connective tissue layer Fibrous zone Externals Median / Cyst membrane Internal ) Sporoblasts Spores Fig. 239. Portion of a cyst of Sarcocystis tenella in sheep, X about 'lOOO (Alexeieff). As to the pathogenic effect of the parasites upon the host animal, fatal cases are not uncommon. In heavily infected animals extensive muscular degeneration appears and the hosts die from the infection. One peculiarity of the Sarcosporidia is that these organisms contain certain toxin, sarcocystine which when injected is highly toxic to other animals (p. 28). Genus Sarcocystis Lankester. In muscles of vertebrates; numer- ous species have been described from various animals en the basis of difference in host species and slight difference in dimensions of spores. ACNIDOSPORIDIA, SARCOSPORIDIA 509 S. Undemanni (Rivolta) (Fig. 240). A few cases of Sarcocystis infection have been reported from man in muscle cells of larynx (Baraban and St. Remy), of biceps and tongue (Darling), of heart (Manifold), of breast (Vasudevan), etc. There seem to be dimensional discrepancies of organisms observed by different investigators. The dimensions of parasitic masses and of spores are as follows: Parasites 1.6 mm. by 170m and banana-shaped spores 8-9/x long (Baraban and % ^ <^%^ ^^» ^. Fig. 240. Sarcocystis Undemanni in human muscle, X1150 (Kudo). St. Remy) ; parasites 84^ by 27)Lt and spores 4.25m by 1.75m (Darling) ; parasites spherical, 500m in diameter and spores over 10m long (Manifold); parasites 5.3 cm. by 320m and spores 8.33m by 1.6m (Vasudevan). The parasitic masses are oval to spindle in form and imbedded in the muscle cells which are distended, and may appear white-streaked to naked eye. Seen in sections, the body is divided into compartments. Gilmore, Kean and Posey (1942) have recently found three bodies in sectioned heart muscles of an eleven year old child who died from an unknown cause, and considered them as sarcosporidian bodies. They measured 25m by 19m, 57m by 30m, and 510 PROTOZOOLOGY 41m by 25m in cross-sections; there were no septa within the bodies; minute bodies present in the masses were mostly rounded and about l/i in diameter, though a few were crescentic. The questions such as what species infect man, how man becomes infected, etc., are un- answered at present. *S. tenella Railliet (Figs. 238, a; 239). In the muscles of tongue, pharynx, oesophagus, larynx, neck, heart, etc., of sheep; large parasites 40/x-2 cm. long with a thin membrane; spores sickleform. S. miescheriana (Kiihn) (Fig. 238, b). In muscles of pig; parasitic mass up to 3-4 mm. by 3 mm; envelope striated; spores reniform, capable of division when young (Manz). S. bertrami Doflein. In the muscles of horse; similar to S. miescher- iana; parasitic mass up to 9-10 mm. ; envelope striated. S. muris Blanchard. In body muscles of rats and mice; parasitic masses up to 3 cm. long; spores 13-15^ by 2.5-3^; transmissible to guinea pig (Negri) which shows experimental infection in muscles in 50-100 days after feeding on infected muscles. S. rileyi Stiles. In muscles of various species of ducks; parasites in muscles, opaque white in color and measure up to 5 mm. by 2 mm.; spores are sausage-shaped and S-lOju by about 3jLt. Order 2 Haplosporidia Caullery and Mesnil This order includes those sporozoans which produce simple spores. In some species the spores may resemble superficially those of Microsporidia, but do not possess any polar filament. The exact boundaries and affinities of this order to other groups are to be de- termined by future investigators. The Haplosporidia are cytozoic, histozoic, or coelozoic parasites of invertebrates and lower vertebrates. The spore is spherical or ellipsoidal in form and covered by a resistant membrane which may possess ridges or may be prolonged into a more or less long tail-like projection. In a few species the spore membrane possesses a lid which, when opened, will enable the sporoplasm to emerge as an amoebula. The sporoplasm is uninucleate and fills the intrasporal cavity. The development of a haplosporidian, Ichthyosporidium gigan- teum, as worked out by Swarczewsky, is as follows (Fig. 241): The spores germinate in the alimentary canal of the host fish and the sporoplasms make their way to the connective tissue of various organs (a). These amoebulae grow and their nuclei multiply in num- ber, thus forming plasmodia. The plasmodia divide into smaller bodies, while the nuclei continue to divide ib-e). Presently the nuclei ACNIDOSPORIDIA, SARCOSPORIDIA 511 become paired (J, g) and the nuclear membranes disappear ih). The Plasmodia now break up into numerous small bodies, each of which contains one set of the paired nuclei (i, j). This is the sporont ij) which develops into 2 spores by further differentiation {k-o). Genus Haplosporidium Caullery and Mesnil. After growing into a large form, Plasmodium divides into uninucleate bodies, each of Fig. 241. The development of IchthT/osporidium giganteum (Swarczewsky). a-e, schizogony; f-n, sporogony; o, stained spore, X about 1280. which develops into a spore; spore truncate with a lid at one end; envelope sometimes prolonged into processes; in aquatic annelids and molluscs. H. chitonis (Lankester) (Fig. 242, a, b). In liver and connective tissue of Craspidochilus cinereus; spores oval, 10/* by 6m; envelope with 2 prolonged projections. H. limnodrili Granata (Fig. 242, c). In gut epithelium of Lim- nodrilus udekemianus; spores 10-12^ by 8-10/x. 512 PROTOZOOLOGY H. nemertis Debaisieux (Fig. 242, d). In connective tissue of Lineus hilineatus; spores oval with a fiat operculum, but without any projections of envelope, 7m by 4^. H. heterocirri C. and M. (Fig. 242, e). In gut epithelium of Het- erocirrus viridis; mature organisms 50-60m by 30-40m; spores 6.5m by 4m. H. scolopli C. and M. (Fig. 242, /). In Scoloplos millleri; fully grown form 100-150m by 20-30m; spores 10m by 6.5m. Fig. 242. a, b, Haplosporidium chitonis, XlOOO (Pixell-Goodrich;) c, H. limnodrili, XlOOO (Granata); d, H. nemertis, XlOOO (Debaisieux); e, H. heterocirii, XlOOO (Caullery and Mesnil); f, H. scolopli, XlOOO (Caullery and Mesnil); g, H. vejdovskii, XlOOO (Caullery and Mesnil); h, i, Uro- sporidium fuliginosum, XlOOO (Caullery and Mesnil); j, k, Bertramia asperospora (j, cyst with spores; k, empty cyst), X1040 (Minchin); 1, m, C oelosporidium periplanetae (1, trophozoite with spores and chromatoid bodies), X2540 (Sprague). H. vejdovskii C. and M. (Fig. 242, g). In a freshwater oligochaete, Mesenchytraeus flavus ; spores 10-12m long. Genus Urosporidium Caullery and Mesnil. Similar to Haplo- sporidium, but spherical spore with a long projection. U. fuliginosum C. and M. (Fig. 242, h, i). In the coelom of the polychaete, Syllis gracilis; rare. ACNIDOSPORIDIA, SARCOSPORIDIA 513 Genus Anurosporidium Caullery and Chappellier. Similar to Haplosporidium, but operculate spore spherical. A. pelseneeri C. and C. In sporocyst of a trematode parasitic in Donax trunculus; schizogony intracellular; cysts extracellular, with up to 200 spores; spores about 5ai long. Genus Bertramia Caullery and Mesnil. Parasitic in aquatic worms and rotifers; sausage-shaped bodies in coelom of host; spherical spores which develop in them, possess a uninucleate sporoplasm and a well-developed membrane. B. asperospora (Fritsch) (Fig. 242, j, k). In body cavity of rotifers: Brachionus, Asplanchna, Synchaeta, Hydatina, etc.; fully grown vermicular body 70-90m with 80-150 spores. B. capitellae C. and M. In the annelid Capitella capitata; spores 2.5m in diameter. B. euchlanis Konsuloff. In coelom of rotifers belonging to the genus Euchlanis. Genus Ichthyosporidium Caullery and Mesnil. In fish; often looked upon as Microsporidia, as the organism develops into large bodies in body muscles, connective tissue, or gills, which appear as conspicuous "cysts," that are surrounded by a thick wall and con- tain numerous spores. I. giganteum (Thelohan) (Fig. 241). In various organs of Creni- lahrus melops and C. ocellatus; cysts 30/x-2 mm. in diameter; spores 5-8m long. /, hertwigi Swarczewsky. In Crenilahrus paro; cysts 3-4 mm. in diameter in gills; spores 6m long. Genus Coelosporidium Mesnil and Marchoux. In coelom of Cla- docera or Malpighian tubules of cockroach; body small, forming cysts; spores resemble microsporidian spores; but without a polar filament. C. periplanetae (Lutz and Splendore) (C. hlatellae Crawley) (Fig. 242, I, m). In lumen of Malpighian tubules of cockroaches; common; spores 5.5-7.5m by 3-4m. References Alexeieff, a. 1913 Recherches sur Sarcosporidies. Arch. zool. exper. gen.. Vol. 51. B ARAB AN, L. and G. St. Remy 1894 Sur une cas de tubes psoro- spermiques observers chez I'homme. C. r. soc. biol., Vol. 10. Caullery, M. and F. Mesnil 1905 Recherches sur les Haplo- sporidies. Arch. zool. exp. g^n.. Vol. 4. Crawley, H. 1914 The evolution of Sarcocystis muris in the intes- tinal cells of the mouse. Proc. Acad. Nat. Sci., Philadelphia, Vol. 66. 514 PROTOZOOLOGY Darling, S. T. 1909 Sarcosporidiosis, with report of a case in man. Arch. Int. Med., Vol. 3. 1919 Sarcosporidiosis in an East Indian. Jour. Paras., Vol. 6. GiLMORE, H. R. Jr., B. H. Kean and F.. M. Posey 1942 A case of sarcosporidiosis with parasites found in heart. Amer. Jour. Trop. Med., Vol. 22. Lambert, S. W. Jr. 1927 Sarcosporidian infection of the myocar- dium in man. Amer. Jour. Path., Vol. 3. Scott, J. W. 1943 Life history of Sarcosporidia, with particular reference to Sarcocystis tenella. Bull. Univ. of Wyoming Agr. Exp. Stat., No. 259. Sprague, V. 1940 Observations on Coelosporidium periplanetae with special reference to the development of the spore. Trans. Amer. Micr. Soc, Vol. 59. SWARCZEWSKY, R. 1914 Ueber den Lebenscyklus einiger Haplo- sporidien. Arch. f. Protistenk., Vol. 33. Teichmann, E. 1912 Sarcosporidia. Prowazek's Handhuch der Path. Protozoen., Vol. 1. Weissenberg, R. 1921 Fischhaplosporidien. Ibid., Vol. 3. Chapter 28 Subclass 3 Cnidosporidia Doflein THE members of this subclass possess without exception resist- ant spores which are of unique structure. Each spore possesses 1-4 polar filaments and one to many sporoplasms. The membrane which envelops these structures may be a single-piece or bi- or tri- valved. The polar filament is typically coiled within a polar capsule. In the order Myxosporidia and Actinomyxidia, there appear several cells during the process of sporulation. These cells give rise to one to many sporoplasms or generative cells, capsulogenous cells, and spore membrane. This condition is not observed in other groups of Protozoa and for this reason some writers recognize a close affinity between these two orders and the Mesozoa. The method of multiplication in the Cnidosporidia is schizogonic and sporogonic. The schizogony is binary or multiple fission, budding, or plasmo- tomy. The nuclear division varies from amitosis to mitosis. Isogam- ous, anisogamous, and autogamous reproduction have been re- ported in a number of species. In many forms, the zygote is the sporont, in which one to many spores become differentiated. No secondary or intermediate host has been found for any of the Cnidosporidia. They are exclusively parasites of the lower verte- brates and invertebrates. Since cnidosporidian infections occur frequently in epidemic forms among such economically important animals as the silkworm, honey bees, and commercial fishes, these organisms possess considerable practical significance. The cnidosporidia are divided into the following four orders: Spores comparatively large Shell bivalve; 1, 2, or 4 polar capsules Order 1 Myxosporidia Shell trivalve; 3 polar capsules Order 2 Actinomyxidia (p. 531) Spores comparatively small Shell one-piece; 1 (or 2) polar filament. .Order 3 Microsporidia (p. 535) Barrel-shaped; a thick filament coiled beneath the shell; 3 sporoplasms Order 4 Helicosporidia (p. 542) Order 1 Myxosporidia Btitschli The spore of a myxosporidian is of various shapes and dimen- sions. It is covered by a bivalve chitinous spore membrane, the two valves meeting in a sutural plane which is either twisted (in three genera) or more or less straight. The membrane may possess various markings or processes. The polar capsule, with its short coiled 515 516 PROTOZOOLOGY filament, varies in number from one to four. Except in the family Myxidiidae, in which one polar capsule is situated near each of the poles of the spore, the polar capusles are always grouped at one end which is ordinarily designated as the anterior end of the spore. Below or between (in Myxidiidae) the polar capsules, there is almost always a sporoplasm. Ordinarily a young spore possesses two sporoplasm nuclei which fuse into one (autogamy) when the spore becomes mature. In Myxobolidae there is a glycogenous substance in a vacu- FiG. 243. Sporogony in Myxosoma catostomi, X2130 (Kudo), a, sporont or pansporoblast; b-h, development of two sporoblasts within the spo- ront; i, a nearly mature spore; j-1, views of spore. ole which stains mahogany red with iodine and is known as the iodinophilous (iodophile) vacuole. The Myxosporidia are exclusively parasites of lower verte- brates, especially fishes. Both fresh and salt water fishes have been found to harbor, or to be infected by, Myxosporidia in various regions of the world. A few occur in Amphibia and Reptilia, but no species has been found to occur in either birds or mammals. When a spore gains entrance into the digestive tract of a specific host fish, the sporoplasm leaves the spore as an amoebula which penetrates through the gut-epithelium and, after a period of migration, enters CNIDOSPORIDIA, MYXOSPORIDIA 517 the tissues of certain organs, where it grows into a trophozoite at the expense of the host tissue cells, and the nucleus divides repeatedly. Some nuclei become surrounded by masses of dense cytoplasm and become the sporonts (Fig. 243). The sporonts grow and their nuclei divide several times, forming 6-18 daughter nuclei, each with a small mass of cytoplasm. The number of the nuclei thus produced depends upon the structure of the mature spore, and also upon whether 1 or 2 spores develop in a sporont. When the sporont de- velops into a single spore, it is called a monosporoblastic sporont, and if two spores are formed within a sporont, which is usually the case, the sporont is called disporoblastic, or pansporoblast. The spore-formation begins usually in the central area of the large tro- phozoite, which continues to grow. The surrounding host tissue becomes degenerated or modified and forms an envelope that is often large enough to be visible to the naked eye. This is ordinarily referred to as a myxosporidian cyst. If the site of infection is near the body surface, the large cyst breaks and the mature spores become set free in the water. In case the infection is confined to internal organs, the spores will not be set free while the host fish lives. Upon its death and disintegration of the body, however, the liberated spores become the source of new infection. The more primitive Myxosporidia are coelozoic in the host's organs, such as the gall bladder, uriniferous tubules of the kidney, urinary bladder, etc. In these forms, the liberated amoebulae make their way into the specific organ and there grow into multinucleate amoeboid trophozoites which are capable of forming pseudopodia of various types. They multiply by exogenous or endogenous bud- ding or plasmotomy. One to several spores are developed in the trophozoite. Almost all observers agree in maintaining the view that the 2 nuclei of the sporoplasm or 2 uninucleate sporoplasms fuse into one (autogamy or paedogamy), but as to the nuclear as well as cyto- plasmic changes prior to, and during, spore-formation, there is a diversity of opinions. To illustrate the views held by those who be- lieve there is a sexual phase in the development of a myxosporidian, Sphaeromyxa sabrazesi (p. 528) may be taken as an example. De- baisieux's observation on this myxosporidian is in brief as follows (Fig. 244) : Sporoplasms after finding their way into the gall bladder of host fish develop into large trophozoites containing many nuclei (a), 2 vegetative nuclei become surrounded by a cytoplasmic mass (c) and this develops into a primary propagative cell (d) which divides (3 chromosomes are noted) (e) and forms secondary propagative 518 PROTOZOOLOGY cells (/). A binucleate sporocyte is formed from the latter by unequal nuclear division ig-i) and 2 sporocytes unite to form a tetranucleate pansporoblast ij) which develops into 2 spores (A;, I). Sporoplasm shows first 2 nuclei, but later 4, of which 2 degenerate and the other 2 fuse into one nucleus. On the other hand, according to Naville (1930) Fig. 244. The development of Sphaeromyxa sabrazesi (Debaisieux). a, vegetative nuclei; b, association of two vegetative nuclei; c, the same within a cell; d, primary propagative cell; e, its division; f, secondary propagative cells; g, their division; h, formation of sporocyte; i, two sporocytes; j, formation of pansporoblast; k, pansporoblast at later stages; 1, pansporoblast with two spores, the sporoplasm of which contains two nuclei; m, four nuclei in sporoplasm; n, two nuclei remain functional, the other two degenerate, o, fusion of the two nuclei. CNIDOSPORIDIA, MYXOSPORIDIA 51! Fig. 245. The development of Sphaeromyxa sabrazesi (Naville). a, uni- nucleate amoebula enters the gall bladder; b, young multinucleate trophozoite; c, development of macrogametes; d, development of micro- gametes; e, f, plasmogamy; g-m, development of pansporoblast; n, fusion of the two nuclei in the sporoplasm. 520 PROTOZOOLOGY uninucleate amoebula (Fig, 245, a) enters the gall bladder and de- velops into multinucleate trophozoite in which nuclear division re- veals 4 chromosomes (b); within the trophozoite macrogametes and microgametes are independently formed, during which process, chromosome number is reduced into half (2) (c, d); plasogamy be- tween a macrogamete and a microgamete results in production of a binucleate pansporoblast (e,/), from which repeated nuclear division {g-l) forms 2 spores (m); each of the 2 nuclei of the sporoplasm is haploid and the diploid number is restored when the 2 nuclei fuse into one (n). The site of infection by Myxosporidia varies among different species. They have been found in almost all kinds of tissues and organs of host fish, although each myxosporidian has its special site of infection in one to several species of fish. The gills and gall bladder are most frequently parasitized by Myxosporidia in freshwater Fig. 246. A channel cat, heavily infected with Hennegitya exilis, Xi (Kudo). fishes, while the gall bladder and urinary bladder of marine fishes harbor one or more species of Myxosporidia. When the infection is concentrated in the fins or integument, the resulting changes are quite conspicuous (Fig. 246). The infection in the gills is usually manifest by whitish pustules which can be frequently detected with the unaided eye. When the wall of the alimentary canal, mesentery, liver, and other organs are attacked, one sees considerable changes in them. Heavy myxosporidian infection of the gall bladder or uri- nary bladder of the host fish may cause abnormal appearance and coloration or unusual enlargement of the organ, but under ordinary circumstances the infection is detected only by a microscopical ex- amination of its contents. Certain histological changes in the host fish have been mentioned elsewhere (p. 27). Severe epidemic diseases of fishes are frequently found to be due to myxosporidian infections. According to Davis, the "wormy" halibut of the Pacific coast of North America is due to the myxo- sporidian, Unicapsula muscalaris (Fig. 248), which invades the mus- cular tissue of the host fish. The "boil disease" of the barbel, Barhus barbus and others, of European waters, is caused by Myxobolus CNIDOSPORIDIA, MYXOSPORIDIA 521 pfeifferi. Myxosoma cerebralis which attacks the supporting tissues of salmonoid fish, is known to be responsible for the so-called "twist disease," which is often fatal, especially to young fishes and which occurs in an epidemic form. The Myxosporidia are divided into three suborders: Largest diameter of spore at right angles to sutural plane; with 1 polar capsule on each side; sporoplasm without iodinophilous vascuole. . Suborder 1 Eurysporea Spore spherical or subspherical with 1, 2, or 4 polar capsules; sporoplasm without iodinophilous vacuole. .Suborder 2 Sphaerosporea (p. 523) Sutural plane coincides with, or is at an acute angle to, largest diameter of spore; 1, 2, or 4 polar capsules; sporoplasm with or without iodino- philous vacuole Suborder 3 Platysporea (p. 526) Suborder 1 Eurysporea Kudo Spores laterally expanded; coelozoic in marine fish, except one species. . Family 1 Ceratomyxidae Spores less laterally expanded; in freshwater fish; histozoic or coelozoic. . Family 2 Wardiidae (p. 522) Family 1 Ceratomyxidae Doflein Spores are laterally prolonged and therefore sutural diameter is smaller than width; 2 polar capsules at anterior margin; one on each side of sutural plane. Genus Ceratomyxa Thelohan. Shell-valves conical and hollow, attached on bases; sporoplasm usually not filhng intrasporal cavity; in gall-bladder of marine fish. Numerous species. C. mesospora Davis (Fig. 247, a). In the gall-bladder of Cestracion zygaena; spores 8m in sutural diameter and 50-65ai wide. C. hopkinsi Jameson (Fig. 247, h, c). In the gall-bladder of Paro- phrys vetulus, Microstomus pacificus and Citharichthys xanthostigmus; trophozoites disporous; spores 5. 7-7. 5m in sutural diameter and 28.8- 39m broad. Genus Leptotheca Thelohan. Shell-valves hemispherical; in gall- bladder or urinary bladder of marine fish and one in amphibians. Numerous species. L. ohlmacheri (Gurley) (Fig. 247, d-j). In the uriniferous tubules of kidney of frogs and toads; spores 9. 5-1 2m in sutural diameter and 13-14. 5m wide; with 2 uninucleate sporoplasms. Genus Mjrxoproteus Doflein. Spores pyramidal with or without distinct processes at base of pyramid; in urinary bladder of marine fish. 3 species. M. cordiformis Davis (Fig. 249, a). In the urinary bladder of Chae- todipterus faber; spores 12 m by 10-1 1m. 522 PROTOZOOLOGY Fig. 247. a, Ceratomyxa mesospora, XlOOO (Davis); b, c, C. hopkinsi, XlOOO (Jameson); d-j, Leptotheca ohlmacheri (d, section of a uriniferous tubule of Rana pipiens, with trophozoites and spores, X800; e, a tropho- zoite with a bud; f-h, disporous trophozoites; i, a spore with extruded polar filaments; j, surface view of spore, X1500) (Kudo). Family 2 Wardiidae Kudo Genus Wardia Kudo. Spores isosceles triangle with 2 convex sides; oval in profile; 2 large polar capsules; tissue parasites of freshwater fish. 2 species. CNIDOSPORIDIA, MYXOSPORIDIA 523 W. ovinocua K. (Fig. 249, 6). In the ovary of Lepomis humilis; spores 9-1 1/i in sutural diameter and 10-12^ wide. Genus Mitraspora Fujita. Spores circular or ovoidal in front view; somewhat flattened in profile; 2 polar capsules; shell striated; with or without posterior filaments; in kidneys of freshwater fishes. This genus apparently includes border-line forms between this and other suborders. 3 species. Fig. 248. Unicapsula muscularis (Davis), a, b, infected muscle fibers, X20; c, cross-section of an infected muscle, X190; d, part of a section of an infected muscle, X575; e-h, spores, X2500. M. elongata Kudo. In the kidney of Apomotis cyanellus; spores 15-17/x by 5-6m. Suborder 2 Sphaerosporea Kudo Spore with 1 polar capsule Famil}^ 1 Unicapsulidae (p. 524) Spore with 2 polar capsules Family 2 Sphaerosporidae (p. 524) Spore with 4 polar capsules Family 3 Chloromyxidae (p. 526) 524 PROTOZOOLOGY Family 1 Unicapsulidae Kudo Genus Unicapsula Davis, Spherical spore with 1 polar capsule; shell-valves asymmetrical; sutural line sinuous; histozoic in marine fish. One species. U. muscularis D. (Fig. 248). Spore about 6m in diameter; 2 uni- nucleate sporoplasms; in muscle fibers of halibut; Pacific coast of North America; the cause of the "wormy" halibut (Davis). Fig. 249. a, Mijxoproteus cordiformis, X 1000 (Davis) ; b, Wardia ovino- cua, X1330 (Kudo); c, Sphaerospora polymorpha, XlOOO (Davis); d-i, S. tincae (d, external appearance of a heavily infected young tench; e, in- ternal appearance, X§; f, mature pansporoblast; g, h, two spores; i, germi- nation of spore, XlOOO) (L^ger); j, k, Sinuolinea dimorpha (j, trophozoite with three gemmules, X420; k, a spore, X930) (Davis); 1, m, Chloro- myxum leydigi (1, X500; m, XlOOO) (Thelohan); n, C. trijugum, X1130 (Kudo). Family 2 Sphaerosporidae Davis Genus Sphaerospora Thelohan. Spore spherical or subspherical; sutural line straight; 2 polar capsules at anterior end; coelozoic or histozoic in marine or freshwater fishes. CNIDOSPORIDIA, MYXOSPORIDIA 525 S. polymorpha Davis (Figs. 249, c; 250, a-e). In the urinary blad- der of toadfish, Opsanus tau and 0. beta. Trophozoites amoeboid with conical pseudopodia; up to 100m long, the majority being 20-50/x long; plasmotomy; disporoblastic; disporous or polysporous. Spores spheroidal; shell-valves finely striated; polar capsules divergent; fresh spores measure 7. 5-9. 5m by 7-8m. The trophozoites suffer fre- quently infection by Nosema notahilis (p. 538). *S. tincae Plehn (Fig. 249, d-i). In the kidney and other viscera of Tinea tinea in France and Germany; cause of epidemic disease Fig. 250. a-e, Sphaerospora polymorpha (Kudo), a, a trophozoite in life, X1840; b, a stage in a simple plasmotomy, X850; c, front view and d, an- terior end view of fresh spores, X1700; e, a spore with the extruded polar filaments (one is shown only in part), X1700. f-h, Myxidium serotimim. f, a stained young trophozoite, X1840 (Kudo); g, h, two views of fresh spores showing the ridges on shell-valves, XllOO (Kudo and Sprague). among young tench; disease is manifest by great distension of anter- ior portion of abdomen and up-turned mouth : infection fatal through rupture of abdominal wall; spores 7-8. 75m in diameter. Genus Sinuolinea Davis. Spherical or subspherical spores; su- tural line sinuous; with or without lateral processes; 2 spherical polar capsules; in urinary bladder of marine fish. S. dimorpha D. (Fig. 249, j, k). In Cynoscion regalis; spores 15m in diameter. 526 PROTOZOOLOGY Family 3 Chloromyxidae Thelohan Genus Chloromyxum Mingazzini. Spore with 4 polar capsules, grouped at anterior end; shell surface often striated or ridged; sutural line frequently obscure; histozoic or coelozoic in freshwater or marine fish and also in amphibians. Numerous species. C. leydigi M. (Figs. 68, c, d; 249, I, m). In the gall-bladder of vari- ous species of Raja, Torpedo and Cestracion; spores 6-9^ by 5-6^; widely distributed. C. trijugum Kudo (Fig. 249, n). In the gall-bladder cf Xenotis megalotis and Pomoxis sparoides; spores 8- 10m by 5-7m. ■:■< .';,.:1?**M;'. • ; -f i Fig. 251. Scattered spores, young and sporulating trophozoites of Myxid- ium serotinum, as seen in the bile of a frog in life, X64 (Kudo). Suborder 3 Platysporea Kudo Without iodinophilous vacuole 2 polar capsules, one at each pole Family 1 Myxidiidae 1 polar capsule Family 2 Coccomyxidae (p. 528) 2 or 4 polar capsules grouped Family 3 Myxosomatidae (p. 528) With an iodinophilous vacuole Family 4 Myxobolidae (p. 530) Family 1 Myxidiidae Thelohan Genus Myxidium Biitschli. Spores fusiform with pointed or rounded ends; polar filament comparatively long, fine; coelozoic or CNIDOSPORIDIA, MYXOSPORIDIA 527 histozoic in fishes, also in amphibians and reptiles. Numerous species. M. lieherkuhni Butschli (Figs. 68, a, h; 252, a~d). In urinary blad- der of Esox spp.; spores 18-20m by 5-6m; widely distributed. M. immersum (Lutz) (Cystodiscus immersus Lutz; M. lindoyense Carini). (Fig. 252, e, /). In the gall bladder of species of Bufo, Leptodactylus, Atelopus, etc.; in Brazil and Uruguay. Trophozoites Fig. 252. a-d, Myxidium lieberkuhni ^a, a trophozoite, X220 (Lieber- kiihn); b, a small trophozoite, XlOOO; c, d, spores, X1400) (Kudo); e, f, M. immersum, X1400 (Kudo); g-i, Sphaeromj/xa balbianii (g, Xf; h, a spore, X1400 (Davis); i, spore with extruded polar filaments, X840 (Th61ohan)); j-1, S. sabrazesi (j, trophozoite, XlO; k, 1, spores, XlOOO) (Schroder); m, n, Zschokkella hildae (m, X600; n, X1060) (Auerbach); o-t, Coccomyxa morovi (o, a young binucleate trophozoite; p-s, develop- ment of sporoblast; t, a spore with the extruded polar filament), X665 (Leger and Hesse). circular to oval, and very thin; up to 4 mm. in diameter; disporo- blastic; polysporous. Spores 11. 8-13. 3m by 7.5-8. 6/x; shell-valves marked with 1 longitudinal and 7-9 transverse ridges. M. serotinum Kudo and Sprague (Figs. 250, f-h; 251). In the gall 528 PROTOZOOLOGY bladder of Bufo terrestris, Rana pipiens, R. clamitans and R. spheno- cephala; in the United States. Trophozoites up to 6.5 by 1.8 mm., extremely thin; cytoplasm highly alveolated; endogenous budding; disporoblastic; polysporous. Spores 16-18m by 9/x; shell-valve with 2-4 longitudinal and 10-13 transverse ridges. M. kudoi Meglitsch. In gall-bladder of Ictalurus furcatus; troph- ozoites large disc-like up to 1 mm. in diameter; spores 8.5-12^ long by 4-6m. Genus Sphaeromyxa Thelohan. Spore fusiform, but ends usually truncate; polar filament short, thick; trophozoites large, discoid; coelozoic in marine fish. Several species. S. halhianii T. (Figs. 68, e; 252, g-i). In gall-bladder of Motella and other marine fish in Europe and of Siphostoma in the United States; spores 15-20m by 5-6//. S. sabrazesi Laveran and Mesnil (Figs. 244; 245; 252, j-l). In gall- bladder of Hippocampus, Motella, etc.; spores 22-28m by 3-4)u. Genus Zschokkella Auerbach. Spore semi-circular in front view; fusiform in profile; circular in cross-section; ends pointed obliquely; polar capsules large, spherical; sutural line usually in S-form, coelo- zoic in fish or amphibians. A few species. Z. hildae A. (Fig. 252, m, n). In urinary bladder of Gadus spp.; spores 16-29/x by 13-18m. Family 2 Coccomyxidae Leger and Hesse Spore ellipsoidal; one polar capsule at one end; circular in cross- section; undoubtedly a border-line form between Myxosporidia and Microsporidia. Genus Coccomyxa Leger and Hesse. Polar filament long, fine; coelozoic parasite in marine fish. C. morovi L. and H. (Fig. 252, o-t). In the gall-bladder of Clupea pilchardus) ; spores 14jLt by 5-6iu. Family 3 Mjrxosomatidae Poche Two or 4 polar capsules at anterior end; sporoplasm without any iodinophilous vacuoles. Genus M3rxosoma Thelohan {Lentospora Plehn). Spore circular, oval or ellipsoid in front view, lenticular in profile; 2 polar capsules at anterior end; histozoic in marine or fresh water fish. Several species. M. catostomi Kudo (Figs. 57; 243). In the muscle and connective tissue of Catostomus commersonii; spores 13-15/x by 10-11. 5jli. CNIDOSPORIDIA, MYXOSPORIDIA 529 M. cerehralis (Hofer) (Fig. 253, a). In the cartilage and perichon- drium of salmonoid fish; young fish are especially affected by in- fection, the disease being known as the "twist-disease" (Dreh- krankheit); spores 6-10m in diameter. Fig. 253. a, Myxosoma cerehralis, X800 (Plehn); b, Agarella gracilis, X1660 (Dunkerley); c, d, Thelohanellus notatus, X1530 (Kudo); e, f, Myxobolus pfeifferi (e, section of a cyst; f, spore treated with Lugol, X17S0) (Keysselitz) ; g-i, M. orbiculatus (g, infected muscle, X600; h, a fresh spore; i, Lugol-treated spore, XlOOO) (Kudo); j, k, M. conspicuus, X1530 (Kudo); l-o, M. squamosus (1, a cyst under a scale, X6.5) (Kudo); p, Henneguya psorospermica, X1330 (Th^lohan); q-s, H. exilis, X1530 (Kudo). Genus Agarella Dunkerly. Spore elongate oval; 4 polar capsules at anterior end; shell prolonged posteriorly into long processes. One species. A . gracilis D. (Fig. 253, h). In the testis of South American lung- fish, Lepidosiren paradoxa. 530 PROTOZOOLOGY Family 4 Myxobolidae Thelohan One, 2, or 4 polar capsules grouped at anterior end; sporo plasm with iodinophilous vacuole. Genus Myxobolus Biitschli. Spores ovoidal or ellipsoidal, flat- tened; 2 polar capsules at anterior end; sporoplasm with an iodin- ophilous vacuole; sometimes with a posterior prolongation of shell; exclusively histozoic in freshwater fish or amphibians. Numerous species. ^- pfeifferi Thelohan (Fig. 253, e,f). In the muscle and connective tissue of body and various organs of Barhus barhus, B. fluviatilis, and B. plebejus; tumor up to a diameter of 7 cm; most of infected fish die from the effect (Keysselitz) ; spores 12-12.5^ by 10-10. 5/i. M. orbiculatus Kudo (Fig. 253, g-i). In muscle of Notropis gilberti; spores 9-10m in diameter by 6.5-7m thick. M. conspicuus K. (Fig. 253, j, k). In corium of head of Moxostoma breviceps; tumors 1/2-4 mm.; spores 9-11. 5m by 6.5-8ju. M. intestinalis K. (Fig. 1, a). In the intestinal wall of Pomoxis sparoides; (fixed unstained) spores, 12-13m by 10-12.5m; the his- tological changes brought about by this protozoan have been men- tioned elsewhere (p. 27). M. squamosus K. (Fig. 253, l-o). In connective tissue below scales of Hybopsis kentuckiensis; spore circular in front view, 8-9m in diameter, 4.5-5iu thick. Genus Thelohanellus Kudo. Pyi'iform spores, each with one polar capsule; sporoplasm with an iodinophilous vacuole; histozoic in freshwater fish. 11 species. T. notatus (Mavor) (Figs, 1, 6; 253, c, d). In subdermal connective tissue of Pimephales notatus, Cliola vigilax, Notropis cornutus, N. blennius, and Leuciscus rutilus; tumor up to 7 mm, in diameter; spores 17-18m by 7.5-10m; host tissue surrounding the organism be- comes so greatly changed that it appears as an epithelium (p. 27). Genus Henneguya Thelohan. Spore circular or ovoidal in front view; flattened; 2 polar capsules at anterior end; each shell-valve prolonged posteriorly into a long process; sporoplasm with an iodino- philous vacuole; mostly histozoic in freshwater fish. Numerous spec- ies. H. psorospermica T. (Fig. 253, p). In gills of Esox and Perca; cyst formation; total length of spores 35-40m. H. exilis Kudo (Figs. 246; 253, q-s). In gills and integument of Ictalurus punctatus; cysts up to 3 mm. in diameter, conspicuous; spores, total length 60-70^, spore proper 18-20ju long by 4-5/^ wide by 3-3.5ju thick. CNIDOSPORIDIA, ACTINOMYXIDIA 531 H. mictospora Kudo. In the urinary bladder of Lepomis spp. and Micropterus salmoides; spores 13.5-15)U long, 8-9m wide, 6-7. 5^ thick; caudal prolongation 30-40m long. Order 2 Actinom3rxidia Stole The Cnidosporodia placed in this order have been less frequently studied and, therefore, not so well known as the Myxosporidia. The spore is enveloped by a membrane, or shell composed of 3 valves which are sometimes drawn out into simple or bifurcated processes. There are also 3 polar capsules in the spore and the polar filaments are plainly visible m vivo. One to several sporoplasms occur in each spore. In the fully grown stage, the body is covered by a membrane and contains always 8 sporoplasts which develop in turn into 8 spores. Whether the pansporoblast is formed by the union of 2 cells or not, is yet to be confirmed. The nuclei and cytoplasm divide and isogamy takes place. The zygote thus formed is the sporont in which a single spore is produced by repeated nuclear division com- bined with cytoplasmic differentiation. The Actinomyxidia inhabit the body cavity or the gut-epithehum of fresh or salt water annelids. Spore with a double membrane; inner membrane a single piece, the outer tri valve; a single binucleate sporoplasm Family 1 Tetractinomyxidae Spore membrane a single trivalve shell; a single octonucleate sporoplasm or 8 uninucleate sporoplasms Family 2 Triactinomyxidae Family 1 Tetractinomyxidae Poche Genus Tetractinomyxon Ikeda. In the coelom of the sipunculid Pt- talostoma minutum; spores tetrahedron, without processes; tropho- zoite a rounded body, when mature; pansporoblast develops 8 spores. Seemingly borderline forms between the Myxosporidia and the Actinomyxidia. T. intermedium I. (Fig. 254, a). Spherical pansporoblasts 20-25/x in diameter; spores 7-8m in diameter; in coelom of the sipunculid, Petalostoma minutum. Family 2 Triactinomyxidae Genus Triactinomyxon Stole. Each of 3 shell-valves drawn out into a long process, the whole anchor-like; spore with 8 or more uninucleate sporoplasms; in the gut-epithelium of oligochaetes. T. ignotum S. (Fig. 254, d). Spore with 8 sporoplasms; in Tuhifex tubifex. 532 PROTOZOOLOGY T. magnum Granata. Spore with 16 sporoplasms; in Limnodrilus udekemianus. T. legeri Mackinnon and Adams. Spore with 24 sporoplasms; in Tubifex tubifex. T. diihium G. Spore with 32 sporoplasms; in Tubifex tubifex. Fig. 254. a, Tetractinomyxon intermedium, X800 (Ikeda) b,; Sphae- ractinomyxon stolci, X600 (Caullery and Mesnil); c, S. gigas, X665 (Granata); d, Triactinomyxon ignoium, Xl65 (L^ger); e, Hexactinoniyxon ■psammoryctis, X300 (Stole); f, g, Synactinomyxon tubificis, X600 (Stole); h, Neoactinomyxum globosiim, X860 (Granata); i, Guyenotia sphaerulosa, X2095 (Naville). T. mrazeki M. and A. Spore with 50 sporoplasms; in Tubifex tubifex. Genus Sphaeractinomyron Caullery and Mesnil. In the coelom of oligochaetes; spores rounded, without any processes; in early stage of development, there are 2 uninucleate bodies surrounded by a bi- CNIDOSPORIDIA, ACTINOMYXIDIA 533 nucleate envelope; 2 inner cells multiply into 16 cells which unite in pairs; nucleus of zygote of sporont divides first into 2; 1 of the nu- clei divides into 6 which form 3 shell-valves and 3 polar capsules, while the other nucleus together with a portion of cytoplasm remains outside the envelope, and undergoes multiplication; multinucleate sporoplasm migrates into spore; sporoplasm later divides into a large number of uninucleate sporoplasms which, when spores gain entrance into a new host, begin development. S. stolci C. and M. (Fig. 254, 6). Spore spherical; in Clitellis are- narius and Hemitubifex henedii. S. gigas Granata (Fig. 254, c). In the coelom of Limnodrilus hoff- meisteri. Genus Hexactinomyxon Stole. Each of 3 shell-valves prolonged into 2 processes; spore appears as a 6-armed anchor. H. psammorydis S. (Fig. 254, e). In the gut-epithelium cf Psam- moryctes harhatus; sporoplasm multinucleate. Genus Synactinomyxon Stole. Spore with 2 prolonged shell-valves and 1 conical valve. S. tuhificis S. (Fig. 254, /, g). In the gut-epithelium of Tuhifex tuhifex. Genus Neoactinomyxum Granata. 3 shell-valves without any pro- cess, distended to hemisphere. A'', glohosum G. (Fig. 254, h). In the gut-epithelium of Limnodrilus udekemianus; spore with numerous sporoplasms. Genus Guyenotia Naville. Pansporoblast with 8 spores; spore spherical with 3 shell-valves, each drawn out posteriorly into digiti- form process, longer than diameter of spore; sporoplasm with 32 nuclei. G. sphaerulosa N. (Fig. 254, i). In the gut-epithelium of Tuhifex tuhifex; spores 15/i in diameter; appendages of mature spore 40m long. References AuERBACH, M. 1910 Die Cnidosporidien. Leipzig. Caullery, M. and F. Mesnil 1905 Recherches sur les Actinomy- xidies. Arch. f. Protistenk., Vol. 6. Davis, H. S. 1917 The Myxosporidia of the Beaufort region. Bull. U. S. Bureau Fish., Vol. 35. Fantham, H. B., a. Porter and L. R. Richardson 1939 Some Myxosporidia found in certain fresh-water fishes in Quebec Province, Canada. Parasitology, Vol. 31. 1940 Some more Myxosporidia observed in Canadian fi,shes. Ibid., Vol. 32. Granata, L. 1924 Gli Attinomissidi. Arch. f. Protistenk., Vol. 50. 534 PROTOZOOLOGY Kudo, R. R. 1920 Studies on Myxosporidia. Illinois Biol. Monogr., Vol. 5. 1933 A taxonomic consideration of Myxosporidia. Trans. Amer. Micr. Soc, Vol. 52. 1934 Studies on some protozoan parasites of fishes of Illi- nois. Illinois Biol. Monogr., Vol. 32. 1943 Further observations on the protozoan, Myxidium serotinum, inhabiting the gall bladder of North American Salien- tia. Jour. Morph., Vol. 72. 1944 The morphology and development of Nosema nota- hilis Kudo, and of its host, Sphaerospora polymorphja Davis, parasitic in Opsanus tau and 0. beta. Illinois Biol. Monogr., Vol. 20. Naville, a. 1930 Le cycle chromosomique d'une nouvelle Actino- mvxidie: Guyenotia sphaerulosa n.gen., n.sp. Quart. Jour. Micr. Sci., Vol. 73. Chapter 29 Order 3 Microsporidia Balbiani THE Microsporidia are far more widely distributed as parasites among various animal phyla than are the Myxosporidia. They are, however, typically parasites of arthropods and fishes. Aside from 1 or 2 species, all Microsporidia invade and destroy host cells. Frequently these infected cells may show enormous hypertrophy of both the cytoplasmic body and the nuclei (Fig. 255), a character- istic feature of the host reaction toward this particular group of protozoan parasites. Fig. 255. Effects of microsporidian infection upon hosts, a, the central nervous system of Lophius piscatoris infected by Nosema lophii (Doflein); b, a smelt infected by Glugea hertwigi (Schrader) ; c, larva of Culex territans infected by Thelohania opacita, XlO (Kudo); d, a Simulium larva in- fected by T. multispora, X8 (Strickland); e, part of testis of Barbus barhus infected by Plistophora longifilis, X 1 (Schuberg) ; f , g, normal and hyper- trophied nucleus of adipose tissue of larval Ci lex pipiens, the latter due to infection by Stempellia magna, XlOOO (Kudo). The microsporidian spore is relatively small. In the vast majority it meastures 3-6m long. The spore membrane, which is apparently of a single piece, envelops the sporoplasm and the polar filament, a very long and fine filament. The latter may directly be coiled in the spore or may be encased within a polar capsule which is similar to that of a myxosporidian or actinomyxidian spore in structure, but which is mostly obscure in vivo, because of the minuteness of the object. When such spores are taken into the digestive tract of a specific 535 536 PROTOZOOLOGY host (Fig, 256), the polar filaments are extruded and perhaps anchor the spores to the gut-epithelium (a). The sporoplasms emerge through the opening after the filaments become completely de- tached (b). By amoeboid movements they penetrate through the in- testinal epithelium and enter the blood stream or body cavity and reach the specific site of infection (c). They then enter the host cells and undergo multiplication at the expense of the latter (d-n).The trophozoites become sporonts, each of which produces a number of Fig. 256. The life-cycle of Stempellia magna, X800 (Kudo), a, b, ger- mination of spore in the mid-gut of culicine larva; c-k, division stages; 1-p, sporont formation; q-t, formation of 1, 2, 4, and 8 sporoblasts; u, sporoblast; v-x, development of sporoblast into spore. spores (p-x) characteristic of each genus. Some spores seem to be capable of germinating in the same host body, and thus the number of infected cells increases. When heavily infected, the host animal dies as a result of the degeneration of enormous numbers of cells thus attacked. Such fatal infections may occur in an epidemic form, as is well known in the case of the pebrine disease of silkworms, the nosema-disease of honey bees, microsporidiosis of mosquito larvae, etc. Spore with a single polar filament Suborder 1 Monocnidea (p. 537) Spore with 2 polar filaments Suborder 2 Dicnidea (p. 542) MICROSPORIDIA 537 Suborder 1 Monocnidea Leger and Hesse Spore oval, ovoid, or pyriform, if subcylindrical length less than 4 times breadth Family 1 Nosematidae Spore spherical or subspherical Family 2 Coccosporidae (p. 541) Spore tubular or cylindrical, width less than 1/5 length, straight or curved Family 3 Mrazekiidae (p. 541) Family 1 Nosematidae Labbe The majority of Microsporidia belong to this family. Genus Nosema Nageli. Each sporont develops into a single spore. Numerous species. A^. bombycis N. (Fig. 257, a, b). In all tissues of embryo, larva, pupa and adult of Bombyx mori; spores 3-4/i by 1.5-2/z, polar fila- Q 6" 0^ B^ Fig. 257. a, b, Nosema bombycis (a, spore, X1470; b, an infected silk- worm larva, X§) (Kudo); c, d, N.bryozoides (c, infected funiculus, X270 (Braem); d, a spore, X1200 (Schroder)); e, f, N. apis, X1560 (Kudo); g-i, N. cydopis, X1560 (Kudo); j, k, N. anophelis, X1600 (Kudo); 1, m, Glugea anomala (1, section of an infected Gasterosteus aculeatus (Th61o- han); m, a spore, X1500 (Stempell)); n, G. herhvigi, X1670 (Weissen- berg); o, Perezia mesnili, XSOO (Paillot); p, q, Gurleya richardi X1200 (C^pede). ment 57-72/x long; the causative organism of the pebrine disease of the silkworm. A^. bryozoides (Korotneff) (Fig. 257, c, d). In germ cells and cavity of Plumatella fungosa and P. repens; spores 7-10m by 5-6^1; A^. apis Zander (Fig. 257, e, /). In the gut cf hcney bees; spores 4-6m by 2-4m. N. cydopis Kudo (Fig. 257, g-i). In Cyclops fuscus; spores 4.5^ by 3m. A'', anophelis K. (Fig. 257, j, k). In Anopheles quadrimaculatus (larvae) ; spores 5-6/x by 2-3)u. 538 PROTOZOOLOGY N. notahilis K. (Fig. 258, a-c). In the trophozoite of a myxospori- dian, Sphaerospora polyjyiorpha (p. 525) which inhabits the urinary bladder of Opsanus tau and 0. beta. The host fish remain free from the microsporidian infection. The entire development takes place in the cytoplasm of the host trophozoites. Trophozoites small binu- cleate, multiply by binary fission. Spores ovoid to ellipsoid; sporo- plasm binucleate; fresh spores 2.9-4)u by 1.4-2.5^*; extruded polar 0-6 oo ^ Fig. 258. a-c, Nosema notahilis, X1400 (Kudo), a, a stained trophozoite of Sphaerospora polymorpha, infected by 6 trophozoites of N. notahilis; b, another stained host trophozoite in which 9 spores and 2 trophozoites of N. notahilis occur; c, 8 fresh spores of N. notahilis. d-g, Duboscqia legeri (Kudo), d, mid-intestine of Reticulitermes flavipes, to which are attached an (enlarged) infected and 2 uninfected fat bodies, X57; e, f, mature sporonts containing 16 spores as seen in Hfe, X1530; g, portions of in- fected and normal fat bodies of the termite as seen in a section, X1530. filament 45-62yu. When heavily infected, the host myxosporidian trophozoites degenerate and disintegrate. A unique example of hy- perparasitism in which two cnidosporidians are involved. MICROSPORIDIA 539 Genus Glugea Thelohan. Each sporont develops into 2 spores; the infected host cells become extremely hypertrophied, and trans- form themselves into the so-called Glugea cysts. Many species. G. anomala (Moniez) (Fig. 257, I, m). In the connective tissue of stickle backs; spores 4-6^ by 2-3;u. G. millleri Pfeiffer. In muscles of Gammarus; spores 5-6m by 2-3iii. G. hertwigi Weissenberg (Figs. 255, h; 257, n). In various tissue cells of Osmerus; spores 4-5. 5m by 2-2. 5/x. Genus Perezia Leger and Duboscq. Each sporont produces 2 spores as in Glugea, but infected host cells are not hypertrophied. A few species. P. mesnili Paillot (Fig. 257, o). In cells of silk glands and Malpi- ghian tubules of larvae of Pieris brassicae; spores 3.4/x by 1.5-2ju. Genus Gurleya Doflein. Each sporont develops into 4 sporoblasts and finally into 4 spores. Not common. G. richardi Cepede (Fig. 257, p, q). In Diaptomus castor; spores 4-6m by 2.8m. Genus Thelohania Henneguy. Each sporont develops into 8 sporo- blasts and ultimately into 8 spores; sporont membrane may degen- erate at different times during spore formation. Numerous species. T. legeri Hesse (Figs. 71; 259, a-e). In fat-bodies of anopheline larvae; spores 4-6/x by 3-4/x; heavily infected larvae die without metamorphosing into adults; widely distributed. T. opacita Kudo (Figs. 255, c; 259, f-h). In fat-bodies of culicine larvae; spores 5.5-6m by 3.5-4^. Genus Stempellia Leger and Hesse. Each sporont produces 1, 2, 4, or 8 sporoblasts and finally 1, 2, 4, or 8 spores. 2 species, S. magna Kudo (Figs. 255, /, g; 256; 259, i-l). In fat-bodies of various culicine larvae; spores 12. 5-16. 5m by 4-5m; polar capsule visible in life; polar filament when extruded under mechanical pres- sure, measures up to 350-400m long. Genus Duboscqia Perez. Sporont develops into 16 sporoblasts and finally 16 spores. Host-cell nuclei extremely hypertrophied. One species. D. legeri P. (Fig. 258, d-g). In the fat-body cells of Reticulitermes lucifugus a,nd R.flavipes. Trophozoites invade the peri-midintestinal adipose tissue cells which become enlarged into "cysts," up to 660m by 300m, because of active multiplication of the organisms; each binucleate schizont becomes a sporont which grows and produces 16 spores. Spores ovoid to ellipsoid; fresh spores are 4. 3-5. 9m by 2.2-3m; sporoplasm uninucleate; extruded polar filament 80-95m long. Genus Trichoduboscqia Leger. Similar to Duboscqia in number of 540 PROTOZOOLOGY spores produced in each sporont; but sporont with 4 (or 3) rigid transparent prolongations, difficult to see in life. One species. T. epeori L. (Fig. 259, m, n). In fat-bodies of nymphs of Epeorus torrentium and Rhithrogena semicolorata; sporonts spherical, 9-10/i in diameter, with usually 16 spores; prolongations of membrane in sporont, 20-22ju long; spores pyriform, 3.5-4;u long. Genus Plistophora Gurley. Sporont develops into variable number (often more than 16) of sporoblasts, each of which becomes a spore. Several species. Fig. 259. a-e, Thelohania legeri (a, b, sporogony; c, d, mature sporonts; e, a fresh spore), X1570 (Kudo); f-h, T. opacita (f, g, octosporous and tetrasporous sporonts; h, a spore) X1570 (Kudo); i-1, Stempellia magna (i-k, spores; 1, a spore with the extruded polar filament), X1570 (Kudo); m, n, Trichoduboscqia epeori (m, sporont with mature spores, X1330; n, a spore, X2670) (L^ger); o, p, Plistophora longifilis, X1280 (Schuberg). P. Simula (Lutz and Splendore). In larvae of Simulium spp.; spores 4.5-8m by 3.5/z. P. longifilis Schuberg (Figs. 255, e; 259, o, p). In the testis of Barbus fluviatilis; spores Sju by 2)u to 12jli by Qfi; extruded polar fila- ments up to 510ju long. Genus Pyrotheca' Hesse. Schizogony and sporogony unknown; spores elongate pyriform, anterior end attenuated, posterior end rounded, slightly curved; sporoplasm in posterior region, with 1-2 nuclei; polar capsule large. One species. MICROSPORIDIA 541 P. incurvata H. (Fig. 260, a, h). In fat-bodies and haemocoele of Megacylcops viridis; spores 14/z by 3/1 ; polar filament ISO/i long. Family 2 Coccosporidae Kudo Genus Coccospora Kudo {Cocconema Leger and Hesse). Spore spherical or subspherical. Several species, C. slavinae (L, and H.) (Fig. 260, c, d). In gut-epithelium of Slavina appendiculata; spores about 3/i in diameter. g ■K ( m Fig. 260. a, b, Pyrotheca incurvata, X2000 (Hesse); c, d, Coccospora slavinae (d, with extruded polar filament), X2000 (L^ger and Hesse); e, f, Mrazekia caudata (e, an infected host cell, X700 (Mrazek) ; f, a spore, X1750 (L^ger and Hesse)); g, Bacillidium limnodrili, X1400 (Jirovec); h, i, Cougourdella magna, X2000 (Hesse); j, Octosporea muscae-domesticae X2150 (Chatton and Krempf); k, 1, Spiroglugea octospora (k, XlOOO, 1, X3000) (L^ger and Hesse); m, n, Toxoglugea vibrio (m, XlOOO; n, X3000) (L^ger and Hesse); o, p, Teloimjxa glugeiformis, X3000 (Leger and Hesse). Family 3 Mrazekiidae L^ger and Hesse Genus Mrazekia L. and H. Spore straight, tubular; a long or short process at one extremity. M. caudata L. and H. (Fig. 260, e, /). In lymphocytes of Limno- drilus and Tubifex; spores 16-18/x by 1.3-1.4/i. 542 PROTOZOOLOGY Genus Bacillidium Janda. Spore cylindrical, without any process; one end narrowed in a few species. 8 species. B. limnodrili Jirovec (Fig. 260, g). In lymphocytes within gonads of Limnodrilus claparedeanus ; spores 22-24/i by 1.5/x. Genus Cougourdella Hesse. Spore cylindrical, with an enlarged extremity, resembling the fruit of Lagenaria cougourda. 3 species. C. magna H. (Fig. 260, h, i). In haemocoele and fat body of Mega- cyclops viridis; spores 18m by 3^; polar filament 110^ long; sporo- plasm with 1-2 nuclei or 2 uninucleate sporoplasms. Genus Octosporea Flu. Spore cylindrical; more or less curved; ends similar. 2 species. 0. muscae-domesticae F. (Fig. 260, j). In gut and germ cells of Musca and Drosophila; spores 5-8^ long. Genus Spiroglugea Leger and Hesse. Spore tubular and spirally curved; polar capsule large. One species. S. octospora L. and H. (Fig. 260, k, I). In fat body of larvae of Ceratopogon sp.; spores 8-8.5/Lt by l/x. Genus Toxoglugea Leger and Hesse. Minute spore curved or arched in semi-circle. One species. T. vibrio L. and H. (Fig. 260, m, n). In the fat body of Ceratopogon sp.; spores 3.5)u by less than 0.3/i. Suborder 2 Dicnidea Leger and Hesse Family Telomyxidae Leger and Hesse Genus Telomyxa Leger and Hesse. Spore with 2 polar capsules; sporont develops into 8, 16, or more sporoblasts and finally 8, 16, or more spores. One species. T. glugeiformis L. and H. (Fig. 260, o, p). In the fat body of the larva of Ephemera vulgata; spores 6.5^ by 4^. Order 4 Helicosporidia Kudo This order has been created to include the interesting organism, Helicosporidium, observed by Keilin. Although quite peculiar in the structure of its spore, the organism seems to be best placed in the Cnidosporidia. The minute spore is composed of a thin membrane of one piece and of three uninucleate sporoplasms, around which is coiled a long thick filament. Young trophozoites are found in the host tissues or body cavity. They undergo schizogony, at the end of which uninu- HELICOSPORIDIA 543 cleate sporonts become differentiated. A sporont divides apparently twice and thus forms four small cells which develop into a spore. The complete life-history is still unknown. Genus Helicosporidium Keilin. Parasitic in arthropods; schizog- ony and sporogony; spore with central sporoplasms and a single thick coiled filament. One species. Fig. 261. Diagram illustrating the probable development of Helico- sporidia, X about 1600 (Keilin). a-c, schizont and schizogony; d, spo- ront(?); e, three stages in formation of four-celled stage; f, hypothetical stage; g, young spore before the spiral filament is formed; h, mature spore; i, j, opening of spore and liberation of sporoplasms. a-h, in living host larva; i, j, in dead host body. H. parasiticum K. (Fig. 261). In body cavity, fat body, and nerv- ous system of larvae of Dasyhelea ohscura and Mycetobia pallipes (Diptera), and Hericia hericia (Acarina), all of which inhabit wounds of elm and horse-chestnut trees; schizonts minute; spores 5-6m in diameter; extruded filament 60-65/x by l/z thick. 544 PROTOZOOLOGY References Debaisieux, p. 1928 Etudes cytologiques siir quelques Micro- sporidies. La Cellule, Vol. 38. Fantham, H. B., a. Porter and L. R. Richardson 1941 Some Microsporidia found in certain fishes and insects in eastern Canada. Parasitology, Vol. 33. Hesse, E. 1935 Sur quelques Microsporidies parasites de Megacy- clops viridis Jurine. Arch. zool. exp. et gen., Vol. 75. JiROVEC, O. 1936 Studien liber Microsporidien. Mem. Soc. Zool. Tchecoslovaque de Prague. Vol. 4. Keilin, D. 1921 On the life-history of Helicosporidium para- siticum. Parasitology, Vol. 13. Kudo, R. R. 1924 A biologic and taxonomic study of the Micro- sporidia. Illinois Biol. Monogr., Vol. 9. 1942 On the microsporidian, Duboscqia legeri Perez 1908, parasitic in Reticulitermes flavipes. Jour. Morph., Vol. 71. 1944 The morphology and development of Nosema notahilis Kudo, and of its host, Sphaerospora polymorpha Davis, parasitic in Opsanus tau and 0. beta. Illinois Biol. Monogr., Vol. 20. ScHRADER, F. 1921 A microsporidian occurring in the smelt. Jour. Parasit, Vol. 7. Chapter 30 Subphylum 2 Ciliophora Doflein THE Ciliophora possess cilia which serve as cell-organs of loco- motion. In Suctoria the cilia are present only during early devel- opmental stages. The members of this subphylum possess a unique organization not seen in the Plasmodroma; namely, except Proto- ciliata, the Ciliophora contain two kinds of nuclei: the macronucleus and the micronucleus. The former is large and massive, and controls the metabolic activities of the organism, while the latter is minute and usually vesicular or less compact, and is concerned with the reproductive processes. Nutrition is holozoic or parasitic; holophytic in Cyclotrichium meunieri (p. 565). Sexual reproduction is mainly by conjugation, and asexual reproduction is by binary fission or budding. The majority are free-living, but a number of parasitic forms also occur. The Ciliophora are divided into two classes: Cilia present throughout trophic life Class 1 Ciliata Adult with tentacles; cilia only while young. . Class 2 Suctoria (p. 695) Class 1 Ciliata Perty The class CiHata includes Protozoa of various habitats and body structures, though all possess cilia or cirri during the trophic stage. They inhabit all sorts of fresh and salt water bodies by free-swim- ming, creeping, or being attached to other objects; some are para- sitic in other animals. Free-swimming forms are usually spherical to elliptical, while the creeping forms are, as a rule, flattened or compressed. The cilia are extremely fine, comparatively short, and as a rule arranged in rows (p. 48). In some forms they diminish in number and are replaced by cirri (p. 50). The cilia are primarily cell-organs of lo- comotion, but secondarily through their movements bring the food matter into the cytostome. Moreover, certain cilia appear to be tac- tile organellae. The food of free-living ciliates consists of small plant and animal organisms which ordinarily abound in the water; thus their nutrition is holozoic. The ciliates vary in size from less than lOju up to 2 mm. in large forms (as in an extended Spirostcmum or Sten- tor). The cytoplasm is distinctly differentiated into the ectoplasm and the endo plasm. The ectoplasm gives rise to the cilia and tricho- cysts and is covered by a pellicle. The endoplasm contains nuclei. 545 546 PROTOZOOLOGY food vacuoles, contractile vacuoles, pigment granules, crystals, etc. In the majority of ciliates, the anterior and posterior extremities are permanent and distinct; in all cytostome-possessing forms, the oral and aboral surfaces are distinguishable, while in numerous creeping forms the dorsal and ventral sides are differentiated. The body is covered by a very thin yet definite membrane, the pellicle, which is ordinarily uniformly thin and covers the entire body surface so closely that it is not recognizable in life. In some forms, such as Coleps, it develops into numerous platelets and in others, such as Trichodina, into hook-like processes. The outer half of the ectoplasm may show alveolar structure which, in section, exhibits radiating and parallel lines. In this portion the myonemes (p. 53) are lodged. The deeper layer of the ectoplasm is structureless and free from granules. In the ectoplasm are embedded the basal granules of cilia, which are arranged in longitudinal, oblique, or spiral rows. In recent years complex fibrillar systems have been recognized in many ciliates (p. 54-61). The cilia may fuse to form cirri, membranellae, and undulating membranes (p. 50) which occur in certain groups. In many euciliates contractile vacuoles with one to several collecting canals are one of the prominent structures. The endoplasm is more fluid and the ground substance is finely granu- lated or reticulated; it undergoes rotation movement or c.yclosis. Two types of nuclei are present in all euciliates. The massive macronucleus is of various forms. The chromatin granules which may reach 20^ in diameter (p. 36) fill compactly the intranuclear space. The macronucleus multiplies by amitosis. The micronucleus is ordinarily so minute that it is difficult to see in a living specimen. It is vesicular in structure, although in some it appears to be com- pact, and consists of an endosome, the chromatin, the nucleoplasm, and the membrane. The number of micronuclei present in an indi- vidual varies among different species. At the time of reproduction it increases in size and divides mitotically ; during conjugation it under- goes a characteristic meiotic division (p. 165). The protociliates possess from two to many nuclei of a uniformly same structure and numerous ovoid or spindle-shaped bodies, endo- spherules, the nature of which is open to speculation. Some authors think that they are nuclei (micronuclei (after Hickson) or macro- nuclei (after Konsuloff)); others consider them as reserve food ma- terials (Patten). Metcalf considers that each nucleus possesses both metabolic chromatin and reproductive chromatin, the former being seen as large flattened peripheral masses and the latter, as smaller spheroidal granules. CILIOPHORA, PROTOCILIATA 547 In all except protociliates and a comparatively small number of astomatous euciliates, there is a cytostome which in its simplest form is represented by a small opening on the pellicle, and may or may not be closed when the animal is not feeding. The cytostome opens into the cytopharynx (or gullet), a canal which ends in the deeper portion of the endoplasm. In the cytopharynx there may be present one or more undulating membranes to facilitate intaking of the food. Oc- casionally the cytostome is surrounded by trichites or trichocysts (p. 62). When the cytostome is not at the anterior region as, for instance, in Paramecium, there is a peristome (or oral groove) which starts at or near the anterior end and runs posteriorly. The peristome is ciliated so that food particles are thrown down along it and ulti- mately into the cytostome which is located at its posterior end. Solid waste particles are extruded from the cytopyge, or cell-anus, which is usually noticeable only at the time of actual defecation (p. 92). Following Metcalf, Ciliata are here divided into 2 subclasses: Two to many nuclei of one kind; sexual reproduction permanent fusion . . . Subclass 1 Protociliata Macronucleus and micronucleus; sexual reproduction conjugation Subclass 2 Euciliata (p. 551) Subclass 1 Protociliata Metcalf The protociliates are almost exclusively inhabitants of the large intestine of Salientia; only a few species have been reported from urodeles, reptiles, and fish (Metcalf, 1923, 1940). The body is cov- ered uniformly by cilia of equal length. There is no cytostome and the nutrition is parasitic (saprozoic). The number of nuclei varies from two to many, all of which are of one type. Asexual reproduction is by binary fission or plasmotomy. In a number of species sexual fusion of 2 gametes has been observed (Fig. 263, a-d). Encystment is common. One family. Family Opalinidae Glaus Genus Opalina Purkinje and Valentin. Highly flattened; multi- nucleate; in amphibians. Numerous species. 0. hylaxena Metcalf (Fig. 262, a). In Hyla versicolor; larger indivi- duals about 420m long, 125^ wide, 28/x thick. Several subspecies (Metcalf). 0. ohlrigonoidea M. (Fig. 262, h-f). 400-840iu long, 175-180^ wide, 20-25^t thick; in various species of frogs and toads (Rana, Hyla, Bufo, GastrophrynO; etc.), North America. Numerous subspecies (Metcalf). 548 PROTOZOOLOGY 0. carolinensisM. 90-400/1 by 32-170/x; in Rana pipiens spheno- cephala. 0. pickeringii M. 200-333/1 by 68-100^; in Hyla pickeringii. 0. oregonensis M. 526/x by 123^; in Hyla regilla. 0. spiralis M. 300-355/z long, 130-140^ wide, 25-42/i thick; in Bujo compactilis. 0. chorophili M. About 470/i by IOOm; in Chorophilus triseriatus. 0. kennicotii M. About 240/1 by 85m; in Rana areolata. Fig. 262. a, Three individuals of Opalina hylaxena, X230; b-f, 0. obtrigonoidea, X60 (b, c, from Bufo fowler i; d-f, from Rana pipiens); g, Cepedea cantabrigensis, X230; h, Zelleriella scaphiopodos, X230. (Met- calf.) Genus Cepedea Metcalf. Cylindrical or pyriform; circular in cross-section; multinucleate; all in Amphibia. Numerous species. C. cantabrigensis M. (Fig. 262, g). About 350/t by 84/t; in Rana cantabrigensis. C. hawaiensis M. 170-200/i by 43-60/i; in Rana catesbeiana; Hawaii. C. obovoidea M. About 315/i by 98/i; in Bufo lentiginosus. C. floridensis M. About 230/i by 89/i; in Scaphiopus albus. CILIOPHORA, PROTOCILIATA 549 Genus Protoopalina Metcalf. Cylindrical or spindle-shaped, cir- cular in cross-sectic n; 2 nuclei; in the colon cf various species of Am- phibia with one exception. Numerous species. P. intestinalis (Stein) (Fig. 263, a-d). About 330m by 68m; in Bombina hombina, and B. pachypa; Europe. Fig. 263. a-d, stages in sexual reproduction in Protoopalina intestinalis (Metcalf); e, f, P. saturnalis, X500 (L^ger and Duboscq); g, P. mitotica. X380 (Metcalf). P. saturnalis Leger and Duboscq (Fig. 263, e, /). In the marine fish, Box hoops; 100-1 52m by 22-60m. P. mitotica (M) (Fig. 263, g). 300m by 37m; in Amhystoma tigrinum. 550 PROTOZOOLOGY Genus Zelleriella Metcalf. Greatly flattened; 2 similar nuclei; all in Amphibia. Numerous species. Z. scajphiopodos M. (Fig. 262, h). In Scaphiopus solitarius; about 150^1 long, 90/x broad, 13/i thick. Z. antilliensis (M). About 180/i long, 113)u wide, 32/i thick; in Bufo marinus. Z. hirsuta M. About 113/i long, 60^1 wide, 22/i thick; in Bufo cog- natus. Z. intermedia M. (Fig. 64). About 94^ by SO/x by 16^; in Bufo intermedicus and B. valliceps. References BtJTscHLi, O. 1887-1889 Protozoa. In: Bronn's Klassen und Ord- nungen des Thier-reichs. Vol. 1. DoFLEiN, F. and E. Reichenow 1929 Lehrbuch der Protozoen- kunde. Jena. Kahl, a. 1930-1935 Urtiere oder Protozoa I: Wimpertiere oder Ciliata (Infusoria). In Dahl: Die Tierwelt Deidschlands und der angrenzenden Meeresteile nach ihren Merkmalen und nach ihrer Lebensweise. Parts 18, 21, 25, 30. Kent, W. S. 1880 to 1882 A manual of Infusoria. Stein, F. 1867 Der Organismus der Infusionsthiere. Vol. 2. Stokes, A. C 1888 A preliminary contribution toward a history of the fresh-water Infusoria of the United States. Jour. Trenton. Natural Hist. Soc, Vol. 1. Metcalf, M. M. 1923 The opalinid ciliate infusorians. Smith- sonian Inst. U. S. Nat. Museum, Bull., No. 120. 1940 Further studies on the opalinid ciliate infusorians and their hosts. Proc. U. S. Nat. Mus., Vol. 87. Chapter 31 Subclass 2 Euciliata Metcalf THE most conspicuous group of Protozoa containing 2 nuclei; macronucleus and micronucleus. Sexual reproduction is through conjugation. We owe Kahl a great deal for his series of comprehen- sive taxonomic studies of free-living ciliates. The euciliates are grouped under the following four orders: Without adoral zone of membranellae Order 1 Holotricha With adoral zone of membranellae Adoral zone winds clockwise to cytostome Peristome not extending beyond general body surface Order 2 Spirotricha (p. 636) Peristome extending out like funnel. . . . Order 3 Chonotricha (p. 681) Adoral zone winds counter-clockwise to cytostome , Order 4 Peritricha (p. 683) Order 1 Holotricha Stein The members of this order show uniform ciliation over the entire body surface. Adoral zone does not occur. The majority possess a cytostome which varies among different forms. Nutrition is holo- zoic or saprozoic. Asexual reproduction is usually by transverse fission and sexual reproduction by conjugation. Encystment is com- mon. The holotrichous ciliates are conspicuous free-living forms in all sorts of fresh, brackish, and salt waters, though some are parasitic. The order is here divided into 6 suborders: Without cytostome Suborder 1 Astomata (p. 552) With cytostome Cytostome not rosette-like Without special thigmotactic ciliated field Cytostome on body surface or in peristome, without strong cilia. . Suborder 2 Gymnostomata (p. 560) Cystome in peristome, bearing special cilia or membranes Peristome lined with rows of free cilia Suborder 3 Trichostomata (p. 593) Peristome with membrane; with or without free cilia Suborder 4 Hymenostomata (p. 608) With well-developed thigmotactic ciliated field; commensals in mus- sels Suborder 5 Thigmotricha (p. 623) Cytostome small rosette-like aperture or obscure ; parasitic Suborder 6 Apostomea (p. 630) 551 552 PROTOZOOLOGY Suborder 1 Astomata Schewiakoff The ciliates placed in this suborder possess no cytostome, although there may occur a slit-like organella which has been looked upon as a vestigial cytostome. The body ciliation is usually uniform. Asexual division is carried on by transverse fission and often by budding which results in chain formation. Sexual reproduction is conjugation and in some encystment is known. These organisms are parasitic in various invertebrates living in fresh or salt water. Without attaching organellae or skeletal structures Macronucleus round to elongate Family 1 Anoplophryidae Macronucleus irregular network Family 2 Opalinopsidae (p. 555) With attaching organellae or skeletal structures Contractile vacuole, a long dorsal canal; usually with a sucking or- ganella Family 3 Haptophryidae (p. 555) Contractile vacuoles not canal-like; with various attaching organellae or skeletal structures Family 4 Intoshellinidae (p. 557) Family 1 Anoplophryidae Cepede Genus Anoplophrya Stein {Collinia Cepede). Oval, elongate, ellipsoid or cylindrical; macronucleus ovoid to cylindrical; micro- nucleus small; one to several contractile vacuoles; ciliation dense and uniform; in coelom and gut of Annelida and Crustacea. Numer- ous species. A. marylandensis Conklin (Fig. 264, a). 36-72iu by 16-42iu; in the intestine of Lumhricus terrestris and Helodrilus caliginosus; Balti- more, Maryland. A. orchestii Summers and Kidder (Fig. 264, 6). Polymorphic ac- cording to size; pyriform to broadly ovoid; 7-45 ciliary rows meri- dional, unequally spaced, and more on one surface; macronucleus voluminous, a compact micro nucleus; body 6-68)u long; in the sand- flea, Orchesiia agilis; Woods Hole, Massachusetts. Summers and Kidder (1936) made careful observation on its conjugation and recrganizaticn. Genus Rhizocaryum Caullery and Mesnil. With hollowed ventral surface which serves for attachment; macronucleus drawn out like a tree-root. One species. R. concavum C. and M. (Fig. 264, c). In the gut of Pohjdora caeca and P. flava (polychaetes). Genus Metaphrya Ikeda, Pyriform, anterior end bent slightly to one side; 12 longitudinal ciliary furrows; below ectoplasm, a layer of refringent materials; endoplasm sparse; macronucleus bas- EUCILIATA, HOLOTRICHA b 553 Fig. 264. a, Anoplophrya marylandensis, X500 (Conklin); b, A. or- chestii, X500 (Summers and Kidder); c, Rhizocaryum concavum, X670 (C^pede); d, Metaphrya sagittae, Xl20 (Ikeda); e, Perezella pelagica, X340 (C^pede); f, Dogielella sphaerii, X470 (Poljansky); g, D. minuta, X670 (Poljansky); h, D. Virginia, X670 (Kepner and Carroll); i, Orchito- phrya stellarum, X870 (G^pede); j, Kofoidella eleutheriae, X270 (C^pede); k, Butschliella opheliae, X350 (C^pede); 1. m, Protophrya ovicola (m, a young Littorina rudis with the ciliate), X80 (C^pede). 554 PROTOZOOLOGY ket-like, large, with a spacious hollow; a micronucleus; no contractile vacuoles. One species. M. sagittae I. (Fig. 264, d). About 250/x by ISO/z; in the body cavity of Sagitta sp. Genus Perezella Cepede. Ovoid; ventral surface concave, serves for attachment; macronucleus ellipsoid; contractile vacuole ter- minal; longitudinally, uniformly, ciliated. A few species. P. pelagica C. (Fig. 264, e). In the coelom of copepods (Ascartia, Clausia, Paracalanus) ; about 48/x long. Genus Dogielella Poljansky. Pyriform; longitudinal ciliary rows; contractile vacuole terminal; macronucleus spherical, with a spheri- cal or elliptical micronucleus; in the parenchyma of flatworms or molluscs. 3 species. D. sphaerii P. (Fig. 264, /). 40-100m by 25-54/i; in Sphaerium corneum. D. minuta P. (Fig. 264, g). 12-28^4 by up to 20ij.; in Stenostomum Icucops (Platyhelminthes). D. Virginia (Kepner and Carroll) (Fig. 264, h). 40-50/x long; in the same host animal; Virginia. Genus Orchitophrya Cepede. Elongate pyriform; ciliary rows oblique; macronucleus spherical, central. One species. 0. stellarum C. (Fig. 264, i). In gonads of the echinoderm, Aster- acanthion (Asterias) ruhens; 35-65/i long. Genus Kofoidella Cepede. Pyriform; macronucleus broadly oval; contractile vacuole, subterminal. One species. K. eleutheriae C. (Fig. 264, j). In gastro vascular cavity of the medusa, Eleutheria dichotoma; 30-80^ long. Genus Herpetophrya Siedlecki. Ovoid; with a pointed, mobile, tactile, non-ciliated cone; macronucleus globular; without con- tractile vacuole. One species. H. astomata S. In coelom of Polymnia (annelid). Genus Biitschliella Awerinzew. Elongate with pointed anterior end, with non-ciliated retractile anterior cap; cilia in about 10 slightly spiral rows; macronucleus band-form; several contractile vacuoles in a longitudinal row. Several species. B. opheliae A. (Fig. 264, A;). In Ophelia limacina; 280-360ju by 35-50m. B. chaetogastri Penard. Elongate lanceolate, slightly flattened; longitudinal rows of long cilia; cytoplasm colorless; macronucleus elongate; micronucleus voluminous, vesicular; without contractile vacuole; 60-1 20)u long; in the oesophagus of Chaetogaster sp. Genus Cepedella Poyarkoff. Pyriform with pointed anterior end, EUCILIATA, HOLOTRICHA 555 where there is a depression for fixation of body, with longitudinal myonemes; macro nucleus globular; without contractile vacuole. One species. C. hepatica P. 16-26m long; intracellular parasite of the liver of the mollusc, Sphaerium corneum. Genus Protophrya Kofoid {Isselina Cepede). Ellipsoid to pyriform; spheroidal macronucleus; contractile vacuole terminal. 2 species. P. ovicola K. (Fig. 264, I, m). About 60m long; in the uterus of the mollusc, Littorina rudis. Genus Protanoplophrya Miyashita. Similar to Anoplophrya; but with rudimentar}^ oral apparatus, a long slit, an undulating mem- brane and cytopharynx in anterior region of body; macronucleus elongate band; numerous contractile vacuoles. One species. P. stomata Miyashita (Fig. 265, a). Cylindrical; up to 1.5 mm. by about 70m; in hind-gut of Viviparus japonicus and V. malleatus. Family 2 Opalinopsidae Hartog Genus Opalinopsis Foettinger. Oval or ellipsoid; macronucleus fragmented; ciliation uniform and close; parasite in the liver of cephalopods. A few species. 0. septolae F. (Fig. 265, b). 40-80/x long; in the liver of Sepiola ron- deletii and Octopus tetracirrhus. Genus Chromidina Gonder {Benedenia Foettinger). Elongate; anterior region broader, ends pointed; uniform ciliation; macro- nucleus in irregular network distributed throughout body; micro- nucleus obscure; budding and encystment; Cheissin holds that this is identical with Opalinopsis. One species. C. elegans (Foettinger) (Fig. 265, c, d). 500-1 500/x by about 30-60^ in kidney and gonad of cephalopods: Sepia elegans, Loligo sp., etc. Family 3 Haptophryidae Cepede Genus Haptophrya Stein. Elongate; uniformly ciliated; anterior end with a neck-like constriction; a circular sucker surrounded by 1-2 rows of cilia. A few species. H. michiganensis Woodhead (Fig. 265, e). 1.1-1.6 mm. long; in the gut of the four-toed salamander, Hemidactylium scutatum; Michigan. MacLennan (1944) made a careful study of its contractile canal (p. 76). H. virginiensis Mej^er. 354^ by 95m; macronucleus about one- third of the body length ; in the intestine of Rana palustris. Genus Steinella Cepede. Anterior end broad; sucker-like depres- sion without encircling cilia, but with 2 chitinous hooks. One species. 556 PROTOZOOLOGY S. uncinata (Schultze). Up to 200yu long; in gastro vascular cavity of Planaria ulvae, Gunda segmentata and Proceros sp. Genus Lachmannella Cepede. With a chitinous hook at anterior end; elongate pyriform, anterior end curved; ciliation longitudinal and dense. One species. Fig. 265. a, Protanoplophrya stomata, XlOO (Miyashita); b, Opalinopsis sepiolae, X670 (Gonder); c, d, Chromidina elegans (c, X330 (Chatton and Lwoff); d, X220 (Wermel)); e, Haptophrya michiganensis, X35 (Wood- head) ; f, Lachmannella recur va, X 100 (Cepede) ; g, Sieboldiellina planaria- rum, XlOO (Cepede); h, i, Intoshellina poljanskyi (h, X300; i, attaching organella seen from ventral side, X870) (Cheissin); j, k, Monodontophrya kijenskiji (j, XlOO; k, anterior end in profile, X870) (Cheissin). L. recurva (Claparede and Lachmann) (Fig. 265,/). In the gastro- vascular cavity of Planaria limacina; about 200/x long. EUCILIATA, HOLOTRICHA 557 Genus Sieboldiellina Collin Vermiform, with neck-like constric- tion; simple sucker at anterior end. One species. S. planariarum (Siebold) (Fig. 265, g). Up to 700/li long; in gastro- vascular cavity of various fresh- and salt-water turbellarians, most frequently Planaria iorva. Family 4 Intoshellinidae Cepede Genus Intoshellina Cepede. Elongate; ciliary rows slightly spiral; macronucleus voluminous, highly elongate; 5-7 contractile vacuoles scattered in posterior region; a complicated attaching organella at anterior end (Fig. 265, i) ; vestigial cytopharynx. /. poljanskyi Cheissin (Fig. 265, h, i). 170-280m long; in the intes- tine of Limnodrilus arenarius. Genus Monodontophrya Vejdowsky. Elongate; anterior end with thick ectoplasm; attaching organella at anterior end, with fibrils; macronucleus elongate; numerous contractile vacuoles in a longi- tudinal row. M. kijenskiji Cheissin (Fig. 265, j, k). 400-800^ long; in anterior portion of intestine of Tubifex inflaius. Genus Maupasella Cepede. Ellipsoid; close longitudinal ciliary rows; with a spinous attaching organella at anterior end, with fibrils; contractile vacuoles in 2 irregular rows; macronucleus elongate. One species. M. nova C. (Fig. 266, a). 70-130m long; in the intestine of Alloloho- phora caliginosa (annelid). Genus Schultzellina Cepede. Similar to Maupasella; but with at- taching organella set obliquely; macronucleus voluminous, reniform. S. mucronata C. (Fig. 266, h). In the intestine of Allurus tetraedurus (annelid). Genus Hoplitophrya Stein. Slender, elongate; elongated macro- nucleus; a micro nucleus; a single longitudinal row of many contrac- tile vacuoles on the dorsal side; a single median spicule with a small pointed tooth at its anterior end; in the intestine of oligochaetes. Several species. H. secans S. Elongated; 160-500^ by 20-35^; 15-30 contractile vacuoles in a row; spicule 10-15m long; in the intestine of Lwnhricus variegatus. Genus Radiophrya Rossolimo. Elongate, often with satellites; attaching organella composed of an arrowhead, a tooth and ecto- plasmic fibrils; macronucleus a narrow long band; a single row of many small contractile vacuoles, close to the nucleus. Many species. 558 PROTOZOOLOGY R. hoplites R. (Fig. 266, d, e). 100-IOOOm long; in the intestine of Lamprodrilus, Teleuscolex, Styloscolex, and other oHgochaetes. Genus Metaradiophrya Heidenreich. Ovoid to elhpsoid; with 2 lateral rows of contractile vacuoles; with a hook attached to a long shaft; ectoplasmic fibers supporting the hook; in the intestine of oligochaetes. Several species. Fig. 266. a, Maupasella nova, X280 (C^pede); b, Schiiltzellina mu- cronata, X670 (C^pede); c, Metaradiophrya lumbrici, Xl40 (Cepede); d, e, Radiophrya hoplites (d, Xl30; e, anterior end in profile, X300) (Cheissin); f, Protoradiophrya fissispiculata, X330 (Cheissin); g, Mrazek- iella intermedia, X210 (Cheissin); h, Mesnilella rostrata, X470 (Cheis- sin); i, M. clavata, X290 (Penard). M. lumbrici (Dujardin) (Fig. 266, c). 120-140m by 60-70m; in the intestine of Lumhricus terrestris, L. ruhellus and Eisenia foetida . M. asymmetrica Beers. 115-150m by55-70M; hook 10m long; shaft 25-30/x by 2/x in anterolateral margin in ectoplasm; 25-30 support- ing fibrils; 2 rows of 4 vacuoles each, which do not contract regularly in vitro ; in the intestine (middle third) of Eisenia lonnbergi. EUCILIATA, HOLOTRICHA 559 Genus Protoradiophrya Rossolimo. Elongate; near anterior end a shallow depression along which is found a spicule which may be split posteriorly. A few species. P. fissispicidata Cheissin (Fig. 266, /). 180-350^ long; in the ante- rior portion of intestine of Styloscolex sp. Genus Mrazekiella Kijenskij. Elongate; anterior portion broad with sucker-like depression, posterior region cylindrical; anterior end with attaching organella composed of arrowhead and skeletal ribs; macro nucleus an elongate band; contractile vacuoles dis- tributed. A few species. M. intermedia Cheissin (Fig. 266, g). 180-260^ long; in the anterior portion of intestine of Branchiura coccinea. Genus Mesnilella Cepede. Elongate; with one or more long spicules imbedded in endoplasm; contractile vacuoles in 1-2 rows. Numerous species. M. rostrata Rossolimo (Fig. 266, h). 100-1200/i long; in the intes- tine of various oligochaetes (Styloscolex, Teleuscolex, Lamprodrilus, Agriodrilus, etc.). M. clavata (Leidy) (Fig. 266, i). 100-200^ long; in the intestine of Lumbricus variegatus. References Beers, C. D. 1938 Structure and division in the astomatous ciliate Metaradiophrya asymmetrica n. sp. Jour. E. Mitchell Sci. Soc, Vol. 54. Cepede, C. 1910 Recherches sur les Infusoires astomes. Arch. zool. exp., Vol. 3 (ser. 5). Cheissin, E. 1930 Morphologic und systematische Studien iiber Astomata aus dem Baikalsee. Arch. f. Protistenk., Vol. 70. Heidenreich, E. 1935 Untersuchungen an parasitischen Ciliaten aus Anneliden. I, II. Arch. f. Protistenk., Vol. 84. MacLennan, R. F. 1944 The pulsatory cycle of the contractile canal in the ciliate Haptophrya. Trans. Amer. Micr. Soc, Vol. 63. Rossolimo, L. L. 1926 Parasitische Infusorien aus dem Baikalsee. Arch. f. Protistenk., Vol. 54. Chapter 32 Order 1 Holotricha Stein (continued) Suborder 2 Gymnostomata Biitschli Cytostome at or near anterior end Tribe 1 Prostomata Cytostome not at or near anterior end Cytostome lateral, narrow or round. . .Tribe 2 Pleurostomata (p. 580) Cytostome ventral, in anterior half. . . .Tribe 3 Hypostomata (p. 585) Tribe 1 Prostomata Sc;hewiakoff Free-living Cytostomal region compressed; bearing trichites Family 1 Spathidiidae Cytostomal region not compressed Cytostome opens into anterior receptaculum; with lorica Family 2 Metacystidae (p. 563) Cytostome at tip of apical cone Family 3 Didiniidae (p. 563) Cytostome otherwise Body covered with regularly arranged, perforated, ectoplasmic plates Family 4 Colepidae (p. 565) Body not covered with plates With radially arranged tentacles Family 5 Actinobolinidae (p. 566) Without tentacles Family 6 Holophryidae (p. 567) Parasitic in mammalian gut Family 7 Biitschliidae (p. 576) Family 1 Spathidiidae Kahl Genus Spathidium Dujardin. Flask- or sack-shaped; compressed; anterior region slightly narrowed into a neck, and truncate; ciliation uniform; cytostome occupies whole anterior end; contractile vacuole posterior; macronucleus elongate; several micronuclei; trichocysts around cytostome and scattered throughout; fresh or salt water. Numerous species. S. spathula Miiller (Figs. 21; 267, a, h). Up to 250m long; fresh water. Woodruff and Spencer (1922) made a careful study of the organism. Genus Paraspathidium Noland. Form resembles that of Spathid- ium; but cytostome an elongate slit, bordered on one side by strong cilia and on the other by weaker cilia and a shelf-like, nonundulatory membrane; 2 longer cilia on dorsal edge near anterior tip; anterior 1/3 compressed; posterior 2/3 nearly cylindrical; 2 oval macro nuclei, each with a micronucleus; cytoplasm filled with numerous refractile granules; about 70 rows of cilia; contractile vacuole terminal; salt water. One species. 560 HOLOTRICHA 561 P. trichostomum N. (Fig. 267, c-e). About 220^ long; macro nuclei 44/u long each; salt water; Florida. Genus Spathidioides Brodsky (Spathidiella Kahl). Somewhat similar to Spathidium; but oral ridge highly flattened on ventral side and conspicuously developed into a wart-like swelling on dorsal side; this knob contains trichocysts; sapropelic. Fig. 267. a, b, Spathidium spathula, X200 (Woodruff and Spencer); c-e, Paraspathidium trichostomum (c, X130; d, cytostomal region X400; e, part of pellicle, XlOOO) (Noland); f, Spathidioides sidcata, X260 (Brod- sky); g, Enchelydium fusidens, X240 (Kahl); h, Homalozoon vermiculare, X80 (Stokes); i, Cranotheridium taeniatum, X300 (Schewiakoff) ; j, Penar- diella crassa, X210 (Kahl); k, Perispira strephosoma, X280 (Kahl); 1, Legendrea bellerophon, Xl90 (Penard). S. sulcata B. (Fig. 267, /). 65-85/x long; posterior end pointed, highly flattened; anterior end elevated at one side where cytostome and cytopharynx with 10 rods are located. Genus Enchelydium Kahl. Somewhat similar to Spathidium; but oral ridge forms a swollen ring with trichocysts; the ridge circular or elongated in cross-section; when swimming, the organisms appear as if cytostome is opened; with dorsal bristle; fresh water. 562 PROTOZOOLOGY E. fusidens K. (Fig. 267, g). Cylindrical, contractile; cilia dense and rather long; macronucleus reniform, often appears as composed of 2 spherical parts; contractile vacuole terminal; oral ring with spindle-like trichocysts; food vacuoles not seen; extended body llO/x long; contracted 75/^; sapropelic. Genus Homalozoon Stokes. Elongate; cilia conspicuous on flat- tened right side; left side swollen or keeled; fresh water. H. vermiculare (S.) (Fig. 267, h). Extended body 450-850/i long; vermiform; macronucleus band form; contractile vacuoles about 30 or more in a row; standing fresh water. Genus Cranotheridium Schewiakoff. Spathidium-like organisms; anterior end obliquely truncate, near the extended side of which is located the cytostome; cytopharynx surrounded by a group of trichites; fresh water. C. taeniatum S. (Fig. 267, i). Anterior end flattened; with a group of trichites; macronucleus long band-form; with many micro nuclei; contractile vacuole terminal; ciliation and striation close; colorless; movement slow; about 170/i long; fresh water. Genus Penardiella Kahl. Ellipsoid, somewhat compressed; oral ridge slightly oblique; a girdle with trichocysts encircling the body; fresh water. P. crassa (Penard) (Fig. 267, j). Elongate ellipsoid, flattened; tri- chocysts in posterior portion of girdle are longer and those in the dorsal region are fewer in number and shorter; macronucleus sau- sage-form; contractile vacuole posterior, in front of the girdle; body 160/x by 50/x; sapropelic. Genus Perispira Stein. Ovoid or cylindrical; oral ridge turns right-spirally down to posterior end. P. strephosoma Stokes (Fig. 267, k). Oval to cylindrical; about 85^ long; standing water with sphagnum. Genus Legendrea Faure-Fremiet. Ellipsoid or ovoid; a peripheral zone with small tentacular processes bearing trichocysts. L. heller o-phon Penard (Fig. 267, I). lOO-lSO/x; fresh water. Genus Teuthophrys Chatton and Beauchamp. Body rounded pos- teriorly, anterior end with 3 radially equidistant, spirally curved arms (counter-clockwise when viewed from posterior end); the de- pressions between arms form furrows; cytostome apical, at the inner bases of arms; contractile vacuole terminal; ciliation uniform, ex- cept the inner surfaces of arms where longer cilia as well as tricho- cysts are present; with zoochlorellae; macronucleus rope-shaped and wound; micronucleus unobserved. One species. HOLOTRICHA 563 T. trisula C and B. (Fig. 268, a). 150-300/x long; length: width 3 : 1-2 : 1 ; ponds in Pennsylvania and California ( Wenrich). Family 2 Metacystidae Kahl Genus Metacystis Cohn. Oblong; ciliation general, except poste- rior end; ciliary circle around cytostome; usually one caudal cilium; with a large posterior vesicle containing turbid fluid. M. truncata C. (Fig. 268, h). Elongate, not much difference in body width at different levels; with about 12 furrow rings; body length up to 30/i; salt water. Genus Vasicola Tatem {Pelamphora Lauterborn), Ovoid with caudal cilia; lorica flask-shape, highly ringed; cytostome at anterior end, its lip with 4 rows of long cilia; body surface with shorter cilia; macronucleus round, central, with a micro nucleus; contractile vacu- ole near macronucleus; fresh or salt water. V. ciliata T. (Pelamphora butschlii L.) (Fig. 268, c). Body about 100m long; sapropelic in fresh water. Genus Pelatractus Kahl. Somewhat similar to Vasicola; but with- out lorica or caudal cilia; with a terminal vacuole; without lip of Vasicola; sapropelic. P. (Vasicola) grandis (Penard) (Fig. 268, d). Free-swimming; elongated fusiform; numerous contractile vacuoles on one side; body 125-220^1 long; sapropelic in fresh water. Family 3 Didiniidae Poche Genus Didinium Stein (Monodinium Fabre-Domergue). Barrel- shaped; one to several girdles of cilia (pectinellae) ; expansible cyto- stome at tip of cone-like elevation at anterior end, containing long fibrils; macronucleus horseshoe-shaped; contractile vacuole pos- terior; feeds on other ciliates; fresh or salt water. Several species. D. nasutum (Miiller) (Fig. 268, e-g). 80-200// long; endoplasm highly granulated; with 2 girdles of pectinelles; feeds on Parame- cium; fresh water. D. halbianii (Fabre-Domergue) (Fig. 268, h). 60-100^ long; a single girdle of pectinelles near anterior end; fresh water. Genus Mesodinium Stein. Ovoid; an equatorial furrow marks conical anterior and spherical posterior parts; in the furrow are in- serted 2 (or 1) rings of strong cilia; one directed anteriorly and the other posteriorly; with tentacle-like retractile processes around the cytostome; fresh and salt water. 564 PROTOZOOLOGY M. pulex (ClaparMe and Lachmann) (Fig. 268, i-k). Oral ten- tacles with trifurcate tips; body 20-3 l/x long; salt water; Florida. Noland states that the freshwater forms are 21-38^ long. Fig. 268. a, Teuthophrijs trisula, X330 (Wenrich), b, Metacystis trun- cata, X270 (Cohn); c, Vasicola ciliata, X250 (Kahl), d, Pelatr actus grandis, Xl70 (Penard); e-g, Didinium nasutuni, Xl70 (Kudo); h, D. balbianii, X290 (Butschli); i-k, Mesodinium pidex (i, X670; j, oral view; k, oral tentacles, X1330) (Noland); 1, m, M. acarus (1, X670; m, oral tentacles, X1330) (Poland); n, Askenasiafaurei, X530 (Faur^-Fremiet); o, Cyclotrichium meunieri, X7S0 (Powers). M. acarus Stein (Fig. 268, I, m). Oral tentacles with capitate tip; 10-16m long; salt water, Florida (Noland). Genus Askenasia Blochmann. Resembles Didinium; ovoid; with HOLOTRICHA 565 2 closely arranged rings of long cilia; anterior ring made up of some 60 pectinelles which are directed anteriorly; posterior ring composed of about the same number of long cilia directed posteriorly and arranged parallel to body surface; fresh or salt water. A. faurei Kahl (Fig. 268, n). Body oval, anterior end broadly rounded; posterior region conical; pectinelles about 13^ long; the second band (lOju) of long cilia; an ellipsoid macronucleus ; a micro- nucleus; body about 58-60/x long; fresh water. Genus Cyclotrichium Meunier. Body spheroid to ellipsoid with a large non-ciliated oral field which is surrounded by a pectinelle-ring, the remaining part naked or slightly ciliated; macronucleus sausage- form; cytopharynx not recognized; endoplasm highly vacuolated; in marine plankton. C. meunieri Powers (Fig. 268, o). Anterior end broadly rounded; posterior region conical; cytostome obscure; oral funnel at ante- rior end in a depression; broad ciliated band at about middle; ecto- plasm with concave chromatophore (covered with haematochrome) plates on surface, below which numerous pyrenoids occur in vacu- oles; endoplasm with numerous granules; 25-42/x by 18-34ju; Powers (1932) found that the 'red water' in Frenchman Bay in Maine was caused by the swarming of this organism. Family 4 Colepidae Claparede and Lachmann Genus Coleps Nitzsch. Body-form constant, barrel-shaped; with regularly arranged ectoplasmic plates; cytostome at anterior end, surrounded by slightly longer cilia; often spinous projections at or near posterior end; 1 or more long caudal cilia, often overlooked; fresh or salt water. Many species. C. Urtus (Miiller) (Fig. 269, a). 40-65^ long; 15-20 rows of plate- lets; 3 posterior processes; fresh water. C. elongatus Ehrenberg (Fig. 269, h). 40-55^ long; slender; about 13 rows (Noland) or 14-17 rows (Kahl) of platelets; 3 posterior processes; fresh water. C. bicuspis Noland (Fig. 269, c). About 55m long; 16 rows of plate- lets; 2 posterior processes; fresh water. C. octospinus N. (Fig. 269, d). 80-1 10m long; 8 posterior spines; about 24 rows of platelets; Geiman (1931) found this organism in an acid marsh pond and noted variation in number and location of ac- cessory spines; fresh water. C. spiralis N. (Fig. 269, e). About 23 longitudinal rows of platelets slightly spirally twisted; posterior spines drawn together; a long caudal cilium; about 50m long; salt water; Florida. 566 PROTOZOOLOGY C. heteracanthus N. (Fig. 269, /). Anterior processes only on one side; posterior spines; caudal cilium; about 90)u by 35/1 ; salt water; Florida. Genus Tiarina Bergh. Somewhat similar to Coleps, but posterior end tapering to a point; salt water. T.fusus (Claparede and Lachmann) (Fig. 269, g). 85-135^ long. Fig. 269. a, Coleps hirtus, X530 (Noland); b, C. elongatus, X530 (No- land); c, C. bicuspis, X530 (Noland); d, C. odospinus, X530 (Noland); e, C. spiralis, X400 (Noland); f, C. heteracanthus, X400 (Noland); g, Tiarina fusus, X530 (Faur^-Fremiet) ; h, Adinobolina vorax, X300 (Wenrich); i, Dactylochlamys pisciformis, X330 (Kahl); j, Enchelyomor- pha vermicularis, X670 (Kahl). Family 5 Actinobolinidae Kent Genus Actinobolina Strand {Adinobolus Stein). Ovate or spheri- cal; ciliation uniform; extensible tentacles among cilia; contractile vacuole terminal; macro nucleus curved band; fresh water. HOLOTRICHA 567 A. vorax (Wenrich) (Fig. 269, h). 100-200m long; elongate oval to spheroid; light yellowish brown in color; Wenrich (1929) found this ciliate in pond water and studied its behavior. Genus Dactylochlamys Lauterborn. Body spindle-form, though variable; posterior end drawn out into tail; pellicle with 8-12 un- dulating spiral ridges on which tentacle-like processes and long ciha are alternately situated; these processes are retractile (Kahl) and similar in structure to those of Suctoria; cytostome has not been detected; possibly allied to Suctoria; fresh water. One species. D. pisciformis L. (Fig. 269, i). Body 80-120m long. Genus Enchelyomorpha Kahl. Conical, compressed; posterior end broadly rounded; anterior portion narrow; cilia on ring-furrows; an- terior half with unretractile short tentacles; cytostome not noted; macro nucleus with a central endosome surrounded by spherules; contractile vacuole terminal, large. E. vermicularis (Smith) (Fig. 269, j). Body 30-45/1; fresh and brack- ish water. Family 6 Holophryidae Schouteden Genus Holophrya Ehrenberg. Oval, globose or ellipsoidal; ciliation uniform; sometimes longer cilia at the anterior or posterior region; systostome circular, simple, without any ciliary ring around it; cytopharynx with or without trichites or trichocysts; fresh or salt water. Numerous species. H. simplex Schewiakoff (Fig. 271, a). Ellipsoidal; 18-20 ciliary rows; cilia uniformly long; cytostome small; cytopharynx without trichocysts or trichites; contractile vacuole and cy to pyge posterior; macronucleus large, round; 34/1 by 18/i; fresh water. Genus Lagynophrya Kahl. Resembles Holophrya; small elongate ovoid to short cylindrical; one side convex, the other more or less flattened; cytopharynx terminates anteriorly in a small cone-like process which may or may not be distinct; stagnant fresh or salt water. Several species. L. mutans K. (Fig. 271, b). Body plastic; oval to cylindrical; colorless; narrowly striated; oval cone hemispherical without any trichocysts; body about 90/x long, when contracted about 65m in diameter; among decaying leaves in fresh water. Genus Ichthyophthirius Fouquet. Body oval; ciliation uniform; pellicle longitudinally striated; cytostome at anterior end, with a short cytopharynx with cilia; horseshoe-shaped macronucleus; micro nucleus adhering to macronucleus; macronucleus undergoes reorganization by discarding small chromatin masses (Haas); no 568 PROTOZOOLOGY division within the host body; multiplication within cyst which is formed after dropping off the fish skin and in which numerous (up to 1000) ciliated bodies (30-45^ in diameter) are produced; conjugation has been reported; parasitic in the integument of freshwater fishes; in aquarium, host fish may suffer death; widely distributed. Fig. 270. Ichthyophthirius multifiliis. a, free-swimming individual, X75 (Butschli); b-e, development within cyst; f, a young individual, X400 (Fouquet); g, section through a fin of infected carp showing numerous parasites, XlO (Kudo); h, a catfish, Ameiurus albidus, heavily infected by the ciliate (Stiles). /. multifiliis F. (Fig. 270). 100-1000^ long; ovoid; produces pus- tules in the epidermis or gills; cytostome is large, 30-40/i in diameter. Pearson (1932) and Kudo (1934) reported extensive infections in large open ponds in Indiana and Illinois. MacLennan (1935, 1937) observed that the grown trophozoites leave the host epithelium and HOLOTRICHA 569 encyst on the bottom of aquarium; the cytostome is absorbed; the body protoplasm divides into 100-1000 small spherical ciliated cells, 18-22/x in diameter, which presently metamorphose into elongated forms, measuring about 40^ by lO/x. These young ciliates break through the cyst wall and seek new host fish by active swim- ming. The young ciliates are able to attack the fish integument for at least 96 hours, though their infectivity decreases markedly after 48 hours. Genus Bursella Schmidt. Oval; anterior end broadly and ob- liquely truncate where a large ciliated groove-like pit occurs; ridges of pit contractile; cilia short; macronucleus, spherical to ellipsoidal; several micro nuclei; endoplasm reticulated; with symbiotic algae; ectoplasm with tricho cysts; fresh water. B. spumosa S. 240-560^1 long; freshwater pond. Genus Spasmostoma Kahl. Somewhat similar to Holophrya; cytostome with flaps which beat alternately; ciliation uniform. S. viride K. (Fig. 271, c). Spherical or oval; always with green food vacuoles containing Euglena and allied flagellates; cytostome at anterior end; cytopharynx with trichocysts, which are extensible at the time when food is taken in; cilia on about 20 rows, near cyto- stome somewhat longer; macronucleus round; body 50-75/i long; sapropelic. Genus Urotricha Clarapar^de and Lachmann {Balanitozoon Stokes), Body oval to ellipsoidal or conical; with 1 or more longer caudal cilia; ciliation uniform, except in posterior region which may be without cilia; cytostome at or near anterior end, surrounded by ring of heavier cilia; contractile vacuole, posterior; macronucleus spherical; fresh water. U. agilis (Stokes) (Fig. 271, d). Body small; about 15-20m long; swimming as well as leaping movement; standing fresh water with sphagnum, U. farda C. and L. (Fig. 271, e). Body 20-30^ long; fresh water. Kahl considers U. parvula Penard and Balanitozoon gyrans Stokes are identical with this species. Genus Plagiocampa Schewiakoff. Ovoid, spindle-form or cylin- drical; slightly asymmetrical; cytostome at anterior end in a slit; right ridge thickened and lip-like, with about 8 long cilia; with or without long caudal cilium; fresh or salt water. Several species. P. marina Kahl (Fig. 271, /, g). Cylindrical; oval macronucleus central; contractile vacuole terminal; a caudal cilium; 55-90/i long; salt water; Florida (Noland). Genus Chilophrya Kahl. Ovoid or ellipsoid ; cytostome at anterior 570 PROTOZOOLOGY end, surrounded by protrusible rods; on one side there is a lip-like ectoplasmic projection; fresh or salt water. C. (Prorodon) utahensis (Pack) (Fig. 271, h). Body ellipsoid, some- what asymmetrical; comparatively small number of furrows; cilia- tion uniform; a finger-like process in front of cytostome; macro- FiG. 271. a, Holophrya simplex, X800 (Roux); b, Lagynophrya mutans, X380 (Kahl); c, Spasniostoma viride, X330 (Kahl); d, Urotricha agilis, X530 (Stokes); e, U. farcta, X470 (Lieberkuhn); f, g, Plagiocampa marina (f, X400; g, anterior end, X670) (Noland); h, Chilophrya utahen- sis, X840 (Pack); i, C. labiata, X500 (Edmondson); j, Platyophrya lata, X280 (Kahl); k, Stephanopogon colpoda, non-ciliated side, X500 (Kahl); 1, Prorodon discolor, x330 (Biitschli); m, Pseudoprorodon farctus, X270 (Roux); n, o, Placus socialis (o, anterior end view), X530 (Noland). nucleus small, central; contractile vacuole terminal; endoplasm with zoochlorellae; encystment common; cysts highly sensitive to light; 50m long; Great Salt Lake, Utah (Pack). HOLOTRICHA 571 C. (Urotricha) lahiata (Edmondson) (Fig. 271, i). Body ovoid; a lip-like process in front of cytostome; macronucleus oblong, central; contractile vacucle terminal; 30^ long; fresh water. Genus Platyophrya Kahl. Compressed; flask-like or elongate ovoid; asymmetrical; dorsal surface convex, ventral surface flat or partly concave; spiral striation; position and direction of cytostome variable; macronucleus round; contractile vacuole terminal; fresh water. P. lata K. (Fig. 271, j). Highly compressed; colorless; many striae; on left edge of cytostome 5-6 cirrus-like projections and on right edge manyshort bristles; lOSju long; freshwater with sphagnum. Genus Stephanopogon Entz. Somewhat resembles Platyophrya; compressed; cytostome at anterior extremity which is drawn out; cytostome surrounded by lobed membranous structures; salt water. S. colpoda E. (Fig. 271, k). Longitudinal striae on 'neck' 4-8 in number; 2 contractile vacuoles; 50-70m long; creeping movement; salt water among algae. Genus Prorodon Ehrenberg (Rhagadostoma Kahl). Ovoid to cylindrical; ciliation uniform, with sometimes longer caudal cilia; oral basket made up of double trichites which end deep in ectoplasm, oval in cross-section; contractile vacuole terminal; macronucleus massive, spherical or oval ; fresh or salt water. Numerous species. P. discolor (E.) (Fig. 271, I). Ovoidal; 45-55 ciliary rows; macro- nucleus ellipsoid; micro nucleus hemispherical; contractile vacuole terminal; 100-130/i long; fresh water; Kahl (1930) states that it oc- curs also in brackish water containing 2.5 per cent salt; sapropelic form in salt water is said to possess often long caudal cilia. P. griseus Claparede and Lachmann. Oblong; 165-200^ long; fresh water. Genus Pseudoprorodon Blochmann. Similar to Prorodon; usually flattened; one side convex, the other concave; ectoplasm conspicu- ously alveolated; trichocysts grouped; 1 or more contractile vacu- oles posterior-lateral or distributed, with many pores; macronucleus elongate; cytopharynx with trichites; fresh or salt water. P. farctus (Claparede and Lachmann) (Figs. 21, h; 271, m). Ellip- soid; cytostome surrounded by long trichites; contractile vacuole posterior, with secondary vacuoles; macronucleus elongate; body 150-200m long; fresh water. Genus Placus Cohn (Spathidiopis Fabre-Domergue; Thoraco- phrya Kahl). Body small; ellipsoid or ovoid; somewhat compressed; pellicle with conspicuous spiral furrows; cytostome a narrow slit at anterior extremity; with strong cilia on right margin of slit; cytopyge 572 PROTOZOOLOGY a long narrow slit with cilia on both sides; macro nucleus ellipsoid to sausage-form; contractile vacuole posterior; salt, brackish or fresh water. P. socialis (Fabre-Domergue) (Fig. 271, n, o). 40-50/i by 28-32^, about 22/i thick; salt water; Florida (Noland). Genus Lacr3miaria Ehrenberg. Polymorphic; cylindrical, spindle- or flask-shaped; with a long contractile proboscis; cytostome round; ciliary rows meridional or spiral to right; near cytostome a ring-like constriction with a circle of longer cilia ; cytopharynx usually dis- tinct; contractile vacuole terminal; fresh or salt water. Numerous species. L. olor (Muller) (Fig. 272, a). Elongate; highly contractile; 2 macronuclei; 2 contractile vacuoles; extended forms 400-500m up to 1.2 mm. long; when dividing, long neck is formed sidewise so that it appears as oblique division (Penard) ; fresh and salt water. L. lagenula Claparede and Lachmann (Fig. 272, b). Body flask- shape; neck highly extensible; striation distinct, spiral when con- tracted; macro nucleus short sausage-like or horseshoe-shape; endo- plasm granulated; body 70^ long, up to ISO/u (Kahl); salt water. L. coronata C. and L. (Fig. 272, c). Large; neck extensible; body form variable, but usually with bluntly rounded posterior end; endo- plasm appears dark; striae spiral; 85-100^1 long; salt and brackish water. Genus Enchelys Hill. Flask-shape; anterior end obliquely trun- cate; cytostome slit-like, rarelj'- round; fresh or salt water. Several species. E. curvilata (Smith) (Fig. 272, d). Elongate ovoid; posterior end rounded; longitudinal striation; macronucleus band-form; contrac- tile vacuole terminal; endoplasm yellowish, granulated; about 150ju long; fresh water among algae. Genus Crobylura Andre. Body when extended spindle-form, with truncate ends; when contracted, thimble-form; cilia short and thick; several long caudal cilia; slit-like cytostome at anterior end; no apparent cytopharynx; macronucleus irregularly rounded, hard to stain; micronucleus not observed; contractile vacuole latero-pos- terior; fresh water. One species. C. pelagica A. (Fig. 272, e). Body 65-95^ long; in freshwater plankton. Genus Microregma Kahl. Small, ovoid; dorsal side convex; ventral side flat; with a small slit-like cytostome near anterior end; with or without caudal bristle; fresh or salt water. M. (Enchelys) auduhoni (Smith) (Fig. 272, /). Body plastic; HOLOTRICHA 573 coarsely ciliated; caudal bristle thin; cytostome at anterior end, surrounded by longer cilia; cy to pharynx small with tricho cysts; round macronucleus central; contractile vacuole near posterior end; 40-55/i ; fresh water. Genus Chaenea Quennerstedt. Elongate; anterior end drawn out into a narrow truncated 'head'; but without any ring furrow; Fig. 272. a, Lacrymaria olor, Xl70 (Roux); b, L. lagenula, X400 (Calkins); c, L. coronata, X530 (Calkins); d, Enchelys curvilata, X200 (Smith); e, Crobyliira pelagica, X500 (Andr^); f, Microregma auduhoni X500 (Smith); g, Chaenea limicola, X310 (Penard); h, Pithothorax ovatus, X550 (Kahl);i, Trachelophyllum clavatum, XlOO (Stokes). 'head' spirally or longitudinally furrowed; often with longer ciha directed anteriorly; cytostome terminal, not lateral; cyto pharynx with trichocysts; body striation meridional, or slightly right spiral; macronucleus often distributed; fresh or salt water. C. limicola Lauterborn (Fig. 272, g). Anterior half of body broad; posterior end drawn out into a point; contractile; cyto pharynx with trichocysts; many trichocysts in endoplasm; contractile vacuoles in a row; 130-150/i long; stagnant fresh w^ater. 574 PROTOZOOLOGY Genus Pithothorax Kahl. Slender, barrel-shaped; with firm pellicle; a fairly long caudal bristle', contractile vacuole in posterior half ; cilia- tion coarse and not over entire body surface; resembles somewhat Coleps; fresh water. P. ovatus K. (Fig. 272, h). Caudal bristle breaks off easily; body 30m long; fresh water among decaying vegetation. Genus Rhopalophrya Kahl. Cylindrical; furrows widely separated; slightly asymmetrical; curved ventrally; dorsal surface convex; ventral surface flat or slightly concave; anterior end with 'neck'; 2 spherical macro nuclei ; fresh or salt water; sapropelic. R. salina Kirby (Fig. 273, a). Cylindrical, tapering gradually to a truncated anterior end, slightly curved ventrally; cilia (6-10^ long) sparsely distributed; 2 macro nuclei, spherical; 29-55ju long; 16-21)u in diameter; in concentrated brine (salts "34.8 per cent"; pH 9.48) from Searles Lake; California. Genus Enchelyodon Claparede and Lachmann. Elongated; cy- lindrical, ovoid or flask-shaped; some with head-like prolongation; cyto pharynx with trichites; cilia long at anterior end; fresh or salt water. Several species. E. calif ornicus Kahl. 120-130/i long; elongate ovoid to nearly cyhndrical; not distinctly flattened; macro nucleus horseshoe-hke, with a large micro nucleus; in mosses; California. Genus Trachelophyllum Claparede and Lachmann. Elongate; flat- tened; flexible, ribbon-like; anterior end neck-like and tip truncate; cyto pharynx narrow, round in cross-section, with trichocysts; ciliary rows widely apart; 2 macronuclei, each with a micronucleus; con- tractile vacuole terminal; fresh or salt water. Several species. T. clavatum Stokes (Fig. 272, i). About 200^ long; fresh water. Genus Ileonema Stokes {Monomastix Roux). Body flattened; flask-shaped; somewhat similar to Trachelophyllum, but differs by the fact that there is a remarkable flagellum-like process extending from anterior end; cytopharynx with trichocysts; fresh water. /. dispar S. (Fig. 273, h). Highly contractile; anterior flagellum half body length, whose basal portion spirally furrowed; cytostome at base of the flagellum; cytopharynx spindle-form with trichites; 2 contractile vacuoles and cytopyge posterior; ovoid macronucleus; movement slow creeping; about 120m long; fresh water among algae. /. ciliata (Roux) (Fig. 273, c). 75m by 14m; fresh water. Genus Trachelocerca Ehrenberg. Elongate, vermiform or flask- shaped; more or less extensible, with drawn-out anterior end; with- out any ring-furrow which marks the 'head' of Lacrymaria, and when HOLOTRICHA 575 contracted pellicular striae not spiral and no neck as is the case with Chaenea; salt water. Many species. T. phoenicopterus Cohn (Fig. 273, d, e). Elongate; extensible and contractile; neck and tail distinct when contracted; cytostome at anterior end, surrounded by a ridge containing indistinctly visible short trichocysts, cytopharynx with trichocysts; macronuclei made up of 4 radially arranged endosomes suspended in the nucleoplasm (Gruber, KahJ); micronucleus difficult to make out; contractile Fig. 273. a, Rhopalophrya salina, X870 (Kirby); b, Ileonema dispar, Xl60 (Stokes); c, /. ciliata, X670 (Roux); d, e, Trachelocerca phaenicop- terus (d, XlOO; e, anterior end, X220) (Kahl); f, g, T. subviridis (f, Xl30; g, nucleus, X400) (Noland); h, Parachaenia myae, X670 (Kofoid and Bush). vacuoles apparently in a row, rarely seen; salt water; Woods Hole (Calkins). T. subviridis Sauerbrey (Fig. 273,/, g). Highly extensible and con- tractile; nucleus contains peculiar crystal-like bodies; size variable; when extended 320-480/^ long; salt water. Noland observed the or- ganism in a salt spring in Florida, Genus Parachaenia Kofoid and Bush. Small; compressed; ventral surface slightly concave; dorsal surface greatly convex; cilia long. 576 PROTOZOOLOGY differentiated into 2 areas, a ventral area consisting of close-set rows and a dorso-lateral area consisting of 7 rows; cytostome circular or slightly oval, at anterior tip; cytopharynx long, narrow; without contractile vacuole. One species. P. myae K. and B. (Fig. 273, h). 40-100m long; 7 rows of long cilia on dorso-lateral surfaces, 8 rows of shorter cilia on ventral surface; cytopharynx half body length; in pericardial cavity and siphon of Mya arenaria; San Francisco Bay. Fig. 274. a, Butschlia parva, X670 (Schuberg); b, Blepharoprosthiiun pireum, X470 (Hsiung); c, Didesmis quadrata, X270 (Hsiung); d, Blepharosphaera intestinalis, X600 (Hsiung); e, Blepharocomis cervicalis, X360 (Hsiung); f, Bundleia postciliata, X530 (Hsiung); g, Blepharozoum zonatum, X200 (Gassovsky). Family 7 Biitschliidae Poche This family includes species that are intestinal parasites of mam- mals; circular cytostome at anterior end, cytopyge usually located at posterior end; ciliation uniform or in a few zones; with refractile concrement vacuole (Fig. 30, d) in anterior portion; one or more con- tractile vacuoles. Genus Butschlia Schuberg. Ovoid, anterior end truncate, posterior HOLOTRICHA 577 end rounded; cytostome at anterior end, surrounded by long cilia; thick ectoplasm at anterior end; macro nucleus spherical micro nu- cleus(?) ; concretion vacuole; ciliation uniform; in stomach of cattle. B. parva S. (Fig. 274, a). 30-50/x by 20-30/1. Genus Blepharoprosthium Bundle. Pyriform, anterior half con- tractile, ciliated; caudal cilia; macronucleus reniform; in the caecum and colon of horse. B. pireum B. (Fig. 274, 6). 54-86m by 34-52m. Genus Didesmis Fiorentini. Anterior end neck-like, with large cytostome; anterior and posterior ends ciliated; macronucleus ellip- soid ; in the caecum and colon of horse. D. quadrata F. (Fig. 274, c). 50-90/i by 33-68m; with a deep dorsal groove. Genus Blepharosphaera Bundle. Spherical or ellipsoidal; ciliation uniform except in posterior region; caudal cilia; in the caecum and colon of horse. B. intestinalis B. (Fig. 274, d). 38-74/4 in diameter. Genus Blepharoconus Gassovsky. Oval; small cytostome; cilia on anterior 1/3-1/2; caudal cilia; macronucleus ovoid; 3 contractile vacuoles; cytopharynx with rods; in the colon of horse. B. cervicalis Hsiung (Fig. 274, e). 56-83m by 48-70)u; Iowa. Genus Bundleia da Cunha and Muniz. Ellipsoid; cytostome small; cilia at anterior and posterior ends, posterior cilia much less numer- ous; in the caecum and colon of horse. B. postciliata (Bundle) (Fig. 274,/). 30-56m by 17-32^. Genus Polymorpha Dogiel. Flask-shaped; ciliation on anterior re- gion, a few caudal cilia; macronucleus disc-shaped; contractile vacu- ole terminal; in the caecum and colon of horse. P. ampulla D. (Fig. 275, a). 22-36/x by 13-21/z. Genus Holophryoides Gassovsky. Oval, with comparatively large cytostome at anterior end; ciliation uniform; macronucleus small, ellipsoid; contractile vacuole subterminal; in the colon and caecum of horse. H. ovalis (Fiorentini) (Fig. 275, h). 95-140^ by 65-90/x. Genus Blepharozoum Gassovsky. Ellipsoid, wdth attenuated pos- terior end; ciliation uniform; cytostome near anterior tip; 2 con- tractile vacuoles; macronucleus small, reniform; in caecum of horse. B. zonatum G. (Fig. 274, g). 230-245/1 by 115-122/1. Genus Prorodonopsis Gassovsky. Pyriform; ciliation uniform; 3 contractile vacuoles; macronucleus sausage-shaped; in the colon of horse. P. coli G. (Fig. 275, c). 55-67/1 by 38-45m. 578 PROTOZOOLOGY Genus Paraisotrichopsis Gassovsky. Body uniformly ciliated; spiral groove from anterior to posterior end ; in the caecum of horse. P. composita G. (Fig. 275, d). 43-56m by 31-40m. Genus Sulcoarcus Hsiung. Ovoid, compressed ; a short spiral groove at anterior end; cytostome at ventral end of the groove; cytopyge terminal; concretion vacuole mid-ventral, contractile vacuole pos- terior to it; cilia on groove, posterior end and mid-ventral region. Fig. 275. a, Polyjnorpha ampulla, X1170 (Hsiung); b, Holophryoides ovalis, X410 (Gassovsky); c, Prorodonopsis coli, X700 (Gassovsky); d, Paraisotrichopsis composita, X450 (Hsiung); e, Sulcoarcus pellucidulus, X410 (Hsiung); f, Alloiozona trizona, X450 (Hsiung). S. pellucidulus H. (Fig. 275, e). 33-56m by 30-40m; in faeces of mule. Genus Alloiozona Hsiung. Cilia in 3 (anterior, equatorial and pos- terior) zones; in the caecum and colon of horse. A. trizona H. (Fig. 275,/). 50-90/x by 30-60m. Genus AmpuUacuia Hsiung. Flask-shaped; posterior half bearing fine, short cilia; neck with longer cilia; in the caecum of horse. A. ampulla (Fiorentini). About llO/i by 40/x. HOLOTRICHA 579 References HsiUNG, T. S. 1930 A monograph on the Protozoa of the large in- testine of the horse. Iowa St. Coll. Jour. Sci., Vol. 4. Kahl, a. 1930 In Dahl's Die Tierwelt Deutschlands. Part 18. KiRBY Jr., H. 1934 Some ciUates from salt marshes in California. Arch. f. Protistenk., Vol. 82. MacLennan, R. F. 1935 Observations on the life cycle of Ichthy- ophthirius, a ciliate parasitic on fish. Northwest Science, Vol. 9. 1937 Growth in the ciliate Ichthyophthirius. I. Maturity and encystment. Jour. Exper. Zool., Vol. 76. NoLAND, L. E. 1925 A review of the genus Coleps with descriptions of two new species. Trans. Amer. Micr. Soc, Vol. 44. 1937 Observations on marine ciliates of the Gulf coast of Florida. Ibid., Vol. 56. Penard, E. 1922 Etudes sur les Infusoires d'eau douce. Geneve. Roux, J. 1901 Faune infusorienne des eaux stagnantes de environs de Geneve. Mem. cour. fac. sci. I'Uni. Geneve. Stokes, A. C. 1888 A preliminary contribution toward a history of the freshwater Infusoria of the United States. Jour. Trenton Nat. Hist. Soc, Vol. 1. Wenrich, D. H. 1929 The structure and behavior of Actinobolus vorax. Biol. Bull., Vol. 56. Chapter 33 Order 1 Holotricha Stein (continued) Suborder 2 Gymnostomata Biitschli (continued) Tribe 2 Pleurostomata Schewiakoff Cytostome on convex ventral surface. Cytostome a long slit Family 1 Amphileptidae Cytostome round, at base of trichocyst-bearing neck Family 2 Tracheliidae (p. 582) Cytostome on concave ventral side Family 3 Loxodidae (p. 584) Family 1 Amphileptidae Schouteden Genus Amphileptus Ehrenberg. Flask-shaped; somewhat com- pressed; ciliation uniform and complete; slit-like cytostome not reaching the middle of body, without tricho cyst-borders; many con- tractile vacuoles; 2 or more macronuclei; fresh or salt water. A. claparedei Stein {A. meleagris Claparede and Lachmann) (Fig. 276, a). Slightly flattened; broadly flask-shaped; with bluntly pointed posterior and neck-like anterior end; cytostome about 2/5 from ventral margin; trichocysts indistinct; dorsal ciliary rows also not distinct; contractile vacuoles irregularly distributed; 120-150iLi long; fresh and salt water, on stalks of Zoothamnium, Carchesium, Epistylis, etc. A. hranchiarum Wenrich (Fig. 276, h). On the integument and gills of frog tadpoles; swimming individuals killed with iodine, 100-135m by 40-60m. Genus Lionotus Wrzesniowski (HemiophrysW.). Flask-shape; elongate, flattened; anterior region neck-like; cilia only on right side; without tricho cyst-borders; cytostome with trichocysts; 1 (terminal) or many (in 1-2 rows) contractile vacuoles; 2 macronuclei; 1 micro- nucleus ; fresh or salt water. L. fasciola (Ehrenberg) (Fig. 276, c). Elongate flask in form; hya- line; with flattened neck and tail, both of which are moderately contractile; posterior end bluntly rounded; without trichocysts; neck stout, bent toward the dorsal side; cytostome a long slit; con- tractile vacuole posterior; 2 spherical macronuclei between which a micronucleus is located; 100m long; fresh water and probably also in salt water. Genus Loxophyllum Dujardin {Opisthodon Stein). Generally simi- lar to Lionotus in appearance; but ventral side with a hyaline border, 580 HOLOTRICHA 581 reaching posterior end and bearing trichocysts; dorsal side with either similar trichocyst-border or with tricho cyst-warts; macro nu- cleus a single mass or in many parts; contractile vacuole, one to many; fresh or salt water. Many species. L. meleagris D. (Fig. 276, d). Form and size highly variable; Fig. 276. a, Amphileptus claparedei, X370 (Roux); b, A. branchiarum, flattened, X490 (Wenrich); c, Lionotus fasciola, x540 (Kahl); d, Loxo- phyllum meleagris, Xl20 (Penard); e, L. setigerum, X570 (Sauerbrey); f, Bryophyllum vorax, X360 (Stokes); g, h, Kentrophoros fasciolatum (g, X50;h, XI 10) (Noland). flask-shape to broad leaf -like; broad ventral seam with trichocysts and often undulating; dorsal seam narrow and near its edge, groups of trichocysts in wart-like protuberances; macronucleus moniliform; micronuclei, of the same number (Penard) ; contractile vacuole ter- 582 PROTOZOOLOGY minal, with a long canal; 300-400^ long, up to 700m (Penard); feeds mainly on rotifers ; fresh water. L. setigerum Quennerstedt (Fig. 276, e). 100-350/x long; average 150/x by 60/i; form variable; 1-4 macronuclei; several contractile vacuoles in a row; salt and brackish water. Genus Bryophyllum Kahl. Similar to Loxophyllum; but uniformly ciliated on both broad surfaces; ventral ridge with closely arranged trichocysts, extends to the posterior extremity and ends there or may continue on to the opposite side for some distance; macro nu- cleus ovoid to coiled bandform; in mosses. B. vorax (Stokes) (Fig. 276, /). Elongate; tricho cyst-bearing ven- tral ridge turns up a little on dorsal side; contractile vacuole pos- terior; macronucleus oval; 130/i long; in fresh water among sphag- num and mosses. Genus Kentrophoros Sauerbrey. Extremely elongate, nematode- like; anterior end greatly attenuated; posterior end pointed; body surface longitudinally striated; ciliation uniform; 1-3 macronuclei; numerous contractile vacuoles in 2 rows; cytostome not observed. K. fasciolaium S. (Fig. 276, g, h). About 270m by 38m. Noland (1937) observed 2 specimens in sediment taken from sandy bottom in Florida; contracted 650m long; extended 1 mm. long. Family 2 Tracheliidae Kent Genus Trachelius Schrank. Oval to spherical; anterior end drawn out into a relatively short finger-like process or a snout; posterior end rounded; round cytostome at base of neck; cyto pharynx with trichites; contractile vacuoles many; macronucleus simple or band- form; fresh water. T. ovum Ehrenberg (Fig. 277, a). Spheroidal to ellipsoid; right side flattened and with a longitudinal groove; left side convex; proboscis about 1/4-1/2 the body length; cilia short and closely set; numerous contractile vacuoles; macronucleus short sausage-form, often di- vided into spherules; endoplasm penetrated by branching cytoplas- mic skeins or bands and often with numerous small brown excretion granules; 200-400m long; fresh water. Genus Dileptus Dujardin. Elongate; snout or neck-like prolonga- tion conspicuous; somewhat bent dorsally; along convex ventral side of neck many rows of trichocysts; a row of strong cilia; dorsal surface with 3 rows of short bristles; cytostome surrounded by a ring; cyto- pharynx with long trichocysts; posterior end drawn out into a tail; contractile vacuoles, 2 or more; body ciliation uniform; macro nu- HOLOTRICHA 583 cleus bandform, moniliform or divided into numerous independent bodies; fresh or salt water. Many species. D. americanus Kahl (Fig. 277, h). Proboscis bent dorsally sickle- like; macro nucleus made up of 2 sausage-shaped or often horseshoe- FiG. 277. a, Trachelius ovum, Xl30 (Roux); b, Dileptus americanus, X250 (Kahl); c, D. anser, XSIO (Hayes); d, Paradileptus conicus, X340 (Wenrich); e, P. robustus, X340 (Wenrich); f, Branchioecetes gammari X200 (Penard); g, Loxodes vorax, Xl90 (Stokes); h, L. magnus, X80 (Kahl); i, j, Remanella riigosa (i, dorsal side, Xl30; j, anterior part show- ing the endoskeleton) (Kahl). 584 PROTOZOOLOGY shaped parts; 2 contractile vacuoles on dorsal side; 200^ long; in mosses. D. anser (Miiller) (Figs. 22, c, d; 277, c). Proboscis slightly flattened; macro nucleus divided into numerous bodies; contractile vacuoles in a row on dorsal side with 2-3 contractile vacuoles in proboscis; 250- 400m, sometimes up to 600^ long; fresh water. Genus Paradileptus Wenrich {TentacuUfera Sokoloff). Body broader at the level of cytostome; with a wide peristomal field that bears the cytostome and is surrounded for 2/3-3/4 its circumference by a raised rim which is continuous anteriorly with the spirally wound proboscis; tricho cyst-zone traversing the rim and anterior edge of proboscis; contractile vacuoles small, numerous, distributed; macronucleus segmented ; fresh water. P. conicus W. (Fig. 277, d). 100-200m by 50-100m. P. rohustus W. (Fig. 277, e). 180-450m long. Genus Branchioecetes Kahl. Preoral part somewhat like that of Amphileptvs, and bent dorsally; ventral side of neck with 2 rows of trichocysts; cytostome at posterior end of neck; cytopharynx with trichocysts; ectocommensals on Asellus or Gammarus. B. gammari (Penard) (Fig. 277, f). 130-200/x long; on Gammarus. Family 3 Loxodidae Biitschli Genus Loxodes Ehrenberg. Lancet-like; strongly compressed; an- terior end curved ventrally, and usually pointed; right side slightly convex; uniform ciliation on about 12 longitudinal rows; ectoplasm appears brownish, because of closely arranged brownish protricho- cysts; endoplasm reticulated ; 2 or more vesicular macro nuclei; one or more micronuclei; 5-25 Miiller's vesicles (p. 76; Fig. 30, a, h) in dor- sal region; fresh water. L. vorax Stokes (Fig. 277, g). 125-140^ long; yellowish brown, a row of slightly longer cilia; sapropelic in standing fresh water. L. magnus S. (Fig. 277, h). Extended about 700^ long; dark brown; 12-20 or more Miiller's vesicles in a row along dorsal border; stand- ing pond water. Genus Remanella Kahl. Similar to Loxodes in general appearance; but with endoskeleton consisting of 12-20^ long spindle-form needles lying below broad ciliated surface in 3-5 longitudinal strings con- nected with fibrils; Miiller's vesicles (Fig. 30, c) in some, said to be different from those of Loxodes (Kahl); sandy shore of sea. R. rugosa K. (Fig. 277, i, j). 200-300^ long. HOLOTRICHA 585 Tribe 3 Hypostomata Schewiakoff Without furrow; free-living; conspicuous oral or pharyngeal basket Ciliation complete; dorsal cilia usually less dense than those on ventral surface Family 1 Nassulidae Ciliation incomplete; dorsal surface without cilia or with a few sensory bristles Posterior ventral surface with a style. .Family 2 Dysteriidae (p. 586) Without a style Family 3 Chlamydodontidae (p. 588) Furrow from anterior end of cytostome; parasitic Family 4 Pycnothricidae (p. 590) Family 1 Nassulidae Schouteden Genus Nassula Ehrenberg. Oval to elongate; ventral surface flat, dorsal surface convex; usually brightly colored, due to food mate- rial; cytostome 1/3-1/4 from anterior end; body often bent to left near cytostome; opening of oral basket deep, in a vestibule with a membrane; macronucleus spherical or ovoid, central; a single micro- nucleus; contractile vacuole large, with accessory vacuoles and opens ventrally through a tubule-pore; fresh or salt water. Many species. N. aurea E. (Fig. 278, a). 200-250^ long; fresh and brackish water (Kahl). Genus Paranassula Kahl. Similar in general appearance to Nas- sula; but with preoral and dorsal suture line; longer caudal cilia on dorsal suture; pharyngeal basket not funnel-like, with 16-18 trichites; about 75 ciliary rows; trichocysts especially in anterior region. P. microstoma (Claparede and Lachmann) (Fig. 278, h). Pellicle roughened by a criss-cross of longitudinal and circular furrows; macronucleus elongate oval, posterior; contractile vacuole near mid- dle and right-dorsal; about 80-95/1 long; salt water; Florida (Noland). Genus Cyclogramma Perty. Somewhat resembling Nassula; but conspicuous oral basket in pyriform depression and opens toward left on ventral surface; depression with a short row of small membranes at its anterior edge; trichocysts usually better developed than in Nassula; fresh water. C. trichocystis (Stokes) (Fig. 278, c). Body colorless or slightly rose-colored; trichocysts thick and obliquely arranged; one con- tractile vacuole; usually full of blue-green food vacuoles; actively motile; about 60/i long; in fresh water among algae. Genus Chilodontopsis Blochmann. Elongate ellipsoid; colorless; ventral surface flattened, dorsal surface slightly convex; both sides ciliated; oral basket without vestibule; cytostome with a mem- branous ring; usually with a postoral ciliary furrow; fresh water. 586 PROTOZOOLOGY C. vorax (Stokes) (Fig. 278, d). Elongate ellipsoid; anterior re- gion slightly curved to left; snout fairly distinct; oral basket with about 16 rods; several contractile vacuoles distributed, a large one terminal; macronucleus large, lenticular, granulated; with a closely attached micro nucleus; 50-160m long; fresh water. Genus Eucamptocerca da Cunha. Elongate; posterior part drawn out into a caudal prolongation; do rso-ventrally flattened; ciliation on both sides; round cytostome with oral basket in anterior ventral sur- face. One species. E. longa da C. (Fig. 278, e). 300/x by 25m; macronucleus ovoid, with a micro nucleus; contractile vacuo le(?); in brackish water (salt con- tent 3 per cent); Brazil. Genus Orthodon Gruber. Oval; contractile; colorless; much flat- tened; anterior region curved toward left; striation on both dorsal and ventral sides; cytostome toward right border; oral basket long; macronucleus oval; contractile vacuole terminal; fresh or salt water. 0. hamatus G. (Fig. 278, /). Extended 200-260m long, contracted 90-150m long; flask-shaped; oral basket with 16 trichites; salt water. Family 2 Dysteriidae Kent Genus Dysteria Huxley (Ervilia Dujardin; Iduna, Aegyria Clapa- rede and Lachmann; Cypridium Kent). Ovate, dorsal surface con- vex, ventral surface flat or concave; left ventral side with nonciliated ventral plate; postoral ciliation is continuation of preoral to right of cytostome and parallel to right margin; cytostome in a furrow near right side; posterior style or spine conspicuous; macronucleus spheroid or ovoid, central; with a micro nucleus; usually 2 contractile vacuoles; fresh or salt water. Numerous species. D. calkinsi Kahl (D. lanceolata Calkins) (Fig. 278, g). About 45/i by 27m; salt water; Woods Hole. Genus Trochilia Dujardin. Similar to Dysteria; but ciliated right ventral side free; fresh or salt water. Several species. T. palustris Stein (Fig. 278, h). 25m long; fresh water. Genus Trochilioides Kahl. Rounded at anterior end, narrowed posteriorly; right side more convex than left; cytostome anterior with cyto pharynx and preoral membrane; conspicuous longitudinal bands on right half with longitudinal striae, becoming shorter toward left; fresh or salt water. T. recta K. (Fig. 278, i). 40-50m long; sapropelic in fresh and brack- ish water. HOLOTRICHA 587 Genus Hartmannula Poche {Onychodactylus Entz). Ventral surf ace uniformly ciliated; cytopharynx with short rods; in salt water. H. entzi Kahl (Fig. 278, j). 80-140m long; salt water. Fig. 278. a, Nassula aurea, Xl90 (Schewiakoff ) ; b, Paranassula micro- stoma, x400 (Noland); c, Cyclogramma trichocystis, X510 (Stokes); d, Chilodo7itopsis vorax, X200 (Stokes); e, Eucamptocerca longa, X320 (da Cunha); f, Orthodon hamatus, Xl60 (Entz); g, Dysteria calkinsi, X540 (Calkins); h, Trochilia palustris, X1070 (Roux); i, Trochilioides recta, X740 (Kahl); j, Hartmannula entzi, X220 (Entz); k, Chlamydodon mnemosyne, X520 (MacDougall); 1, Phascolodon vorticella, X340 (Stein). 588 PROTOZOOLOGY Family 3 Chlamydodontidae Glaus Genus Chlamydodon Ehrenberg. Ellipsoid, reniform, elongate tri- angular, etc, ; cilia only on ventral surface, anterior cilia longer; cyto- stome elongate oval and covered with a membrane bearing a slit; oral basket made up of closely arranged rods with apical processes; along lateral margin, there is a characteristic striped band which is a canalicule of unknown function; fresh or salt water. C. mnemosyne E. (Fig. 278, A;). Ellipsoid or reniform; right side convex, left side concave; ventral side flat, dorsal side greatly con- vex; a band of trichites, 'railroad track,' parallel to body outline; oral basket with 8-10 rods; macronucleus oval; 4-5 contractile vacuoles distributed; 60-90m long; salt water. MacDougall (1928) observed it in the brackish water at Woods Hole and studied its neuromotor system. Genus Phascolodon Stein. Ovoid; with broad anterior end and bluntly pointed posterior end ; ventral side concave or flat, dorsal side convex; ciliated field on ventral surafce narrowed laterally behind cytostome, forming V-shaped ciliated area (about 12 rows); cyto- stome ellipsoid with oral basket; macronucleus oval with a micro- nucleus; 2 contractile vacuoles; fresh water. P. vorticella S. (Fig. 278, I). 80-1 lO/x long; cytostome covered by a slit-bearing membrane; with 2 preoral membranes; macronucleus ovoid; fresh water. Genus Cryptopharynx Kahl. Ellipsoid, anterior third bent to left; ventral surface flat, dorsal surface with hump; spiral interciliary fur- rows ridged; oval cytostome at anterior end; no cytopharynx; dorsal hump yellowish, granulated with gelatinous cover; 2 macro nuclei; 1 micro nucleus; 2 contractile vacuoles, one posterior and the other to- ward left side at the bend of body. One species. C. setigerus K. (Fig. 279, a, h). Elongate ellipsoid; anterior region bent to left; ventral surface flat, dorsal surface with a hump; about 15 ventral ciliary rows; 2 vesicular macronuclei and 1 micro nucleus dorso-central; 33-96/x by 21-45/x (Kirby). Kirby found the organism in salt marsh pools (salinity 1.2-9.7 per cent) wnth purple bacteria; California. Genus Chilodonella Strand (Chilodon Ehrenberg). Ovoid; dorso- ventrally flattened; dorsal surface convex, ventral surface flat; ven- tral surface with ciliary rows; anteriorly flattened dorsal surface wdth a cross-row of bristles; cytostome round; oral basket conspicuous, protrusible; macronucleus rounded; contractile vacuoles variable in number; fresh or salt water or ectocommensal on fish and amphi- pods. Many species. HOLOTRICHA 589 C. cucullulus (Miiller) {Chilodon steini Blochmann) (Figs. 52; 279, c-e). 19-20 ventral ciliary rows; oral basket with about 12 rods and with 3 preoral membranes; macro nucleus oval, a characteristic con- centric structure; micro nucleus small; body 100-300ju long, most often 130-1 50/i long; fresh and brackish water. .^\XU^^ Fig. 279. a, b, Cryptopharynx setigerus, X650 (Kirby); c-e, Chilodonella cucullulus (c, X270 (Stein); d, oral region; e, nucleus (Penard)); f, C. caudata, XlOOO (Stokes); g, C. fluviatilis, X800 (Stokes); h, C. cyprini, X670 (Moroff); i, Allosphaerium palustris, XlOOO (Kidder and Sum- mers). C. caudata (Stokes) (Fig. 279,/). About 42^ long; standing water. C. fluviatilis (S.) (Fig. 279, g). About 50m long; fresh water. C. uncinata (Ehrenberg) (Fig. 86). 50-90/x long; about 11 ventral 590 PROTOZOOLOGY ciliary rows; some 7 dorsal bristles; widely distributed in various freshwater bodies; several varieties. C. cyprini (Moroff) (Fig. 279, h). 50-70/x by 30-40m; in the integu- ment and gills of cyprinoid fishes ; the organism, if freed from the host body, dies in 12-24 hours. C. longiphanjnx Kidder and Summers. 17-21^ (average 19^) long; cytopharynx long, reaches posterior end; ectocommensal on amphi- pods, Talorchestia longicornis and Orchestia palustris; Woods Hole. C. hyalina K. and S. 40/i (36-47^) long; ectocommensal on Or- chestia agilis; Woods Hole. C. rotunda K. and S. 29/x (27-34/i) long; ectocommensal on Or- chestia agilis; Woods Hole. Genus Allosphaerium Kidder and Summers. Oval; right side con- cave, left side more or less fiat; body highly flattened; arched dorsal surface devoid of cilia; ventral surface slightly concave with 12-27 ciliary rows; right and left margin of ventral surface with a pellicu- lar fold; cytostome anterior-ventral, oval or irregular, surrounded by ridge on posterior border, extending to left margin; 3 groups of ciliary membranes extending out of cytostome; macro nucleus oval, central or anterior; a micro nucleus; 2 (or 1) contractile vacuoles; a refractile spherule regularly present in posterior portion of endo- plasm; ectocommensal en the carapace and gills of amphipods. A. palustris K. and S. (Fig. 279, i). 46-59m long; 27 ventral ciliary rows; on Orchestia palustris and Talorchestia longicornis; Woods Hole. A. sulcatum K. and S. 24-32/ilong; 12 ciliary rows; on the carapace of Orchestia agilis and 0. palustris; Woods Hole. A. granulosum K. and S. 32-42/i long; rotund; 17 ciliary rows; cytoplasm granulated; on carapace of Orchestia agilis and 0. palus- tris; Woods Hole. A. caudatum K. and S. Resembles A. palustris; 35-45)u long; 14 cihary rows; 1 contractile vacuole; ectoplasm at posterior end, drawn out into a shelf ; on Orchestia agilis; Woods Hole. A. convexa K. and S. 24-36iu long; 17 ciliary rows; on the carapace and gill lamellae of Talorchestia longicornis; Woods Hole. Family 4 Pycnothricidae Poche Ciliation uniform; ectoplasm thick and conspicuous; a furrow or groove connects the cytostome with the anterior end; parasitic in the alimentary canal of mammals. Genus Pycnothrix Schubotz. Large, elongate; with broadly rounded anterior and narrowed posterior end; somewhat flattened; HOLOTRICHA 591 short thick cilia throughout; ectoplasm thick; macro nucleus spheri- cal, in anterior 1/6; micronucleus(?); 2 longitudinal grooves, one be- ginning on each side near anterior end, united at the notched pos- terior end; a series of apertures in grooves considered as cytostomes; at posterior 1/3, an aperture gives rise to branching canals running through endoplasm, and is considered as excretory in function; in the colon of Procavia capensis and P. brucei. One species. Fig. 280. a, Pycnothrix monocystoides, X50; b, Nicollella denodactyli, X170; c, Collinella gundi, X170 (Chatton and Perard); d, Buxtonella sulcata, X400 (Jameson). P. monocystoides S. (Fig. 280, a). 300^-2 mm. long. Genus Nicollella Chatton and Perard. Elongate; a narrow groove extends from the anterior end to cytostome, located at the middle of body; bilobed posteriorly; contractile vacuole terminal; macronu- cleus ellipsoid, anterior; a micro nucleus; ectoplasm thick anteriorly; ciliation uniform; in the colon of Ctenodactylus gundi. One species. 592 PROTOZOOLOGY A^. denodactyli C. and P. (Fig. 280, h). 70-550/^ by 40-1 50m. Genus Collinella Chatton and Perard. More elongate than Nicol- lella; uniform ciliation; a groove extends from end to end; cytostome at posterior end of the groove; contractile vacuole terminal; macro- nucleus much elongated, central or posterior; in the colon of Cteno- dactylus gundi. C. gundi C. and P. (Fig. 280, c). 550-600m by 100m. Genus Buxtonella Jameson. Ovoid; a prominent curved groove bordered by 2 ridges from end to end; cytostome at anterior end; ciliation uniform ; in the caecum of cattle. One species. B. sulcata J. (Fig. 280, d). 55-124m by 40-72m. References Chatton, E. and C. Perard 1921 Les Nicollelidae, infusoires in- testinaux des gondis et des damans, et le 'cycle 6volutif des cilies.' Bull. biol. Fr. et Bel., Vol. 55. Kahl, a. 1931 Urtiere oder Protozoa. Dahl's Die Tierwelt Deutsch- lands. Part 21. Kent, W. S. 1880-1882 A manual of Infusoria. Stein, F. 1867 Der Organismus der Infusionstiere. Vol. 2. Stokes, A. C. 1888 A preliminary contribution toward a history of the freshwater Infusoria of the United States. Jour. Trenton Nat. Hist. Soc, Vol. 1. Wenrich, D. H. 1929 Observations on some freshwater ciliates. II. Paradileptus, n.g. Trans. Amer. Micr. Soc, Vol. 48. Chapter 34 Order 1 Holotricha Stein (continued) Suborder 3 Trichostomata Biitschli With gelatinous lorica; swimming backward Family 1 Marynidae (p. 594) Without lorica Compressed, armor-like pellicle; ciliation sparse, mainly on flat right side in 2-9 broken rows on semicircular or crescentic keel; cy- tostome on flattened ventral surface, with an obscure membrane . Family 2 Trichopelmidae (p. 595) Body form and ciliation otherwise With a long caudal cilium; cilia in 3-4 spiral rows on anterior half, very small forms Family 3 Trimyemidae (p. 595) Without a caudal cilium; form and ciliation otherwise With a spiral zone of special cilia, from cytostome to posterior end Spiral zone extends from anterior right to posterior left Family 4 Spirozonidae (p. 596) Spiral zone extends from anterior left to posterior right Family 5 Trichospiridae (p. 596) Without a spiral zone of special cilia Ciliated cross-furrow in anterior 1/5 on ventral surface, leads to cytostome Family 6 Plagiopylidae (p. 596) Without ciliated cross-furrow Cytostome in flat oval groove with heavily ciliated ridge in anterior 1/4 Family 7 Clathrostomidae (p. 598) Cytostome funnel-like, deeply situated Cytostomal funnel with strong cilia; peristome from an- terior left to posterior right Family 8 Parameciidae (p. 598) Without such a peristome Free-living; oral funnel deep; cilia at bottom and top. . Family 9 Colpodidae (p. 601) Endozoic Commensal in vertebrates Family 10 Entorhipidiidae (p. 603) Parasitic in vertebrates Ciliation uniform With concrement vacuoles Family 11 Paraisotrichidae (p. 605) Without such vacuoles Family 12 Isotrichidae (p. 605) Ciliation not uniform Cytostome occupies the entire anterior end; cilia only in anterior region Family 13 Cyathodiniidae (p. 606) Cytostome not terminal; tufts of cilia above and below cytostome and in posterior region .... Family 14 Blepharocoridae (p. 607) 593 594 PROTOZOOLOGY Family 1 Marynidae Poche Genus Maryna Gruber, Peristome makes a complete circle, thus the cone is entirely separated from anterior edge of body; cytostome left ventral, elongate slit; ridge also with a slit; gelatinous lorica dichotomous. Fig, 281. a, b, Maryna socialis (a, X40; b, Xl60) (Gruber); c, Mydero- thrix erlangeri, X310 (Kahl); d, Trichopelma sphagnetorum, X570 (Kahl); e, f, Pseudomicrothorax agilis (e, X340; f, X670) (Kahl); g, Drepanomonas dentata, X540 (Penard); h, Microthorax sinmlans, X620 (Kahl); i, Trim- yema compressiim, X410 (Lackey); j, Spirozona caudata, X370 (Kahl); k, Trichospira inversa, X360 (Kahl). M. socialis G. (Fig. 281, a, h). About 150/i long; in infusion made from long-dried mud. Genus Mycterothrix Lauterborn {Trichorhynchus Balbiani). An- terior cone continuous on dorsal side with body ridge; hence free edge of body only on ventral side; no ventral slit. HOLOTRICHA 595 M. erlangeri L. (Fig. 281, c). Nearly spherical with zoochlorellae; 5Q-55M by 40-50^; fresh water. Family 2 Trichopelmidae Kahl Genus Trichopelma Levander {Leptopharynx Mermod). Com- pressed; surface with longitudinal furrows, seen as lines in end-view; coarse ciliation throughout; cytostome toward left edge about 1/3 from the anterior end; cytopharynx tubular; macro nucleus spheroid, central; 2 contractile vacuoles; fresh water. T. sphagnetorum (L.) (Fig. 281, rf). 25-40ju long; in fresh water. Genus Pseudomicrothorax Mermod (Craspedothorax Sondheim). More or less compressed; cytostome opens in anterior half toward left side, in a depression surrounded by ciliary rows; body surface marked with a broad longitudinal ridge with cross striation; furrows canal-like; cilia on ventral side; cytopharynx tubular, wdth elastic rods ; fresh water. P. agilis M. (Fig. 281, e,f). Ellipsoid ; 48-58m long; in fresh water. Genus Drepanomonas Fresenius (Drepanoceras Stein). High'y flat- tened; aboral surface convex; oral surface flat or concave; with a few deep longitudinal furrows; ciliation sparse; cytostome and a small cytopharynx simple, near the middle of body; fresh water. Several species. D. dentata F. (Fig. 281, g). With a small process near cytostome; 2 rows of ciliary furrows on both oral and aboral surfaces; cilia on both ends of oral surface; 40-65/i long; in fresh water. Genus Microthorax Engelmann {Kreyella Kahl). Small, flattened; with delicate keeled armor which is more or less pointed anteriorly and rounded posteriorly; ventral armor with 3 ciliary rows; oral de- pression posterior-ventral, with a stiff ectoplasmic lip on right side, below which there is a small membrane, and with a small tooth on left margin; no cytopharynx; macro nucleus spherical; 2 contractile vacuoles; in fresh water. Many species. M. simulans Kahl (Fig. 281, h). 30-35^ long; decaying plant infu- sion, also in moss. Family 3 Trimyemidae Kahl Genus Trimyema Lackey {Sciadostoma Kahl). Ovoid, more or less flattened; anterior end bluntly pointed, posterior end similar or rounded; with a long caudal cilium; cilia on 3-4 spiral rows which are usually located in the anterior half of body; round cytostome near anterior end with a small cytopharynx; spherical macro nucleus cen- 596 PROTOZOOLOGY tral with a small micro nucleus; one contractile vacuole; active swim- mer; fresh or salt water. T. compressum L. (Fig. 281, i). About 65/x by 35ju; Lackey found it in Imhoff tank; fresh and salt water (Kahl). Klein (1930) studied its silverline system. Family 4 Spirozonidae Kahl Genus Spirozona Kahl. Short spindle-form; anterior end truncate, posterior region drawn out to a rounded end, with a group of longer cilia; spiral ciliation; beginning near right posterior third the central ciliary row runs over ridge to left and then reaches the cytostome; other rows are parallel to it; cytostome in anterior 1/4, with cyto- pharynx; ellipsoid macro nucleus nearly central; contractile vacuole terminal; fresh water, sapropelic. S. caudata K. (Fig. 281, j). 80-100m long. Family 5 Trichospiridae Kahl Genus Trichospira Roux. Body cylindrical; posterior end rounded, anterior end conical in profile, where the cytostome surrounded by 2 spiral rows of cilia, is located; a special ciliary band beginning in the cytostomal region runs down on ventral side, turns spirally to left and circles partially posterior region of body; ciliary rows parallel to it; macro nucleus oval, with a micro nucleus ; contractile vacuole pos- terior; fresh water, sapropelic. T. inversa (Claparede and Lachmann) (Fig. 281, A;). 70-100^1 long. Family 6 Plagiopylidae Schewiakoff Genus Plagiopyla Stein. Peristome a broad ventrally opened groove from which body ciliation begins; peristomal cilia short, except a zone of longer cilia at anterior end ; cytostome near median line at the end of the peristome; cytopharynx long; a peculiar 'stripe band' lo- cated on dorsal surface has usually its origin in the peristomal groove, after taking an anterior course for a short distance, curves back and runs down posteriorly near right edge and terminates about 1/3 the body length from posterior end; macro nucleus rounded; a micronucleus; contractile vacuole terminal; free-living or endozoic. P. nasuta S. (Fig. 282, a). Ovoid; tapering anteriorly; peristome at right angles or slightly oblique to the edge; trichocysts at right an- gles to body surface; macro nucleus round to irregular in shape; body about 100/i (80-180m) long; sapropelic in brackish water. Lynch (1930) observed this ciliate in salt water cultures in California and found it to be 70-1 14/i by 31-56m by 22-37/x. HOLOTRICHA 597 P. minuta Powers (Fig. 282, 6). 50-75m by 36-46m; in the intestine of Strongylocentrotus droehachiensis; the Bay of Fundy. Genus Lechriopyla Lynch. Similar to Plagiopyla; but with a large internal organella, furcula, embracing the vestibule from right, and a large crescentic motorium at left end of peristome; in the intestine of sea-urchins. Fig. 282. a, Plagiopyla nasuta, X340 (Kahl); b, P. mimda, X400 (Powers); c, Lechriopyla niystax, X340 (Lynch); d, Sonderia pharyngea, X590 (Kirby); e, S. vorax, X310 (Kahl); f, Clathrostoma viniinale, X220 (Penard); g, Physalophrya spumosa, X160 (Penard). L. mystax L. (Fig. 282, c). 113-174ju long; in the gut of Strongylo- centrotus purpuratus and S. franciscanus; California. Genus Sonderia Kahl. Similar to Plagiopyla in general appear- ance; ellipsoid; flattened; peristome small and varied; body covered by 2-4;u thick gelatinous envelope which regulates osmosis, since no contractile vacuole occurs (Kahl); with or without a striped band; trichocysts slanting posteriorly; in salt or brackish water. Kirby (1934) showed that several species of the genus are common in the 598 PROTOZOOLOGY pools and ditches in salt marshes of California, salinities of which range 3.5-10 per cent or even up to 15-20 per cent. *S. pharyngea Kirby (Fig. 282, d). Ovoid to ellipsoid; flattened; 84- llOju by 48-65/x; gelatinous layer about 2;u thick, with bacteria; about 60 longitudinal ciliary rows, each with 2 borders; peristome about 35/i long, at anterior end, oblique; with closely set cilia from the opposite inner surfaces; cytopharynx conspicuous; spherical macro nucleus anterior, with a micro nucleus; trichocysts (7-9/i long) distributed sparsely and unevenly, oblique to body surface; a group of bristle-like cilia at posterior end; often brightly colored because of food material; in salt marsh, California. S. vorax Kahl (Fig. 282, e). Broadly ellipsoid; size variable, 70- 180iu long; ventral surface flattened; posterior border of peristomal cavity extending anteriorly; in salt marsh; California (Kirby). Family 7 Clathrostomidae Kahl Genus Clathrostoma Penard. Ellipsoid; with an oval pit in anterior half of the flattened ventral surface, in which occur 3-5 concentric rows of shorter cilia; cytostome a long slit located at the bottom of this pit; with a basket composed of long fibrils on the outer edge of the pit ; in fresh water. C. viminale P. (Fig. 282, /). Resembles a small Frontonia leucas; macro nucleus short sausage-form; 4 micro nuclei in a compact group; endoplasm with excretion crystals; 5 preoral ciliary rows; 130-180/z long; in fresh water. Family 8 Parameciidae Grobben Genus Paramecium Hill {Paramaecium Miiller). Cigar- or foot- shaped; circular or ellipsoid in cross section; with a single macro nu- cleus and 1 to several vesicular or compact micro nuclei; peristome long, broad, and slightly oblique; in fresh or brackish water. Several species. P. caudatum Ehrenberg (Figs. 22, e; 36; 41, a-e; 50; 77; 283, a). 180-300/i long; with a compact micro nucleus, a massive macro nu- cleus; 2 contractile vacuoles on aboral surface; posterior end bluntly pointed ; in fresh water. The most widely distributed species. P. aurelia E. (Figs. 81; 56; 283, b). 120-180iu long; 2 small vesicu- lar micro nuclei, a massive macro nucleus; 2 contractile vacuoles on aboral surface; posterior end more rounded than P. caudatum; in fresh water. P. multimicronucleatum Powers and Mitchell (Figs. 19; 20; 28; 29; 283, c). Slightly larger than P. caudatum; 3-7 contractile vacuoles; 4 HOLOTRICHA 599 or more vesicular micronuclei; a single macronucleus; in fresh water. P. bursaria (Ehrenberg) (Fig. 283, d). Foot-shaped, somewhat compressed; about lOO-lSOiuby 50-60ju; green, with zoochlorellae as symbionts; micro nucleus compact; 2 contractile vacuoles; in fresh water. Fig. 283. Semi-diagrammatic drawings of nine species of Paramecium in oral surface view, showing distinguishing characteristics taken from fresh and stained specimens, X230 (several authors), a, P. caudatum; b, P. aurelia; c, P. multurvicronucleahun; d, P. hxirsaria; e, P. putrinum; f, P. calkinsi; g, P. trichium; h, P. -pohjcaryum; i, P. woodruffi. P. putrinum ClaparMe and Lachmann (Fig. 283, e). Similar to P. bursaria, but a single contractile vacuole and an elongated macronu- cleus; no zoochlorellae; 80-150^ long; in fresh water. 600 PROTOZOOLOGY P. calkinsi Woodruff (Fig. 283, /). Foot-shaped; posterior end broadly rounded; 100-150/x by 50)u; 2 vesicular micronuclei; 2 con- tractile vacuoles; rotation of body clockwise when viewed from pos- terior end; in fresh and brackish water P. trichium Stokes (Fig. 283, g). Oblong; somewhat compressed; 60-120/i long; micro nucleus compact; 2 contractile vacuoles deeply situated, each with a convoluted outlet; in fresh water. P. polycaryum Woodruff and Spencer (Fig. 283, h). Form similar to P. hursaria; 70-1 10m long; 2 contractile vacuoles; 3-8 vesicular micronuclei; in fresh water. Fig. 284. a-c, encystment in a species of Paramecium (Curtis and Guthrie); d-f, encystment of P. caudatum, X380 (Michelson). P. woodruffi, Wenrich (Fig. 283, ^). Similar to P. polycaryum; 150- 210ju long; 2 contractile vacuoles; 3-4 vesicular micronuclei; brackish water. Although Paramecium occurs widely in various freshwater bodies throughovit the world and has been studied extensively by numerous investigators by mass or pedigree culture method, there are only a few observations concerning the process of encystment. Biitschli con- sidered that Paramecium was one of the Protozoa in which encyst- ment did not occur. Stages in encystment were however observed in P. hursaria (by Prowazek) and in P. putrinum (by Lindner). In re- cent years, four observers recorded their findings on the encystment of Paramecium. Curtis and Guthrie (1927) give figures in their text- book of zoology, showing the process (in P. caudatum?) (Fig. 284, a-c), HOLOTRICHA 601 while Cleveland (1927) injected Paramecium culture into the rectum of frogs and observed that the ciliate encysted within a thin mem- brane. Michelson (1928) found that if P. caudatum is kept in Knop- agar medium, the organism becomes ellipsoidal under certain condi- tions, later spherical to oval, losing all organellae except the nuclei, and develops a thick membrane; the fully formed cyst is elongated and angular, and resembles a sand particle (Fig. 284,/). Michelson considers its resemblance to a sand grain as the chief cause of the cyst having been overlooked by workers. In all these cases, it may how- ever be added that excystment has not been established. Genus Physalophrya Kahl. Without peristome; but cytostome lo- cated near the anterior half of body, resembles much that of Para- mecium; although there is no membrane, a ciliary row occurs in the left dorsal wall of cytopharynx; in fresh water. Taxonomic status is not clear; but because of its general resemblance to Paramecium, the genus with only one species is mentioned here. P. spumosa (Penard) (Fig. 282, g). Oval to cylindrical; highly plastic; cytoplasm reticulated; numerous contractile vacuoles; 150- 320/i long; in fresh water. Family 9 Colpodidae Poche Genus Colpoda Mliller. Reniform; flattened; right border semi- circular; posterior half of left border often convex; oral funnel in the middle of flattened ventral side, but toward left border where de- pression occurs, which leads into peristome cavity and gives rise dorsally to a diagonal groove; left edge of cytostome bears a cross- striped ciliated area, but no protruding membrane as in Bryophrya (p. 602) ; macro nucleus spherical or oval, central; contractile vacuole terminal; in fresh water. Many species. C. cucullus M. (Fig. 285, a, h). About 80m (50-120m) long; anterior keel with 8^10 indentations; macronucleus with a stellate endosome; trichocysts rod-form; food vacuoles dark; in fresh waiter with decay- ing plants and infusion. C. inflata (Stokes) (Fig. 285, c). 40-80^ long; anterior keel with 6-8 indentations; in fresh water in vegetation. C. calif ornica Kahl (Fig. 285, d). About 30^ long; highly flat- tened; cytostome small; pro trichocysts very granular; cilia delicate, long, in a few rows; macronucleus M-ith a stellate endosome; in moss; California. C. steini Maupas. 30-50m long; 5-6 preoral ridges; in fresh water. Reynolds (1936) found that it adopts itself to various organs of the land slug, Agriolimax agrestis. 602 PROTOZOOLOGY C. duodenaria Taylor and Furgason. 20-40^ (9-60/i) long; 12 longi- tudinal ciliary rows; 3 postoral rows; 2 long cilia at the posterior end; long cilia project out from the cytostome along its posterior margin, forming a "beard"; a contractile vacuole terminal; macro- nucleus ovoid, with crescentic micro nucleus; division into 2-8 indi- viduals in division cyst; but no division in trophozoite stage; bac- teria-feeder; fresh water. Taylor and Strickland (1939) find that crowding causes encystment. Genus Tillina Gruber. Similar to Colpoda in general appearance and stmcture; but cytopharynx a long curved, ciliated tube; in fresh water. Fig. 285. a, b. Colpoda cucullus (a, X340; b, oral region) (Kahl); c, C. inflata, X540 (Stokes); d, C. calif ornica, X670 (Kahl); e, f, Tillina magna, XlOO (Bresslau); g, Bresslaua vorax, XlOO (Kahl); h, Bryophrya bavariensis, X280 (Kahl); i, Woodruffia rostrata, Xl90 (Kahl). T. magna G. (Fig. 285, e, /). 180-200m long (Gruber); up to 400/i long (Bresslau); macronucleus oval, with 6 micronuclei; contractile vacuole terminal, with 6 long collecting canals; in stagnant water and also coprozoic. Genus Bresslaua Kahl. General body form resembles Colpoda; but cytopharynx large and occupies the entire anterior half. B. vorax K. (Fig. 285, g). 80-250;u long; in fresh water. Genus Bryophrya Kahl. Ovoid to ellipsoid; anterior end more or less bent toward left side; cytostome median, about 1/3 from an- terior end, its right edge continues in horseshoe form around the posterior end and half of the left edge; anterior portion of left edge of HOLOTRICHA 603 the cytostome with posteriorly directed membrane; macro nucleus oval or spherical; micro nuclei; in fresh water. B. havariensis K. (Fig. 285, h). 50-120m long. Genus WoodruflBa Kahl. Form similar to Chilodonella (p. 588); highly flattened snout bent toward left; cytostome, a narrow diago- nal slit, its left edge with a membranous structure and its right edge with densely standing short cilia; macro nucleus spherical; several (?) micro nuclei; contractile vacuole flattened, terminal; in salt water. W. rostrata K. (Fig. 285, i). 120-180ai long; salt water culture with Oscillatoria. W. nictabolica Johnson and Larson. 85-400iu long; division cysts 85-1 55/i in diameter; resting cysts 40-62/x in diameter; in freshwater ponds. Johnson and Evans (1939, 1940) find two types of protective cysts in this ciliate: "stable" and "unstable" cysts, formation of both of which depends upon the absence of food. These cysts have three membranes: a thin innermost endocyst, a rigid mesocyst and a gela- tinous outer ectocyst. The protoplasmic mass of the stable cyst is smaller, and free from vacuoles, and its ectocyst is thick, while that of the unstable cyst is larger, contains at least one fluid vacuole and its ectocyst is very thin. Crowding, feeding on starved Paramecium, increasing the temperature, and increasing the salt concentration of the medium, are said to influence the formation of unstable cysts. The two authors (1941) further reported that when free-swimming individuals were subjected, in the absence of food, to extremes of temperature, high concentrations of hydrogen-ions, and low oxygen tensions, unstable cysts were formed; when the oxygen tension de- creased, the tendency to encyst increased, even when ample food was present. The unstable cysts are said to remain viable for six months. Family 10 Entorhipidiidae Madsen Genus Entorhipidium Lynch. Triangular in general outline; color- less; large, 155-350^ long; flattened; posterior end drawn out, with a bristle; anterior end bent to left; cytostome in depression close to left anterior border^ with long cilia; with or without a cross-groove from preoral region; cytopharynx inconspicuous; trichc cysts; macro- nucleus oval to sausage-form; one to several micro nuclei; several (ex- cretory) vacuoles left-ventral; in intestine of the starfish, Strongy- locentrotus purpuratus. Four species. E. echini L. (Fig. 286, a). About 253iu by 125m; California. Genus Entodiscus Madsen. Broadly or narrowly lancet-like, with- out narrowed posterior portion; cytostome small on left narrow side, 604 PROTOZOOLOGY about 2/5 the body length from anterior end; without trichocysts; macro nucleus central, with a micro nucleus; contractile vacuole sub- terminal; swimming movement rapid without interruption. Two species. E. indomitus M. (Fig. 286, h). 80-1 17^ by 20-23^; in the intestine of Strongylocentrotus droehachiensis. Fig. 286. a, Entorhipidium echini, X270 (Lynch); b, Entodiscus in- domitus, X380 (Madsen); c, E. borealis, X380 (Powers); d, Biggaria bermudense, X380 (Powers); e, B. echinometris, X380 (Powers); f, Ano- phrys elongata, X390 (Powers); g, A. aglycus, X390 (Powers). E. horealis (Hentschel) (Fig. 286, c). Oval; cytostome nearer an- terior end; 105-170iu by 60-1 15ju; in the gut of Strongylocentrotus droehachiensis and Echinus esculentus; Powers (1933) studied this species in the first-named host from Maine, and found a supporting HOLOTRICHA 605 rod which is imbedded in the margin along the right wall of the oral cavity and which he named stomato style. Genus Biggaria Kahl. Scoop-like form; anterior 2/3 thin, posterior region thickened, terminating in a rudder-like style; cilia in longi- tudinal rows; longer cilia on caudal prolongation; cytostome in the posterior half, opening into a vestibule, into which long cilia project from the roof; aperture to cyto pharynx with 2 membranes; contract- ile vacuole subterminal; in the intestine of sea-urchins. B. bermudense (Biggar) (Fig. 286, d). 90-185m by 48-82m; in Lij- techinus variegatus; Bermuda (Biggar), North Carolina (Powers). Powers (1935) found the organism at Tortugas in Lytechinus variega- tus, Centr echinus antillarum, Echinometra lucunter, Tripneustes escu- lentus and Astrophyga magnifica. B. echinometris (B.) (Fig. 286, e). 80-195/x by 33-70m; in Echi- nometris suhangularis (Bermuda) and Lytechinus variegatus (North Carolina). Genus Anophrys Cohn. Cigar-shaped; flexible; longitudinal ciliary rows; peristome begins near the anterior end, parallel to body axis and about 1/3 the body length; a row of free cilia on right edge of peristome; cytostome inconspicuous; spherical macro nucleus cen- tral; contractile vacuole terminal; in the intestine of sea-urchins. A. elongata Biggar (Fig. 286, /). About 96m long (Powers); 166m long (Biggar); in the gut of Lytechinus variegatus and Echinometris suhangularis; Bermuda (Biggar); Powers (1935) found this species also in the hosts mentioned for Biggaria bermudense. A. aglycus Powers (Fig. 286, g). 56-120m by 16-35m; in the gut of Centrechinus antillarum and Echinometra lucunter; Tortugas. Family 11 Paraisotrichidae da Cunha Genus Paraisotricha Fiorentini. Uniformly ciliated in more or less spiral longitudinal rows; longer cilia at anterior end; cytostome near anterior tip; contractile vacuole posterior; in the caecum and colon of horse. P. colpoidea F. (Fig. 287, a). 70-100m by 42-60m. P. beckeri Hsiung (Fig. 287, b). 52-98m by 30-52m. Family 12 Isotrichidae Biitschli Genus Isotricha Stein. Ovoid; flattened; dense longitudinal ciliary rows; cytostome at or near anterior end; several contractile vacuoles; reniform macronucleus and a micronucleus connected with, and suspended by, fibrils, karyophore; locomotion with posterior end directed forward; in the stomach of cattle and sheep. 606 PROTOZOOLOGY I. prostoma S. (Fig. 287, c). 80-195m by 53-85/x. I. intestinalis S. (Fig. 287, d). 97-130/x by 68-88m. Genus Dasytricha Schuberg. Oval, flattened; cilia in longitudinal spiral rows; no karyophore; in the stomach of cattle. D. ruminantium S. (Fig. 287, e). 50-75/i by 30-40^. Fig. 287. a, Paraisotricha colpoidea, X270 (Hsiung); b, P. beckeri, X360 (Hsiung); c, Isotricha prostoma, X500 (Becker and Talbott); d, /. intes- tinalis, X500 (Becker and Talbott); e, Dasytricha ruminantium, X330 (Becker and Talbott); f, Cyathodinium piriforme, X1290 (Lucas); g, Blepharocorys uncinata, X540 (Reichenow); h, B. bovis, X850 (Dogiel); i, Charon equi, X570 (Hsiung). Family 13 Cyathodiniidae da Cunha Genus Cyathodinium da Cunha. Conical or pyriform; broad cyto- stome occupies the entire anterior end and extends posteriorly 1/4- 3/4 the body length; deep with prominent ridges; oral cilia in a sin- gle row on left ridge; body cilia comparatively long, confined to an- terior half; macro nucleus round or ellipsoid; a micro nucleus; one to several contractile vacuoles; in the caecum and colon of guinea pigs. C. conicum da C. Inverted cone; 50-80/i by 20-30m; in the caecum of Cavia aperea and C. porcella. HOLOTRICHA 607 C. piriforme da C. (Fig. 287, /). Typical form inverted pyriform; second form conical with tapering anterior end; contractile vacuole posterior; 30-40jli by 20-30^; in the caecum of Cavia aperea and C. porcella. Lucas (1932) who made a cytological study of the organism, found some 52 per cent of guinea pigs which she examined in Phila- delphia and St. Louis harboring this ciliate. Family 14 Blepharocoridae Hsiung Genus Blepharocorys Bundle. Oral groove deep, near anterior end; 3 (oral, dorsal and ventral) ciliary zones at anterior end; a caudal ciliary zone; in the caecum and colon of horse or stomach of cattle. Many species. B. uncinata (Fiorentini) {B. equi Schumacher) (Fig. 287, g). With a screw-like anterior process; 55-74^ by 22-30m; in the caecum and colon of horse. B. hovis Dogiel (Fig. 287, h). 23-37)u by 10-17^; in the stomach of cattle. Genus Charon Jameson. Two caudal ciliary zones; in the colon of horse or in stomach of ruminants. C. equi Hsiung (Fig. 287, i). 30-48m by 10-14m; in the colon of horse. References Johnson, W. H. and F. R. Evans 1939 A study of encystment in the ciUate, Woodruffia metabolica. Arch. f. Protistenk., Vol. 92. ■ 1940 Environmental factors affecting cystment in Woodruffia metabolica. Physiol. Zool., Vol. 13. 1941 A further study of environmental factors af- fecting cystment in Woodruffia metaholica. Ibid., Vol. 14. Lackey, J. B. 1925 The fauna of Imhoff tanks. Bull. N. J. Agr. Exp. Stat., No. 417. Lucas, Miriam S. 1932 A study of Cyathodinium piriforme. Arch. f. Protistenk., Vol. 77. Lynch, J. 1929 Studies on the ciliates from the intestine of Stron- gylocentrotus. L Univ. Calif. Publ. Zool., Vol. 33. 1930 II. Ibid., Vol. 33. Powers, P. B. A. 1933 Studies on the ciliates from sea urchins. I, II. Biol. Bull., Vol. 65. 1935 Studies on the ciliates of sea urchins. Papers from Tortugas Lab., Vol. 29. Taylor, C. V. and W. H. Furgason 1938 Structural analysis of Colpoda duodenaria sp. nov. Arch. f. Protistenk., Vol. 90. and A. G. R. Strickland 1939 Reactions of Colopoda duodenaria to environmental factors. II. Factors influencing the formation of resting cysts. Physiol. Zool., Vol. 12. Wenrich, D. H. 1928 Eight well-defined species of Paramecium. Trans. Amer. Micr. Soc, Vol. 47. Chapter 35 Order 1 Holotricha Stein (continued) Suborder 4 Hymenostomata Hickson Cytostome not connected with peristome Family 1 Frontoniidae Oytostome at end or bottom of peristome Peristome sickle-form, ciliated slit; sunk at right angles to body surface Family 2 Ophryoglenidae (p. 617) Peristome long, begins at anterior end of body Peristome with a one-layered membrane which forms a pocket sur- rounding cytostome on right edge and a row of cilia or mem- brane on left Family 3 Pleuronematidae (p. 618) Peristome otherwise Peristome with 2 one-layered membranes; no distinct ectoplasmic pocket around cytostome. .Family 4 Cohnilembidae (p. 620) Peristome furrow either covered densely with cilia, besides an un- dulating membrane on right edge, or with only a thick undu- lating membrane on the right edge Family 5 Philasteridae (p. 621) Family 1 Frontoniidae Kahl Genus Frontonia Ehrenberg. Ovoid to ellipsoid; anterior end more broadly rounded than posterior end; flattened; oral groove lies in anterior third or more or less flattened ventral surface, to right of median line; lancet-like with pointed anterior and truncate poste- rior end; left edge is more curved than right edge, and posteriorly be- comes a prominent ectoplasmic lip; cytostome with a complex or- ganization (on left edge a large undulating membrane composed of 3 layers, each being made up of 4 rows of cilia; on right, semi- membranous groups of cilia; 3 outer rows of cilia from the postoral suture; along this suture ectoplasm is discontinuous so that large food matter is taken in; with a small triangular ciliated field poste- rior to cytostome and left of suture); a long narrow postoral groove which is ordinarily nearly closed; cytopharynx with numerous strong fibrils; ciliary rows close and uniform; ectoplasm w4th numerous fusiform trichocysts; macro nucleus oval; one to several micro nuclei; 1-2 contractile vacuoles, with collecting canals and an external pore; fresh or salt water. Bullington (1939) recognizes 14 species. F. leucas E. (Figs. 22, a, h; 288, a). 150-600^* long; fresh water. F. branchiostomae Codreanu (Fig. 288, b). 75-1 00m by 55-95ju; commensal in the branchial cavity of Amphioxus. Genus Disematostoma Lauterborn. Somewhat similar to Fron- tonia; pyriform; with broadly rounded, truncate or concave anterior 608 HOLOTRICHA 609 end and bluntly pointed narrow posterior end; preoral canal wide; a dorsal ridge in posterior region of body; macro nucleus sausage- form; a micro nucleus; contractile vacuole in middle of body, with long collecting canals; in fresh water. Fig. 288. a, Frontonia leucus, XHO (Kahl); b, F. branchiostomae, X490 (Codreanu); c, Disematostoma biitschlii, X340 (Kahl); d, Lembadion bid- linum, Xl70 (Kahl); e, Tetrahymena geleii, X950 (Furgason); f, Leuco- phrys patula, X280 (Man pas); g, Colpidiiim colpoda, XlSO (Kahl); h, i, Lambornella stegomyiae, X340 (Keilin); j, Paraglaucoma rostrata, X400 (KaM)]k, Malacophrysrotans, X 500 (Kahl). 610 PROTOZOOLOGY D. hutschlii L. (Fig. 288, c). 135-155/1 long; with or without zoo- chlorellae; in fresh water. Genus Lembadion Perty. Oval; dorsal side convex, ventral side concave; cytostome 3/4-4/5 the body length; on its left with a large membrane composed of many ciliary rows and on its right, numerous narrow rows of short free cilia; an undulating membrane and ciliary rows near posterior end; contractile vacuole in mid-dorsal region with a long tubule opening at posterior-right side; close ciliation uniform; macronucleus ellipsoid, subtermi^ial ; a micro nucleus; long caudal cilia; in fresh water. L. hullinum P. (Fig. 288, d). 120-200/x long; posterior cilia 40-50^ long. Genus Tetrahymena Furgason. Pyriform; small forms; uniform ciliation; ciliary rows or meridians less than 20; 2 postoral meridians; preoral suture straight; cytostome small, close to anterior end, pyri- form; its axis parallel to body axis; inconspicuous ectoplasmic ridge or flange on the left margin of mouth; an undulating membrane on right side and 3 membranellae on left of the cytostome; a single con- tractile vacuole; macronucleus ovoid; micronucleus absent (?) in one species; conjugation unobserved; fresh water. Furgason (1940) established this genus after making a comparative study with Leuco- phrys, Glaucoma and Colipidium, as the most primitive genus of the group. T. geleii F. (Figs. 288, e; 289, a, e, /). Pear to cucumber in shape; 40-60m long; 17-19 ciliary meridians; pyriform cytostome about 1/10 the body length; macronucleus irregularly ovoid; micronucleus un- observed; bacteria-feeder, but may be cultured in sterile media; pond water. T. vorax (Kidder, Lilly and Claff) {Glaucoma vorax K. L. and C.) (Fig. 38). Form and size vary; bacteria-feeders elongate pyriform, 50-75)u long; sap ro zoic forms fusiform, 30-70/x long, decreasing in size with the age of culture; sterile particle-feeders, 60-80^ long; carnivores and cannibals broadly pyriform, 100-250^ long; 19-21 ciliary meridians; macronucleus ovoid, central; in carnivores, out- line irregular; a single micronucleus; pond water. Genus Leucophrys Ehrenberg. Broadly pyriform; cytostome large, pyriform, with its axis parallel to body axis; ectoplasmic flange along left margin; undulating membrane on right and 3 membranellae on left of mouth; 5 postoral ciliary meridians; macronucleus ovoid; a micronucleus; fresh water. L. patula E. (Figs. 288, /; 289, h, g). Broadly pyriform; 80-160m long; occasionally small forms occur; cytostome pyriform, about 1/3 HOLOTRICHA 611 the body length; 40-45 ciliary meridians; macro nucleus irregularly ovoid; a micro nucleus attached to macro nucleus; carnivorous, but may be cultured in sterile media (Kidder); fresh water. Genus Glaucoma Ehrenberg (Dallasia Stokes). Ovoid or ellipsoid; cytostome about one-fourth the body length, near anterior end, ellipsoid; cytostome with an inconspicuous undulating membrane on right and 3 membranellae on left; ectoplasmic ridge on right bor- der of mouth; ciliation uniform; 30-40 ciliary meridians; 7 postoral meridians; macro nucleus rounded; a micro nucleus; a contractile vacuole; with or without 1 or more caudal bristles; fresh water. Fig. 289. Diagrammatic oral views and oral apparatus of four genera. Ciliary meridians of: a, Tetrahymena geleii; b, Leucophrys patula; c, Glau- coma scintillans; and d, Colpidium campijlum. All X about 535. e, cyto- stome of Tetrahymena geleii, showing the ectoplasmic ridge and 3 mem- branellae on left and a large undulating membrane on right. Diagrams of cytostome of: f, T. geleii; g, Leucophrys patula; h, Glaucoma scintillans; and i, Colpidium colpoda. (a, c, d, modified after Kidder; b, e-i, modified after Furgason.) G. scintillans E. (Fig. 289, c, h). Ovate with rounded ends; 45-75/x long; U-shaped cytostome, about one-fourth the body length, ob- lique; ectoplasmic flange and 3 membranellae conspicuous; a con- tractile vacuole in posterior one-third; macro nucleus oval, central; a micro nucleus; bacteria-feeder, but cultivable in bacteria-free •culture media (Kidder) ; fresh water. Genus Colpidium Stein. Elongate reniform; ciliary meridians variable in number, but typically one postoral meridian; small tri- 612 PROTOZOOLOGY angular cytostome one-fourth from anterior end toward right side; a small ectoplasmic flange along right border of cytostome which shows an undulating membrane on right and 3 membranellae on left; rounded macro nucleus; a micro nucleus; a contractile vacuole; fresh or salt water. C. colpoda (Ehrenberg) {Tillina helia Stokes) (Figs. 10; 288, g; 289, i). Elongate reniform; 90-150^ long; cytsotome about one- tenth the body length ; 55-60 ciliary meridians; preoral suture curved to left; macro nucleus oval, central; a micro nucleus; fresh water. Burbank (1942) recently examined the effect of various food bacteria on the division rate of this ciliate. C. campylum (Stokes) (Fig. 289, d). Elongate reniform; 27-30 ciliary meridians; preoral suture curved to right; 50-70/ilong; Kidder cultured the organism bacteria-free; in fresh and brackish water. C. striatum S. Similar to the last species; contractile vacuole further posterior; 50/i long; in standing water. Genus Lambornella Keilin. Ellipsoid; densely ciliated; close longi- tudinal striation; small oral pit in anterior half; macronucleus spherical; a micro nucleus; cyst hemispherical; parasitic. One spe- cies. L. stegomyiae K. (Fig. 288, h, i). 50-70m long; cysts 30-40/i in di- ameter; in the haemocoele of Stegomyia scutellaris. Genus Paraglaucoma Kahl. Somewhat similar to Glaucoma; but without perioral ectoplasmic ridge; a membrane on right ridge of the cytostome; anterior end drawn out to a point in profile, posterior end rounded; a stiff posterior bristle; a contractile vacuole; rapid zig-zag movement. One species. P. rostrata K. (Fig. 288, j). 60-80^ long; in fresh water (often in dead rotiferan body); California, Wisconsin (Kahl). Genus Malacophrys Kahl. Ellipsoid or cylindrical; plastic; cilia uniformly close-set in longitudinal rows; slit-like cytostome at an- terior extremity; in fresh water. M. rotans K. (Fig. 288, k). Oval; close and dense ciliation; spheri- cal macronucleus central; a micro nucleus; a single contractile vacu- ole; body 40-50m long; fresh water. Genus Espejoia Burger (Balantiophorus Penard). Ellipsoid; an- terior end obliquely truncate; large cytostome at anterior end; post- oral groove on ventral side, 1/4-1/3 the body length ; a conspicuous membrane on the left edge of groove; in gelatinous envelope of eggs of insects and molluscs. E. musicola (P.) (Fig. 290, a). Elongate; right side flat, left side convex; 80-100^ long. HOLOTRICHA 613 Genus Cryptochilidium Schouteden. Ellipsoid; with rounded an- terior end, posterior end pointed in profile; highly compressed; uni- form and close ciliation; cytostome near middle; one or more longer cilia at posterior end; contractile vacuole posterior; macronucleus round; a micro nucleus; commensal. C. echini (Maupas) (Fig. 290, b). 70-140m long; in the gut of Echi- nus lividus. Genus Eurychilum Andre. Elongate ellipsoid; anterior end some- what narrowed; cilia short; dense ciliation not in rows; contractile vacuole terminal; macronucleus band-form; cytostome about 2/5 from anterior end and toward right, with a strong undulating mem- brane on left; no cytopharynx; actively swimming. One species. E. actiniae A. (Fig. 290, c). About 155^ long; in gastro vascular cavity of Sagartia parasitica. Genus Monochilum Schewiakoff. Ovoid to ellipsoid; medium large; uniform and dense ciliation in rows; oblong cytostome left of median line, in about 1/4 the body length from anterior end; short cytopharynx conical, with an undulating membrane; contractile vacuole near middle; in fresh water. M. frontatum S. (Fig. 290, d). Anterior end broader; ventrally flattened, dorsally somewhat convex; macronucleus ellipsoid; a micro nucleus ; feeds on algae; 80m by 30/x. Genus Dichilum Schewiakoff. Similar to Monochilum; but mem- brane on both edges of the cytostome; in fresh or salt water. D. cuneiforme S. (Fig. 290, e). Ellipsoid; cytostome about 1/5 the body length from anterior end; right membrane larger than left; small cytopharynx; macronucleus ellipsoid; about 40^ by 24/i; in fresh water. Genus Loxocephalus Eberhard. Ovoid to cyhndrical; sometimes compressed; crescentic cytostome on slightly flattened area near anterior end, with 2 membranes; often a zone of cilia around body; usually 1 (or more) long caudal cilium; endoplasm granulated, yel- lowish to dark brown; macronucleus ovoid; a single contractile vacuole; in fresh or brackish water. Many species. L. plagius (Stokes) (Fig. 290, /). 50-65m long; nearly cylindrical; 15-16 ciliary rows; endoplasm usually darkly colored; in fresh water among decaying vegetation. Genus Balanonema Kahl. Similar to Loxocephalus; but with plug- like ends; cytostome diflftcult to see; a caudal cilium; macronucleus oval; contractile-vacuole; ciliation uniform or broken in the middle zone ; fresh water. B. biceps (Penard) (Fig. 290. g). Ellipsoid; no cilia in the middle 614 PROTOZOOLOGY region; contractile vacuole central; macro nucleus posterior to it; 42-50/x long. Genus Platynematum Kahl. Ovoid or ellipsoid; highly flattened; with a long caudal cilium; contractile vacuole posterior-right; small cytostome more or less toward right side, with 2 outer membranes; ciliary furrows horseshoe-shaped; in fresh or salt water. P. sociale (Penard) (Fig. 290, h). Anterior half more flattened; ventral side concave; cytostome in the anterior third; yellowish and granulated; 30-50jLt long; sapropelic in fresh and brackish water. Fig. 290. a, Espejoia musicola, X300 (Penard); b, Cryptochiliduim echini, X380 (Powers); c, Eunjchilum actiniae, X360 (Andr6); d, Mono- chilum frontatum, X440 (Schewiakoff ) ; e, Dichilum cuneiforme, X700 (Schewiakoff) ; f, Loxocephalus plagius, X380 (Stokes); g, Balanonema biceps, X600 (Penard); h, Platynematum sociale, X500 (Kahl); i, Sapro- philus agitatus, X450 (Stokes); j, S. muscorum, X440 (Kahl); k, Cineto- chilum margaritaceum, X440 (Kahl). Genus Saprophilus Stokes. Ovoid or pyriform; compressed, cy- tostome in anterior 1/4-1/3 near right edge, with two membranes; macronucleus spherical; contractile vacuole posterior; in fresh water, S. agitatus S. (Fig. 290, i). Ellipsoid; ends bluntly pointed; com- pressed; plastic; close striation; about 40ju long; in fresh water in decomposing animal matter such as Gammarus. HOLOTRICHA 615 *S. muscorum Kahl (Fig. 290, j). Cytostome large, with a large membrane; trichocysts; contractile vacuole with a distinct canal; body about 35iu long; in fresh water. Genus Cinetochilum Perty. Oval to ellipsoid; highly flattened; ciha on flat ventral surface only; cytostome right of median line in posterior half, with a membrane on both edges which form a pocket; oblique non-ciliated postoral field leads to left posterior end; with 3-4 caudal cilia; macro nucleus spherical, central; contractile vacuole terminal; in fresh or salt water. C. margaritaceum P. (Fig. 290, k). 15-45^ long; in fresh and brackish water. Genus Dexiotrichides Kahl (Deziotricha Stokes). Reniform; com- pressed; cytostome near middle, with two membranes; long cilia sparse; a special oblique row of cilia; a single caudal cilium; contrac- tile vacuole terminal; spheroidal macro nucleus anterior; a micro- nucleus; in fresh water. One species. D. centralis (Stokes) (Fig. 291, a). About 30-45/i long; in decaying vegetable matter. Genus Cyrtolophosis Stokes. Ovoid or ellipsoid; with a mucilagi- nous envelope in which it lives, but from which it emerges freely; cytostome near anterior end with a pocket-forming membrane; on right side a short row of special stiff cilia, bent ventrally; sparse ciliation spiral to posterior-left; spherical macro nucleus central; a contractile vacuole; in fresh water. C. mucicola S. (Fig. 291, 6). 25-28^ long; in infusion of leaves. Genus Urocentrum Nitzsch. Short cocoon-shaped, constricted be- hind the middle; ventral surface flat; 2 broad girdles of cilia; fused cilia at posterior end; with a zone of short cilia in the constricted area; cy to pharynx with a stiff ectoplasmic membrane which sepa- rates 2 undulating membranes (on left) and ciliated zone (on right) ; macro nucleus, horseshoe-shape, posterior; a micro nucleus; contrac- tile vacuole terminal, with 8 long canals which reach the middle of body; in fresh water. U. turbo (Miiller) (Fig. 291, c). 50-80^ long. Kidder and Diller (1934) studied its fission. Genus Urozona Schewiakoff. Ovoid, both ends broadly rounded; a distinct constriction in the ciliated middle region; ciliary band composed of 5-6 rows of cilia, directed anteriorly and arranged longi- tudinally; cytostome with a membrane; rounded macro nucleus and a micronucleus posterior ; contractie vacuole subterminal ;in freshwater. U. butschlii S. (Fig. 291, d). 20-25^ long (Kahl); 30-40^ (Schewi- akoff) ; in stagnant water. 616 PROTOZOOLOGY Genus Uronema Dujardin (Cryptochilum Maupas). Oval to elon- gate ovoid; slightly flattened; anterior region not ciliated; incon- spicuous peristome with ciliated right edge; cytostome on the ven- FiG. 291. a, Dexiotrichides centralis, X500 (Kahl); b, Cyrtolophosis mucicola, X670 (Kahl); c, Urocentriun turbo, X200 (Biitschli); d, Urozona butschlii, X440 (Kahl); e, Uronema marina, X490 (Kahl); f, g, U. pluri- caudatum, X940 (Noland); h, Homalogastra setosa, X450 (Kahl); i, j, Stokesia vernalis, X340 (Wenrich); k, Ophryoglena collini, Xl50 (Lichten- stein); 1, 0. pyriformis, Xl80 (Rossolimo) ; m, 0. intestinalis, X55 (Rossolimo). tral side close to left border in the anterior half, with a small tongue- like membrane; cyto pharynx indistinct; macro nucleus spherical, central; contractile vacuole terminal; in salt or fresh water. HOLOTRICHA 617 U. marina D. (Fig. 291, e). 30-50/i long; in salt water in decaying U. pluricaudatum Noland (Fig. 291, /, g). Body appears to be twisted in dorsal view, due to a spiral depression that runs obliquely down toward cytostome; with about 8 caudal cilia; in salt water; Florida. Genus Homalogastra Kahl. Broad fusiform; furrows spiral to left; a long caudal cilium; a group of cilia on right and left side of it; macronucleus spherical, anterior; contractile vacuole posterior; in fresh water. H. setosa K. (Fig. 291, h). About SOn long; fresh water. Genus Stokesia Wenrich. Oblique cone with rounded angles; flat anterior surface uniformly ciliated; with peristome bearing zones of longer cilia, at the bottom of which is located the cytostome; a girdle of longer cilia around the organism in the region of its greatest diameter; pellicle finely striated; with zoochlorellae; trichocysts; free-swimming; in freshwater pond. One species. S. vernalis W. (Fig. 291, i,j). 100-160/x in diameter; macronucleus; 2-4 micro nuclei; fresh water. Family 2 Ophryoglenidae Kent Genus Ophryoglena Ehrenberg. Ellipsoidal to cylindrical; ends rounded or attenuated; preoral depression in form of *6' due to an ectoplasmic membrane extending from the left edge, cilia on the right edge; cytostome deep-seated; 1 (or 2) contractile vacuole with long radiating canals, opens through pores on right ventral side; macronucleus of various forms with several endosomes; a micro- nucleus; fresh or salt water or parasitic. Many species. 0. collini Lichtenstein (Fig. 291, k). Pyriform; macronucleus horseshoe-shape; 200-300/i by 120-230|u; in the caecum of Baetis larvae. 0. parasitica Andre. Ovoid; dark; micronucleus (?); 170-350ai by 180-200iLt; in the gastro vascular cavity of Dendrocoelum lacteum. 0. pyriformis Rossolimo (Fig. 291, I). Flask-shape; 240-300iu long; in the gastrovascular cavity of various Turbellaria. 0. intestinalis R. (Fig. 291, m). Up to 1.5 mm. by 450-500^; small- est 60/x long; in the gastrovascular cavity of Dicotylus sp. 0. atra Lieberkiihn. Oval, posterior end broadly rounded; 300- 500/x long; grayish; filled with globules; cytostome near anterior end; macronucleus elongated; a contractile vacuole; trichocysts; stagnant fresh water. 618 PROTOZOOLOGY Family 3 Pleuronematidae Kent Genus Pleuronema Dujardin. Ovoid to ellipsoid; peristome begins at anterior end and extends for 2/3 the body length ; a conspicuous membrane at both edges; semicircular swelling to left near oral area; no cytopharynx; close striation longitudinal; one to many posterior sensory stiff cilia; macro nucleus round or oval; a micro nucleus; a contractile vacuole; trichocysts in some species; fresh or salt water, also commensal in freshwater mussels. P. crassum D. (Fig. 292, a). 70-120/x long; somewhat compressed; Woods Hole (Calkins). Fig. 292. a, Pleuronema crassum, X240 (Kahl); b, P. anodontae, X290 (Kahl); c, d, P. setigerum, X540 (Noland); e, P. coronatuni, X540 (Noland); f, P. marinum, X400 (Noland); g, Cyclidium litomesurn, X300 (Stokes); h, Cristigera phoenix, X500 (Penard); i, C. media, X400 (Kahl). P. anodontae Kahl (Fig. 292, b). About 55^ long; posterior cilium about 1/2 the body length; in Sphaerium, Anodonta. P. setigerum Calkins (Fig. 292, c, d). Ellipsoid; flattened; ventral surface slightly concave; about 25 ciliary rows; 38-50m long (No- land); in salt water; Massachusetts, Florida. P. coronatum Kent (Fig. 292, e). Elongate ovoid; both ends equally rounded; caudal cilia long; about 40 ciliary rows; 47-75/1 long (Noland); in fresh and salt water; Florida. HOLOTRICHA 619 P. marinum D. (Fig. 292,/). Elongate ovoid ;tricho cysts distinct; caudal cilia medium long; about 50 ciliary rows; 51-126m long (Noland) ; in salt water; Florida. Genus Cyclidium Miiller. Small, 15-60m long; ovoid; usually with refractile pellicle; with a caudal cilium; peristome near right side; on its right edge occurs a membrane which forms a pocket around cytostomal groove and on its left edge either free cilia or a membrane which unites with that on right; no semicircular swelling on left of oral region; round macronucleus with a micro nucleus; con- tractile vacuole posterior; fresh or salt water. Numerous species. C. litomesum Stokes (Fig. 292, g). About 40/i long; dorsal surface slightly convex with a depression in middle; ventral surface more or less concave; cilia long; in fresh water. Genus Cristigera Roux. Similar to Cyclidium; much compressed; with a postoral depression; peristome closer to mid-ventral line; fresh or salt water. Several species. C. 'phoenix Penard (Fig. 292, h). 35-50^ long; fresh water. C. media Kahl (Fig. 292, i). 45-50^ long; in salt water. Genus Ctedoctema Stokes. Similar to Cyclidium in body form; peristome nearer median line, diagonally right to left; right peri- stomal ridge with a sail-like membrane which surrounds the cyto- stome at its posterior end; trichocysts throughout; fresh water. C. acanthocrypta S. (Fig. 293, a). Ovoid; anterior end truncate; macronucleus round, anterior; about 35/x long; in fresh water among vegetation. Genus Calyptotricha Phillips. Somewhat resembles Pleuronema or Cyclidium; but dwelling in a lorica which is opened at both ends; with zoochlorellae; fresh water. C. pleuronemoides P. (Fig. 293, b). Lorica about 85/x high; body about 50m long; Kellicott's (1885) form is more elongated; in fresh water. Genus Histiobalantium Stokes. Ovoid; ventral side flattened; ciliation uniform; long stiff cilia distributed over the body surface; peristome deep; both anterior and posterior regions with a well- developed membrane, connected with the undulating membrane; macronucleus in 2 parts; 1-2 micro nuclei; several contractile vacu- oles distributed; fresh water. H. natans (Claparede and Lachmann) (Fig. 293, c). 70-1 10m long. H. semisetatum Noland (Fig. 293, d). Elongate ellipsoid ; posterior end bluntly rounded; macronucleus spherical; longer cilia on pos- terior half only; contractile vacuoles on dorsal side; 126-205^ long; salt water; Florida. 620 PROTOZOOLOGY Genus Pleurocoptes Wallengren. Ovoid, dorsal side hemispher- ical, ventral side flattened; peristome large, reaching the posterior 1/3; cyto pharynx indistinct; longer cilia along peristome; macro- nucleus spherical; several micro nuclei; contractile vacuole terminal; ectocommensal. P. hydractiniae W. (Fig. 293, e). 60-70)u long; on Hydractinia echinata. f ^^^/ d Fig. 293. a, Ctedoctema acanthocrypta, X840 (Kahl); b, Calyptotricha pleuronempides, Xl80 (Kalh); c, Histiohalantium nutans, X420 (Kahl); d, H. semisetatuvi, X270 (Noland); e, Pleurocoptes hydractiniae, X470 (Wallengren); f, Cohnilemhus fusijorrnis, X560 (Kahl); g, C. caeci, X390 (Powers); h, Philaster digitifomris, X220 (Kahl); i, P. armata, X240 (Kahl); j, Helicostoma buddenbrocki, Xl90 (Kahl). Family 4 Cohnilembidae Kahl Genus Cohnilembus Kahl {Lemhus Cohn). Slender spindle-form; flexible; peristome from anterior end to the middle of body or longer, curved to right, with 2 membranes on right edge; a caudal cilium or a few longer cilia at posterior end; macro nucleus oval, central; in salt or fresh water, some parasitic. HOLOTRICHA 621 C . fusiformis (C.) (Fig. 293,/). Striation spiral; peristome about 1/6 the body length; a few cilia at posterior end; oval macronucleus central; contractile vacuole posterior; about 60m long; in fresh water. C. cacci Powers (Fig. 293, g). About 32-92^ long; in the intestine of Tripneustes esculentus and other echinoids; Tortugas. Family 5 Philasteridae Kahl Genus Philaster Fabre-Domergue {Philasterides Kahl). Body cylindrical; peristome about 1/3-2/5 the body length, broader near cytostome and with a series of longer cilia; cytostome with a triangu- lar membrane; cytopharynx (?); ciliation uniform; a caudal cilium; trichocysts; oval macronucleus with a micro nucleus, central; con- tractile vacuole terminal or central; in salt or fresh water. P. digiliformis F-D. (Fig. 293, h). Anterior region bent dorsally; contractile vacuole terminal; l()0-150/i long; salt water. P. armata (K.) (Fig. 293, i). Anterior end more or less straight; peristome difficult to see; contractile vacuole central; 70-80)u long; fresh water. Genus Helicostoma Cohn. Similar to Philaster in general appear- ance; preoral side-pouch curved around posterior edge of peristome and separated from it by a refractile curved band; with or without a pigment spot near cytostome; macronucleus oval or band-form; contractile vacuole terminal; in salt water. H. buddenbrocki Kahl (Fig. 293, j). 130-200/i long; in salt and brackish water. References BuLLiNGTON, W. E. 1939 A study of spiraling in the ciliate Fron- tonia with a review of the genus and a description of two new species. Arch. f. Protistenk., Vol. 92. BuRBANK, W. D. 1942 Physiology of the ciliate Colpidium colpoda. I. The effect of various bacteria as food on the division rate of Colpidium colpoda. Physiol. Zool., Vol. 15. FuRGASON, W. H. 1940 The significant cytostomal pattern of the "Glaucoma-Colpidium group," and a proposed new genus and species, Tetrahymena geleii. Arch. f. Protistenk., Vol. 94. Kahl, A. 1931 Urtiere oder Protozoa. In: Dahl's Die Tierwelt Deutschlands, Part 21. Kidder, G. W. 1941 Growth studies on ciliates. VII. Biol. Bull., Vol. 80. D. M. Lilly and C. L. Claff 1940 Growth studies on ciliates. IV. Ibid., Vol. 78. NoLAND, L. E. 1937 Observations on marine ciliates of the Gulf coast of Florida. Trans. Amer. Micr. Soc, Vol. 56. 622 PROTOZOOLOGY Parducz, B. 1940 Verwandtschaftliche Beziehungen zwischen den Gattungen Uronema und Cyclidium. Arch. f. Protistenk., Vol. 93. Wenrich, D. H. 1929 Observation on some freshwater ciHates. I. Teutophrys trisula Chatton and de Beauchamp and Stokesia vernalis n. sp. Trans. Amer. Micr. Soc, Vol. 48. T Chapter 36 Order 1 Holotricha Stein (continued) Suborder 5 Thigmotricha Chatton and Lwoff HE majority of the ciliates placed in this suborder inhabit the mantle cavity of mussels. They possess thigmotactic cilia with which they attach themselves to the host body. Though appearing heterogeneous, Chatton and Lwoff hold that there is a phylogenetic unity among them, which has been brought about by the degenera- tive influence because of the similar conditions of habitat. Without tentacles Ciliation uniform; ciliary rows meridional, close; peristome does not begin near the anterior end Thigmotactic cilia on entire broad side; with large peristome Family 1 Conchophthiridae Thigmotactic cilia only on a small field of left broad side; peristome small Family 2 Thigmophryidae (p. 624) Long cilia only on posterior margin where cytostome is located; sucker at anterior end Family 3 Hysterocinetidae (p. 624) Ciliation unequal on 2 broad sides or spirally arranged, or highly rudimentary Cytostome with conspicuous peristome bearing long cilia Family 4 Ancistrumidae (p. 626) Cytostome rudimentary Family 5 Sphenophryidae (p. 628) With tentacular attaching organella . . . Family 6 Hypocomidae (p. 629) Family 1 Conchophthiridae Reichenow Genus Conchophthirus Stein. Oval to ellipsoid; flattened; right margin concave at cytostomal region, left margin convex; ventral surface somewhat flattened, dorsal surface convex; cytostome on right sidie near middle in a depression with an undulating membrane; macronucleus; micro nucleus; contractile vacuole opens through a canal to right side ; in the mantle cavity and gills of various mussels, Kidder made careful studies of several species. C. anodontae (Ehrenberg) (Figs. 63; 294, a). Ovoid; cytostome in anterior third, wdth an overhanging projection in front; cyto- pharynx, surrounded by circular fibrils, continues down as a fine, distensible tubule, to near the macronucleus; with peristomal bas- ket; ciliary grooves originate in a wide ventral suture near anterior end; anterior region filled with refractile granules; macronucleus posterior; contractile vacuole between nuclei and peristome, with a slit-like aperture (Fig. 27); 65-125m by 47-86m; in the mantle 623 624 PROTOZOOLOGY cavity, gills and on non-ciliated surface of palps of Elliptio com- planatus; Woods Hole. C. curtus Engelmann. Somewhat broader; 60-125)U by 50-90)u; peristomal field smaller; cytopharynx less conspicuous, but longer; ciliation dense; endoplasmic granules are more closely packed and do not extend as far out toward anterior end; macro nucleus central. Kidder found this ciliate in the mantle cavity of Anodonta marginata, A. implicata, A. catarecta, Lampsilis radiata, L. cariosa and Alasmi- donta undulata which were obtained from the freshwater lakes of Massachusetts and New York. C. magna Kidder. Much larger; 123-204/i by 63-116m; closer cilia- tion; anterior 1/3 filled with smaller granules; irregularly outlined macro nucleus, 25-30m in diameter, central; 2 (or 1) micro nuclei; aperture for contractile vacuole large; mantle cavity of Elliptio com- planatus; Massachusetts. C. caryoclada K. (Fig. 294, h). Oval; extremely flattened; leaf- like; cytostome small, in posterior fourth; macronucleus conspic- uously branched; 2 (or 1) micronuclei; 140-250^ by 90-160m; mantle cavity of the edible clam, Siliqua patula; Oregon. C. mytili de Morgan (Fig. 55). Reniform; 130-220^ by 76-161^; peristomal groove on the right side; trichocysts conspicuous along frontal margin; macronucleus oval; 2 micronuclei. Kidder (1933) found the organism on the foot of the common mussel, Mytilus edulis, in New York and studied its division and conjugation. Genus Myxophyllum Raabe. Oval or spheroid ; pellicle elastic and flexible; peristome on posterior right, without undulating membrane; 7 macro nuclei; a micronucleus; ciliation uniform; in the slime cover- ing land pulmonates. M. steenstrupi (Stein) (Fig. 294, c). 120^ by 100-120//; on Succinea putris, etc. Family 2 Thigmophryidae Chatton and Lwoff Genus Thigmophrya Chatton and Lwoff. Elongate ; round or oblong in cross section; cytostome in posterior third; contractile vacuole opens in cytopharynx; on the gills or palps of lamellibranchs. T. macomae C. and L. Elongate ovoid; flattened; ventral surface slightly concave; oral funnel opened; contractile vacuole opens at the bottom of c3'topharynx ; numerous ciliary rows; about llO/i by 40ju; on the gills of Macoma (Tellina) halthica. Family 3 Hysterocinetidae Diesing Inclusion of this family in the present suborder is provisional, HOLOTRICHA 625 since its affinity to other forms is not yet clear. Beers who placed it in Hymenostomata, in agreement with Cheissin states that the nu- trition in two genera is in part saprozoic, and that the organisms are in the process of acquiring the saprozoic habit and the astomatous condition. Fig. 294. a, Conchophthirus anodontae, X300 (Kidder); b, C. caryoclada, X200 (Kidder); c. Myxophyllum steenstrupi, X280 (Raabe); d, Hystero- cineta eiseniae, Xl90 (Beers); e, Ptychoslomum bacteriophilum, X375 (Miyashita); f, g, dorsal and side views of Ancistruma mytili, X500 (Kidder); h, A. isseli, X500 (Kidder). Genus Hysterocineta Diesing {Ladopsis Cheissen). Elongate; flattened; flexible, an inverted V- or U-shaped sucker conspicuously present in antero-ventral margin; ciliation uniform; cytostome and cytopharynx at the posterior end; an undulating membrane along peristome which borders the posterior margin of body; macro nucleus elongate; a micronucleus; contracile vacuole posterior; in the intes- tine of gastropods and oligochaetes. 4 species (Beers, 1938). H. eiseniae Beers (Fig. 294, d). 190-210^1 by 35-40)li; cytostome not functional; endo plasm with small granules; macro nucleus 45-50/i long; sucker inverted V, about 25-30/i long; in the intestine of Ei- senia lonnhergi. 626 PROTOZOOLOGY Genus Ptychostomum Stein {Lada Vejdovsky). Sucker circular or ovoid; macronucleus ovoid or reniform, not elongate; in oligochaetes. Several species. P. hacteriophilum Miyashita (Fig. 294, e). Elongate oval; 70-130/i by 30-45m; sucker oval and large, about SO/x in diameter; macronu- cleus ellipsoid ; endoplasm with numerous rods (symbiotic bacteria?) ; in Criodrilus sp. (Oligochaeta). Family 4 Ancistrumidae Issel Genus Ancistruma Strand {Ancistrum Maupas). Ovoid, pyriform or somewhat irregular; flattened; right side with more numerous large cilia than the left; peristome on right side; cytostome near posterior extremity; macronucleus round or sausage-shape, central; a micro nucleus; contractile vacuole posterior; commensal in the mantle cavity of various marine mussels. Many species. A. mytili (Quennerstedt) (Figs. 18; 294,/, g). Oval; dorsal surface convex, ventral surface concave; dorsal edge of peristome curves around the cytostome; peristomal floor folded and protruding; longitudinal ciliary rows on both surfaces; three rows of long cilia on peristomal edges; macronucleus sausage-form; a compact micro- nucleus anterior; 52-74/i by 20-38m. Kidder (1933) found it in abund- ance in the mantle cavity of Mytilus edulis at Woods Hole and New York. A. isseli Kahl (Fig. 294, h). Bluntly pointed at both ends; 70-88m by 31-54/i. Kidder (1933) observed it abundantly in the mantle cav- ity of the solitary mussel, Modiola modiolus, Massachusetts and New York, and studied its conjugation and nuclear reorganization. Genus Eupoterion MacLennan and Connell. Small ovoid ; slightly compressed; cilia short, in longitudinal rows; rows of long cilia in peristome on mid-ventral surface and extend posteriorly, making a half turn to left around cytostome; small conical cytostome lies in postero-ventral margin of body; contractile vacuole terminal; large round macronucleus anterior; a micro nucleus; commensal. E. pernix M. and C. (Fig. 295, a). 46-48 ciliary rows; 6 rows of heavy peristomal cilia; 38-56m long; in the intestinal contents of the mask limpet, Acmaea persona; California. Genus Ancistrina Cheissin. Ovoid; anterior end attenuated; peri- stomal field along narrow right side; 15-18 ciliary rows parallel to peristomal ridges; cytostome right-posterior, marked with oral ring, with a membrane and a zone of membranellae; right ridge of peri- stome marked by two adoral ciliary rows; macronucleus anterior, spheroidal; a micro nucleus; commensal. HOLOTRICHA 627 A. ovata C. (Fig. 295, h). 38-48m by 15-20^; in the mantle cavity of molluscs: Benedictia hiacalensis, B. limneoides and Choanomphalus sp. Fig. 295. a, Eupoterion pernix, X670 (MacLennan and Connell); b, Ancistrina ovata, X840 (Cheissin); c, Ancistrella choanomphali, X840 (Cheissin); d, Boveria teredinidi, X550 (Pickard); e, Plagiospira crinita, X740 (Issel); f, Hendspeira asteriasi, X940 (Wallengren) ; g, h, Hypo- coma acinetarum, X400 (Collin); i-k, H. patellarum (i, j, X820; k, X670) (Lichtenstein). Genus Ancistrella Cheissin. Elongate; ends rounded; ventral sur- face less convex than dorsal surface; 16-17 longitudinal ciliary rows; ciliation uniform, except anterior-dorsal region, bearing bristle-like 628 PROTOZOOLOGY longer cilia; 2 adoral ciliary rows on right of peristome, curved dor- sally behind cytostome; contractile vacuole posterior; macronucleus single or divided into as many as 7 parts ; micronucleus ; commensal. A. choanomphali C. (Fig. 295, c). 55-90ju by 18-20ju; in the mantle cavity of Choanomphalus sp. Genus Ancistrospira Chatton and Lwoff. Ciliation meridional to spiral; peristome right spiral; commensal. A. veneris C. and L. 50-60^ by 22-28^1; ovoid, anterior end pointed; ciliary rows meridional; thigmotactic field on the left side, sharply marked from body ciliation; on the gills of Venus fasciata. Genus Boveria Stevens {Tiarella Cheissin). Conical; cytostome at posterior end; peristome spiral posteriorly; macronucleus oval, in anterior half; a micronucleus; contractile vacuole posterior; ecto- commensal on gills of various marine animals such as Teredo, Bankia, Tellina, Capsa and Holothuria. Several species. B. teredinidi Pickard (Fig. 295, d). 27-173m by 12-3 1^; on gills of Teredo navalis; California. Genus Plagiospira Issel. Conical; anterior end attenuated; peri- stome runs spirally from middle of body to cytostome, with long cilia; marcronucleus oval, anterior; a micronucleus; contractile vacu- ole near middle of body; somewhat spirally arranged striae widely apart on right side; commensal, P. crinita I. (Fig. 295, e). 32-58/i bj^ 18-34jli; in Cardita calyculata and Loripes lacteus. Genus Hemispeira Fabre-Domergue. Nearly spherical; flattened; longitudinal non-ciliated furrow on ventral surface, which encircles thigmotactic posterior cilia; 4-5 cross-furrows of cilia; a huge adoral membrane at anterior end; macronucleus, micronucleus large; con- tractile vacuole, anterior-right; commensal. H. asteriasi F.-D (Fig. 295, /). 20-30/i long; ectocommensal on Asterias glacialis. Genus Hemispeiropsis Konig. Oval; body surface not ciliated, except the adoral end which bears 1-2 cross-rows of cilia and thig- motactic cilia; adoral membrane double; macronucleus large, spheri- cal, with an imbedded micronucleus; contractile vacuole central; ectocommensal. H. comatulae K. About 23-27m long, excluding membrane; on Comatula mediterranea. Family 5 Sphenophryidae Chatton and Lwoff Genus Sphenophrya Chatton and Lwoff. Triangular to crescentic; in mature state, basal rows of cilia distinct on the broad side, con- HOLOTRICHA 629 verging toward middle, from which budding takes place sidewise; in the gills of mussels. S. dosiniae C. and L. 120iLt by 15-20/x; fixed to the interfilamental space of gills of Dosinia exoleta. Family 6 Hypocomidae Biitschli Genus Hypocoma Gruber. Cilia confined, or reduced, to hold-fast organella at anterior end, arranged in longitudinal rows; with a suck- ing tentacle which serves probably for obtaining nourishment; cyto- stome apprently vestigial; commensal. The genus had been placed in Suctoria; but Chatton and Lwoff showed that ciliation is lengthwise and not crosswise as in Suctoria. H. acinetarum Collin (Fig. 295, g, h). On Acineta papillifera. H. patellarum Lichtenstein (Fig. 295, i-k). On the gills of Patella caerulea; about 30;u long. H. cardii Chatton and Lwoff. On Cardium edule. Genus Hypocomides Chatton and Lwoff. Ovate; slightly flat- tened; anterior end attenuated, a few meridional striae; adoral rows of cilia reduced; commensal in mussels. H. zyrphaeae C. and L. 25-30/i by 12-15^; in the gills of Zyrphaea crispata. References Beers, C. D. 1938 Hysterocineta eiseniae n.sp., an endoparasitic ciliate from the earthworm Eisenia lonnhergi. Arch. f. Protis- tenk.. Vol. 9L Chatton, E. and A. Lwoff 1926 Diagnoses de cilies thigmotriches nouveaux. Bull. soc. zool. Fr., Vol. 51. Cheissin, E. 1931 Infusorien Ancistridae und Boveriidae aus dem Baikalsee. Arch. f. Protistenk., Vol. 73. Kahl, a. 1931, 1935 Dahl's Die Tierwalt Deutschlands. Parts 21, 30. Kidder, G. W. 1933 Studies on Conchophthirus mytili de Morgan. I, II. Arch. f. Protistenk., Vol. 79. 1933 On the genus Ancistruma Strand (Ancistrum Mau- pas). I. Biol. Bull. Vol. 64; 11. Arch. f. Protistenk., Vol. 81. 1934 Studies on the ciliates from freshwater mussels. I, II. Biol. Bull, Vol. 66. MacLennan, R. F. and F. H. Connell 1931 The morphology of Eupoterion pernix gen. nov., sp. nov. Uni. Calif. Publ. Zool., Vol. 36. MiYASHiTA, Y. 1933 Drei neue parasitische Infusorien aus dem Darme einer Japanischen Siisswasseroligochaete. Annot. Zool. Japon., Vol. 14. Stevens, N. M. 1903 Further studies on the ciliate Infusoria, Licnophora and Boveria. Arch. f. Protistenk., Vol. 3. Chapter 37 Order 1 Holotricha Stein (continued) Suborder 6 Apostomea Chatton and Lwoff ASYMMETRICAL forms with a rosette-like cytostome through which liquid or small solid particles are taken into the body; sparse ciliary rows spiral; adoral rows short; macro nucleus oval to band-form; a micronucleus; a single contractile vacuole. The life-cycle of the ciliates grouped here appears to be highly complex and Chatton and Lwoff (1935) distinguished several devel- opmental phases (Fig. 296), as follows: (1) Trophont or vegetative phase: right-spiral ciliary rows; nucleus pushed aside by food bodies; body grows, but does not divide. (2) Protomont: transitory stage be- tween 1 and 3 in which the organism does not nourish itself, but pro- duces "vitelloid" reserve plates; nucleus central, condensed; ciliary rows become straight. (3) Tomont: the body undergoes division usually in encysted condition into more or less a large number of small ciliated individuals. (4) Protomite: a stage in which a renewed torsion begins, and which leads to to mite stage. (5) Tomite: small free-swimming and non-feeding stage, but serves for distribution. (6) Phoront: a stage which is produced by a tomite when it becomes at- tached to a crustacean and encysts; within the cyst a complete trans- formation to trophont takes place. Family Foettingeriidae Chatton Genus Foettingeria Caullery and Mesnil. Trophonts large, up to 1 mm. long; sublenticular, anterior end attenuated; dorsal surface con- vex, ventral surface concave; right side less convex than left side; 9 spiral ciliary rows nearly evenly arranged; in gastro vascular cavity of various actinozoans; tomont on outer surface of host body, gives rise to numerous tomites with meridional ciliary rows; each tomite becomes a phoront by encysting on a crustacean, and develops into a trophont when taken into gastrovascular cavity of an actinozoan. One species. F. actiniarum (Claparede) (Fig. 297, a). Phoronts on Copepoda, Ostracoda, Amphipoda, Isopoda and Decapoda; trophonts in Ac- tinia messembryanthemum, A. equina, Anemo7iia sulcata and other actinozoans in European waters; Chatton and Lwoff found Metri- dium marginatum, Sagartia leucolena and Astrangia danae of Woods Hole free from this ciliate. 630 HOLOTRICHA 631 Genus Spirophrya Chatton and Lwoff. Trophonts ovoid, pointed anteriorly; 16 uninterrupted ciliary rows of which striae 1 and 2 ap- proach each other in posterior-dorsal region; phoronts attached to a Phoront (Idyaea furcata) ^f. Young trophont Fig. 296. Diagram illustrating the life-cycle of Spirophrya subparasitica (Chatton and Lwoff). crustacean; when eaten by Cladonema, trophonts enter the crusta- cean body and complete growth; protomonts upon leaving the host body encyst and each divides into 4-82 tomites (Fig. 296). One species. 632 PROTOZOOLOGY S. suhvarasitica C. and L. (Figs. 296; 297, h). Phoronts attached to Idyaea jurcata; ovoid trophonts enter the copepod when eaten by Cladnema radiatum. Fig. 297. a, Foettingeria actiniarum, a trophont; h,Spirophrya subpara- sitica, a trophont, XlOOO; c, Phoretrophyra nebaliae, X1180; d, Syno- phrya hypertrophica (Chatton and Lwoff). Genus Gymnodinioides Minkiewicz {PJujsophaga Percy; Oospira Chatton and Lwoff). Trophonts twisted along equatorial plane; gen- erally 9 ciliary rows, in some a rudimentary row between striae 5 and 6 at anterior end. Many species. HOLOTRICHA 633 G. calkinsi Chatton and Lwoff. Phoronts on gills and trophonts in the moult of Palaemonetes sp. ; Woods Hole. Genus Phoretrophrya Chatton and Lwoff. Trophonts generally with 9 ciliary rows; striae 1, 2, and 3, close to one another. One spe- cies. Fig. 298, a, Ophiurespha weilli; b, Photorophrya insidiosa, a trophont in a phoront of Gymnodinioides, X800; c, Vampyrophrya pelagica, a trophont, X740; d, Pericaryon cesticola, a trophont (Chatton and Lwoff). P. nehaliae C. and L. (Fig. 297, c). Phoronts and tomonts on ap- pendages, and trophonts in the moult, of Nebalia geoffroyi. Genus Synophrya Chatton and Lwoff. Trophonts and tomonts 634 PROTOZOOLOGY similar to those of Gymnodinioides; but development highly compli- cated. One species. S. hypej'trophica C. and L. (Fig. 297, d). Phoronts in branchial lamellae, and trophonts in the moult, of Portunus depurator, etc. Fig. 299. a, Polyspira delagei; b, Calospira minkiewiczi, a trophont, X1300; c, Vampyrophrya pelagica, d, Traumatiophtora punctata, X1300 (Chatton and Lwoff). Genus Ophiurespira Chatton and Lwoff. Trophonts ovoid; 10 ciliary rows; striae 9 and 10 interrupted. One species. 0. weilli C. and L. (Fig. 298, a). Trophonts in the intestine of Ophiothrix fragilis and Amphiura squamata (Ophiuroidea). Genus Photorophrya Chatton and Lwoff. Trophonts small; ciliation HOLOTRICHA 635 approximately that of Ophiurespira; massive macro micleus; with peculiar trichocysts comparable with the nematocysts of Polykrikos (p. 257) ; ecto- or endo -parasitic in encysted stages of other aposto- means. Several species. P. insidiosa C. and L. (Fig. 298, b). Phoronts, trophonts and tomites in phoronts of Gymnodinioides. Genus Polyspira Minkiewicz. Trophonts reniform; 9 rows and several extra rows; striae 1-4 and 5-9 with 2 others in 2 bands. P. delagei M. (Fig. 299, a). Phoronts on gills and trophonts in the moult of Eupagurus berhardus. Genus Pericaryon Chatton. Trophonts ellipsoid; 14 ciliary rows. P. cesticola C. (Fig. 298, d). Trophonts in the gastro vascular cavity of the ctenophore, Cestus veneris; other stages unknown. Genus Calospira Chatton and Lwoff. Trophonts resemble those of Spirophrya; 20 ciliary rows; macro nucleus twisted band-form; a micronucleus. C. minkiewiczi C. and L. (Fig. 299, b). Phoronts attached to in- tegument of Harpacticus gracilis (copepod); trophonts in its fresh carcass; tomonts and tomites in water. Genus Vampyrophrya Chatton and Lwoff. Trophonts ovoid; 10 ciliary rows, of which striae 308 are uninterrupted. One species. V. pelagica C. and L. (Fig. 298, c; 299, c). Phoronts on Paracala- nus parvus, Clausocalanus furcatus, etc., and trophonts in their fresh carcasses. Genus Traumatiophtora Chatton and Lwoff. Trophonts oval; 11 ciliary rows. One species. T. punctata C. and L. (Fig. 299, d). Trophonts in fresh carcass of Acartia clausi. Genus Hyalospira Miyashita. Trophonts in the moult of a fresh- water crustacean, with a contractile vacuole and a long accessory canal, and with a band-shaped macro nucleus; protomont encysts in narrow crevices; tomont divides into 2-16 tomites; tomite with a tubular macro nucleus, two ciliated grooves on ventral side, and 9 ciliary rows; phoront cysts occur on the body hairs of Xiphocaridina to metamorphose into trophont. H. caridinae M. Fully grown trophonts 80-120^ long; phoronts and phoront cysts present in fresh moults and body hairs respect- ively of Xiphocaridina compressa. References Chatton, E. and A. Lwoff 1935 Les cih^s apostomes. Arch. zool. exp. et gen., Vol. 77. Miyashita, Y. 1933 Studies on a freshwater foettingeriid ciliate, Hyalospira caridinae n.g., n.sp. Japan. Jour. Zool., Vol. 4. Chapter 38 Order 2 Spirotricha Butschli With free cilia only; exceptionally with small groups of cirrus-like pro- jections in addition to cilia Uniformly ciliated; in Peritromidae dorsal surface without or with a few cilia; in Licnophoridae cilia only on edge of attaching disk; peristome usually extended; peristomal field mostly ciliated Suborder 1 Heterotricha Ciliation much reduced or none at all Rounded in cross-section; cilia usually much reduced; adoral zone encloses a non-ciliated peristomal field in spiral form Suborder 2 Oligotricha (p. 652) Compressed; carapaced; peristomal zone reduced to 8 membranellae which lie in an oval hollow. .Suborder 3 Ctenostomata (p. 665) Cirri only, on ventral side; dorsal side usually with rows of short bristles . . Suborder 4 Hypotricha (p. 668) Suborder 1 Heterotricha Stein Body ciliation complete and uniformly the same Peristome sunk in a funnel-like hollow at anterior end, thus mostly covered Family 1 Bursariidae (p. 637) Peristome lies almost completely free, leading to a short and narrow oral funnel (absent in one family) Peristome in anterior region A narrow non-ciliated zone on right of adoral zone; usually an undulating membrane or ciliary row to right of this non-ciliated zone and anterior to cytostome; a small peristomal field between the membrane and adoral zone Adoral zone extends diagonally to posterior-right on ventral surface; highly developed forms, with a long zone twisting spirally around body Family 2 Metopidae (p. 640) Adoral zone parallel to body axis on flat ventral surface, turns somewhat to right in front of cytostome; oral funnel dis- tinct; typically an undulating membrane or a double ciliated furrow in front of cytostome Family 3 Spirostomidae (p. 641) Without the non-ciliated zone; a large peristomal field with a half or completely spiral adoral zone Peristomal field not ciliated; with a large undulating membrane on its right edge Family 4 Condylostomidae (p. 645) Peristomal field ciliated; without undulating membrane Peristomal field not drawn out in 2 wings; free-swimming or secretes gelatinous lorica Family 5 Stentoridae (p. 645) Peristomal field drawn out into 2 wings; with flask-shaped, thin pseudochitinuous lorica .. Family 6 Folliculinidae (p. 647) 636 SPIROTRICHA, HETEROTRICHA 637 Peristome at posterior end; cyto pharynx directed anteriorly Family 7 Clevelandellidae (p. 648) Body ciliation either confined to ventral side or lacking Free-living; flattened; cilia only on ventral surface; adoral zone sur- rounds anterior region of ventral surface; cytostome on left edge near the middle of body Family 8 Peritromidae (p. 649) Ectocommensal; extremities discoid; body narrowed; anterior disk surrounded spirally by adoral zone; posterior disk bears mem- branous cilia Family 9 Licnophoridae (p. 649) Family 1 Bursariidae Perty Genus Bursaria Mliller. Ovoid; anterior end truncate, posterior end broadly rounded; dorsal surface convex, ventral surface flat- tened; deep peristome begins at anterior end and reaches about Fig. 300. a, Bursaria truncatella, X60 (Kahl); b, Thylacidium trunca- tum, X440 (Schewiakoff ) ; c, Bursaridium difficile, X210 (Kahl); d, Balantidium duodeni, X170 (Stein); e, B. praenucleatum, X950 (Kudo and Meglitsch). central part of body, where it gives rise to cytostome and cyto- pharynx, which is bent to left; lengthwise fold divides peristome into 2 chambers; striation longitudinal; ciliation complete and uniform; macro nucleus band-form; several micronuclei; many contractile vacuoles distributed along lateral and posterior borders; cysts with a double envelope; fresh water. One species. 638 PROTOZOOLOGY B. truncatella M. (Fig. 300, a). SOO-lOOOju long. Genus Thylacidium Schewiakoff. Similar to Bursaria in general appearance; but smaller in size; peristome simple in structure with- out longitudinal fold; with zoochlorellae; fresh water. One species. T. truncatum S. (Fig. 300, b). 60-lOOju long. Genus Bursaridium Lauterborn. Similar to Bursaria; peristome funnel turns to right; fresh water. B. difficile Kahl (Fig. 300, c). Anterior end truncate, cyto pharynx slanting toward right; about 130/x long. Genus Balantidium Claparede and Lachmann (Balantidiopsis Biitschli; Balantiodoides Alexeieff). Oval, ellipsoid to subcylindrical; peristome begins at or near anterior end; cyto pharynx not well de- veloped; longitudinal ciliation uniform; macro nucleus elongated; a micro nucleus; contractile vacuole and cytopyge terminal; in the gut of vertebrates and invertebrates. Numerous species. Hegner (1934) states that the size and shape of body and macronucleus could be made a satisfactory basis for specific identification. B. coli (Malmsten) (Fig. 301). Ovoid; 40-80^ by 30-60m, but length varies 30-1 50ai; body covered by many slightly obliquely longitudinal rows of cilia; peristome small near anterior tip, lined with coarser cilia; inconspicuous cytostome and cyto pharynx are located at the end of peristome; 2 contractile vacuoles, one terminal, the other near the middle of body; macronucleus sausage-shape and a vesicular micronucleus; cytopyge near the posterior tip; food particles are of various kinds, including erythrocytes and other host cell fragments, starch grains, faecal debris, etc. The trophozoite multiplies by binary fission. Conjugation was reported by Brumpt. The cysts are circular to ovoid in outline; slightly yellowish or greenish and refractile; 40-60/i in diameter; cyst wall made up of 2 membranes; cytoplasm hyaline; macronucleus and a contractile vacuole are usually seen. This ciliate lives in the colon and caecum of man and causes balantidiosis or balantidial dysentery. Strong (1904) made the first histological study of the infection. The organisms invade the tissues and blood vessels of the mucosa and submucosa. At the beginning there is hjq^eraemia with punctiform haemorrhages, and later vascu- lar dilatation, round cell infiltration, eosinophilia, etc., develop in the infected area. Finally deep-seated ulcers are produced. The bal- antidial dysentery is usually of chronic type. It has a wide geograph- ical distribution. In the United States a few cases of infections have been observed in recent years. In the Philippine Islands, more cases have been noticed than anywhere else. SPIROTRICHA, HETEROTRICHA 639 Balantidium coli is a very common parasite in the intestine of pigs, and also in chimpanzee and orang-outang. In pigs, the ciHate ordinarily confines itself to the lumen of the intestine, but according to Ratcliffe (1934), when the host animals become infected by an organism belonging to Salmonella, it invades and ulcerates the in- testinal wall. The cysts developing in pigs appear to become the *i..:^ 3 4 Fig. 301. Balantidium coli, X530 (Kudo). 1, a living trophozoite; 2, a stained trophozoite; 3, a fresh cyst; 4, stained cyst. chief source of infection, since balantidial dysentery is more com- monly found among those who come in contact with pigs cr pig in- testine. The cysts remain viable for weeks in pig faeces in moist and dark places, though they are easily killed by desiccation or ex- posure to sun light. The cysts may reach human mouth in food or in water contaminated with them, through unclean hands of persons who come in contact with faeces or intestine of pigs, and in some cases perhaps through uncooked sausage. B. sids McDonald. Ellipsoid; 35-1 20m by 20-60/i; macro nucleus more elongate than that of B. coli; in the intestine of pigs. Levine (1940) through a series of culture studies, has come to consider that B. coli and B. suis are only morphological variations due to the nutritional condition and that B. suis is synonymous with B. coli. Other domestic and wild animals harbor various species of Bal- antidium. 640 PROTOZOOLOGY B. duodeni Stein (Fig. 300, d). 70-80^ by 55-60^1 ; in the intestine of the frog. B. praeniicleatum Kudo and Meglitsch (Fig. 300, e). 42-127/x long, 32-102jLt thick, 25-80ju wide; macronucleus close to anterior end; in the colon of Blatta orientalis. Family 2 Metopidae Kahl Genus Metopus Claparede and Lachma^n. Body form changeable; when extended oblong or fusiform; peristome conspicuous, slightly spirally diagonal, beginning at the anterior end and reaching the middle of body; when contracted, peristome much spirally coiled; cytopharynx short; body ciliation uniform, longitudinal or in some, spiral; longer cilia at ends; conspicuous contractile vacuole terminal; macronucleus ovoid to elongate; fresh or salt water (sapropelic), some parasitic. Numerous species. M. es Muller {M. sigmoides C. and L.) (Figs. 80; 302, a). 120-200^ long; sapropelic. Noland's (1927) study on its conjugation has been described (p. 161). M. striatus McMurrich (Fig. 302, h). 80-120^ long; fresh water. M. fuscus Kahl (Fig. 302, c). 180-300^ long by OO/x wide and 40m thick; fresh water. M. circumlahens Biggar (Fig. 302, d). 70-165^ by 50-75^; in the digestive tract of sea urchins, Diadema setosum and Echinomeiris subangularis; Bermuda (Biggar). Powers observed it in Centrechinus antillarum, etc., at Tortugas. Genus Spirorhynchus da Cunha. Fusiform; somewhat flattened; anterior end drawn out and curved toward left; posterior end also drawn out; spiral peristome; cytopharynx small with an undulating membrane; cilia uniformly long; contractile vacuole posterior; longi- tudinally striated; body surface with closely adhering bacteria (Kirby); three spherical macronuclei; micronucleus (?); in brackish water. S. verrucosus da C. (Fig. 302, e). 122-140m by 20-22^. Kirby ob- served it in salt marsh with 3 per cent salinity; California. Genus Caenomorpha Perty (Gyrocoris Stein). Bell-shaped; car- apaced ectoplasm in some species bears protricho cysts; strong mar- ginal zone of about 8 rows of cilia; 1-2 dorsal rows of longer cilia and a dense spiral field around caudal prolongation; peristome long; cytostome posterior; cytopharynx directed anteriorly; a single elongate or two spherical macronuclei; a micronucleus; fresh or salt water (sapropelic). Several species. SPIROTRICHA, HETEROTRICHA 641 C. medusula P. (Fig. 302, /). 150^ by 130m; fresh and brackish water. Several varieties. Fig. 302. a, Metopvs es, X260 (Kahl); b, M. striatus, X220 (Kahl); c, M.fuscus, Xl50 (Kahl); d, M. circumlabens, x370 (Powers^; e, Spiro- rhynchus verrucostis, X360 (Kirby); f, Caenomorpha medusula, X200 (Blochmann); g, Blepharisma lateritium, Xl60 (Penard); h, B. persici- num, X290 (Penard); i, B. steini, X340 (Penard); j, Protocrxizia piger- rinia, X390 (Faria, da Cunha and Pinto); k, Phacodinium vietschnicoffi,, X270 (Kahl). Family 3 Spirostomidae Kent. Genus Spirostomum Ehrenberg. Elongated; cylindrical; some- what compressed; ectoplasm with highly developed mj^onemes which are arranged lengthwise independent of ciliary rows, hence highly contractile; yellowish to brown; excretory vacuole terminal large, with a long dorsal canal; macro nucleus either ovoid or chain form; cilia short; rows longitudinal; caudal cilia are thigmotactic, secrete 642 PROTOZOOLOGY mucous threads (Jennings); peristome closely lined with short mem- branellae; fresh or salt water. Several species. S. ambiguum E. (Figs. 37; 303, a). 1-3 mm. long (length: width, Fig. 303. a, Spirostomum ambiguum, X65 (Kahl); b, S. minus, Xl40 (Kahl); c, S. loxodes, X240 (Stokes); d, S. intermedium, Xl40 (Kahl); e, S. teres, X200 (Kahl); f, S. fihnti, Xl90 (Penard); g, Gruberia calkinsi, X140 (Bertran); h, Pseudoblepharisma tenuis, X310 (Kahl); i, Parable- pharisma pellitum, X340 (Kahl). SPIROTRICHA, HETEROTRICHA 643 10:1); macronucleus chain-form; peristome 2/3 the body length; fresh water. *S. minus Roux (Fig. 303, b). 500-800/i long; macronucleus chain-form; in fresh and salt water (Kahl). S. loxodes Stokes (Fig. 303, c). About 300/i long (length: width, 6-7:1); peristome about 1/3 the body length; oblique striation; longer cilia at ends; macronucleus chain-form; fresh water. S. intermedium Kahl (Fig. 303, d). Slender; 400-600m long; macro- nucleus chain-form; fresh water. *S. teres Claparede and Lachmann (Fig. 303, e). 150-400/x long; macronucleus oval; in fresh water and also reported from salt water. S. filum (E.) (Fig. 303, /). Peristome 1/4 the body length; poster- ior end drawn out; 200-300)u up to 700^ long; fresh water. Genus Gruberia Kahl. Similar to Spirostomum in general appear- ance; but posterior end drawn out; slightly contractile; contractile vacuole posterior; macronucleus compact or beaded; salt water. G. calkinsi Beltran (Fig. 303, g). 200-800^ long; peristome 2/3 the body length; many (contractile?) vacuoles distributed; Woods Hole. Genus Blepharisma Perty. Pyriform, spindle-form or ellipsoid; somewhat narrowed anteriorly; compressed; peristome on the left border, which is twisted to right at posterior end and connected with oral funnel with membrane; in front of cytostome a 2-layered undulating membrane on right edge; ciliary rows longitudinal; cilia- tion dense; contractile vacuole and cytopyge terminal; macronu- cleus one or divided into several parts; several species rose-colored; fresh or salt water. Many species. B. lateritium (Ehrenberg) (Fig. 302, g). 130-200m long; pyriform; macronucleus oval; a micronucleus; rose-colored; fresh water among decaying leaves. B. yersicinum P. (Fig. 302, h). 80-120^ long; elongate oval; posterior end pointed; left peristomal edge sigmoid; preoral mem- brane large; macronucleus in 3-7 parts; rose-colored; fresh water among decaying vegetation. B. stcini Kahl (Fig. 302, i). 80-200/^ long; macronucleus ovoid; reddish to colorless; fresh water in sphagnum. B. undulans Stein. 150-300/x long; macronucleus in 2 parts; un- dulating membrane long; cyto pharynx directed posteriorly; fresh water among decaying vegetation. Moore (1934) studied its con- tractile vacuole and Giese (1938) observed the influence of light upon its coloration (p. 38). Since gigantism has been noticed by Penard it has been studied by several observers. Giese (1938) found that the 644 PROTOZOOLOGY giants are carnivorous individuals feeding on small bacteria-fed in- dividuals or other ciliates and remain large (with larger macronucle- us and undulating membrane) after division, as long as appropriate diet is supplied. Genus Protocruzia Faria, da Cunha and Pinto. Peristome does not turn right, leads directly into cytostome; convex left side not ciliated, but bears bristles; flat right side with 3-5 faintly marked ciliary rows; peristome begins at pointed anterior end and extends 1/4-1/3 the body length; cytopharynx (?); macronucleus simple; contractile vacuole subterminal ; salt water. P. pigerrima (Cohn) (Fig. 302, j). About 20/x (da Cunha); 50- 60^1 long (Kahl) ; peristome 1/4-1/3 the body length; salt water. Genus Phacodinium Prowazek. Oval; marked grooves on body surface; cilia in cirrus-like fused groups; peristome long on left mar- gin; cytostome posterior; contractile vacuole terminal; macronu- cleus horseshoe-shape; 5-9 micro nuclei; fresh w^ater. One species. P. metschnicoffi (Certes) (Fig. 302, k). About 100m long. Genus Pseudoblepharisma Kahl. Body form intermediate be- tween Spirostomum and Blepharisma; right peristomal edge with 2 rows of cilia; fresh water. P. tenuis K. (Fig. 303, h). 100-200m long. Genus Parablepharisma Kahl. Similar to Blepharisma; but peri- stome-bearing anterior half , narrowed neck-like and pointed; ecto- plasm covered with gelatinous layer in which symbiotic bacteria are imbedded; salt water. P. pellitum K. (Fig. 303, i). 120-180/1 long. Genus Nyctotherus Leidy. Oval or reniform; compressed; peri- stome begins at anterior end, turns slightly to right and ends in cytostome located midway between the ends; cytopharynx runs dorsally and posteriorly, a long tube with undulating membrane; ciliary rows longitudinal and close-set; massive macronucleus in anterior half with a micro nucleus; in some, nuclei are suspended by a karyophore; endoplasm with discoid glycogen bodies, especially in anterior region, hence yellowish to brown; contractile vacuole and cytopyge terminal; in the colon of Amphibia and various invertebrates. Numerous species. N. ovalis L. (Figs. 3; 304, a, b). Ovoid; anterior half compressed; macronucleus elongate, at right angles to dorso-ventral axis at anterior 1/3; micro nucleus in front of macronucleus; distinct karyo- phore; glycogen bodies; QO-lSS/x by 62-95iu; giant forms up to 360iu by 240m; cysts 72-106iu by 58-80^; in the colon of cockroaches. The chromatin spherules of the macronucleus are often very large (p. 36). SPIROTRICHA, HETEROTRICHA 645 N. cordiformis (Ehrenberg) (Figs. 79; 304, c). 60-200m by 40- 140/1 ; ovoid; micro nucleus behind macro nucleus; no karyophore; in the colon of frogs and toads. Wichterman (1936) studied its life- cycle in Hyla versicolor (p. 160). Family 4 Condyle stomidae Kahl Genus Condylostoma Bory. Ellipsoid; anterior end truncate, posterior end rounded or bluntly pointed; slightly flattened; peri- stome wide at anterior end and V-shaped, peristomal field not cili- ated; a large membrane on right edge and adoral zone on left; macro- nucleus moniliform; one to several contractile vacuoles often with canal; cytopyge posterior; fresh or salt water. Many species. C. vorticella (Ehrenberg) (Fig. 304, d). 100-200/x long; fresh water. C. -patens (Miiller). 250-550/x long; salt water; Woods Hole (Cal- kins). Family 5 Stentoridae Carus Genus Stentor Oken. When extended, trumpet-shaped or cylindri- cal; highly contractile; some with mucilaginous lorica; usually oval to pyriform while swimming; conspicuous peristomal field frontal; adoral zone encircles peristome in a spiral form, leaving a narrow gap on ventral side; the zone and field sink toward cytostome and the former continues into cytopharynx; macro nucleus round, oval or elongated, in a single mass or moniliform; contractile vacuole anterior-left; free-swimming or attached; fresh water. *S. coeruleus Ehrenberg (Figs. 14; 304, e). Fully extended body 1-2 mm. long; anterior end greatly expanded; the beautiful blue color is due to a pigment, stentorin, lodged in interstriation gran- ules; macronucleus beaded. Burnside (1929) studied its body and nuclear sizes (p. 171). S. striatus Barraud-Maskell. Dark bluish green; funnel-shaped; peristomal edge irregularly undulating; striation conspicuous; macro- nucleus beaded; up to 2.2 mm. long. S. polymorphus (MiiWer) (Fig. 304,/). Colorless; with zoochlorellae; 1-2 mm. long when extended; macronucleus beaded; anterior end expanded. S. miilleri (Bory) (Fig. 304, g). Colorless; with zoochlorellae; 2-3 mm. long; anterior end expanded; posterior portion drawn out into stalk, often housed in a gelatinous tube; on body surface 3-4 longer and stiff cilia grouped among cilia; macronucleus moniliform. *S. roeseli Ehrenberg (Fig. 304, h). 0.5-1 mm. long; anterior end expanded; body surface with groups of longer cilia; posterior por- 646 PROTOZOOLOGY Fig. 304. a, b, Nyctotherus ovalis, X340 (Kudo); c, N. cordiformis X 170 (Stein) ; d, C ondylostoma vorticella, X 120 (Penard) ; e, Stentor coend- eus, somewhat contracted, X70 (Roux); f, S. polymorphus, X60 (Roux); g, S. mulleri, X50 (Kahl); h, S. roeseli, X75 (Roux); i, S. igneus, Xl60 (Kahl); j, S. amethystinus, XlOO (Kahl). tion drawn out and often housed in a gelatinous tube; macronucleus long band-form. S. igneus E. (Fig. 304, i). Rose-colored or colorless; 200-400/x long; macronucleus oval; ciliation uniform. SPIROTRICHA, HETEROTRICHA 647 S. niger (Mliller). Yellowish or brown; macro nucleus oval; 200- 300m long. S. multiformis (M.) Dark blue to bluish green; anterior end not expanded; 150-200/x long; macronucleus oval. S. amethystinus Leidy (Fig. 394, j). Habitually pyriform (con- tracted); amethyst-blue; with zcochlorellae; 300-600/i long; macro- nucleus oval. S. pyriformis Johnson. When extended 500/i long; anterior end 200m in diameter. Genus Fabrea Henneguy. Pyriform; posterior end broadly round- ed, anterior end bluntly pointed; peristome extends down from anterior end 2/5 or more the body length, its posterior portion closely wound; peculiar black spot beneath membranellae in anterior portion of spiral adoral zone, composed of numerous pigment gran- ules; without contractile vacuole; macronucleus, a sausage-shaped body or in 4 parts; in salt water. F. salina H. (Fig. 306, a, h). 120-220m by 67-125^ (Kirby); 130- 450/x by 70-200/x (Henneguy); cysts ovoidal, with gelatinous enve- lope; 89-IIIm by 72-105^. Kirby (1934) found the organism in ditches and pools in salt marshes, showing salinities 7.5-20.1 per cent in California. Genus Climacostomum Stein. Oval; flattened; right edge of peri- stome without membrane, left edge, semicircular or spiral with a strong adoral zone; peristomal field ciliated; cytopharynx a long curved tube with a longitudinal row of cilia; macronucleus band- form; contractile vacuole terminal, with two long canals; fresh or brackish water. C. virens (Ehrenberg) (Fig. 306, c). 100-300m long; with or without zoochlorellae; fresh and brackish water. Family 6 Folliculinidae Dons Genus FoUiculina Lamarck. Lorica attached on broad surface; neck oblique to perpendicular; sometimes with a collar or spiral ridge; neck uniform in diameter; salt water. F. moebiusi Kahl (Fig. 306, d). Lorica about 500m long. F. producta (Wright) (Fig. 306, e). Lorica yellowish brown; 250m long; neck often long; Atlantic coast. Genus Microfolliculina Dons. Posterior end or sides of lorica with sack-like protuberances. M. limnoriae (Giard). Lorica dark blue; pellicle faintly striated; salt water. Genus Pseudofolliculina Dons. Lorica attached with its posterior 648 PROTOZOOLOGY end; more or less vertical; without ring-furrow in middle; with or without style ; salt water. P. arcHca D. (Fig. 306, /). Lorica about 430/i high, with spiral ridge; off Norweigian coast 15-28 m. deep. Genus ParafoUiculina Dons. Neck of lorica with a basal swelling; attached either with posterior end or on a lateral surface; salt water. P: violacea (Giard) (Fig. 306, g). 175-310/i long; salt water; widely distributed (Andrews, 1942). Family 7 Clevelandellidae Kidder Genus Clevelandella Kidder (ClevelandiaK.). Elongate pyriform or spear-shaped; posterior region drawn out, at the end of which Fig. 305. a, b, ventral (outline) and dorsal views of Clevelandella panesthiae, X300; c, ventral view (in outline) of Paradevelandia brevis, X300; d, a ventral view of P. brevis, X760; e, cyst of P. brevis, X740. (Kidder.) peristome and cytostome are located; body more or less flexible; completely ciliated; one macronucleus supported by a karyophore; a micronucleus; a contractile vacuole at posterior left, near cytopyge; endocommensals in the colon of wood-feeding roaches, Panesthia javanica and P. spadica. Several species. C. panesthiae K. (Fig. 305, a, b). Broadly fusiform with bluntly pointed anterior end and truncate posterior end; 87-156(123)m by 53-78(62)/i; peristomal projection about one-fifth the body length; peristome is nearlj^ enclosed; macronucleus massive; a vesi- cular micronucleus on its anterior border; karyophore separates the endoplasm into 2 parts: anterior part with glycogenous platelets, posterior part with numerous food particles; often parasitized by Sphaerita (p. 722) ; in the colon of Panesthia javanica and P. spadica. Genus Paradevelandia Kidder. Elongate pyriform; body rigid; SPIROTRICHA, HETEROTRICHA 649 ppsterior end truncated obliquely to left; no peristomal projection; one macronucleus and one micro nucleus; at anterior end, there is a sac connected with the karyophore, which is said to be a "macro- nuclear reservoir"; endocommensals in the colon of Panesthia javanica and P. spadica. 2 species. P. hrevis K. (Fig. 305, c-e). Conical in shape; 16-38 (38)m by 9-21 (19)m; macronucleus spherical to elongate ellipsoid; micronucleus comparatively large, retains nuclear stains longer than macronu- cleus; anterior sac may sometimes be absent; cysts, 14-19^ long; ovoid; with a spherical macronucleus and a micronucleus; in the co- lon of Panesthia javanica and P. spadica. Family 8 Peritromidae Stein Genus Peritromus Stein. Ovoid; ventral surface flattened, dorsal surface with hump of irregular outline bearing a few stiff cilia; ciliary rows only on ventral surface; a small undulating membrane at posterior end of peristome; short marginal spines; 2 macro- and 2 micro-nuclei; salt water. P. calif amicus Kirby (Fig. 306, h). Peristome short; left margin slightly concave; dorsal hump with wart-like protuberances, bear- ing spines (about 12/x long); 16-19 or more ventral ciliary rows; 2 spherical macronuclei, one anterior right and the other posterior left of hump; micronuclei 4 (2-5); 89-165ju by 60-96^; salt marsh pools with salinity "1.2-6 per cent" in California. P. emmae S. 90-100/x long; creeping on bottom; Woods Hole. Family 9 Licnophoridae Stevens Genus Licnophora Claparede. Discoid; body roughly divisible into basal disc, neck and oral disc; basal disc for attachment, with several concentric ciliary coronas; neck flattened, contractile nar- rowed part with or without a ventral furrow^ and fibril-bundles (both running from oral groove to basal disc) ; oral disc highly flat- tened, round or ovoid; edge with membranelle zone which extends to pharyngeal funnel; macronucleus long chain-form; without con- tractile vacuole; free-swimming or commensal in fresh or salt water animals. L. macfarlandi Stevens (Fig. 306, i). Average 90-1 lO/x by 45-60^; diameter of basal disc 40-45^; basal disc circular; macronuclei in 25-35 parts in 4 groups; commensal in the respiratory tree of Sticho- pus californicus. Balamuth (1941, 1942) made excellent studies on its morphology, fission and regeneration. 650 PROTOZOOLOGY L. conklini S. (Fig. 306, j). 100-1 35;u long; commensal in Crepidula plana of Atlantic coast. Fig. 306. a, b, Fabrea salina (a, Xl70; b, X330) (Kirby); c, Clima- costomum virens, XlOO (Stein); d, Folliculina moebiusi, X170 (Stein); e, F. produda, XllO (Wright); f, PseudofolKculina ardica, X50 (Dons); g, Parafolliculina violacea, XlOO (Dons); h, Peritromus calif ornicus, X360 (Kirby); i, Lichnophora macfarlandi, X420 (Stevens); j, L. conklini, X340 (Stevens). SPIROTRICHA, HETEROTRICHA 651 References Andrews, E. A. 1921 American Folliculinas : taxonomic notes. Amer. Nat., Vol. 55. 1942 A folliculinid at Beaufort, North Carolina. Trans. Amer. Micr. Soc, Vol. 61. 1944 FolliculiniH Protozoa on North American coasts. Amer. Miclland Natural., Vol. 31. Balamuth, W. Studies on the organization of ciliate Protozoa. 1941, Jour. Morph., Vol. 68; 1942, Jour. Exper. Zool., Vol. 91. Hegner, R. 1934 Specificity in the genus Balantidium based on size and shape of body and macronucleus, with description of six new species. Amer. Jour. Hyg., Vol. 19. Kahl, a. 1932 Urtiere oder Protozoa. In Dahl's Die Tierwell Deutschlands. Part 15. Kidder, G. W. 1937 The intestinal Protozoa of the wood-feeding roach Panesthia. Parasitology, Vol. 29. KiRBY Jr., H. 1934 Some ciliates from salt marshes in California. Arch. f. Protistenk., Vol. 82. Kudo, R. R. 1936 Studies on Nydotherus ovalis Leidy, with special reference to its nuclear structure. Ibid., Vol. 87. and P. A. Meglitsch 1938 On Balantidium praenucleatum n.sp., inhabiting the colon of Blatta orientalis. Ibid., Vol. 91. Levine, N. D. 1940 The effect of food intake upon the dimensions of Balantidium from swine in culture. Amer. Jour. Hyg., Vol. 32. McDonald, J. D. 1922 On Balantidium coli (Malmsten) and B. suis (sp. nov.). Uni. Calif. Publ. Zool, Vol. 22. Powers, P. B. A. 1935 Studies' on the ciliates of sea urchins. Papers from Tortugas Lab., Vol. 29. ScHMAHL, O. 1926 Die Neubildung des Peristoms bei den Teilung von Bursaria truncatella. Arch. f. Protistenk., Vol. 54. Stevens, N. M. 1903 Further studies on the ciliate Infusoria, Licnophora and Boveria. Ibid., Vol. 3. Strong, R. P. 1904 The clinical and pathological significance of Balantidium coli. Bur. Gov. Labs. Manila, Biol. Lab., Bull. No. 26. Chapter 39 Order 2 Spirotricha BUtschli (continued) Suborder 2 Oligotricha Butschli THE cilia are greatly reduced in number in the Oligotricha and the adoral zone encloses a non-ciliated spiral peristomal field. Free-living Oral portion of peristome lies free on ventral surface Family 1 Halteriidae Adoral zone encloses frontal peristomal field Without lorica Family 2 Strobilidiidae (p. 653) With lorica or test Family 3 Tintinnidae (p. 654) Parasitic Adoral and dorsal zones, both directed anteriorly and retractile; no other cilia Family 4 Ophryoscolecidae (p. 654) In addition to adoral and dorsal zones, groups of cirri in posterior half of body, directed posteriorly and nonretractile P'amily 5 Cycloposthiidae (p. 659) Family 1 Halteriidae Claparede and Lachmann Genus Halteria Dujardin. Spherical or broadly fusiform; anterior border bears conspicuous adoral zone; oral part of peristome with a small membrane on right edge and cirri on left; with an equatorial zone of small oblique grooves, each bearing 3 long cirri or bristles; macro nucleus oval; a micro nucleus; contractile vacuole left of cyto- stome; fresh water. A few species. H. grandinella (Miiller) (Fig. 307, a). About 7 bristle-bearing grooves; 15 frontal and 7 adoral membranellae; 20-40/i long. Kahl (1932) distinguishes 2 varieties: var. cirrifcra (Fig. 307, h), 25-50^ long, with huge cirri instead of fine body cirri; and var. chlorelligera (Fig. 307, c), 40-50/1 long, with bristles and large zcochlorellae; fresh water. Genus Strombidium Claparede and Lachmann. Ovoid to spher- ical; adoral zone very conspicuous (2-4 conspicuous sickle-form frontal membranellae and adoral membranellae extend down cyto- pharynx, the first section surrounding an apical process); no body bristles or cirri; trichocysts; macro nucleus oval or band-form; a micro nucleus ; a contractile vacuole; salt or fresh water. Numerous species. *S. calkinsi Faur^-Fremiet (Fig.307,c?). 35-60/x long; brackish and salt water; Calkins (1902) first observed it at Woods Hole. 652 SPIROTRICHA, OLIGOTRICHA 653 Genus Tontonia Faiire-Fremiet. With well-developed apical col- lar; a long cytoplasmic (contractile) caudal process; salt water. T. gracilUma F.-F. (Fig. 307, e). 48-52^t long; caudal process 250-300/i long; macronucleus moniliform; with zoochlorellae. Fig. 307. a, Halteria grandinella, X490 (Kahl); b, //. g. var. cirrifera, X370 (Kahl); c, H. g. var. chlorelligera, X260 (Kahl); d, Strombidium calkinsi, X900 (Calkins); e, Tontonia gracilUma, X540 (Faure-Fremiet) ; f, Strobilidium gijrans, X340 (Kahl); g, Tintinnidium fluviatile, Xl40 (Kent); h, i, T. semiciliatum , Xl40 (Sterki); j, Strombidinopsis gyrans, X270 (Kent); k, Tintinnopsis cylindrata, X440 (Daday); 1, T. illinoisen- sis, x420 (Hempel); m, Codonella crater a, X540 (Faure-Fremiet). Family 2 Strobilidiidae Kahl Genus Strobilidium Schewiakoff. Pyriform or turnip-shaped; cyto- stome at anterior end; without cytopharynx; horseshoe-shaped 654 PROTOZOOLOGY macronucleus anterior; a micro nucleus; a contractile vacuole; fresh or salt water. Several species. S. gyrans (Stokes) (Fig. 307, /). Lateral border with rounded ele- vation near anterior end, posterior end truncate; 40-70^ long; in standing fresh water. Family 3 Tintinnidae Claparede and Lachmann Conical or trumpet-like, attached inside a lorica of various forms, composed of gelatinous or pseudochitinous substances; with longi- tudinal rows of cilia, and 2 (1-4) macro- and a micro-nuclei; mostly pelagic, a few inhabiting fresh or brackish water. Kofoid and Camp- bell (1929) distinguished more than 300 species and placed them in 12 families and 51 genera, of which 23 genera were created by them. A few genera and species are mentioned here. Genus Tintinnidium Stein. Elongated lorica, highly irregular in form; soft; aboral end closed or with a minute opening; wall viscous and freely agglomerates foreign bodies; salt or fresh water. T.fluviatile Stein (Fig. 307, g). Lorica 100-200^ by 45m; on vege- tation in fresh water. T. semiciliatum Sterki (Fig. 307, h, i). 40-60^ long; on plants in fresh water. Genus Strombidinopsis Kent. Lorica often absent; ovate or pyri- form; frontal border with numerous long cirrus-like cilia; body covered by fine cilia; contractile vacuole posterior; fresh water. S. gyrans K. (Fig. 307, j). 30-80m long; fresh water pond. Genus Tintinnopsis Stein. Lorica bowl-shaped; always with a broad aperture; aboral end closed; wall thin and covered with foreign bodies; salt or fresh water. T. cylindrata Kofoid and Campbell (Fig. 307, k). Lorica 40-50m long; in lakes. T. illinoisensis Hempel (Fig. 307, 1). Lorica 59iu long; in rivers. Genus Codonella Haeckel. Lorica urn- to pot-shaped; sharply divided externally and internally into a collar and bowl; collar with- out spiral structure; in fresh water. C. cratera (Leidy) (Fig. 307, m). Lorica 60-70/x by 40m ; a number of varieties are often mentioned. Family 4 Ophryoscolecidae Stein Elongate oval, asymmetrical; with 1 or 2 (adoral and dorsal) zones of membranellae ; in digestive tract of mammals. Sharp (1914) employed "forma" to distinguish forms in Entodinium with com- mon characteristics, differing in certain others, which scheme was SPIROTRICHA, OLIGOTRICHA 655 extended to the whole family by Dogiel (1927). It is most probable that many species are varieties of a single species as judged by the work of Poljansky and Strelkow (1934) ; but since information is still incomplete, the present work ranks various formae with species, in agreement with Kofoid and MacLennan (1930). Genus Ophryoscolex Stein. Ovoid; with adoral and dorsal zones of membranellae; dorsal zone some distance behind anterior end, encircling 3/4 the body circumference at middle, broken on right ventral side; 3 skeletal plates extend over the body length on right- ventral side; 9-15 contractile vacuoles in 2 (anterior and posterior) circles; macro nucleus simple, elongate; in the stomach of cattle, sheep, goat and wild sheep (Ovis orientalis cycloceros). Several species. Dogiel (1927) designated the following species as 3 formae of 0. caudatus Eberlein. 0. hicoronatus Dogiel (Fig. 308, a). 120-170^ by 81-90^; primary spine 38-58/i long; in sheep. 0. caudatus Eberlein (Fig. 308, b). 137-162^ by 80-98/^; preanal spines 47-60^ long; in sheep, goat, and cattle. 0. quadricoronatus Dogiel (Fig. 308, c). 128-180ai by 86-100^; preanal spines 48-63m long; in sheep and Ovis orientalis cycloceros. Genus Caloscolex Dogiel. Ovoid; anterior end truncate, posterior end rounded with or without processes; 2 zones of membranellae; dorsal zone encircles the bod}^ completely; 3 skeletal plates variously modified; 7 contractile vacuoles in a single circle; nucleus elongate; in the stomach of Camelus dromedarius. Several species. C. cuspidatus D. (Fig. 308, d). 130-160^ by 73-90^. Genus Entodinium Stein. Without dorsal zone; adoral zone at truncate anterior end; without skeleton; contractile vacuole ante- rior; macronucleus, cylindrical or sausage-form, dorsal; micronucleus anterior to middle and on left-ventral side of macronucleus; in cattle and sheep. Numerous species. E. caudatum S. (Fig. 308, e). 50-80/i long; in cattle and sheep. E. bursa S. (Fig. 308, /). 55-114^ by 37-78/1 (Schuberg); SO/x by 60ju (Becker and Talbott) ; in the stomach of cattle. Genus Amphacanthus Dogiel. Similar to Entodinium; but spinous processes at both anterior and posterior ends ; in stomach of Camelus dromedarius. One species. A. ovum-rajae D. (Fig. 308, g). 46-55/x by 32-48/x. Genus Eodinium Kofoid and MacLennan. Dorsal zone on the same level as adoral zone; without skeleton; macronucleus a straight, rod-like body beneath dorsal surface; 2 contractile vacuoles; in cattle and sheep. Several species. 656 PROTOZOOLOGY E. lohatum K. and M. (Fig. 309, a). 44-60ai by 29-37m; in Bos indicus. Genus Diplodinium Schuberg. Adoral and dorsal zones at the same level; without skeletal plates; macronucleus beneath right side, its anterior third bent ventrally at an angle of 30°-90°; 2 contractile Fig. 308. a, Ophryoscolex hircoronatus, X340 (Dogiel); b, 0. caudatus, X310 (Dogiel); c, 0. quadricoronatus, X340 (Dogiel); d, Caloscolex cuspidatus, X310 (Dogiel); e, Entodinuim caudatum, X500 (Becker and Talbott); f, E. bursa, X390 (Schuberg); g, Amphacanthus ovum-rajae, X350 (Dogiel). vacuoles; in cattle, antelope, Camelus dromedarius, reindeer, goat. Numerous species. D. dentatum (Stein) (Fig. 309, h). 65-82/^ by 40-50^; in cattle (including Bos indicus). SPIROTRICHA, OLIGOTRICHA 657 Genus Eremoplastron Kofoid and MacLennan. Adoral and dorsal zones at anterior end; a single narrow skeletal plate beneath right surface; triangular or rod-like macronucleus, anterior end of which is often bent ventrally; 2 contractile vacuoles; in cattle, antelope, sheep, reindeer. Numerous species. E. hovis (Dogiel) (Fig. 309, c). 52-100m by 34-50^; in cattle and sheep. Genus Eudiplodinium Dogiel. Adoral and dorsal zones at anterior end; a single, narrow, skeletal plate beneath right surface; rod-like macronucleus with its anterior end enlarged to form a hook opening dorsally; pellicle and ectoplasm thick; 2 contractile vacuoles with heavy membranes and prominent pores; in cattle. E. maggii (Fiorentini) (Fig. 309, d). 104-255ai by 63-170m; in cat- tle, sheep and reindeer. Genus Diploplastron Kofoid and MacLennan. Adoral and dorsal zones at anterior end; 2 skeletal plates beneath right surface; macro- nucleus narrow; rod-like; 2 contractile vacuoles below dorsal surface, separated from macronucleus. One species. D. affine (Dogiel and Fedorowa) (Fig. 309, e). 88-120/^ by 47-65^; in the stomach of cattle, sheep, and goat. Genus Metadinium Awerinzew and Mutafowa. Adoral and dor- sal zones at anterior end; 2 skeletal plates beneath right surface sometimes fused posteriorly; macronucleus with 2-3 dorsal lobes; 2 contractile vacuoles; pellicle and ectoplasm thick; conspicuous oesophageal fibrils beneath dorsal and right sides; in the stomach of cattle, sheep, goat, and reindeer. M. medium A. and M. (Fig. 309,/). 180-272^ by 111-175^; in cat- tle. Genus Polyplastron Dogiel. Adoral and dorsal zones at anterior end; 2 skeletal plates beneath right surface, separate or fused; 3 longitudinal plates beneath left surface, with anterior ends con- nected by cross bars; contractile vacuoles beneath dorsal surface in a longitudinal row, also with additional vacuoles; in the stomach of cattle and sheep. P. multivesiculatum (D. and Fedorowa) (Fig. 310, a). 120-1 90^ by 78-140/x; in cattle and sheep. MacLennan (1934) found that the skeletal plates are made up of small, roughly prismatic blocks of glycogen, each with a central granule. Genus Elytroplastron Kofoid and MacLennan. 2 zones at anterior end, 2 skeletal plates beneath right surface, a small plate beneath ventral surface, and a long plate below left side; pellicle and ecto- 658 PROTOZOOLOGY plasm thick; conspicuous fibrils beneath dorsal-right side. One species. E. huhali (Dogiel) (Fig. 310, h). 110-160m by 67-97ju; in cattle, sheep, Buffelus buhalus and Bos indicus. Fig. 309. a, Eodinium lobatum, X540 (Kofoid and MacLennan); b, Diplodinium dentatiim, X250 (Kofoid and MacLennan); c, Eremoplastron bovis, X550 (Kofoid and MacLennan); d, Eudiplodinium maggii, X500 (Dogiel); e, Diploplastron affine, X320 (Dogiel); f, Metadinium medium, X320 (Dogiel). Genus Ostracodinium Dogiel. 2 zones at anterior end; broad skele- tal plate beneath right side; 2-6 contractile vacuoles in a dorsal row; SPIROTRICHA, OLIGOTRICHA 659 cytopharyngeal fibrils thick, extend to posterior end; in cattle, sheep, antelope, steenbok, and reindeer. Numerous species. 0. dentatum (Fiorentini) (Fig. 310, c). 52-110^ by 31-68^; in the stomach of cattle. Genus Enoploplastron Kofoid and MacLennan. 2 zones near an- terior end; 3 skeletal plates beneath right-ventral side, either separate or partly fused; 2 contractile vacuoles; heavy pharyngeal fibrils; in cattle, reindeer and antelope. E. triloricatum (Dogiel) (Fig. 310, d). Dogiel (1927) mentions size differences among those occurring in different host species, as fol- lows: in cattle, 85-112/i by 51-7 0^; in reindeer, 75-103ju by 40-58^; in antelope (Rhaphiceros sp.), 60-1 lO/x by 37-56ju. Genus Epidinium Crawley. Elongate; twisted around the main axis; 2 zones; dorsal zone not at anterior end; 3 skeletal plates, with secondary plates; simple macronucleus club-shaped; 2 contractile vacuoles; in cattle, sheep, reindeer, camels, etc. E. caudatum (Fiorentini) (Fig. 310, e). 113-151^ by 45-61^; in cattle, camels, Cervus canadensis and reindeer. E. {Diplodinium) ecaudatum (F.) (Figs. 16; 310,/). 112-140/x by 40-60/x (Becker and Talbott); in cattle, sheep, and reindeer. The classical observation of Sharp (1914) on its neuromotor system has been described elsewhere (p. 54). Genus Epiplastron Kofoid and MacLennan. Elongate; 2 zones; dorsal zone not at anterior end; 5 skeletal plates, with secondary plates; macronucleus simple, elongate; 2 contractile vacuoles; in antelopes. E. africanum (Dogiel) (Fig. 310, g). 90-140^ by 30-55^; in Rha- phiceros sp. Genus Ophisthotrichum Buisson. 2 zones; dorsal zone at middle or near posterior end of body; one-piece skeletal plate well developed ; 2 contractile vacuoles posterior; conjugation (Dogiel); in many Afri- can antelopes. One species. 0. janus (Dogiel) (0. thomasi B.) (Fig. 311, a). 90-150m by 42-60m. Genus Cunhaia Hasselmann. Cytostome near anterior end, with adoral zone; dorsal zone on 1/3 of anterior-dorsal surface; 2 con- tractile vacuoles; skeleton (?); in the caecum of guinea pig, Cavia aperea. One species. C. curvata H. (Fig. 311,6). 60-80m by 30-40/x; in Brazil. Family 5 Cycloposthiidae Poche Pellicle firm and body rigid; zones of membranellae at anterior and posterior ends; more or less compressed; cytopharynx short 660 PROTOZOOLOGY and wide; macronucleus elongate; a single micronucleus; 2 or more contractile vacuoles; in horse and anthropoid apes. Genus Cycloposthium Bundle. Large, elongate barrel-shaped; cytostome in center of a retractile conical elevation at anterior end; adoral zone conspicuous; an open ring-zone of membranellae near posterior end on both dorsal and ventral sides ; pellicle ridged ; skele- FiG. 310. a, Polyplastron multivesiculatuvi, X360 (Dogiel); b, Ely- troplastron bubali, X340 (Dogiel); c, Ostracodinium dentatum, X440 (Dogiel); d, Enoploplastron triloricatum, X370 (Dogiel); e, Epidinium caudatum^ X340 (Becker and Talbott); f, E. ecaudatum, X340 (Becker and Talbott); g, Epiplastron ajricanum, X300 (Dogiel), ton club-shaped; several contractile vacuoles in a row along band- form macronucleus; in the caecum and colon of horse. Many species. C. bipalmatum (Fiorentini) (Fig. 311, c). 80-1 27/x by 35-57^. C. dentiferum Gassovsky (Fig. 311, t^). 140-222^ by 80-1 lO/x. Genus Spirodinium Fiorentini. Elongate, more or less fusiform; adoral zone at anterior end, zone making at least one complete spiral SPIROTRICHA, OLIGOTRICHA 661 near anterior end; posterior zone only half-spiral; in the caecum and colon of horse. One species. S. eqid F. (Fig. 311, e). 77-180m by 30-74//; widely distributed. Genus Triadinium Fiorentini. More or less helmet-shaped; com- pressed; adoral zone at anterior end; 2 posterior (ventral and dorsal) Fig. 311. a, Ophisthotrichutn janus, X370 (Dogiel); b, Cunhaia curvata X670 (Hasselmann); c, Cycloposthiwm hipalmatum, X300 (Bundle) d, C. dentiferum, X270 (Hsiung); e, Spirodinium equi, X270 (Hsiung) f, Triadinium caudatxmi, X300 (Hsiung) ;g, T. minimum, X440 (Hsiung) h, Tetratoxum unijasciculatum, X280 (Hsiung). zones; with or without a caudal projection; in the caecum and colon of horse. T. caudatum F. (Fig. 31 IJ). 59-86/x by 5(>-68m. • 7". ^aZea Gassovsky. 59-78^ by 50-60m. T. minimum G. (Fig. 311, gr). 35-58m by 30-40^. 662 PROTOZOOLOGY Fig. 312. a, Tripalmaria dogieli, Xl80 (Gassovsky); b, Cochliatoxum periachtum, X270 (Hsiung); c, Ditoxum funinucleum, X270 (Hsiung); d-f, Troglodytella abrassarti (d, X670 (Swezey); e, ventral and f, dorsal view, X210 (Bi-umpt and Joyeux)), SPIROTRICHA, OLIGOTRICHA 663 Genus Tetratoxum Gassovsky. Slightly compressed; 2 anterior and 2 posterior zones of membranellae ; in the colon of horse. P. unifasciculatum (Fiorentini) (Fig. 311, h). 104-168^* by 62- 100)u; widely distributed. T. escavatum Hsiung. 95-135)u by 55-90)u. T. parvum H. 67-98/x by 39-52^. Genus Tripalmaria Gassovsky {Tricaudalia Buisson). Adoral zone at anterior end; 2 dorsal and 1 ventral-posterior zones in tuft-form; macronucleus inverted U-shape; in the colon of horse. T. dogieli G. (Fig. 312, a). 77-123/x by 47-62^. Genus Triplumaria Hoare. Adoral zone; 2 dorsal and 1 ventral cirrose tufts (caudals); skeleton, composed of polygonal plates ar- ranged in a single layer, surrounds the body except the dorsal sur- face; dorsal groove supported by rod-like skeleton; macronucleus elongate sausage-form, with a micronucleus attached to its dorsal surface near middle; about 6 contractile vacuoles arranged in line along dorsal surface of body; in the intestine of Indian rhinoceros. T. hamertoni H. 129-207^ long, 65-82m thick, 4-39/x broad; endo- commensal in the intestine of Rhinoceros unicornis in Zoological Garden in London. Genus Cochliatoxum Gassovsky. Adoral zone near anterior end; 3 additional zones, 1 antero-dorsal, 1 postero-dorsal and 1 postero- ventral; macronucleus with curved anterior end; in the colon of horse. One species. C. periachtum G. (Fig. 312, b). 210-370^ by 130-210^. Genus Ditoxum Gassovsky. Large adoral zone near anterior end; 2 dorsal (anterior and posterior) zones; macronucleus curved club- shaped; in the colon of horse. D.funinucleum G. (Fig. 312, c). 135-203/x by 70-101^. Genus Troglodytella Brumpt and Joyeux. Ellipsoid; flattened; adoral zone; 3 additional zones (anterior zone continuous or not con- tinuous on ventral surface; posterior zone continuous on dorsal surface; between them a small zone on each side); skeletal plates in anterior region; macronucleus L-form; contractile vacuoles in 2 cir- cles; in the colon of anthropoid apes. T. abrassarti B. and J. (Fig. 312, d-j). About 145-220m by 120- 160iu; in the colon of chimpanzees. Reichenow (1927) distinguished var. acuminata on the basis of drawn-out posterior end, which was found by Swezey (1932) to be a variant of T. abrassarti. T. gorillae Reichenow. 200-280m by 120-160/^; in the colon of gorilla; with anterior zone not reaching the right side. 664 PROTOZOOLOGY References Becker, E. R. and Mary Talbott 1927 The protozoan fauna of the rumen and reticulum of American cattle. Iowa St. Coll. Jour. Sci., Vol. 1. DoGiEL, V. 1927 Monographic der Familie Ophryoscolecidae. I. Arch. f. Protistenk., Vol. 59. HsiuNG, T. S. 1930 A monograph on the Protozoa of the large in- testine of the horse. Iowa St. Coll. Jour. Sci., Vol. 4. Kahl, a. 1932 Dahl's Die Tierwelt Deutschlands. Part 25. KoFOiD, C. A. and A. S. Campbell 1929 A conspectus of the ma- rine and freshwater Ciliata, belonging to the suborder Tintin- noinea, etc. Uni. Calif. Publ. Zool., Vol. 34. and J. F. Christenson 1934 Cihates from Bos gaurus H. Smith. Ibid., Vol. 39. and R. F. MacLennan 1930, 1932, 1933 Ciliates from Bos indicus Linn. I, II, III. Ibid., Vols. 33, 37, 39. SwEZEY, W. W. 1934 Cytology of Troglodyiella ahrassarti, an intes- tinal ciliate of the chimpanzee. Jour. Morph., Vol. 56. Chapter 40 Order 2 Spirotricha Butschli (continued) Suborder 3 Ctenostomata Lauterborn THE ciliates placed in this group are carapaced and compressed forms with a very sparse ciHation. The adoral zone is also re- duced to about 8 membranellae: These organisms are exclusively free living and sapropelic in fresh, brackish, or salt water. Posterior half of carapace with 4 ciliated rows on left and at least 2 rows on right; with anterior row of cilia on left side. .Family 1 Epalcidae Posterior half of carapace with cirrus-like groups on left only, none on right; without frontal cilia Long ciliated band extends over both broad sides Family 2 Discomorphidae Short ciliated band ventral, extending equally on both broad sides. . . Family 3 Mylestomidae (p. 666) Family 1 Epalcidae Wetzel Genus Epalxis Roux. Rounded triangular; anterior end pointed toward ventral surface, posterior end irregularly truncate; dorsal surface more convex; right carapace with 1 dorsal and 1 ventral ciliary row in posterior region; usually 4 (2-3) median teeth; all anal teeth without spine; with comb-like structures posterior to oral aper- ture; 1-2 oval macronuclei dorsal; contractile vacuole posterior- ventral; sapropelic in fresh or salt water. Many species. E. mirahilis R. (Fig. 313, a). 38-45m by 27-30^; fresh water. Genus Saprodinium Lauterborn. Similar to Epalxis; but some (left and right) of anal teeth with spines; sapropelic in fresh or salt water. Several species. S. dentatum L. (Fig. 313, 6). 60-80m long; fresh water. S. putrinium Lackey (Fig. 313, c). 50/x long, 40jli wide, about 15/z thick; in Imhoff tanks. Genus Pelodinium Lauterborn. Right carapace with 2 median rows of cilia, its median anal teeth fused into one so that there are only three teeth. One species. P. reniforme L. (Fig. 313, d). 40-50)u long; sapropelic. Family 2 Discomorphidae Poche Genus Discomorpha Levander. Oval; ventrally directed anterior spine long; posterior end without teeth or ridges; ciliated bands on 665 666 PROTOZOOLOGY both lateral surfaces; 2 spines on right side; 2 cirrus-like groups on posterior-left; sapropelic. A few species. D. pectinata L. (Fig. 313, e,/). 70-90/x long; sapropelic. Fig. 313. a, Epalxis mirabilis, X1200 (Roux); b, Sa-prodinium den- tation, X430 (Kahl); c, S. putrinium, X470 (Lackey); d, Pelodinium renijorme, X600 (Lauterborn); e, f, Disconiorpha pectinata, (e, X500; f, X220) (Kahl); g, Mylestoma bipartituni, X470 (Kahl); h, Atopodinium fibulatum, X520 (Kahl). Family 3 Mylestomidae Kahl Genus Mylestoma Kahl. Posterior margin without any indenta- tion, though sometimes a small one on right side, but none on left; SPIROTRICHA, CTENOSTOMATA 667 3 often long ribbon-like cirri on peristome; fresh or salt water. Sev- eral species. M. bipartitum (Gourret and Roesner) (Fig. 313, g). 35-50/x long; two caudal processes; salt water. Genus Atopodinium Kahl. Posterior left side with one large, and right side with 2 indentations; macronucleus spherical; sapropelic. A.fihulatum K. (Fig. 313, A). 40-50m long. References Kahl, A. 1932 Ctenostomata (Lauterborn) n. subord. Arch. f. Protistenk., Vol. 77. 1932 Urtiere oder Protozoa. In Dahl's Die Tierwelt Deiitsch- lands. Part 25. Chapter 41 Order 2 Spirotricha BUtschli (continued) Suborder 4 Hypotricha Stein THE members of this suborder are, as a rule, flattened and strong cilia or cirri are restricted to the ventral surface. Except the fam- ily Aspidiscidae, the dorsal surface possesses rows of short slightly moveable tactile bristles. The peristome is very large with a well- developed adoral zone. The cirri on the ventral surface are called, according to their location, frontals, ventrals, marginals, anals (transversals), and caudals, as was mentioned before (Fig. 11, 6). Asexual reporduction is by binary fission and sexual reproduction by conjugation. Encystment is common. Mostly free-living in fresh, brackish or salt water; a few parasitic. Adoral zone fully formed Cirri on ventral surface Ventrals in rows, though in some reduced; 2 rows of marginals. . . . Family 1 Oxytrichidae Ventrals and marginals not in longitudinal rows Family 2 Euplotidae (p. 676) No ventral cirri; caudal cirri Family 3 Paraeuplotidae (p. 677) Adoral zone reduced Family 4 Aspidiscidae (p. 679) Family 1 Oxytrichidae Kent Genus Oxytricha Ehrenberg (Histrio Sterki; Opisthotricha Kent; Steinia Diesing). Ellipsoid; flexible; ventral surface flattened, dorsal surface convex; 8 frontals; 5 ventrals; 5 anals; short caudals; mar- ginals may or may not be continuous along posterior border; macro- nucleus in 2 parts, rarely single or in 4 parts; fresh or salt water. Numerous species. 0. fallax Stein (Fig. 314, a). Posterior region broadly rounded; about 150/i long; fresh water. 0. bifaria Stokes (Fig. 314, b). Right side convex; left side flat- tened; posterior end pointed; about 250^ long; fresh water infusion. 0. ludibunda S. (Fig. 314, c). Ellipsoid; flexible; 100/x long; fresh water among sphagnum. 0. setigera S. (Fig. 314, d). Elongate ellipsoid; 5 frontals; ventrals shifted anteriorly; 50/i long; fresh water. 668 SPIROTRICHA, HYPOTRICHA 669 Genus Tachysoma Stokes {Actinotricha Cohn). Flexible; frontals 8-10, of which anterior three are usually the largest; 5 ventrals scattered; 5 anals; marginals at some distance from lateral borders, interrupted posteriorly; fresh or salt water. T. parvistyla S. (Fig. 314, e). 10 frontals scattered; about 63^ long; in shallow freshwater pools. Fig. 314. a, Oxytrichafallax, X230 (Stein); b, 0. bifaria, Xl80 (Stokes); c, 0. ludibunda, x400 (Stokes); d, 0. setigera, X870 (Stokes); e, Tachj- soma parvistyla, X490 (Stokes); f, Urosoma caudata, X250 (Stokes); g, Amphisiella thiophaga, X380 (Kahl); h, Eschaneustyla brachytona, X240 (Stokes); i, Gonostomum strenuum, Xl60 (Engelmann); '],Hemi- cycliostyla sphagni, XlOO (Stokes); k, 1, Cladotricha koltzowii (k, Xl70; 1, X300) (Kahl). Genus Urosoma Kowalewski. Similar to Oxytricha; but posterior portion drawn out and much narrowed; fresh water. U. caudata (Stokes) (Fig. 314,/). 200-250/i long; pond water. 670 PROTOZOOLOGY Genus Amphisiella Gourret and Roeser. With a single row of ventrals and 2 marginal rows; salt or fresh water. Several species. A. thiophaga (Kahl) (Fig. 314, g). TO-lOOyu long; salt water. Genus Eschaneustyla Stokes. Elliptical or ovate; narrow peri- stome 1/3 the body length; frontals numerous, about 22 in addition to 2 at anterior margin; ventrals small and numerous in 3 oblique rows; no anals; marginals uninterrupted; contractile vacuole a long canal near left border; fresh water. One species. E. brachytona S. (Fig. 314, h). 170-220/1 long. Genus Gonostomum Sterki {Plagiotricha Kent). Flexible; 8 or more frontals; 1-2 oblique ventral rows of short cirri; 4 or 5 anals; 2 marginal rows; fresh water. G. strenuum (Engelmann) (Fig. 314, i). Elongate; with caudal bristles; about 150^1 long; fresh water. Genus Hemicycliostyla Stokes. Elongate oval; flexible; ends rounded; 20 or more frontals, arranged in 2 semicircular rows; adoral row begins near center on right side of peristomal field; ventral sur- face entirely covered with fine cilia; no anals; one or more contractile vacuoles ; nucleus distributed ; fresh water. H. sphagni S. (Fig. 314, j). About 400-500iu long; marsh water with sphagnum. Genus Hypotrichidium Ilowaisky. Two ventral and marginal rows of cirri spirally arranged; peristome large, extends 1/2 the body length, with a large undulating membrane; 2 macro- and micro-nu- clei; contractile vacuole anterior-left; fresh water. H. conicum I. (Fig. 315, a). 90-1 50ai long. Genus Cladotricha Gajevskaja. Elongate band-form; anterior end rounded, posterior end rounded or attenuated; frontals only 2 featherly cirri; macronucleus spheroidal; micronucleus; without con- tractile vacuole; salt water, with 5-20 per cent salt content. One species. C. koltzowii G. (Fig. 314, k, I). Band-form up to about 200/z long; posteriorly attenuated forms up to about 100^ long. Genus Psilotricha Stein. Oval to ellipsoid; frontals and anals un- differentiated; ventrals and marginals long cirri, few; ventrals in 2 rows and a rudimentary row toward left; with or without zoochlo- rellae; fresh water. A few species. P. acuminata S. (Fig. 315, 6). 80-1 00)u long. Genus Kahlia Horvath. Frontal margin with 3-4 strong cirri; 5-8 ventral longitudinal rows ; marginals ; sapropelic in fresh water. K. acrohates H. (Fig. 315, c), 100-200/i long; soil infusion. SPIROTRICHA, HYPOTRICHA 671 Genus Uroleptus Ehrenberg. Elongate body drawn out into a tail- like portion; 3 f rentals; 2-4 rows of ventral cirri; marginals; no anals; sometimes rose- or violet-colored; fresh or salt water. Many species. Fig. 315. a, Hypotrichidium conicum., X200 (Kahl); b, Psilotrlcha acuminata, X230 (Stein); c, Kahlia acrobates, X240 (Kahl); d, Uroleptus Umnetis, X240 (Stokes); e, U. longicaudatus, X240 (Stokes); f, U. dispar X240 (Stokes); g, Uroleptopsis citrina, X260 (Kahl); h, Strongylidium calif ornicum, X200 (Kahl); i, Stichotricha secunda, X340 (Kahl); j, Urostyla grandis, Xl40 (Stein); k, U. trichogaster, Xl50 (Kahl). U. Umnetis Stokes (Fig. 315, d). About 200m long; fresh water among vegetation. U. longicaudatus S. (Fig. 315, e). About 200/x long; marsh water with sphagnum. U. dispar S. (Fig. 315,/). 150-170m long; fresh water. U. halseyi Calkins (Fig. 317, a). About 160/i by 20m ; peristome 1/6-1/7 the body length; 3 ventrals; macronucleus divided into 672 PROTOZOOLOGY many (up to 26) parts; 2 (1-3) micronuclei; fresh water. Genus Uroleptopsis Kahl. Ventrals in 2 uninterrupted rows; salt water. A few species. U. citrina K. (Fig. 315, g). Elongate; flexible; ectoplasm with pale-yellow ringed bodies which give the organism yellowish color; marginals discontinuous posteriori}^; 2 contractile vacuoles near left border; 150-250^ long; salt water. Genus Strongylidium Sterki. 2-5 ventral rows of cirri; marginals spirally arranged; 3-6 frontals; 2 or more macronuclei; fresh or salt water. Many species. S. californicum Kahl (Fig. 315, ^). 4-5 frontals; macronuclei about 30 in number; 4 micronuclei; contractile vacuole with short canals; about 250m long; fresh water among vegetation. Genus Stichotricha Perty. Slender ovoid or fusiform; peristome- bearing part narrowed; not flexible; usually 4 spiral rows of cirri; sometimes tube-dwelling, and then in groups; fresh or salt water. Many species. S. secunda P. (Fig. 315, i). lS0-200fj, long; in fresh water. Genus Chaetospira Lachmann. Similar to Stichotricha; but peri- stome-bearing part flexible ; fresh or salt water. C. miilleri L. 150-250^ long; in lorica; fresh water. Genus Urostyla Ehrenberg. Ellipsoid; flexible; ends rounded; flattened ventral surface with 4-10 rows of small cirri and 2 mar- ginal rows; 3 or more frontals; 5-12 anals; macronucleus a single body or in many parts; fresh or salt water. Numerous species. U. grandis E. (Figs. 47; 315, j). 300-400^ long; macronucleus in 100 or more parts; 6-8 micronuclei; fresh water. U. trichogaster Stokes (Fig. 315, k). 250-330/1 long; fresh water. U. caudata S. (Fig. 316, a). Elongate ellipsoid; flexible; narrowed anterior part bent to left; peristome 1/3 the body length; macro- nucleus in many parts; contractile vacuoles near left margin; about 600/x long; fresh water with sphagnum. Genus Kerona Ehrenberg. Reniform; no caudals; 6 oblique rows of ventral cirri; commensal. One species. K. polyporum E. (Fig. 316, 6). 120-200m long; commensal on Hydra. Genus Keronopsis Penard. Two ventral rows of cirri reaching frontal field; caudals variable; macronucleus usually in several (rarely 2) parts; fresh or salt water. Numerous species. K. rubra (Ehrenberg) (Fig. 316, c). Reddish; 200-300m long; salt water. SPIROTRICHA, HYPOTRICHA 673 Genus Epiclintes Stein. Elongate; spoon-shaped; flattened ven- tral surface with more than 2 rows of cirri; 2 marginal rows; frontals undifferentiated; anals; no caudals; salt or fresh water. A few species. E. pluvialis Smith (Fig. 316, d). About 375/x long; fresh water. Fig. 316. a, Urostyla caudata, X90 (Stokes); b, Kerona polyporum, X200 (Stein); c, Keronopsis rubra, X270 (Entz); d, Epiclintes pluvialis, XlOO (Smith); e, Holosticha vernalis, X220 (Stokes); f, H. hymenophora, X180 (Stokes); g, Paraholosticha herbicola, X200 (Kahl); h, Trichotaxis stagnatilis, Xl90 (Stokes); i, Balladyna elongata, X800 (Roux); j, Pleu- rotricha lanceolata, X250 (Stein); k, Gastrostyla muscorum, X200 (Kahl). Genus Holosticha Wrzesniowski. Three frontals along anterior margin; 2 ventral and 2 marginal rows of cirri; anals; fresh or salt water. Numerous species. H. vernalis Stokes (Fig. 316, e). 7 anals; about 180^ long; shallow pools with algae. H. hymenophora S. (Fig. 316,/). 5 anals; 2 contractile vacuoles; 160-200/i long; shallow pools. 674 PROTOZOOLOGY Genus Paraholosticha Kahl. Elongate-oval; flexible; ventral cirri in 2 parallel oblique rows; with a row of stiff cirri along frontal mar- gin, posterior to it 2 short rows of cirri; marginals continuous or interrupted at posterior border; fresh water. P. herhicola K. (Fig. 316, g). 150-190m long; fresh water among algae. Genus Trichotaxis Stokes. Similar to Holosticha; but with 3 rows of ventral cirri ; fresh or salt water. T. stagnatilis S. (Fig. 316, h). About 160^1 long; ellipsoid; in fresh water among decaying vegetation. Genus Balladjua Kowalewski. Ellipsoid; frontals not well de- veloped or lacking; 1 ventral and 2 marginal rows of cirri; long dorsal and lateral stiff cirri; fresh water. B. elongata Roux (Fig. 316, i). 32-35/x by 11-12/x; fresh water among plants and detritus. Genus Pleurotricha Stein. Oblong to ellipsoid; marginals continu- ous; 8 frontals; 3-4 ventrals; 7 anals of which 2 are more posterior; 2 rows of ventral cirri; between ventrals and marginals 1-3 rows of few coarse cilia; fresh water. P. lanceolata (Ehrenberg) (Fig. 316, j). 100-165^ long; 2 macro- and 2 micro-nuclei. Manwell (1928) studied its conjugation, division, encystment and nuclear variation. Genus Gastrostyla Engelmann. Frontals distributed except 3 along the frontal margin; ventrals irregular; 5 anals; macronucleus divided into 2-8 parts ; fresh or salt water. G. muscorum Kahl (Fig. 316, k). 130-200/x long; macronucleus in 8 parts; fresh water in vegetation. Genus Stylonychia Ehrenberg. Ovoid to reniform; not flexible; ventral surface flat, dorsal surface convex; 8 frontals; 5 ventrals; 5 anals; marginals; 3 caudals; with short dorsal bristles; fresh or salt water. Many species. S. mylilus (Miiller) (Fig. 317, h). 100-300)U long; fresh, brackish and salt water. S. pustulata E. (Figs. 84; 317, c). About 150m long; fresh water; nuclear changes were studied by Summers (1935). S. putrina Stokes (Fig. 317, d). 125-150^ long; fresh water. S. notophora S. (Fig. 317, e). About 125/i long; standing water. Genus Onychodromus Stein. Not flexible; somewhat rectangular; anterior end truncate, posterior end rounded; ventral surface flat, dorsal surface convex; peristome broadly triangular in ventral view; 3 frontals; 3 rows of cirri parallel to the right edge of peristome; 5-6 SPIROTRICHA, HYPOTRICHA b c ,((/////>. h 675 Fig. 317. a, Uroleptus halseyi, X470 (Calkins); b, Shjlonychia mytihis, X200 (Stein); c, S. pustulata, X400 (Roux); d, S. putrina, X200 (Stokes); e, S. notophora, X200 (Stokes); f, Onychodromus grandis, X230 (Stein); g, Onychodromopsis flexilis, X240 (Stokes); h, Euplotes patella, X420; i, E. eurystomus, X330; j, E. woodruffi,, X310; k, E. aediculatus, X290 (h-k, Pierson, modified). 676 PROTOZOOLOGY anals; marginals uninterrupted; 4-8 macronuclei; contractile vacu- ole ; fresh water. One species. 0. grandis S. (Fig. 317,/). 100-300/x long. Genus Onychodromopsis Stokes. Similar to Onychodromus ; but flexible; 6 frontals of which the anterior three are the largest; fresh water. One species. O.fiexilis S. (Fig. 317, g). 90-125m long; standing pond water. Family 2 Euplotidae Glaus Genus Euplotes Ehrenberg. Inflexible body ovoid; ventral surface flattened, dorsal surface convex; longitudinally ridged; peristome broadly triangular; frontal part of adoral zone lies in flat furrow; 9 or more f rontal-ventrals ; 5 anals; 4 scattered caudals; macronucleus band-like; a micronucleus; contractile vacuole posterior; fresh or salt water. Numerous species. E. patella (Miiller) (Fig. 317, h). Subcircular to elliptical; average dimensions 91m by 52ju; 9 f rontal-ventrals ; aboral surface with 6 pro- minent ridges with rows of bristles embedded in rosettes of granules; peristome narrow; peristomal plate small triangle; macronucleus simple C-form band; micronucleus near anterior-left end; membra- nellae straight; posterior end of cytopharynx anterior to, and to left of, the fifth anal cirrus; post-pharyngeal sac; fresh and brackish water. E. eurystomus Wrzesniowski (Fig. 317, i). Elongated ellipsoid; length 100-195m; average dimensions 138/x by 78^; 9 f rontal-ventrals ; no aboral ridges, but 7 rows of bristles; peristome wide, deep; peri- stomal depression sigmoid; membranellae forming sigmoid curve; end of cytopharynx far to left and anterior to the fifth anal cirrus; post-pharyngeal sac; macronucleus 3-shaped; micronucleus near flattened anterior corner of macronucleus ; fresh and brackish water. E. woodruffi Gaw (Fig. 317, j). Oval; length 120-165^; average dimensions 140^ by 90//; 9 f rontal-ventrals ; aboral surface often with 8 low ridges; peristome wide, with a small peristomal plate; end of cytopharynx almost below the median ridge; 4th ridge between anal cirri often extends to anterior end of body ; post-pharyngeal sac ; macronucleus consistently T-shaped; micronucleus anterior-right; brackish (with salinity 2.30 parts of salt per 1000) and fresh water. E. aediculatus Pierson (Fig. 317, k). Elliptical; length 110-165^; average dimensions 132/x by 84/i; 9 f rontal-ventrals ; aboral surface usually without ridges, but with about 6 rows of bristles; peristome narrow; peristomal plate long triangular, drawn out posteriorly; a niche midway on the right border of peristome; anal cirri often form SPIROTRICHA, HYPOTRICHA 677 a straight transverse line; 4th ridge between anals may reach anterior end of body; macronucleus C-shape with a flattened part in the left- anterior region; micronucleus some distance from macronucleus at anterior-left region; post-pharyngeal sac; fresh and brackish (salin- ity 2.30 parts of salt per 1000) water. E. plumipes Stokes. Similar to E. eurystomus. About 125/i long; fresh water. E. carinatus S. (Fig. 318, a). About 70/x by 50/i; fresh water. E. Charon (Miiller) (Fig. 318, h). 70-90^ long; salt water. Genus Euplotidium Noland. Cylindrical; 9 frontal-ventrals in 2 rows toward right; 5 anals; a groove extends backward from oral region to ventral side, in which the left-most anal cirrus lies; peri- stome opened widely at anterior end, but covered posteriorly by a transparent, curved, flap-like membrane; adoral zone made up of about 80 membranellae; longitudinal ridges (carinae), 3 dorsal and 2 lateral; a row of protrichocysts under each carina; a broad zone of protrichocysts in antero-dorsal region; cytoplasm densely granu- lated; salt water. One species. E. agitatum N. (Fig. 318, c, d). 65-95^ long; erratic movement rapid ; observed in half -dead sponges in Florida. Genus Certesia Fabre-Domergue. Ellipsoid; flattened; dorsal surface slightly convex, ventral surface flat or concave; 5 frontals at anterior border; 7 ventrals; 5 anals; no caudals; marginals small in number; 4 macronuclei; salt water. One species. C. quadrinucleata F.-D. (Fig. 318, e). 70-100/x by about 45)u. Genus Diophrys Dujardin. Peristome relatively large, often reaching anals; 7-9 frontal-ventrals; 5 anals; 3 strong cirri right- dorsal near posterior margin; salt water. D. appendiculata (Ehrenberg) (Fig. 318, /). 60~100/x long; salt water; Woods Hole (Calkins). Genus Uronychia Stein. Without frontals and ventrals; 5 anals; 3 right-dorsal cirri (as in Diophrys); 2 left-ventral cirri near posterior margin; peristome, oval with a large undulating membrane on right edge; salt water. Several species. U. setigera Calkins (Fig. 318, g). 40/x by 25^; salt water; Woods Hole. Family 3 Paraeuplotidae Wichterman Genus Paraeuplotes Wichterman. Ovoid; ventral surface slightly concave, dorsal surface highly convex and bare, but with one ridge; frontal and adoral zones well developed; ventral surface with a semi- circular ciliary ring on the right half, posterior half of which is 678 PROTOZOOLOGY Fig. 318. a, Euploies carinalus, X430 (Stokes); b, E. charon, X440 (Kahl); c, d, Euplotidium agitatum, X540 (Noland); e, Certesia quad- rinucleata, X670 (Sauerbrey); f, Diophrys appendiculata, X570 (Wal- lengren); g, Uronychia setigera, X870 (Calkins); h, Aspidisca lynceus, X300 (Stein); i, A. polyshjla, X290 (Kahl). SPIROTRICHA, HYPOTRICHA 679 marked by a plate and with two ciliary tufts, near the middle of an- terior half; 5-6 caudal cirri; macro nucleus curved band-form; a terminal contractile vacuole; zooxanthellae, but no food vacuole in cytoplasm; marine, on the coral. P. tortugensis W. (Fig. 319). Subcircular to ovoid; average indi- viduals 85ju by 75m: ciliary plate 37/1 long, with longer cilia; adoral zone reaches nearly the posterior end; "micro nucleus not clearly differentiated" (Wichterman) ; 5-6 caudal cirri about 13/i long; zoo- xanthellae yellowish brown, about 12/x in diameter, fill the body; found on Eunicea crassa (coral); Tortugas, Florida. Fig. 319. a, b, dorsal and ventral views of Paraeuplotes tortugensis in life (Wichterman). avc,,"anterior ventral cilia; cp, ciliary plate; cpc, ciliary plate cilia; cv, contractile vacuole; ds, dorsal swelling; fm, frontal membranellae; om, adoral membranellae; sp, caudal cirri; tc, tufts of cilia; zo, zooxanthellae. X about 470. Family 4 Aspidiscidae Claus Genus Aspidisca Ehrenberg. Small; ovoid; inflexible; right and dorsal side convex, ventral side flattened; dorsal surface conspicu- ously ridged; adoral zone reduced or rudimentary; 7 frontal-ventrals; 5-12 anals; macro nucleus horseshoe-shaped or occasionally in 2 rounded parts; contractile vacuole posterior; fresh or salt water. Numerous species. A. lynceus E. (Figs. 54; 318, h). 30-50^ long; fresh water. Division was studied by Summers (1935). A. polystyla Stein (Fig. 318, i). About 50/i long; salt water; Woods Hole (Calkins). 680 PROTOZOOLOGY References Calkins, G. N. 1902 Marine Protozoa from Woods Hole. Bull. U. S. Fish. Comm., Vol. 21. Kent, S. 1881-1882 A manual of Infusoria. London. NoLAND, L. E. 1937 Observations on marine ciliates of the Gulf coast of Florida. Trans. Amer. Micr. Soc, Vol. 56. PiERSON, Bernice F. 1943 A comparative morphological study of several species of Euplotes closely related to Euplotes patella. Jour. Morph., Vol. 72. Roux, J. 1901 Faune infusorienne des eaux stagnantes des en- virons de Geneve. Mem. fac. sci. I'Univ. Geneve. Stein, F. 1867 Der Organismus der Infusionstiere. Vol. 2. Stokes, A. C. 1888 A preliminary contribution toward a history of the freshwater Infusoria of the United States. Jour. Trenton N. H. Soc, Vol. 1. Wichterman, R. 1942 A new ciliate from a coral of Tortugas and its symbiotic zooxanthellae. Carnegie Inst. Washington, Papers Tortugas Lab., Vol. 33. Chapter 42 Order 3 Chonotricha Wallengren THESE ciliates live attached to aquatic animals, especially crus- taceans and have developed a peculiar organization. The body is, as a rule, vase-form with an apical peristome, around which extends a more or less complicated ectoplasmic collar or funnel and along which are found ciliary rows that lead to the deeply located cyto- stome and cytopharynx. The macronucleus is oval and situated cen- trally; there is a contractile vacuole usually near the cytopharynx. Asexual reproduction is by lateral budding, and conjugation has been observed in a few species. Family Spirochonidae Stein Genus Spirochona Stein. Peristome funnel spirally wound; ciliary zone on floor of the spiral furrow; attached to Gammarus in fresh Fig. 320. a, Spirochona gemmipara, X300 (Hertwig); b, Stylochona coronata, X400 (Kent); c, Kentrochona nebaliae, X970 (Rompel); d, Heliochona scheuteni, X550 (Wallengren); e, H. sessilis, X510 (Wallen- gren); f, Chilodochona quennerstedti, X400 (Wallengren). 681 682 PROTOZOOLOGY water. Several species. Swarczewsky (1928) described several species from Lake Baikal in Siberia. S. gemmipara S. (Fig. 320, a). 80-120)u long; attached to the gill- plates of Gammarus pulex and other species. Genus Stylochona Kent. Peristomal funnel with an inner funnel. One species. S. coronata K. (Fig. 320, b). About 60^ long; on marine Gammar- us. Genus Kentrochona Rompel { Keritrochonopsis Doflein). Peri- stomal funnel wide, simple, membranous; with or without a few (2) spines. K. nebaliae R. (Fig. 320, c). About 40ju long; much flattened, with its broad side attached by means of gelatinous substance to epi- and exo-podite of Nebalia geoffroyi; salt water. Genus Heliochona Plate. Peristomal funnel with numerous needle- like spines. H. scheuteni (Stein) (Fig. 320, d). About 80-90^ long; on append- ages of Gammarus locusta; salt water. H. sessilis P. (Fig. 320, e). About 60/i long; on Gammarus locusta; salt water. Genus Chilodochona Wallengren. Peristome drawn out into two lips; with a long stalk. C. quennerstedti W. (Fig. 320, /). 60-1 15^* long; stalk, 40-160/x; on Ebalia turnefacta and Portunus depurator; salt water. Reference Kahl, a. 1935 Uriiere oder Protozoa. In Dahl's Die Tierwelt Deutschlands. Part 30. Chapter 43 Order 4 Peritricha Stein THE peritrichous ciliates possess a much enlarged disk-like ante- rior region which is conspicuously ciliated. The adoral zone is counter-clockwise to the cytostome viewed from the anterior end. The body ciliation is more or less limited. The stalked forms produce free-swimming individuals, telotrochs. Asexual reproduction is by bi- nary fission; and conjugation occurs commonly. The majority are free-living or attached to various aquatic animals and plants, al- though a few are parasitic. Attached to submerged objects; usually no body cilia, though telotroch possesses a posterior ring of cilia Suborder 1 Sessilia Free-swimming; but with highly developed attaching organellae on aboral end Suborder 2 Mobilia (p. 692) Suborder 1 Sessilia Kahl Without lorica, although some with a gelatinous or mucilaginous en- velope Tribe 1 Aloricata With definite pseudochitinous lorica Tribe 2 Loricata (p. 690) Tribe 1 Aloricata Kahl Posterior end with 1-2 short spines; swimming with peristome-bearing end forward Family 1 Astylozoonidae Posterior end, directly or indirectly through stalk, attached to submerged objects Anterior region a long cylindrical, highly contractile neck; contractile vacuole posterior, connected with vestibule by a long canal; reservoir of contractile vacuole distinct; with or without a thin stalk Family 2 Ophrydiidae (p. 685) Anterior portion not drawn out into a neck Without stalk Family 3 Scyphidiidae (p. 685) With stalk Stalk non-contractile Family 4 Epistylidae (p. 686) Stalk contractile Family 5 Yorticellidae (p. 687) Family 1 Astylozoonidae Kahl Genus Astylozoon Engelmann {Geleiella Stiller). Free-swimming; pyriform or conical; aboral end attenuated, with 1-2 thigmotactic stiff cilia; pellicle smooth or furrowed; with or without gelatinous envelope; in fresh water. A few species. A.fallax E. (Fig. 321, a). 70-100^; fresh water. Genus Hastatella Erlanger. Free-swimming; body surface with 2-4 rings of long conical ectoplasmic processes; fresh water. 683 684 PROTOZOOLOGY H. aesculacantha Jarocki and Jacubowska (Fig. 321, b). 30-52/i by 24-40/i ; in stagnant water. Fig. 321. a, Astylozoon Jallax, Xl70 (Engelmann) ; b, Hastatella aescula- cantha, X580 (Jarocki); c, Ojnsthonecta henneguyi, X500 (Lynch and Noble); d, e, Ophridiuni sessile (d, Xl.5; e, X65) (Kent); f, 0. vernalis, Xl60 (Stokes); g, Scyphidia constricta, X360 (Stokes); h, Paravorticella clymenellae, X65 (Shumway). Genus Opisthonecta Faure-Fremiet. Conical; ends broadly- rounded; a ring of long cilia close to aboral end; adoral zone about PERITRICHA 685 1.1 turns, composed of 2 parallel rows; a papilla with about 12 long cilia, just above the opening into vestibule; macronucleus sausage- form; micronucleus; 3 contractile vacuoles connected with cyto- pharynx; fresh water. One species. 0. henneguyi F.-F. (Fig. 321, c). 148-170^ long. The organisms studied by Ljmch and Noble (1931) were infected by endoparasitic suctorian, Endosphaera engelmanni (p. 705). Family 2 Ophrydiidae Kent Genus Ophyrdium Ehrenberg (Gerda Claparede and Lachmann) • Cylindrical with a contractile neck ; posterior end pointed or rounded ' variable number of individuals in a common mucilaginous mass' pellicle usually cross-striated; fresh water. 0. sessile Kent (Fig. 321, d, e). Fully extended body up to 300/i long; colorless or slightly brownish; ovoid colony up to 5 mm. by 3 mm. ; attached to freshwater plants. 0. vernalis (Stokes) (Fig. 321, /). About 250m long; highly con- tractile; in shallow freshwater ponds in early spring (Stokes). 0. ectatum Mast. 225-400^ long; with numerous zoochlorellae. In a creek near Falmouth, Mass. Family 3 Scyphidiidae Kahl Genus Scyphidia Dujardin. Cylindrical; posterior end attached to submerged object by an attaching disk; cross-striated; fresh or salt water. S. constricta Stokes (Fig. 321, 6^). About 55-60m long; pond water. Genus Paravorticella Kahl. Similar to Scyphidia; but posterior portion is much elongated and contractile; salt water, attached or parasitic. P. clymenellae (Shumway) (Fig. 321, h). 100m long; in the colon of the annelid, Clymenella iroquata; Woods Hole. Genus Glossatella Butschli. With a large adoral membrane; often attached to fish and amphibian larvae. G. tintinnahulum (Kent) (Fig. 322, a). 30-43m long; attached to the epidermis and gills of young Triton. Genus Ellobiophrya Chatton and Lwoff. Posterior end drawn out into 2 arm-like processes by means of which the organism holds fast to the gill bars of the mussel, Donax vittatus. One species. E. donacis C. and L. (Fig. 322, h). 50m by 40m, excluding the proc- 686 PROTOZOOLOGY Family 4 Epistylidae Kent Genus Epistylis Ehrenberg. Inverted bell-form ; individuals usually on dichotomous non-contractile stalk, forming large colonies; at- tached to fresh or salt water animals. Numerous species. Fig. 322. a, Glossatella tintinnabulum, X610 (Penard); b, Ellobiophrya donacis, X900 (Chatton and Lwoff); c, Epistylis plicatilis, X200 (Stein); d, E. fugitans, X260 (Kellicott); e, f, E. cambari (e, Xl40; f, X340) (Kellicott); g, Rhabdostyla vernalis, X320 (Stokes); h, Opisthostyla an- nulata, X440 (Stokes); i, Campanella umbellaria, X180 (Schroder); j, Pyxidium vernale, X240 (Stokes); k, P. urceolatum, Xl40 (Stokes); 1, Opercularia stenostoma, Xl40 (d'Udekem); m, n, 0. plicatilis (m, X40; n, X60) (Stokes). E. plicatilis E. (Fig. 322, c). 90-100^ long; colony often up to 3 mm. in height; fresh water. PERITRICHA 687 E. fugitans Kellicott (Fig. 322, d). 50-60^ long; attached to Sida in early spring. E. cambari K. (Fig. 322, e,j). About 50m long; attached to the gills of Cambarus. Genus Rhabdostyla Kent. Similar to Epistylis; but solitary with a non-contractile stalk ; attached to aquatic animals in fresh or salt water. Numerous species. R. vernalis Stokes (Fig. 322, g). About 50^ long; attached to Cy- clops and Cypris in pools in early spring. Genus Opisthostyla Stokes. Similar to Rhabdostyla; but stalk long, is bent at its point of attachment to submerged object, and acts like a spring; fresh or salt water. 0. annulata S. (Fig. 322, h). Body about 23^ long; fresh water. Genus Campanella Goldfuss. Similar to Epistylis; but adoral double zone turns 4-6 times ; fresh water. C. umhellaria (Linnaeus) (Fig. 322, i). Colony may reach several millimeters in height; individuals 130-250ai long (Kent). Genus Pyxidium Kent. Stalk simple, not branching; peristome even when fully opened, not constricted from the body proper; frontal disk small, oblique, supported by style-like slender process arising from peristome ; attached to freshwater animals and in vege- tation. P. vernale Stokes (Fig. 322, j). Solitary or few together; 70-85/x long; fresh Avater among algae. P. urceolatum S. (Fig. 322, A-). About 90^ long; fresh water on plants. Genus Opercularia Stein. Individuals similar to Pyxidium; but short stalk dichotomous; peristome border like a band, 0. sienostoma S. (Fig. 322, I). When extended up to 125^ long; at- tached to Asellus aquaticus and others. 0. plicatilis Stokes (Fig. 322, w, n). About 254^ long; colony 1.25- 2.5 mm. high; pond water. Family 5 Vorticellidae Fromental Genus Vorticella Linnaeus. Inverted bell-form; colorless, yellow- ish, or greenish ; peristome more or less outwardly extended ; pellicle sometimes annulated; with a contractile stalk, macronucleus band- form; micronucleus; 1-2 contractile vacuoles; solitary; in fresh or salt water, attached to submerged objects. Noland and Finley (1931) gave a taxonomic consideration of the genus. Numerous species. V. campanula Ehrenberg (Fig. 323, a-c). Usually in groups; endo- plasm filled with refractile reserve granules; vestibule very large 688 PROTOZOOLOGY with an outer pharyngeal membrane; 50-1 57/i by 35-99^; peristome 60-125m wide; stalk 50-4150^ by 5.6-12)u fresh water. V. convallaria (L.) (Fig. 323, d, e). Resembles the last-named species; but anterior end somewhat narrow; usually without refrac- tile granules in endoplasm; 50-95^ by 35-53/x; peristome 55-75/i wide; stalk 25-460^ by 4-6.5iu; fresh water. Fig. 323. a-c, Vorticella campamda (a, X400; b, part of stalk, X800; c, telotroch, X200); d, e, V. convallaria (d, X400; e, X800); f-p, V. micro- stoma {i, g, X400; h, X 840 ; i, telotroch, X400; j-p, telotroch-formation in vitro, X270); q, r, V. picta (q, X400; r, X800); s, t, V. monilatais, X400; t, X800) (Noland and Finley). V. microstoma Ehrenberg (Fig. 323, f-p). 35-83m by 22-50^; peristome 12-25^ wide; stalk 20-385/i by 1.5-4/x; common in fresh- water infusion. PERITRICHA 689 V. picta (E.) (Fig. 323, q, r). 41-63^ by 20-37m; peristome 35-50m; stalk 205-550/x by 4-7^; 2 contractile vacuoles; with refractile gran- ules in stalk; fresh water. V. monilata Tatem (Fig. 323, s, t). Body with pellicular tuber- cles; 2 contractile vacuoles; 50-78/1 by 35-57^; peristome 35-63/i wide; stalk 50-200^ by 5-6. 5/x; fresh water. Genus Carchesium Ehrenberg. Similar to VorticeUa; but colonial; myonemes in stalk not continuous, and therefore individual stalks contract independently; attached to fresh or salt water animals or plants; occasionally colonies up to 4 mm. high. Several species. Fig. 324. a, Carchesium polypinum, X200 (Stein); b, C. granulatum, X220 (Kellicott); c, Zoothamnium arbuscula, X200 (Stein); d, Z. adamsi, X150 (Stokes). C. polypinum (Linnaeus) (Figs. 35; 324, a). 100-125^ long; fresh water. C. granulatum Kellicott (Fig. 324, 6). About 100/x long; 2 con- tractile vacuoles anterior; on Cambarus and aquatic plants. Genus Zoothamnium Bory. Similar to Carchesium; but myonemes (Fig. 15) of all stalks of a colony are continuous with one another, so that the entire colony contracts or expands simultaneously; fresh or salt water; colonies sometimes several millimeters high. Numerous species. Z. arbuscula Ehrenberg (Fig. 324, c). 40-60^ long; colony up to more than 6 mm. high; fresh water. Z. adamsi Stokes (Fig. 324, d). About 60/i long; colony about 250/x high; attached to Cladophora. 690 PROTOZOOLOGY Tribe 2 Loricata Kahl Peristomal margin not connected with lorica; body attached only at posterior end, and extends, out of lorica . . Family 1 Vaginicolidae Peristomal margin connected with inner margin of aperture of lorica; stalked disk only extends out of lorica Family 2 Lagenophryidae (p. 691) Fig. 325. a, Vaginicola leptosoma, Xl30 (Stokes); b, V. anmilata, Xl70 (Stokes); c, Cothurnia canthocampti, X150 (Stokes); d, C. an- nulata, X340 (Stokes); e, Thuricola folliculata, XllO (Kahl); f, Thuri- colopsis kellicottiana, XHO (Stokes); g, Caulicola valvata, X760 (Stokes); h, i, Pyxicola affinis, X170 (Kent); j, P. socialis, Xl70 (Kent); k, Platy- cola longicollis, X200 (De Fromentel); I, Lagenophrys vaginicola, X380 (Penard); m, L. patina, X150 (Stokes); n, L. labiata, X340 (Penard). Family 1 Vaginicolidae Kent Genus Vaginicola Lamarck. Lorica without stalk, attached to substratum directly with its posterior end; body elongate and cylin- drical; fresh or salt water. Numerous species. V. leptosoma Stokes (Fig. 325, a). Lorica about 160/x high; when extended, about 1/3 of body protruding; on algae in pond water. V. annulata S. (Fig. 325, h). Lorica about 120;u high; below middle, a ring-like elevation; anterior 1/3 of body protruding, when ex- tended; pond water. PERITRICHA 691 Genus Cothumia Ehrenberg. Similar to Vaginicola; but lorica stands on a short stalk; fresh or salt water. Numerous species. C. canthocampti Stokes (Fig. 325, c). Lorica about 80/i high; on Canthocamptus minutus. C. annulata S. (Fig. 325, d). Lorica about 55ai high; fresh water. Genus Thuricola Kent. Body and lorica as in Vaginicola; but lorica with a simple or complex valve-like apparatus which closes obliquely after the manner of a door when protoplasmic body con- tracts; salt or fresh water. T. folliculata (Mliller) (Fig. 325, e). Lorica 127-170^ high (Kent) ; 160-200/i high (Kahl) ; salt and fresh water. Genus Thuricolopsis Stokes. Lorcia with an internal, narrow, flexible valve-rest, adherent to lorica wall and projecting across cavity to receive and support the descended valve; protoplasmic body attached to lorica by a pedicel; on freshwater plants. T. kellicottiana S. (Fig. 325,/). Lorica about 220iu long. Genus Caulicola Stokes. Similar to Thuricola; but lorica-lid at- tached to aperture; fresh or brackish water. 2 species. C. valvata S. (Fig. 325, g). Lorica about 50^ high; stalk about 1/2; body protrudes about 1/3 when extended; brackish water. Genus Pyxicola Kent. Body attached posteriorly to a corneous lorica; lorica colorless to brown, erect, on a pedicel; a discoidal corneous operculum developed beneath border of peristome, which closes lorica when organism contracts; fresh or salt water. Many species. P. affinis K. (Fig. 325, h, i). Lorica about 85/1 long; in marsh water. P. socialis (Gruber) (Fig. 325, j). Lorica about 100/x long; often in groups; salt water. Genus Platycola Kent. Body similar to that of Vaginicola; but lorica always decumbent and attached throughout one side to its fulcrum of support; fresh or salt water. Many species. P. longicollis K. (Fig. 325, k). Lorica yellow to brown when older; about 126/x long; fresh water. Family 2 Lagenophryidae Biitschli Genus Lagenophrys Stein. Lorica with flattened adhering surface, short neck and convex surface; "striped body" connects body with lorica near aperture; attached to fresh or salt water animals. Many species. 692 PROTOZOOLOGY L. vaginicola S. (Fig. 325, 1). Lorica 70^ by 48/x; attached to caudal bristles and appendages of Cyclops minutus and Canthocamptus sp. L. patina Stokes (Fig. 325, w). Lorica 55/i by 50^; on Gammarus. L. labiata S. (Fig. 325, n). Lorica 60/i by 55/i; on Gammarus. Suborder 2 Mobilia Kahl Family Urceolariidae Stein Genus Urceolaria Lamarck. Peristome more or less obliquely placed; external ciliary ring difficult to see; horny corona of attach- ing disk with obliquely arranged simple teeth without radial proc- esses; commensal. A few species. U. mitra (Siebold) (Fig. 326, a). 80-140^ long; on planarians. U. paradoxa (Claparede and Lachmann) (Fig. 326, 6). 70-80^ in diameter; colonial forms; in the respiratory cavity of Cyclostoma elegans. Genus Trichodina Ehrenberg. Low barrel-shaped; with a row of posterior cilia; horny ring of attaching disk with radially arranged hooked teeth; commensal on, or parasitic in, aquatic animals. Several species. T. pediculus (Miiller) (Fig. 326, c). A shallow constriction in mid- dle of body; 50-70^1 in diameter; on Hydra, amphibian larvae and probably fish. Those found on Hydra and gills of Necturus and Tri- turus larvae are probably identical (Fulton, 1923). T. urinicola Fulton (Fig. 326, d). 50-90/i long; teeth 28-36; in urinary bladder of a moribund Bufo sp. and Triturus. T. sp. Diller (Fig. 326, e). 30-40m in diameter; on the skin and gills of frog and toad tadpoles. Genus Cyclochaeta Jackson. Saucer-form; peristomal surface parallel to the basal disc ; upper surface with numerous fiat wrinkles ; basal disc composed of cuticular rings, velum, cirri, and membranel- lae; commensal on, or parasitic in, fresh or salt water animals. Sev- eral species. MacLennan (1939) made a careful study of two species. C. spongillac J. (Fig. 326,/). About 60/x in diameter; in interstices of Spongilla fluviatilis. C. domerguei Wallengren (Fig. 326, g, h). 23-56^ in diameter; about one-fifth high; 18-25 denticles, each with a narrow slightly curved spine; outer cuticular ring more finely striated than inner ring; cirri longer than membranellae (MacLennan); on fresh water fishes. PERITRICHA 693 Fig. 326. a, Urceolaria mitra, X340 (Wallengren); b, U. paradoxa, X270 (Claparede and Lachmann); c, Trichodina pediculus, X 530 (James- Clark); d, T. urinicola, X590 (Fulton); e, T. sp., X600 (Diller); f, Cyclo- chaeta spongillae, X600 (Jackson); g, h, front and side views of C. domerguei, X670 (MacLennan). 694 PROTOZOOLOGY References Fulton, Jr., J. F. 1923 Trichodina pediculus and a new closely related species. Proc. Boston Soc. Nat. Hist., Vol. 37. Kahl, a. 1935 Dahl's Die Tierwelt Deutschlands. Part 30. Kent, S. 1881-1882 A manual of Infusoria. MacLennan, R. F. 1939 The morphology and locomotor activities of Cyclochaeta domerguei Wallengren. Jour. Morph., Vol. 65. Mast, S. O. 1944 A new peritrich belonging to the genus Ophry- dium. Trans. Amer. Micr. Soc, Vol. 63. Noland, L. E. and H. E. Finley 1931 Studies on the taxonomy of the genus Vorticella. Trans. Amer. Micr. Soc, Vol. 50. Penard, E. 1922 Etudes sur les Infusoires d'eau douce. Geneva. Stiller, J. 1939 Die Peritrichenfauna der Nordsee bei Helgoland. Arch. f. Protistenk., Vol. 92. Stokes, A. C. 1888 A preliminary contribution toward a history of the freshwater Infusoria of the United States. Jour. Trenton Nat. Hist. Soc, Vol. 1. Chapter 44 Class 2 Suctoria Claparede and Lachmann THE Suctoria which have been also known as Acinetaria, Tentaculifera, etc., do not possess any cilia or any other cell- organs of locomotion in the mature stage. The cilia are present only on young individuals which are capable of free-swimming, and lost with the development of a stalk or attaching disk, and of tentacles. Therefore, an adult suctorian is incapable of active movement. The body may be spheroidal, elliptical, or dendritic ; and is covered with a pellicle and occasionally possesses a lorica. There is no cytostome, and the food-capturing is carried on exclusively by the tentacles. Tentacles are of two kinds: one is suctorial in function and bears a rounded knob on the extremity and the other is for piercing through the body of a prey and more or less sharply pointed. The tentacles may be confined to limited areas or may be distributed over the entire body surface. The food organisms are usually small ciliates and nutrition is thus holozoic. Asexual reproduction is by binary fission or by budding. The buds which are formed by either exogenous or endogenous gemmation are ciliated, and swim around actively after leaving the parent individ- ual. Finally becoming attached to a suitable object, the buds meta- morphose into adult forms. Sexual reproduction is through a com- plete fusion cf ccnjugants. The Suctoria live attached to animals, plants or non-living matter submerged in fresh or salt water, although a few are parasitic. With only suctorial tentacles Body irregular or branching Without proboscis or special arms; sometimes with stolon; without stalk Family 1 Dendrosomidae (p. 696) With proboscis or special arms With rectractile processes bearing tentacles Family 2 Ophryodendridae (p. 698) With branched arms Family 3 Dendrocometidae (p. 699) Body more or less bilaterally symmetrical Exogenous budding and division. .Family 4 Podophryidae (p. 699) Endogenous budding Pellicle thin; within or without lorica; with or without stalk. . . . Family 5 Acinetidae (p. 700) Pellicle thick; without lorica; a few tentacles, variable in form; stalk short, stout Family 6 Discophryidae (p. 706) With suctorial and prehensile tentacles; with or witho t lorica; ex- ogenous budding; commensals on marine hydroids Family 7 Ephelotidae (p. 709) 695 696 PROTOZOOLOGY Family 1 Dendrosomidae Biitschli Genus Dendrosoma Ehrenberg. Dendritic; often large; nucleus band-form, branched; numerous contractile vacuoles; fresh water. D. radians E. (Fig. 327, a). Brownish; 1.2-2.5 mm. high; on vege- tation. Genus Trichophrya Claparede and Lachmann. Body small; rounded or elongate, but variable; without stalk; tentacles in fascicles, not branching; endogenous multiple budding; fresh or salt water. T. epistylidis C. and L. (T. sinuosa Stokes) (Fig. 327, h). Form irregular; with many fascicles of tentacles; nucleus band-form, curved; numerous vacuoles; up to 240^ long; on Epistylis, etc., in fresh water. T. salparum Entz (Fig. 327, c). On various tunicates such as Molgula manhattensis; 40-60^ long; tentacles in 2 groups; salt water; Woods Hole (Calkins). T. columbiae Wailes (Fig. 327, d). 60-75m by 40-48/x in diameter; cylindrical; tentacles at ends; nucleus spherical; in marine plankton; Vancouver (Wailes). T. micro-pteri Davis. Body elongate, irregular or rounded; up to 30-40m long by 10-12/i; fully extended tentacles 10-12;u long; cyto- plasm often filled with yellow to orange spherules; a single micro- nucleus; a single contractile vacuole; attached to the gill of small mouth black bass, Micropterus dolomieu. Davis (1942) states that when abundantly present, the suctorian may cause serious injury to the host. Genus Astrophrya Awerinzew. Stellate; central portion drawn out into 8 elongate processes, each with a fascicle of tentacles; body cov- ered by sand grains and other objects. One species. A. arenaria A. (Fig. 327, e). 145-188^ in diameter; processes 80- 190ai long; in Volga river plankton. Genus Lernaeophrya Perez. Body large; with numerous short pro- longations, bearing very long multifasciculate tentacles; nucleus branched; brackish water. One species. L. capitata P. (Fig. 327, /). Attached to the hydrozoan, Cordy- lophora lacustris in brackish water; 400-500^ long; tentacles 400^ long. Genus Dendrosomides Collin. Branched body similar to Dendro- soma, but with a peduncle; reproduction by budding of vermicular form; salt water. One species. D. paguri C. (Fig. 327, g). 200-300^ long; vermicular forms 350/i long; on the crabs, Eupagurus excavatus and E. cuanensis. SUCTORIA 697 Genus Rhabdophrya Chatton and Collin. Elongate, rod-form; with short peduncle, not branched; tentacles distributed over entire sur- face; macronucleus ellipsoid; micronucleus small; 2-3 contractile vacuoles; salt or brackish water. Several species. Fig. 327. a, Dendrosoma radians, X35 (Kent); b, Trichophrya episty- lidis, X250 (Stokes); c, T. salparum, Xl70 (Collin); d, T. columhiae, X200 (Wailes); e, Astrophrya arenaria, X65 (Awerinzew); f, Lernaeo- phrya capitata, X35 (P6rez); g, Dendrosomides paguri, X200 (Collin). R. trimorpha C. and C. (Fig. 328, a). Up to 150^ long; on the cope- pod, Cleiodes longicaudaius. Genus Staurophrya Zacharias. Rounded body drawn out into 6 processes. S. elegans Z. (Fig. 328, b). Tentacles not capitate; macronucleus 698 PROTOZOOLOGY round; 1-2 contractile vacuoles; about 50/i in diameter; in fresh water. _, ., _ , t amily 2 Ophryodendridae Stein Genus Ophryodendron Claparede and Lachmann. With one long b Fig. 328. a, Rhabdophrya trimorpha, X650 (Collin); b, Staurophrya elegans, X300 (Zacharias); c, Ophryodendron porcellanum, X330 (CoHin); d, 0. helgicum, X270 (Fraipont); e, Dendrocometes paradoxus, X270 (Wrzesnowski) ; f, g, Podophrya fixa (f, X600 (Wales); g, X330 (Col- lin)); h, P. gracilis, XlOOO (Collin); i, P. elongata, X240 (Wailes). or 3-6 shorter retractile processes, bearing suctorial tentacles; on Crustacea, Annelida, etc.; salt water. Several species. SUCTORIA 699 0. porcellanum Kent (Fig. 328, c). 60-100^ long; on Porcellana platycheles, etc. 0. belgicum Fraipont (Fig. 328, d). 38-1 14/i long; vermicular form 100)u; on Bryozoa and hydrozoans; Vancouver (Wailes). Family 3 Dendrocometidae Stein Genus Dendrocometes Stein. Body rounded; with variable num- ber of branched arms; fresh water. D. paradoxus S. (Fig. 328, e). Up to 100m long; on Gammarus pulex, G. puteanus, etc. Genus Stylocometes Stein. Arms not branched; tentacles finger- like ; fresh water. S. digitatus (Claparede and Lachmann). Up to llOju long; on the gills of Asellus aquaticus and on Aphrydium versatile. Family 4 Podophryidae Biitschli Genus Podophrya Ehrenberg. Subspherical; normally with a rigid stalk; suctorial tentacles in fascicles or distributed on entire body surface; encystment common; fresh or salt water. Many species. P. fixa Miiller (Fig. 328, /, g). Spherical; tentacles of various lengths; stalked; nucleus spheroid; one contractile vacuole; 10-28ju long; fresh water. P. collini Root. Ovoid; stalked; 30-60 capitate tentacles, dis- tributed; nucleus spherical; one contractile vacuole; 40-50/1 in di- ameter; in swamp. P. gracilis Calkins (Fig. 328, h). Small; spherical; long filiform stalk; 1-2 contractile vacuoles; nucleus near attachment of stalk; 8/1 in diameter; stalk 40/i long; salt water; Woods Hole. P. elongata Wailes (Fig. 328, i). Elongate; flattened; with a pedi- cel; tentacles distributed; nucleus cylindrical; 95-105/i long; stalk 65-85/i by 7-9/i; on the marine copepod, Euchaeta japonica; Van- couver. Genus Parapodophrya Kahl. Spherical; tentacles radiating, a few long, more or less conical at proximal portion; stalk thin; salt water. P. typha K. (Fig. 329, a). 50-60/i in diameter; salt water. Genus Sphaerophrya Claparede and Lachmann. Spherical, with- out stalk; with or w^ithout distributed tentacles; multiplication by binary fission or exogenous budding; fresh water, free-living or para- sitic. S. soliformis Lauterborn (Fig. 329, b). Spherical; numerous tenta- cles about 1/4-1/3 the body diameter; a contractile vacuole; nu- cleus oval; diameter about lOO/i; sapropelic. 700 PROTOZOOLOGY S. magna Maupas. Spherical; about 50/x in diameter; numerous tentacles of different length ; nucleus spheroid ; standing fresh water with decaying vegetation. S. stentoris M. Parasitic in Stentor; swarmers ciliated on posterior end; the other end with capitate tentacles; nucleus spheroid; 2 con- tractile vacuoles; about 50/i long. Genus Paracineta Collin. Spherical to ellipsoidal; tentacles dis- tributed ; mostly in salt water, a few in fresh water. P. limbata (Maupas) (Fig. 329, c, d). With or without gelatinous envelope; 20-50/i in diameter; swarmer with many ciliated bands, contractile; on plants and animals in salt water. Genus Metacineta Blitschli. Lorica funnel-shaped, lower end drawn out for attachment; tentacles grouped at anterior end; nu- cleus spherical; one contractile vacuole. One species. M. mystacina (Ehrenberg) (Fig. 329, e). Lorica up to 700/1 long; in fresh and salt water. Genus Urnula Claparede and Lachmann. Lorica colorless; lower end pointed, attached; aperture narrowed, round or triangular; body more or less filling lorica; 1-2 (up to 5) long active tentacles; nucleus central, oval; one or more contractile vacuoles; fresh water. U. epistylidis C. and L. (Fig. 329,/). Up to 80^ long; on Epistylis, Dendrosoma, etc. Genus Lecanophrya Kahl. Body rounded rectangular in cross sec- tion; anterior region bowl-shaped; somewhat rigid tentacles located on the inner surface of bowl ; salt water. L. drosera K. (Fig. 329, g). 40-70^ high; hollow stalk; tentacles in 3-5 indistinct rows; attached to the antennae of the copepod, Nitocra typica. Genus Ophryocephalus Wailes. Spheroidal, stalked; a single long mobile, capitate tentacle; multiplication by multiple exogenous bud- ding from apical region; on Ephelota gemmipara and E. coronata (p. 709) ; salt water. One species. 0. capitatum W. (Fig. 329, h). About 55^1 long; tentacle up to 100)u by L 5-5/1 ; Vancouver. Family 5 Acinetidae Butschli Genus Acineta Ehrenberg. Lorica more or less flattened; usually with stalk; tentacles in 2 (1 or 3) fascicles; body completely or partly filling lorica; swarmer with ciliated band or completely ciliated; fresh or salt water. Numerous species. A. tuherosa E. (Fig. 330, a). Lorica 50-100/x high; with stalk; salt and brackish water. SUCTORIA 701 A. cuspidata Stokes (Fig. 330, h). Lorica cup-shaped; front end with 2 opposing sharp points; lorica 32-42/i high; on Oedogonium in fresh water. Fig. 329. a, Parapodophrya typha, X270 (Kahl); b, Sphaerophrya soliformps, X200 (Lauterborn); c, d, Paracineta limhata (c, a bud is ready to leave; d, basal part of stalk), X460 (Collin); e, Metacineia mystacina, capturing Halteria, X400 (Collin); f, Urnula epistylidis, Xl40 (Claparede and Lachmann); g, Lecanophrya drosera, X390 (Kahl); h, Ophryocephalus capitatum, X200 (Wailes); i, Acineta lacustris, X200 (Stokes). A. lacustris S. (Fig. 329, i). Lorica elongate ovoid; flattened; 75- 185/x high; on Anacharis in pond. Genus Tokophrya Biitschli. Pyriform or pyramidal; without lo- 702 PROTOZOOLOGY rica; tentacles in 1-4 fascicles on anterior surface; stalk not rigid; swarmers oval, with several ciliary bands and long cilia; fresh water. Several species. Fig. 330. a, Acineta tuberosa, X670 (Calkins); b, A. cuspidata, X670 (Stokes); c-e, Tokophrya injusionum (c, X400; d, a free-swimming bud; e, a young attached form, X800) (Collin); f, T. cydopum, a young individual, X500 (ColHn). T. injusionum (Stein) (Fig. 330, c-e). Inverted pyramid; stalk with or without attaching disk; macro nucleus oval; 2 contractile vacuoles; about 60/1 long. T. cycloputn (Claparede and Lachmann) (Fig. 330, /). Oval or SUCTORIA 703 spherical; stalk short; tentacles in 2-5 bundles; macronucleiis spheri- cal; 1-2 contractile vacuoles; about 50/x long; on Cyclops, etc. Genus Thecacineta Collin. Lorica with free margin; body usually attached to bottom of lorica, more or less long; tentacles from an- terior end; salt water. Several species. T. cothurnioides C. (Fig. 331, a). Lorica about 50^ high; stalk knobbed; on Cletodes longicaudatus. T. gracilis (Wailes) (Fig. 331, h). Lorica 110/x by 35^; stalk 200^ by 4/i;onhydrozoans. Genus Periacineta Collin. Elongate lorica; attached with its drawn-out posterior end; tentacles from the opposite surface in bundles; fresh water. P. huckei (Kent) (Fig. 331, c). Attached end of lorica with basal plate; 3 contractile vacuoles; up to 125/1 long; on Lymnaea stagnalis and Ranatra linearis. Genus Hallezia Sand. Without lorica; with or without a short stalk; tentacles in bundles; fresh water. H. brachypoda (Stokes) (Fig. 331, c?). 34-42/i in diameter; in stand- ing water among leaves. Genus Solenophrya Claparede and Lachmann. Lorica attached di- rectly with its under side; body usually not filling lorica; tentacles in fascicles; fresh water. S. inclusa Stokes (Fig. 331, e). Lorica subspherical; about 44/x in diameter; standing fresh water. S. pera S. (Fig. 331, /). Lorica satchel-form; about 40-45At high; body about 35m long; standing fresh water. Genus Acinetopsis Robin. Lorica in close contact with body on sides; stalked; 1-6 large retractile tentacles and numerous small tentacles from apical end; mainly salt water. A. tentaculata Root (Fig. 331, g, h). Lorica 187/x high; stalk 287)u long; large tentacles up to SOO/x long; body about 138/x by lOO/i; on Obelia commissuralis and 0. geniculata; Woods Hole. Genus Tachyblaston Martin. Lorica with short stalk; tentacles distributed on anterior surface; nucleus oval; salt water. One species. T. ephelotensis M. (Fig. 331, i, j). Lorica 30-93^ high; stalk 20-30/x long; attached to Ephelota gemmipara. Genus Dactylophrya Collin. Cup-like lorica, filled with the proto- plasmic body; with a short stalk; 12-15 arm-like tentacles from an- terior surface; salt water. One species. D. roscovita C. (Fig. 331, fc). About 40^ long excluding stalk; on the hydrozoan, Diphasia attenuata. Genus Pseudogemma Collin. Attached with a short stalk to larger 704 PROTOZOOLOGY suctorians; without tentacles; endogenous budding; swarmer with 4 ciUary bands; salt water. P. pachystyla C. (Fig. 333, a). About 30m long; stalk 3-4m wide; swarmer 15/x by Q^t; on Acineta tuherosa. Fig. 331. a, Thecacinela cothurnioides, X400 (Collin); b, T. gracilis, X270 (Wailes); c, Periacineta biickei, feeding on Chilodonella, X530 (Collin); d, Hallezia hrachypoda, X200 (Stokes); e, Solenophnja inclusa, X230 (Stokes); f, S. pera, X230 (Stokes); g, h, Acinetopsis tentaculata (g, Xl30; h, X230) (Root); i, j, Tachijhlaston ephelotensis (i, a young individual in Ephelota, X260; j, mature form, X500) (Martin); k, Dadylophrya roscovita, X830 (Collin). SUCTORIA 705 Genus Endosphaera Engelmann. Spherical without lorica; without tentacles; budding endogenous; swarmer with 3 equatorial ciliary bands ; parasitic in Peritricha ; fresh and salt water. E. engelmanni Entz (Fig. 333, b). 15-41)u in diameter; imbedded in the host's cytoplasm; swarmer 13-19^ in diameter; in Opisthonecta henneguyi (p. 685), and other peritrichs. Genus Allantosoma Gassovsky. With neither lorica nor stalk; elongate; one or more tentacles at ends; macronucleus oval or spheri- cal; compact micronucleus; a single contractile vacuole; cytoplasm often filled with small spheroidal bodies; development unknown; in mammalian intestine. A. intestinalis G. (Fig. 333, c). 33-60/i by 18-37/x; attached to vari- ous ciliates living in the caecum and colon of horse. A. dicorniger Hsiung (Fig. 333, d). 20-33)u by 10-20/1; unattached; in the colon of horse. A. hrevicorniger H. (Fig. 333, e). 23-36)U by 7-11^; attached to various ciliates in the caecum and colon of horse. Genus Anarma Goodrich and Jahn. Radially or somewhat bi- laterally symmetrical; without stalk or lorica; attached directly or by a short protoplasmic process to substratum; 1-2 fascicles of capi- tate tentacles; multiplication by external budding near base or by a single internal ciliated bud; conjugation; ectocommensal on Chryse- mys picta hellii. A. multiruga G. and J. (Fig. 332, a-d). Body cylindrical, 70-150)U by 35-70/z; body surface with 7 or 8 longitudinal folds; pellicle thin; cytoplasm granulated ; nucleus ribbon-form ; 2-6 contractile vacuoles, each with a permanent canal and a pore; attached directly or indi- rectly to the carapace and plastron of the turtle. Genus Squalorophrya Goodrich and Jahn. Elongate; radially sym- metrical; lorica, rigid, close-fitting, covered with debris; with a stalk; capitate tentacles at distal end; ectocommensal on C/ir?/scm?/s pt'cto hellii. S. macrostyla G. and J. (Fig. 332, e, /). Cylindrical, with 4 longi- tudinal grooves; body about 90/x by 40yu; striated stalk, short and thick, about SO/jl long; lorica highly viscous with debris; nucleus ovoid to elongate, sometimes Y-shaped; 2 contractile vacuoles, each with a permanent canal and a pore; on Chrysemys picta hellii. Genus Multifasciculatum Goodrich and Jahn. Radially or bilat- erally symmetrical; stalked; without lorica; pellicle thin; several fascicles of tentacles on distal, lateral and proximal regions of body; ectocommensal on Chrysemys picta hellii. M. elegans G. and J. (Fig. 332, g). Body ovoid; 50-90)U by 20-50^; 706 PROTOZOOLOGY stalk striated, about 150-270m long; tentacles in 4 groups; nucleus ovoid; 1-3 contractile vacuoles; attached to the plastron of the tur- tle. Family 6. Discophryidae Colhn Genus Discophrya Lachmann. Elongate; a short stout pedicel with a plate; tentacles evenly distributed on anterior surface or in fasci- FiG. 332. a-d, Anarma multiruga, X about 230; b, budding individual; c, cross-section; d, with an internal ciliated bud; e, f, Squalor ophnj a macrostyla, X about 670; f, cross-section; g, Multifasciculatum elegans, X about 660 (Goodrich and Jahn). cles; contractile vacuoles, each with a canalicule leading to body surface; mainly fresh water. Several species. D. elongata (Claparede and L.) (Fig. 333, /). Cylindrical; tentacles on anterior end and in 2 posterior fascicles; stalk striated; about 80/i long; on the shell of Paldina vivipara in fresh water. Genus Thaumatophrya Collin. Spherical; long stalk; tentacles dis- tributed, tapering toward distal end; salt water. One species. T. trold (Claparede and Lachmann) (Fig. 333, g). About 75/i in diameter. SUCTORIA 707 Genus Rhynchophrya Collin. Oblong; bilaterally symmetrical; a short striated stalk; 1 main long and a few shorter tentacles; 6-10 contractile vacuoles, each with a canalicule leading to outside; fresh water. One species. Fig. 333. a, Pseudogemma pachystyla, X400 (Collin); b, Endosphaera engelnianni, X500 (Lynch and Noble); c, Allantosom,a intestinalis, X1050 (Hsiung); d, A. dicorniger, X1300 (Hsiung); e, A. hrevicorniger, X1400 (Hsiung); f, Discophrya elongata, X440 (Collin); g, Thaumatophrya trold, X1150 (Claparede and Lachmann); h, Rhynchophrya palpans, X440 (Collin). R. palpans C. (Fig. 333, h). 85 fx by 50^; tentacles retractile, 10- 200/1 long; stalk 20;u by 10/*; oij Hydrophilus piceus. 708 PROTOZOOLOGY Genus Choanophrya Hartog. Spheroidal to oval; stalked; 10-12 tentacles; tubular, expansible at distal end to engulf voluminous food particles; macronucleus oval to spherical; a micronucleus; fresh wa- ter. One species. C. infundihulifera H. (Fig. 334, a). 65^ by 60^; fully extended ten- tacles 200m long; on Cyclops ornatus. Fig. 334. a, Choanophrya inftmdihdifera, feeding on disintegrating part of a Cyclops, X400 (Collin); b, c, Rhyncheta cyclopurn (b, XlOO; c, end of tentacle, X400) (Zenker); d, Ephelota gemmipara, X200 (Hert- wig); e, E. coronata, Xl40 (Kent); f, E. plana, front view, with two at- tached Ophryocephalus, X35 (Wailes); g, Podocyathus diadema, X200 (Kent). Genus Rh3mcheta Zenker. Protoplasmic body attached directly to an aquatic animal; with a long mobile tentacle bearing a sucker at its end. R. cyclopum Z. (Fig. 334, b, c). About 170/i long; on Cyclops. SUCTORIA 709 Family 7 Ephelotidae Sand Genus Ephelota Wright. Without lorica; stalk stout, often striated; suctorial and prehensile tentacles distributed; macronu- cleus usually elongate, curved; on hydroids, bryozoans, algae, etc.; salt water. Numerous species. E. gemmipara Hertwig (Fig. 334, d). About 250/i by 220/x; stalk up to 1.5 mm. long; on hydroids, bryozoans, etc. E. coronata Kent (Fig. 334, e). Flattened; 90-200^ long; stalk lon- gitudinally striated (Kent); on hydroids, bryozoans, algae, etc. E. plana Wailes (Fig. 334,/). 150-320)i^ by lOO-lSO/x; stalk 100^-1 mm. long; on bryozoans; Vancouver, Genus Podocyathus Kent. It differs from Ephelota in having a con- spicuous lorica; salt water. One species. P. diadema K. (Fig. 334, g). Lorica about 42At long; on bryozoans, hydrozoans, etc. References Collin, B. 1912 Etudes monographique sur les Acinetiens. Arch, zool. exp6r. et gen., Vol. 51. Davis, H. S. 1942 A suctorian parasite of the small mouth black bass, with remarks on other suctorian parasites of fishes. Trans. Amer. Micr. Soc, Vol. 61. Goodrich, J. P. and T. L. Jahn 1943 Epizoic Suctoria (Protozoa) from turtles. Trans. Amer. Micr. Soc, Vol. 62. Kahl, a. 1934 Suctoria. Grimpe's Die Tierwelt der Nord- und Ost- see. Part 26. Leipzig. Kent, S. 1881-1882 A manual of the Infusoria. Vol. 2. Wailes, G. H. 1928 Dinoflagellates and Protozoa from British Co- lumbia. Vancouver Museum Notes, Vol. 3. Chapter 45 Collection, Cultivation, and Observation of Protozoa Collection IN THE foregoing chapters it has been pointed out that various species of Protozoa have characteristic habitats and that many of free-Uving forms are widely distributed in bodies of water: fresh, brackish, and salt; while the parasitic forms are confined to specific host animals. Of free-living Protozoa many species may occur in large numbers within a small area under favorable conditions, but the majority are present in comparatively small numbers. If one who has become acquainted with the representative forms, intends to make collection, it is well to carry a compound microscope in order to avoid bringing back numerous jars containing much water, but few organisms. Submerged plants, decaying leaves, surface scum, ooze, etc., should be examined under the microscope. When desired forms are found, they should be collected together with a quantity of water in which they occur. When the material is brought into the laboratory, it is often nec- essary to concentrate the organisms in a relatively small volume of water. For this purpose the water may partly be filtered rapidly through a fine milling cloth and the residue quickly poured back into a suitable container before filtration is completed. The container should be placed in a cool moderately lighted room to allow the or- ganisms to become established in the new environment. Stigma- bearing Phytomastigina will then be collected in a few hours on the side of the container, facing the strongest light, and the members of Sarcodina will be found among the debris on the bottom. Many forms will not only live long, but also multiply in such a container. For obtaining large freshwater amoebae, fill several finger bowls with the collected material and water, and place one or two rice grains to each. After a few days, examine the bottom surface of the bowls under a binocular dissecting microscope. If amoebae were in- cluded in the collection, they will be found particularly around the rice grains. Pipette them off and begin separate cultures (p. 712). In order to collect parasitic Protozoa, one must, of course, find the host organisms that harbor them. Various species of tadpoles, frogs, cockroaches, termites, etc., which are of common occurrence or easily obtained and which are hosts to numerous species of Protozoa, are useful material for class work. 710 COLLECTION, CULTIVATION, OBSERVATION 711 Intestinal Protozoa of man are usually studied in the faeces of an infected person. Natural movement should be collected. Do not use oily purgatives in obtaining faecal specimens, as they make the microscopical examination difficult by the presence of numerous oil droplets. The receptacle must be thoroughly cleaned and dry, and provided with a cover. Urine or water must be excluded completely. The faeces must be examined as soon as possible, since the active trophozoites degenerate quickly once leaving the human intestine. If dysenteric or diarrhoeic stools are to be examined, they must not be older than one hour or two. In case this is not possible, wrap the container with woolen cloth while transporting and keep it in an in- cubator at 37°C. The organisms may live for several hours. Care must however be exercised during the microscopical examination, as there will be present unavoidably a large number of degenerating forms. If the stool is formed and normal, it would contain usually encysted forms and no trophozoites if the host is infected by a protozoan, unless mucus, puss, or blood is present in it. Examination of such faeces can be delayed, as the cysts are quite resistant. Cultivation For extensive study or for class work, a large number of certain species of Protozoa are frequently needed. Detection and diagnosis of human Protozoa are often more satisfactorily made by culture method than by microscopical examination of the collected material. Success in culturing Protozoa depends upon several factors. First an abundant supply of proper food material must be made available. For example, several species of Paramecium live almost exclusively on bacterial organisms, while Didinium and allied ciliates depend upon other ciliates as sources of food supply. For cultivating chroma- tophore-bearing forms successfully, good light and proper kinds and amount of inorganic substances are necessary. In the second place, the temperature and chemical constituents of the culture medium must be adjusted to suit individual species. As a rule, lower tempera- tures seem to be much more favorable for culture than higher tem- peratures, although this is naturally not the case with those parasitic in homoiothermal animals. Furthermore, proper hydrogen ion con- centration of the culture must be maintained. In the third place, both Protozoa and Metazoa which prey upon the forms under cultivation must be excluded from the culture. For instance, it is necessary to remove Didinium nasutum in order to obtain a rich culture of Para- mecium. For successful culture of Amoeba proteus, Aeolosoma, Daph- nia, Cyclops, etc., must be excluded from the culture. 712 PROTOZOOLOGY Mixed cultures of many free-living Protozoa are easily maintained by adding from time to time a small amount of ripe hay-infusion or dried lettuce powder to the collected water mentioned before. Chilo- monas, Peranema, Bodo, Arcella, Amoeba, Paramecium, Colpoda, Stylonychia, Euplotes, etc., often multiply in such cultures. To ob- tain a large number of a single species, individuals are taken out under a binocular dissecting microscope by means of a finely drawn- out pipette and transferred to a suitable culture medium. Aside from the cultures of blood-inhabiting Protozoa, the so-called protozoan cultures are by no means "pure" cultures in the bacterio- logical sense, even if only one species of Protozoa is present, since bacteria and other microorganisms are invariably abundantly pres- ent in them. However in recent years, many holophytic or saprozoic Protozoa have been cultivated in vitro free from bacteria. Glaser and Coria (1930) by using a V-tube and utilizing negative geotropic movement of organisms succeeded in obtaining bacteria-free sev- eral species of flagellates and ciliates. Claff (1940) also using the same response of certain rapidly swimming ciliates set up a "migra- tion-dilution" apparatus by which he obtained organisms free from bacteria. Taylor and Van Wagtendonk (1941) used a sterile viscous agar medium in sterilizing Colpoda duodenaria. A. Free-living Protozoa To deal with all the culture media employed by numerous workers for various free-living Protozoa is beyond the scope of the present work. Here only a few examples will be given. For further informa- tion, the reader is referred to Belaf (1928), Needham et al. (1937), etc. Chromatophore-hearing fiagellates. — There are a number of culture fluids. Two examples: (a) Peptone or tryptone 2 . 0 gm. KH2PO4 0.25 gm. MgS04 0.25 gm. KCl 0.25 gm. FeCla trace Sodium acetate 2.0 gm. Pyrex distilled water 1000 cc. (b) Peptone or tryptone 2.5 gm. KNO3 0.5 gm. KH2PO4 0.5 gm. COLLECTION, CULTIVATION, OBSERVATION 713 MgS04 0.1 gm, NaCl 0.1 gm, Sodium acetate 2.5 gm, Dextrose 2.0 gm. Glass distilled water 1000 cc. Peranema, Chilomonas, Astacia and other colorless flagellates. — A number of culture fluids have been advocated. A simple yet satis- factory one is as follows: Fill a finger bowl with about 150 cc. of glass distilled water and place 4 rice grains on the bottom. Let the dish stand for a few days, and then introduce with a pipette a number of desired flagellates from a mass culture into it. Cover the bowl and keep it at about 20° C. Mast (1939) used the following media for Chilomonas Paramecium. (a) Glucose-peptone solution: Peptone 8 gm. Glucose 2 gm. Water 1000 cc. (b) Acetate-ammonium solution: Sodium acetate 1.5 gm. Ammonium chloride 0.46 gm. Ammonium sulphate 0.1 gm. Dipotassium hydrogen phosphate 0.2 gm. Magnesium chloride 0.01 gm. Calcium chloride 0.012 gm. Water 1000 cc. Amoeba proteus and other freshwater amoebae. — Fill a finger bowl with 200 cc. of glass distilled water, and place 4 rice grains. After a few days seed with amoebae (p. 710), add about 5 cc. of Chilomonas culture, and cover the bowl with a glass cover. In about two weeks a ring of amoebae will be found around each rice grain, and if Chilo- monas do not overmultiply, the amoebae will be found abundantly in another two weeks. If properly maintained, subcultures may be made every 4-6 weeks. Chalkley (1930) advocates substitution of the plain water with a salt solution which is composed of NaCl 0.1 gm. KCl 0.004 gm. CaCla 0.006 gm. Glass distilled water 1000 cc. 714 PROTOZOOLOGY If the culture water becomes turbid, make subcultures or pour off the water and fill with fresh distilled water or the solution. Culture should be kept at 18-22°C. Hahnert (1932) used the following culture solution: KCl 0.004 gm. CaCla 0.004 gm. CaH4(P04)2 0.002 gm. Mg3(P04)2 0.002 gm. Ca3(P04)2 0.002 gm. Pyrex water 1000 cc. Pelomyxa carolinensis. — These amoebae grow well in a finger bowl with 150 cc. of redistilled water to which large numbers of Parame- cium are added daily. Pace and Belda (1944) advocate the following solution instead of distilled water: K2HP04 0.08 gm, KH2P04 0.08 gm, CaCl2 0.104 gm, Mg3(P04)2.4H20 0.002 gm, Pyrex water 1000 cc. Small mono- or di-phasic amoebae. — Musgrave and Clegg's me- dium, modified by Walker, is as follows: Agar 2.5 gm. NaCl 0.05 gm. Liebig's beef-extract 0.05 gm. Normal NaOH 2cc. Distilled water 100 cc. Arcella and other Testacea. — The testaceans commonly multiply in a mixed culture for several weeks after the collection was made. Hegner's method for Arcella: Pond water with weeds is shaken up violently and filtered through eight thicknesses of cheese cloth, which prevents the passage of coarse particles. The filtrate is distributed among Petri dishes, and when suspended particles have settled down to the bottom, specimens of Arcella are introduced. This will serve also for Difflugia and other testaceans. Hay or rice infusion is also a good culture medium for these organisms. Actinophrys and Actinosphaerium. — Belaf cultivated these helio- zoans successfully in Knop's solution: COLLECTION, CULTIVATION, OBSERVATION 715 Magnesium sulphate 0.25 gm. Calcium nitrate 1 gm. Potassium phosphate 0.25 gm. Potassium chloride 0.12 gm. Iron chloride trace Distilled water 1000 cc. Freshwater ciliates. — They are easily cultivated in a weak infusion of hay, bread, cracker, lettuce leaf, etc. The battery jars containing the infusions should be left standing uncovered for a few days to al- low a rich bacterial growth in them. Seed them with material such as submerged leaves or surface scum containing the ciliates. If de- sired, culture may be started with a single individual in a watch glass. For bacteria-free cultures, various culture media have been used by recent investigators. For example, Glaser and Coria (1933) cultured Paramecium caudatum bacteria-free in a medium composed of Lily liver extract, killed yeast and rabbit kidney, for a period of six months. Kidder (1941) used the following basic medium for bac- teria-free culture of Glaucoma and Colpidium: 10 grams of Brewers yeast and 1000 cc. of Pyrex distilled water are brought to a boil and filtered, through cotton and then through Schleicher and Schiill No. 595 filter paper. After adding 20 grams of Difco proteose peptone, the whole is autoclaved at 15 pounds pressure for 20 minutes. B. Parasitic Protozoa Intestinal flagellates of man. — There are numerous media which have been used successfully by several investigators. (a) Ovo-mucoid medium (Hogue, 1921). White of two eggs are broken in a sterile flask with beads. Add 200 cc. of 0.7 % NaCl solu- tion and cook the whole for 30 minutes over a boiling water bath, shaking the mixture constantly. Filter through a coarse cheese cloth and through cotton-wool with the aid of a suction pump. Put 6 cc. of the filtrate in each test tube. Autoclave the tubes for 20 minutes un- der 15 pounds pressure. After cooling, a small amount of fresh faecal material containing the flagellates is introduced into the tubes. Incu- bate at 37°C. (b) Sodium chloride sheep serum water (Hogue, 1922). Composed of 100 cc. of sterile 0.95% NaCl and 10-15 cc. of sterile sheep serum water (dilution 1:3). 15 cc. to each tube. Trichomonas hominis, T. elongata, and Retortamonas intestinalis grow well. Trichomonas vaginalis. — Bland et al. (1932) used the following me- 716 PROTOZOOLOGY dium: 5 cc. of Bacto nutrient agar dissolved in boiling water, is tubed and the tubes are autoclaved for 15 minutes at 15 pounds pressure and slanted. After cooling, a modified Ringer's solution is added to the agar slants to a height of 2-3 inches. The composition of Ringer's solution used, is as follows : Sodium chloride 6 gm. Potassium chloride 0 . 1 gm. Sodium bicarbonate 0 . 1 gm. Calcium chloride 0.1 gm. Glass distilled water 1000 cc. Loeffler's dried blood serum 2 . 5 gm. The tubes are inoculated with vaginal material and incubated at 36-37°C. Transfers are made every 3 or 4 days. Lophomonas hlattarum and L. striata. — A mixture of one sterile egg-white and 100 cc. of sterile Ringer's solution, to which a small amount of yeast cake is added, is an excellent culture medium. Incu- bation at room temperature ; subcultures every 4-6 days. Trypanosoma and Leishmania. — Novy, MacNeal and Nicolle (NNN) medium: 14 gm. of agar and 6 gm. of NaCl are dissolved by heating in 900 cc. of distilled water. When the mixture cools to about 50°C., 50-100 cc. of sterile defibrinated rabbit blood is gently added and carefully mixed so as to prevent the formation of bubbles. The blood agar is now distributed among sterile test tubes to the height of about 3 cm., and the tubes are left slanted until the medium be- comes solid. The tubes are then incubated at 37°C. for 24 hours to determine sterility and further to hasten the formation of conden- sation water (pH 7.6). Sterile blood or splenic puncture containing Trypanosoma cruzi or Leishmania is introduced by a sterile pipette to the condensation water in which organisms multiply. Incubation at 37°C. for trypanosomes and at 20-24°C. for Leishmania. Entamoeba harreti. — Barret and Smith (1924) used a mixture of 9 parts of 0.5% NaCl and 1 part of human blood serum. Incubation at 10-15°C. E. invadens. — Ratcliffe and Geiman (1938) used a mixture of gastric mucin 0.3 gm., "ground alum" salt 0.5 gm., and distilled water 100 cc. About 2 mg. of sterile rice starch is added to each cul- ture tube at the time of inoculation. Culture at 20-30° C. and sub- culture every 7 days. E. histolytica and other amoebae of man. — The first successful cul- COLLECTION, CULTIVATION, OBSERVATION 717 ture was made by Boeck and Drbohlav (1925) who used the follow- ing media. (a) Locke-egg-serum (LES) medium. The contents of 4 eggs (washed and dipped in alcohol) are mixed with, and broken in, 50 cc. of Locke's solution in a sterile flask with beads. The solution is made up as follows: NaCl 9 gm. CaCl2 0.2 gm. KCl 0.4 gm. NaHCOa 0.2 gm. Glucose • 2.5 gm. Distilled water 1000 cc. The emulsion is now tubed so that when coagulated by heat, there is 1-1.5 inches of slant. These tubes are now slanted and heated at 70°C. until the medium becomes solidified. They are then autoclaved for 20 minutes at 15 pounds pressure (temperature must be raised and lowered slowly). After cooling the slant is covered with a mix- ture of 8 parts of sterile Locke's solution and 1 part of sterilean- activated human blood serum. The tubes are next incubated to determine sterility. The culture tubes are inoculated with a small amount of faecal matter containing active trophozoites. Incubation at 37°C. Yorke and Adams (1926) obtained rich cultures by inocu- lating this medium with washed and concentrated cysts of E. his- tolytica in 24 hours. (b) Locke-egg-albumin (LEA) medium. The serum in LES medium is replaced by 1% solution of crystallized egg albumin in Locke's solution which has been sterilized by passage through a Berkefeld filter. Dobell and Laidlaw (1926) used Ringer's solution instead of Locke's. (c) Ringer-egg-serum (RES) or Ringer-egg-albumin (REA) me- dium. Solid medium is the same as that of (a) or (b), but made up in Ringer's solution which is composed of NaCl 9 gm. KCl 0.2 gm. CaCla 0.2 gm. Distilled water 1000 cc. The covering liquid is serum-Ringer or egg-albumin. The latter is prepared by breaking one egg white in 250 cc. of Ringer's solution 718 PROTOZOOLOGY which is passed through a Seitz filter. Before inoculating with amoe- bae, a small amount of sterile solid rice-starch (dry-heated at 180°C. for 1 hour) is added to the culture tube. (d) Horse-serum-serum (HSS) or Horse-serum-egg-albumin (HSA) medium. Whole horse-serum, sterilized by filtration, is tubed and slanted at 80°C. for about 60-70 minutes (do not heat longer). When the slants have cooled, they are covered with diluted serum or egg-albumin given for (c). The tubes are incubated for sterility and sterile rice-starch is added immediately before inoculation. Frye and Meleny (1939) substituted the liquid portion of this medium by 0.5% solution of Lily liver extract No. 343 in 0.85% NaCl. (e) Liver-agar-serum (LAS) medium. Cleveland and Sanders (1930) used the following medium: Liver infusion agar (Difco dehydrated) 30 gm. Glass distilled water 1000 cc. The medium is tubed, autoclaved, and slanted. The slants are cov- ered with a 1 :6 dilution of sterile fresh horse serum in 0.85% NaCl solution. A 5 mm. loop of sterile rice flour or powdered unpolished rice is added to each tube. In making subculture, remove 2 or 3 drops of the rice flour debris from the bottom with a sterile pipette. Plasmodium.— BsLSS and John's (1912) culture is as follows: 10 cc. of defibrinated human blood containing Plasmodium and 0.1 cc. of 50% sterile dextrose solution are mixed in test tubes and incubated at 37-39°C. In the culture, the organisms develop in the upper layer of erythrocytes. Although several attempts have since been made by several workers, Plasmodium has not been cultivated in vitro for more than a few generations. Balantidium coli. — Barret and Yarb rough (1921) first cultivated this ciliate in a medium consisting of 16 parts of 0.5% NaCl and 1 part of inactivated human blood serum. The medium is tubed. Inoculation of a small amount of the faecal matter containing the trophozoites is made into the bottom of the tubes. Incubation at 37°C. Maximum development is reached in 48-72 hours. Subcul- tures are made every second day. Reese used a mixture of 16 parts of Ringer's solution and 1 part of Loeffler's dehydrated blood serum. Atchley (1935) employed a medium composed of 4 parts of Ringer's solution and 1 part of faeces, which is filtered after 24 hours, centri- fuged and sterilized by passage through a Seitz filter. Nelson (1940) also used 1 part of caecal contents of pig in 9 parts of Ringer's solu- COLLECTION, CULTIVATION, OBSERVATION 719 tion, which mixture is passed through a sieve and then filtered through a thick absorbent cotton. Balantidium which shows posi- tive geotropism, is freed of faecal debris by passage downward through cotton in V-tube. The ciliates are introduced into the cul- ture tubes. Incubation at 37°C. Subcultures are made every 7-22 days. Nelson found that autoclaved medium is unsuitable until a living bacterial population has been established. Balantidium can also be cultivated in the media given for the intestinal amoebae. Microscopical examination Protozoa should be studied as far as possible in life. Permanent preparations while indispensable in revealing many intracellular structures, cannot replace fresh preparations. The microscopic slides of standard size, 3" by 1", should be of white glass and preferably thin. The so-called No. 1 slides measure about 0.75 mm. in thickness. For darkfield illumination thin slides are essential. No. 1 coverglasses should be used for both fresh and permanent preparations. They are about 130-1 70m thick. The most convenient size of the coverglass is about 7/8 square inch which many prefer to circular ones. The slides and coverglasses must be thoroughly cleaned before being used. Immerse them in concentrated mineral acids (nitric acid is best fitted) for 10 minutes. Pour off the acid, wash the slides and coverglasses for about 10 minutes in running water, rinse in distilled water, and keep them in 95% alcohol. When needed they are dried one by one with clean cheese cloth. Handle slides and covers with a pair of forceps. If thumb and fingers are used, hold them edgewise. A. Fresh preparations In making fresh preparations with large Protozoa care must be ex- ercised to avoid pressure of the coverglass on the organisms as this will cause deformities. If small bits of detritus or debris are included in the preparation, the coverglass will be supported by them and the organisms will not be subjected to any pressure. Although ordinary slides are used most frequently, it is sometimes advisable to use a depression slide especially for prolonged observation. To make a preparation with this slide, a small drop of water containing speci- mens is placed in the center of a coverglass, and is covered by a small circular coverglass (about 1 cm. in diameter), which in turn is cov- ered by a depression slide with a thin coat of vaseline along the edge of the depression, so as to make an air-tight compartment. In turning over the whole, care must be taken to prevent the smaller circular 720 PROTOZOOLOGY cover from touching any part of the sUde, as this would cause the water to run down into the depression. Nemeczek (1926) seems to have been the first one who used the second coverglass for this prepa- ration. If the Protozoa to be examined are large and observation can be made under a low power objective, the small coverglass should be omitted. As far as possible examine fresh preparations with low power ob- jectives. The lower the magnification, the brighter and the larger the field. The microscopical objects can quickly and easily be measured, if an ocular micrometer division has been calculated in combination with different objectives. For observation of cilia, flagella, extruded polar filament of Micro- sporidia, etc., the so-called changeable condenser is useful, since it gives both bright and dark fields under dry objectives. The ordinary dark field condenser is used almost exclusively in conjunction with an oil immersion objective and therefore for very active organisms a great deal of time is often lost before satisfactory observation is made. When treated with highly diluted solutions of certain dyes, living Protozoa exhibit some of their organellae or inclusions stained with- out apparent injury to the organisms. These vital stains are usually prepared in absolute alcohol solutions. A small amount is uniformly applied to the slide and allowed to dry, before water containing Pro- tozoa is placed on it. Congo red (1 : 1,000) is used as an indicator, as its red color of the salt changes blue in weak acids. Janus Green B (1:10,000-20,000) stains chondriosomes. Methylene blue (1:10,000 or more) stains cytoplasmic granules, nucleus, cytoplasmic processes, etc., Neutral red (1:3,000-30,000) is an indicator: yellowish red (alkaline), cherry red (weak acid), and blue (strong acid). It also stains nucleus slightly. Golgi bodies are studied in it, though its specificity for this structure is not clear. Parasitic Protozoa should be studied in the tissue or body fluids in which they occur. When they are too small in amount to make a suitable preparation, one of the following solutions may bq used. Physiological salt solution. Widely used concentrations of NaCl solutions are 0.5-0.7% for cold-blooded animals and 0.8-0.9% for warm-blooded animals. Ringer's solution. The one Dobell advocated has been given al- ready (p. 717). Another frequently used solution consists of NaCl 0.8 gm. KCl 0.02 gm. CaCl2 0.02 gm. COLLECTION, CULTIVATION, OBSERVATION 721 (NaHCOs 0.02 gm.) Glass distilled water 100 cc. For demonstrating organellae, the following reagents which kill the Protozoa upon application, may be used on living Protozoa. Lugol's solution. This is made up of potassium iodide 1.5 gm., water 25 cc, and iodine 1 gm. The solution deteriorates easily. Flagella and cilia stain clearly. Glycogen bodies stain ordinarily red- dish brown. Cysts of intestinal Protozoa are more easily studied in Lugol's solution. Sudan III and IV. 2% absolute alcohol solution diluted before use with the same amount of 45% alcohol. Neutral fats are stained red. Methyl green. 1% solution in 1% acetic acid solution makes an excellent nuclear stain. Nigrosin. 10% solution if used in smears and air-dried makes the pellicular patterns of flagellates and ciliates stand out clearly. In the case of faecal examination if the stool is dysenteric, a small portion is placed by a tooth-pick or platinum loop on a slide and covered with a cover glass. Before placing the cover, all large parti- cles must be removed quickly so that the smear will be uniformly thin. Smears of diarrhoeic stools can be made in a similar way. But if the faecal material is formed or semiformed, a small drop of warm (37°C.) 0.85% NaCl solution is first placed on the slide, and a small portion of the faeces, particularly mucus, pus or blood, is emulsified in it. The whole is covered by a coverglass. The faecal smear should not be too thick or too thin for a satisfactory observation. If the smear is too thick, it will be impossible to distinguish objects clearly, and on the other hand, if it is too thin, there will be much time lost in observing widely scattered Protozoa. The optimum thickness of the smear is one through which the print of this page can be read. The success in faecal examination for intestinal Protozoa depends almost entirely on continued practice, since the faecal matter con- tains myriads of objects which may resemble Protozoa. Aside from certain coprozoic Protozoa (p. 21) which appear in old faeces, Blastocystis hominis (Fig. 335, 3-6) occur in almost all faeces. This organism which is considered to be a fungus and harmless to its host, is usually spherical and measures about 5-25/i in diameter. Within a very thin membrane, there is a narrow peripheral cytoplasmic layer in which 1 or 2 nuclei and several refractile granules are present. The cytoplasmic ring encloses a large homogeneous body which is some- what eosinophile, but not iodinophile. In some the cytoplasm may be 722 PROTOZOOLOGY more abundant and the inclusion body smaller. Dividing forms ap- pear peanut-shaped. In a number of parasitic Protozoa, there occur foreign organ- isms which may be mistaken for food inclusions or chromatin. They are vegetable organisms which were named by Dangeard as Sphaerita and Nucleophaga (Fig. 335, 1,2). The former occurs in the cytoplasm and the latter in the nucleus of the host protozoan. These parasites are spherical and about 0.5-1^ in diameter; they are found most frequently in spherical masses composed of vary- ing numbers of individuals. Nucleophaga appears to destroy the host nucleus. Degenerating epithelial cells or leucocytes (Fig. 335, 7, 8) may simulate parasitic amoebae. Fishes and birds are often in- fected by Coccidia and when they are consumed as food, the oocysts pass the alimentary canal unchanged and appear ,in the stools. The cysts of intestinal Protozoa are, as a rule, distributed through- out the formed faeces and difficult to detect in small portions of the voided specimens. Flecks of mucus in the fluid stool obtained by use of a saline purge may contain more numerous cysts than naturally passed one. Several methods for concentrating cysts for microscopi- cal examination are known. The simplest one is to emulsify thor- oughly a small mass of faeces about the size of a lump sugar in a mortar by adding a small amount of once-boiled tap water. Add to it about 500 cc. of water and pour the whole emulsion into a glass cylinder, and let it stand for about 15 minutes. Remove the scum floating on the surface and draw off the turbid fluid into another cylinder, leaving the sediment and a little fluid just above it un- touched. The majority of cysts are suspended in the drawn-off por- tion of the emulsion. Centrifuge the fluid, pour off the supernatant fluid and add water. Centrifuge again. Repeat this three times until the supernatant fluid becomes clear. The sediment will be found to contain more numerous cysts than small sample specimens. B. Permanent preparations Permanent preparations are employed, as was stated before, to supplement, and not to supplant, fresh preparations. Smear prepa- rations are more frequently studied, while section preparations are indispensable in extensive studies of Protozoa. a. Smear preparations Smears are made either on coverglasses or slides. However, cover- glass-smears are more properly fixed and require smaller amount of reagents than slide-smears. Greater care must be excerised in han- COLLECTION, CULTIVATION, OBSERVATION 723 dling coverglasses, as they are easily broken. Large free-living Protozoa do not frequently adhere to the glass, since there is not enough albuminous substance in the culture fluid. If a small drop of fresh egg-white emulsified in sterile distilled water is smeared on the coverglass very thinly with the tip of a clean finger, before mounting material for smear, more specimens will adhere to and remain on the %^ O J Q) C3 % Fig. 335. 1, Sphaerita in a stained trophozoite of Entamoeba coli; 2, Nucleophaga in a stained trophozoite of lodamoeha butschlii; 3, 4, fresh specimens of Blastocystis hominis; 5, 6, stained Blastocystis hominis; 7, an epithelial cell found in faeces; 8, a polymorphonuclear with three ingested erythrocytes. X1150 (Kudo). coverglass upon the completion of the preparation. Let the smear lie horizontally for 5-10 minutes or longer. Parasitic Protozoa live in media rich in albuminous substances, and therefore, easily adhere to the coverglass in smear. Make uni- formly thin smears on coverglasses. If the smears are made from dysenteric or fluid stools, they should be fixed almost immediately. Smears made from diarrhoeic or formed stools by emulsifying in warm salt solution, should be left for a few minutes. In any case, do not let the smear become dry except a narrow marginal zone. The smears are fixed next. The most commonly used fixative for Protozoa is Schaudinn's fluid. This is made up as follows: Cold saturated mercuric bichloride (6-7%) 66 cc. Absolute or 95% alcohol 33 cc. Glacial acetic acid 1 cc. The first two can be kept mixed without deterioration, but the acid must be added just before fixation. Fix at room temperature or 724 PROTOZOOLOGY warmed to 50°C. The fixative is placed in a square Petri dish and the smear is gently dropped on it with the smeared surface facing down- ward. With a little experience, air bubbles can be avoided and make the smear float on the surface of the fixative. After about one minute, turn it around and let it stay on the bottom of the dish for 5 to 10 more minutes. In case the smear is too thick, a thin coat of vaseline on the upper side of the coverglass will make it to float. About six coverglass-smears may be fixed in the dish simultaneously. The coverglass-smears are now transferred to a Columbia staining jar for coverglasses, containing 50% alcohol for 10 minutes, followed by two changes for similar length of time. Transfer the smears next to 30% alcohol for 5 minutes, and then to a jar with water, which is now placed under gently running tap water for 15 minutes. Rinse them in distilled water and stain. Other fixatives frequently used for Protozoa are as follows: Bouin's fluid Picric acid (saturated) 75 cc. Formaldehyde 25 cc. Glacial acetic acid 5 cc. Fixation for 5-30 minutes; wash with 70% alcohol until picric acid is completely washed away from the smears. Sublimate-acetic Saturated sublimate solution 100 cc. Glacial acetic acid 2 cc. This is the original fixative for Feulgen's nucleal reaction (p. 726). Fixation and after-treatment similar to Schaudinn's fluid. Carney's fluid Absolute alcohol 30 cc. Glacial acetic acid 10 cc. Fixation for 5-30 minutes; wash in 95% alcohol. Osmium tetroxide The vapor from or the solution itself of 1% Osmium tetroxide may be used. Fixation in 2-5 minutes; wash in running water. Flemming's fluid 1% chromic acid 30 cc. 2% osmium tetroxide 8 cc. Glacial acetic acid 2 cc. COLLECTION, CULTIVATION, OBSERVATION 725 Fixation for 10-50 minutes; wash for one hour or longer in running water. The most commonly used stain is Heidenhain's iron haematoxy- lin, as it is dependable and gives a clear nuclear picture, although it is unsatisfactory for voluminous organisms or smears of uneven thickness. It requires a mordant, ammonio-ferric sulphate (iron alum) and a dye, haematoxylin. Crystals of iron alum become yellow and opaque very easily. Select clear violet crystals and prepare 2% aqueous solution. Haematoxylin solution must be well "ripe." The most convenient way of preparing it is to make 10% absolute alcohol solution. By diluting this stock solution with distilled water, pre- pare 0.5 or 1% slightly alcoholic solution which will be ready for immediate and repeated use. Smears are left in the mordant in a jar for 1-3 hours or longer. Wash them with running water for 5 min- utes and rinse in distilled water. Place the smears now in haematoxy- lin for 1-3 hours or longer. After brief washing in water, the smears are decolorized in Petri dish in a diluted iron alum, 0.5% HCl in wa- ter or 50% alcohol, or saturated aqueous solution of picric acid under the microscope. Upon completion, the smears are washed thor- oughly in running water for about 30 minutes. Rinse them in dis- tilled water. Transfer them through ascending series of alcohol (50 to 95%). If counter-staining with eosin is desired, dip the smears which were taken out from 70%, alcohol, in 1% eosin in 95% alcohol for a few seconds, and then in 95% plain alcohol. After two passages through absolute alcohol and through xylol, the smears are mounted one by one on a slide in a small drop of mixture of Canada balsam and xylol. The finished preparations are placed in a drying oven at about 60°C. for a few daj^s. Other stains that are often used are as follows : Delafield's haematoxylin. If the stock solution is diluted to 1:5- 10, a slow, but progrcvssive staining which requires no decolorization may be made; but if stock solution is used, stain for 1-16 hours, and decolorize in 0.5% HCl water or alcohol. If mounted in a neutral mounting medium, the staining remains true for a long time. Mayer's paracarmine. In slightly acidified 70% alcohol solution, it is excellent for staining large Protozoa. If over-stained, decolorize with 0.5% HCl alcohol. Giemsa's stain. Shake the stock solution bottle well. By means of a stopper-pipette dilute the stock with neutral distilled water (5-10 drops to 10 cc). Smears fixed in Schaudinn's fluid and washed in neutral distilled water are stained in this solution for 10 minutes to 726 PROTOZOOLOGY 6 hours to overnight. Rinse them thoroughly in neutral distilled water and transfer them through the following jars in order (about 5 minutes in each): (a) acetone alone; (b) acetone: xylol, 8:2; (c) acetone : xylol, 5:5; (d) acetone : xylol, 2:8; (e) two changes of xylol. The smears are now mounted in cedar wood oil (which is used for immersion objectives) and the preparations should be placed in a drying oven for a longer time than the balsam-mounted prepara- tions. Feulgen's nucleal reaction. The following solutions are needed. (a) HCl solution. This is prepared by mixing 82.5 cc. of HCl (spe- cific gravity 1.19) and 1000 cc. of distilled water. (b) Fuchsin-sodium bisulphite. Dissolve 1 gm. of powdered fuchsin (basic fuchsin, diamant fuchsin or parafuchsin) in 200 cc. of distilled water which has been brought to boiling point. After frequent shak- ing for about 5 minutes, filter the solution when cooled down to 50°C. into a bottle and add 20 cc. HCl solution. Cool the solution further down to about 25°C. and add 1 gm. of anhydrous sodium bisulphite. Apply stopper tightly. Decolorization of the solution will be com- pleted in a few hours, but keep the bottle in a dark place for at least 24 hours before using it. (c) Sulphurous water. Distilled or tap water 200 cc. 10% anhydrous sodium bisulphite 10 cc. HCl solution (a) 10 cc. Feulgen's reaction is used to detect thymonucleic acid, a constitu- ent of chromatin. By a partial hydrolysis, certain purin-bodies in the acid are split into aldehydes which show a sharp Schiff's reaction upon coming in contact with fuchsin-sodium bisulphite. Thus this is a reaction, and not a staining method. Smears fixed in sublimate- acetic or Schaudinn's fluid are brought down to running water, after being placed for about 24 hours in 95% alcohol. Immerse them in cold HCl for one minute, then place them in HCl kept at 60°C. (over a microburner or in an incubator) for 5 minutes, quickly immerse in cold HCl. After rapidly rinsing in distilled water, place the smears in solution (b) for 30-minutes to 3 hours. There is no overstaining. The smears are then washed in three changes (at least 2 minutes in each) of solution (c). Wash them in running water for 30 minutes. If counterstaining is desired, dip in 0.1% light green solution and rinse again in water. The smears are now dehydrated through a series of alcohol in the usual manner and mounted in Canada balsam. COLLECTION, CULTIVATION, OBSERVATION 727 Silver-impregnation methods. Since Klein (1926) applied silver nitrate in demonstrating the silver-line system of ciliates, various modifications have been proposed. Dry silver method (Klein, 1926). Air-dried cover glass smears are placed for 6-8 minutes in a 2 per cent solution of silver nitrate and thoroughly washed. The smears are exposed to sunlight for 2-8 hours in distilled water in a white porcelain dish, with occasional control under the microscope. The smears are then washed thoroughly and air-dried; finally mounted in Canada balsam. Wet silver method (modified after Gelei and Horvath, 1931). The ciliates are fixed in a centrifuge tube for 5-10 minutes in sublimate- formaldehyde solution, composed of saturated corrosive sublimate 95 cc. and formaldehyde 5 cc. The specimens are now washed twice in nonchlorinated water and once in distilled water; they are then treated in 1.5-2 per cent solution of silver nitrate for 5-20 minutes. Without washing, the specimens in the tube are exposed to direct sunlight for 10-60 minutes in distilled water, after which the speci- mens are washed 4-6 times in distilled water, one minute each. Pass- ing through a gradually ascending alcohol series and xylol, the speci- mens are mounted in Canada balsam. Fontana's method. For staining filamentous structures such as the extruded polar filament of microsporidian spores, this method is the most satisfactory one. After air-drying the smears are fixed for 5 minutes in a mixture of formaldehyde, 20 cc; glacial acetic acid, 1 cc; and distilled water, 100 cc After washing in running water, the smears are placed in the following mordant composed of equal parts of 5 per cent tannic acid and 1 per cent carbolic acid, for about 2 minutes at about 60°C. Wash the smears in water and place them for 3-5 minutes in 0.25 per cent solution of silver nitrate warmed to 60°C., to which ammonia has been added drop by drop until a gray- ish brow n cloud appeared. Wash thoroughly and air-dry. After pass- ing through 95 per cent and absolute alcohol, and xylol, the smears are mounted in Canada balsam b. Blood film preparations Thin film. The finger tip or ear lobe is cleaned with 70% alcohol. Prick it with an aseptic blood lancet or a sterilized needle. Wipe off the first drop with gauze and receive the second drop on a clean slide about half an inch from one end (Fig. 336, 1). Use care not to let the slide touch the finger or ear-lobe itself. Quickly bring a second slide, one corner of which had been cut away, to the inner margin of the blood drop (i), and let the blood spread along the edge of the second 728 PROTOZOOLOGY slide. Next push the second shde over the surface of the first shde at an angle of about 45° toward the other end (2). Thus a thin film of blood is spread over the slide (3). Let the slide lie horizontally and dry, under a cover to prevent dust particles falling on it and to keep away flies or other insects. If properly made, the film is made up of a single layer of blood cells. Thick films. Often parasites are so few that to find them in a thin film involves a great deal of time. In such cases, a thick film is advo- FiG. 336. Diagrams showing how a thin blood film is made on a slide. cated. For this, 4 to 6 drops of blood are placed in the central half- inch square area, and spread them into an even layer with a needle or with a corner of a slide. Let the film dry. With a little practice, a satisfactory thick smear can be made. It will take two hours or more to dry. Do not dry by heat, but placing it in an incubator at 37°C. will hasten the drying. When thoroughly dry, immerse it in water and dehaemoglobinize it. Air dry again. Thin and thick film. Often it is time-saving if thin and thick films are made on a single slide. Place a single drop of blood near the center COLLECTION, CULTIVATION, OBSERVATION 729 and make a thin film of it toward one end of the sUde. Make a small thick smear in the center of the other half of the slide. Dry. When thoroughly dry, immerse the thick film part in distilled water and de- haemoglobinize it. Let the slide dry. Blood smears must be stained as soon as possible to insure a proper staining, as lapse of time or summer heat will often cause poor stain- ing especially of thick films. Of several blood stains, Giemsa's and Wright's stains are used here. For staining with Giemsa's stain, the thin film is fixed in absolute methyl alcohol for 5 minutes. Rinse well the slide in neutral distilled water. After shaking the stock bottle (obtained from reliable makers) well, dilute it with neutral distilled water in a ratio of one drop of stain to 1-2 cc. of water. Mix the solu- tion and the blood film is placed in it for 0.5-2 hours or longer if needed. Rinse the slide thoroughly in neutral distilled water and wipe off water with a tissue paper from the underside and edges of the slide. Let the slide stand on end to dry. When thoroughly dry, place a drop of xylol and a drop of cedar wood oil (used for immersion objectives) and cover with a coverglass. The mounting medium should be absolutely neutral. Do not use Canada balsam for mount- ing, as acid in it promptly spoils the staining. For Wright's stain, fixation is not necessary. With a medicine dropper, cover the dried blood film with drops of undiluted Wright's stain, and let the film stand horizontally for 3-5 minutes; then the same number of drops of neutral distilled water is added to the stain and the whole is left for 10-30 minutes. The stain is then poured off and the film is rinsed in neutral distilled water. Dry. Mount in xylol and cedar wood oil. Use of coverglass on a stained blood film is advocated, since a cedar wood oil mounted slide allows the use of dry objectives which in the hand of an experienced worker would give enough magnifica- tion for species determination of Plasmodium, and which will very clearly reveal any trypanosomes present in the film. Furthermore, the film is protected against scratches, and contamination by many objects which may bring about confusion in detecting looked-for organisms. Films made from splenic punctures for Leishmania or Trypano- soma are similarly treated and prepared. c. Section preparations Paraffin sections should be made according to usual histological technique. Fixatives and stains are the same as those mentioned for smear preparations. 730 PROTOZOOLOGY References Bela^, K. 1928 Untersuchung der Protozoen. Methodik d. wiss. Biologie, Vol. 1. Bland, P. B., L. Goldstein, D. H. Wenrich and E. Weiner 1932 Studies on the biology of Trichomonas vaginalis. Amer. Jour. Hyg., Vol. 16. BoECK, W. C. and J. Drbohlav 1925 The cultivation of End- amoeba histolytica. Amer. Jour. Hyg., Vol. 5. Claff, C. L. 1940 A migration-dilution apparatus for the steriliza- tion of Protozoa. Physiol. Zool., Vol. 13. Cleveland, L. R. and Elizabeth P. Sanders 1930 Encystation, multiple fission without encystment, excystation, metacystic development, and variation in a pure line and nine strains of Entamoeba histolytica. Arch. f. Protistenk,, Vol. 70. DoBELL, C. and P. P. Laidlaw 1926 On the cultivation of Ent- amoeba histolytica and some other entozoic amoebae. Parasitol- ogy, Vol. 18. Gatenby, J. B. and T. S. Painter 1937 The microtomist's vade mecum (Bolles Lee). London. Glaser, R. W. and N. A. Coria 1930 Methods for the pure culture of certain Protozoa. Jour. Exp. Med., Vol. 51. Hahnert, W. F. 1932 Studies on the chemical needs of Amoeba proteus: a cultural method. Biol. Bull., Vol. 62. Kidder, G. W. 1941 Growth studies on ciliates. VIL Biol. Bull, Vol. 80. Kudo, R. R. 1944 Manual of human Protozoa. Springfield, Illinois. Needham, J. G., P. S. Galtsoff, F. E. Lutz and P. S. Welch 1937 Culture methods for invertebrate animals. Ithaca, New York. Ratcliffe, H. L., and Q. M. Geiman 1938 Spontaneous and ex- perimental amebic infection in reptiles. Arch. Path., Vol. 25. Reyer, W. 1939 Ueber die Vermehrung von Blastocystis in der Kultur. Arch. f. Protistenk., Vol. 92. Taylor, C. V. and W. J. Van Wagtendonk 1941 Growth studies of Colpoda duodenaria. I. Sterilization of the ciliates. Physiol. Zool., Vol. 14. Wenyon, C. M. 1926 Protozoology. Vol. 2. Author and Subject Index Numbers in bold-face type indicate pages on which are given the defini- tions, explanations, or discussions of technical terms; the characterizations or differentiations of taxonomic subdivisions; or the descriptions of genera and species. Numbers in italics indicate pages on which appear those illustrations that could not be placed on the same pages as the related text matter. A Actinocephalidae, 441, 452-455 Actinocephalus, 452 acutispora, 450, 452 parvus, 140, 452 Actinocoma, 407 ramosa, 408 Actinocomidae, 407-408 Actinolophus, 410 pedunculatus, 410, 4^^ Actinomonas, 44, 195, 265 mirabilis, 265 Actinomyxidia, 65, 515, 531-533 Actinophryidae, 407, 408-409 Actinophrys, 19, 42, 86, 135, 408, 714 sol, 140, 164, 166, 168, 408-409 vesiculata, 409 Actinopoda, 328, 406-425 Actinosphaerium, 11, 34, 37, 42, 86, 90, 99, 409, 714 arachnoideum, 409 eichhorni, 37, 44, 164, 170, 408, 409 Actinotricha, 669 Actinozoa, 631 Actipylea, 418, 419, 420-421 Acutispora, 449 macrocephala, 448, 449 Adams, 358, 359, 717 Adaptability of Protozoa, 18, 29-30 Adelea, 70, 477 ovata, 140, 152, 477, 478 Adeleidae, 477-480 Adeleidea, 464, 477-482 AdeUna, 477 deronis, 140, 166, 479 dimidiata, 478, 479 odospora, 478, 479 Adler, 282 Adoral membranellae, 51, 54 zone, 49, 51 Aedes, 490, 495, 497 aegypti, 430, 438 albopichis, 438 Aegyria, 586 Aeschna constricta, 455 Aethalium septicum, 91 African Coast fever, 505 Agarella, 529 gracilis, 529 Aggregata, 70, 131, 145, 146 eherthi, 140, 152, 166, 466-467 Abderhalden, 94 Abiogenesis, 11 Acanthamoeba, 350 castellanii, 349, 350 hyalina, 21, 349, 350-351 Acanthociasma, 420 plamirn, 421 Acanthociasmidae, 420 Acanthocystidae, 407, 412-414 Acanthocystis, 22, 42, 136, 145, 412 aculeata, 23, 131, 412, 413 Acanthodactylus vulgaris, 477 Acanthometridae, 420 Acanthometron, 420 elasticum, 54, 4^1 Acanthoma, 420 tetracopa, 421 Acanthoniidae, 420 Acanthospora, 451 polymorpha, 450, 451 Acanthosporidae, 441, 451-452 Acariia clausi, 256, 636 Acephahna, 431-440 Achlya glomerata, 341 Achromatic figure, 35, 133, 134, 135, 141 Acidified methylgreen on nucleus, 35 Acineta, 700 caspidata, 701, 702 lacustris, 701 papillifera, 629 tuberosa, 700, 702, 704 Acinetaria, 695 Acinetidae, 695, 700-706 Acinetopsis, 703 tentaculata, 703, 704 Acis, 451 Acrnaea persona, 626 Acnidosporidia, 196, 427, 507-513 Actineliidae, 420 Actinelius, 420 primordialis, 421 Actinia equina, 630 mesembryanthemum, 630 Actinobolina, 566 borax, 566, 567 ActinoboUnidae, 560, 566-567 Actinobolus, 566 731 732 PROTOZOOLOGY Aggregatidae, 465, 466-469 Aging in Protozoa, 166-170 Agriodrilus, 559 Agriolimax agrestis, 30, 601 Agrion puella, 447 Ahlstrom, 228 Aikinetocystidae, 431, 434 Aikinetocystis, 434 singularis, 434, 435 Akaryomastigont, 315 Alasmidonta undulata, 624 Albertisella, 436 crater, 436 Alexeieff, 130 Algae, 91, 92, 329, 330, 331, 333, 709 Alisma, 342 AUantocystidae, 431, 440 Allantocystis, 440 dasyhelei, 439, 440 Allantosoma, 705 brevicorniger, 705, 707 dicorniger, 705, 707 intestinalis, 705, 707 AUegre, 236 Allman, 65 AUogromia, 374 AUoiozona, 578 trizona, 578 Allolobophora caliginosa, 557 AUomorphina, 404 trigona, 404 AUosphaerium, 590 caudatum, 590 convexa, 127, 590 granulosum, 590 palustris, 589, 590 sulcatum, 590 Allurus tetraedurus, 557 Aloricata, 683-689 Alveolinella, 400 mello, 399 Alveolinellidae, 400 Amara axigustata, 452 Amaroucium, 459 Amaurochaete, 339 fuliginosa, 339 Amaurochaetidae, 339 Amberson, 102 Ambystoma tigrinum, 549 Ameuirus albidus, 568 Amiba, 345 Amitosis, 122-130 Ammodiscidae, 398 Ammodiscus, 398 incertus, 397, 398 Amoeba, 6, 18, 19, 90, 91, 114, 115, 116, 117, 176,345,713 discoides, 105, 345, 346 dofleini, 87 dubia, 44, 87, 90, 91, 105, 345, 346 gorgonia, 347, 348 guttula, 42, 346 Amoeba — continued limicola, 346, 347 meleagridis, 266 mira, 104 proteus, 24, 42, 44, 52, 69, 70, 72, 87, 88, 90, 92, 94, 103, 105, 107, 108, 109, 110, 141, 142, 143, 170, 345,34^,713 radiosa, 18, 42, 87, 347, 348 spumosa, 347-348 striata, 39, 42, 73, 345-346 verrucosa, 18, 21, 22, 39, 103, 105, 106, 107, 170, 345, 346 vespertilio, 347, 348 Amoebiasis, 355, 357, 365 Amoebic dysentery, 354, 357, 364 Amoebidae, 343, 344, 345-351 Amoebina, 195, 329, 343-371 Amoebodiastase, 91 Amoeboid movements, 106-110, 114, 328 Amphacanthus, 655 ovum-rajae, 655, 656 Amphibia, 25, 239, 267, 279, 299, 301, 313, 365, 367, 473, 475, 476, 480, 505, 521, 527, 547, 548, 549, 550, 555, 685, 692 Amphidinium, 253 fusiforme, 253 lacustre, 21, 253, 253 scissum, 252, 253 Amphileptidae, 580-582 Amphileptus, 23, 65, 580 branchiarum, 580, 581 claparedei, 21, 580, 581 meleagris, 580 Amphilonche, 421 hydrometrica, 421 Amphilonchidae, 420 Amphimonadidae, 268, 285-287 Amphimonas, 285 globosa, 285, 286 Amphimixis, 161 Amphionts, 436 Amphioxus, 608 Amphipoda, 630 Amphisiella, 670 thiophaga, 669, 670 Amphisteginidae, 403 Amphitrema, 388 flavum, 387, 388-389 Amphiura squamata, 634 Amphizonella, 382 violacea, 382 Amphorocephalus, 454 amphorellus, 453, 454 Amphoroides, 452 calverti, 450, 452 AmpuUacula, 578 ampulla, 578 Anabolic products, 98-101 Anacharis, 701 Anal cirri, 49, 50, 51 AUTHOR AND SUBJECT INDEX 733 Anarma, 705 multiruga, 705, 706 Anas p. platyrhyncos, 501 rubripes tristis, 501 Anaspides tasmaniae, 440 Ancistrella, 627 choanomphali 627, 628 Ancistrina, 626 ovata, 627 Ancistrodon mokasen, 365 Ancistrospira, 628 veneris, 628 Ancistrum, 626 Ancistruma, 56, 626 isseli, 141, 625, 626 mytili, 58, 625, 626 Ancistrumidae, 623, 626-628 Ancyromonas, 272 contorta, 272 Ancyrophora, 451 gracilis, 450, 451-452 Anderson, 283 Anderotermone, 151 Andrews, 648 Anemonia sulcata, 630 Angeiocystis, 469 audouiniae, 469 Angerer, 345 Anguilla vulgaris, 280 Anisogametes, 150, 154 Anisogamy, 150, 151, 152, 153, 464, 467 Anisolobus, 445 dacnecola, 445, 446 Anisonema, 241 acinus, 240, 241 emarginatum, 240, 241 truncatum, 240, 241 Anisonemidae 230, 241-243 Annelida, 431, 432, 433, 434, 435, 436, 437, 438, 439, 441, 442, 460, 461, 462, 468, 469, 478, 479, 511, 512, 513, 531, 532, 533, 541, 542, 552, 554, 557, 558, 559, 625, 626, 685, 698 Annulus, 245 Anodonta, 618 catarecta, 624 implicata, 624 marginata, 624 Anomalina, 404 punctulata, 404 Anomalinidae, 404 Anopheles, 7, 8, 490, 539 alhimanus, 490 crucians, 490 gambiae, 490 macidipennis, 490 pseudopunctipennis, 490 punctipennis, 490 quadrimaculatus, 490, 491, 499, 537 walkeri, 490 Anophrys, 196, 605 aglycus, 604, 605 elongata, 604, 605 Anoplophrya, 552 marylandensis, 552, 553 orchestii, 552, 553 Anoplophryidae, 552-559 Antelope, 656, 657, 659 Anthophysa, 288 Anthophysis, 11, 65, 146, 287, 288- 289 vegetans, 139, 288, 289 Anthropoid apes, 495, 639, 660, 663 Anthorhynchus, 454 sophiae, 453, 454 Anurosporidium, 513 pelseneeri, 513 Aphrydium versatile, 699 Apis mellifica, 365, 537 Apocynaceae, 281 Apodinium, 255-256 mycetoides, 255, 256 Apolocystis, 432 gigantea, 432, 433 minuta, 432, 433 Apomotis cyanellus, 523 Apostomea, 57, 551, 630-635 Arachnida, 454, 482 Arachnula, 332-333 impatiens, 332, 333 Aragao, 500 Arboroid colony, 146 Arcella, 21, 40, 44, 143, 170, 378, 714 artocrea, 379, 380 caiinus, 379 dentata, 178, 379-380 discoides, 379 mitrata, 379 polypora, 178 vulgaris, 37, 38, 378-379 var. angulosa, 379 gibbosa, 379 Arcellidae, 374, 378-384 Archoterrnopsis wroughtoni, 310, 322 Arcichovskij, 38 Arcyria, 340 punicea, 339 Arcyriidae, 340 Arenicola ecaudata, 438 Argentophilous substance, 48, 69 Armadillos, 277 Arndt, 131 Arsenic acid, 180 Artificial digestion, 35 Artodiscus, 376 saltans, 375, 376 Ascaris, 368 Ascartia, 554 Ascidian, 459 Asclepiadaceae, 281 Ascoglena, 237 vaginicola, 237, 238 Ascorbic acid, 98 Asellus aquaticus, 687, 699 734 PROTOZOOLOGY Asexual reproduction, 147-149 Asida, 450 opaca, 450 Askenasia, 564-565 faurei, 564, 565 Asparagin, 96 Aspidisca, 21, 679 lynceus, 126, 678, 679 pobjstyla, 678, 679 Aspidiscidae, 668, 679 Asplanchna, 513 Assulina, 391 seminulum, 391, 392 Astasia, 11, 38, 47, 70, 194, 239, 713 klehsi, 239, 240 laevis, 138 Astasiidae, 232, 239-241 Aster acanthion rubens, 554 Asterias glacialis, 628 rubens, 554 Asterigerina, 403 carinata, 402 Asterophora, 452 philica, 450, 452 Astomata, 65, 93, 145, 146, 551, 552- 559 Astral rays, 133, 134 Astrangia danae, 630 Astrocystella, 436 lohosa, 435, 436 Astrodisculus, 410 radians, 410, 41 ^ Astrophrya, 696 arenaria, 696, 697 Astrophyga magnifica, 605 Astropyle, 417 Astrorhizidae, 398 Astrosiga, 269 Astylozoon, 683 fallax, 683, 684 Astylozoonidae, 683-685 Atchley, 718 Atelopus, 527 Athene noctua, 279 Atopodinium, 667 fibulatum, 666, 667 Atyaephrya desmaresti, 444 Audouinia lamarcki, 441 tentaculata, 469 Aulacantha, 136, 424 scolymantha, 140, 424 Aulaeanthidae, 424 Aulosphaera, 424 labradoriensis, 424 Aulosphaeridae, 424 Autogamy, 129, 161, 162-164, 169, 516, 517 Automixis, 161-165 Autotrophic nutrition, 92-93 Auxin, 98 Averintzia, 388 cydostoma, 388 Axial fibrils, 42 filament, 45, 46, 48 rod, 42, 43, 44 Axolotls, 267, 301 Axopodia, 42-43, 44, 86, 195, 406, 418 Axostylar filaments, 61-62, 66, 293 Axostyle, 61, 293, 303 B Babesia, 14, 502 bigemina, 502-504 bovis, 504 canis, 505 Babesiidae, 486, 502-506 Bacillidium, 542 limnodrili, 541, 542 Bacteria and Protozoa, 5, 9, 24 Badhamia, 335, 338 utricularis, 338 Baetis, 617 Baker, 11, 97 Balamuth, 649 Balanitozoon, 569 gyrans, 569 Balanonema, 613 biceps, 613-614 Balantidiopsis, 638 Balantidiosis, 638 Balantidium, 54, 56, 74, 99, 638 coli, 8, 9, 14, 15, 26, 91, 93, 638-639, 718 duodeni, 637, 640 praenucleatum, 637, 640 suis, 639 Balantiodoides, 638 Balantiophorus, 612 Balanus amphitrite, 445 eburneus, 445 Balbiani, 13, 14 Ball, 96 Balladyna, 674 elongata, 673, 674 Bankia, 628 Baraban, 509 Barbel, 520 Barbulanympha, 35, 133, 134, 323 laurabuda, 139, 324 uf alula, 139, 323, 324 Barbus barbus, 520, 530 fluviatilis, 530, 540 plebejus, 530 Barret, 15, 716, 718 Barrouxia, 477 ornata, 476, 477 Basal granule, 45, 46, 47, 48, 49, 50, 52, 54, 59, 67 plate, 49 Bass, 15, 718 Bat, 277 Beccaricystis, 436 loriai, 436, 437 AUTHOR AND SUBJECT INDEX 735 Becker, 98, 470, 659 Bed bug, 277 Beers, 625 Behrend, 127 Belaf, 37, 131, 135, 136, 138, 164, 166, 168, 409, 467, 712, 714 Belkin, 91 Beloides, 454 firmus, 453, 454 Benedenia, 555 Benedictia biacalensis, 627 limneoides, 627 Ber, 282 Bernstein, 103 Berthold, 106 Bertramia, 513 asperospora, 512, 513 capitellae, 513 euchlanis, 513 Bibio marci, 454 Bicosoeca, 147, 270 socialis, 270, 271 Bicosoecidae, 268, 270-271 Biggar, 605, 640 Biggaria, 605 bermudense, 604, 605 echinometris, 604, 605 Binary fission, 143-144 Biomyxa, 333 cometa, 333 vagans, 332, 333 Bird malaria, 495-499 Birds, 266, 364, 475, 495, 496, 497, 498, 499, 500, 501, 502, 506 Bishop, 266 Black birds, 475 Black duck, 501 Black flies, 502 Black-head of turkey, 9, 266 Blattner, 117 Bland, 715 Blastocysiis hominis, 368, 721-722, 723 Blastodiniidae, 248, 254-256 Blastodinium, 254 spinulosum , 254, 255 Blastula, 6 Blatta orientalis, 444, 640 BlatteUa lapponica, 444 Blattidae, 8 Blepharisma, 21, 38, 65, 92, 643 lateritium, 641, 643 persicinum, 64I, 643 steini, 64I, 643 undulans, 23, 70, 643-644 Blepharoconus, 577 cervicalis, 576, 577 Blepharocoridae, 593, 607 Blepharocorys, 607 bovis, 606, 607 equi, 607 uncinata, 606, 607 Blepharoplast, 47, 66, 67-68, 131, 180 Blepharoprosthium, 77, 577 pireum, 676, 577 Blepharosphaera, 577 intestinalis, 676, 577 Blepharozoum, 577 zonatum, 676, 577 Blood-films, 727-729 Bloom, 487 Blue bird, 497 Boaedon lineatus, 473 Boderia, 42, 378 turneri, 377, 378 Bodo, 20, 289 caudatus, 289, 290 edax, 289, 290 uncinatus, 21 Bodonidae, 196, 268, 289-292 Boeck, 15, 355, 357, 358, 717 Boell, 157 Boil-disease of fish, 520, 530 Bold, 222, 223, 225 Bolivina, 403 punctata, 402 Bombina bombina, 549 pachypa, 549 Bombyx mori, 537 Bonanni, 11 Boophilus annulalus, 503 Borgert, 136 Bos indicus, 656, 658 Bothriopsis, 455 histrio, 453, 455 Botryoidae, 424 Boveria, 56, 628 teredinidi, 627, 628 Bowling, 166 Boyd, 28, 179, 486, 488, 490, 491 Box boops, 301, 549 Brachiomonas, 218 westiana, 219 Brachionus, 513 Branchioecetes, 584 gammari, 583, 584 Brachiura coccinea, 559 Brand, 26 Brandt, 88, 170, 417 Brassica, 341 Braun, 28 Bresslau, 602 Bresslaua, 90, 602 vorax, 602 Brodsky, 64 Brown, 56, 69, 138 Bruce, 14 Brug, 87 Brumpt, 638 Brumptina brasiliensis, 365 Bryophyllum, 582 vorax, 581, 582 Bryophrya, 602-603 bavariensis, 602, 603 Bryozoa, 537, 699, 709 Bubos, 284 736 PROTOZOOLOGY Buccinum, 468 undatum, 468 Budding, 145 BudingtoD, 95 Buffelus bubalus, 658 Bufo, 547, 692 compactilis, 548 cognatus, 550 intermedicus, 550 lentiginosus, 548 marinus, 550 terrestris, 528 valliceps, 550 Bulbocephalus, 450 elongatus, 450, 451 Buliminidae, 403 Bullanympha, 306 silvestrii, 306, 307 Bullington, 608 BuUinula, 388 indica, 387, 388 Bundleia, 577 postciliata, 576, 577 Bundesen, 357 Bunting, 296 Burbank, 612 Burnside, 171, 645 Bursaria, 33, 100, 144, 637 Iruncatella, 637, 638 Bursariidae, 636, 637-640 Bursaridium, 638 dijficile, 637, 638 Bursella, 569 spumosa, 569 Btitschli, 13, 14, 106, 110, 111, 600 Biitschlia, 576-577 parva, 576, 577 Biitschliella, 554 chaetogastri, 554 opheliae, 553, 554 Butschliidae, 77, 560, 576-578 Buxtonella, 592 sulcata, 591, 592 Cabbage, 341 Caduceia, 306 bugnioni, 306, 307 Caementella, 424 stapedia, 424 Caementellidae, 424 Caenis, 432 Caenomorpha, 640 medusula, 21, 641 Cailleau, 98 Calanus finmarchicus, 256 Calcarina, 403 defrancei, 404 Calcarinidae, 403 Calkins, 6, 13, 37, 38, 72, 84, 123, 126, 135, 166, 167, 171, 180, 575, 618, 645, 652, 679, 696 Callimastigidae, 293, 299 Callimastix, 299 cyclopis, 299 equi, 299, 300 frontalis, 299, 300 Calliphora, 282, 361 erythrocephala, 361 Callipus lactarius, 452 Callitriche, 341 Calonympha, 315 grassii, 139, 315, 316 Caloscolex, 655 cuspidatus, 655, 656 Calospira, 635 minkiewiczi, 634, 635 Calymma, 417 Calyx, 134 Calyptotricha, 619 pleuronemoides, 619, 620 Cambarus, 687, 689 Cambell, 654 Camel, 278, 655, 656, 659 Camelus dromedarius, 655, 656 Camerinidae, 402 Campanella, 687 umbellaria, 686, 687 Campascus, 386 cornutus, 385, 386 Campbell, 56 Camptonema, 42, 85, 409 nutans, 408, 409 Canary, 495 Cannosphaera, 424 Cannosphaeridae, 424 Canthocamptus, 692 niinutus, 691 Capillitium, 337 Capitella capitata, 513 Capsa, 628 Capsellina, 384 timida, 383, 384 Carabus, 452 auratus, 452 violaceus, 452 Carbohydrate metabolism, 26, 91 Carbon dioxide, 103 Carchesium, 11, 33, 88, 89, 580, 689 granulatum, 39, 689 polypinum, 88, 141, 166, 689 Carcinoectes, 445 hesperus, 445, 446 Cardita calyculata, 457, 628 Cardium edule, 629 Carini, 365 Carotin, 78 Carp, 280, 285 Carteria, 222 cordiformis, 222, 223 ellipsoidalis, 222 obtusa, 23 Carteriidae, 217, 222-224 Caryospora, 475 simplex, 475, 476 AUTHOR AND SUBJECT INDEX 737 Caryotropha, 468 mesnili, 468 Cassidulina, 404 laevigata, 404 Cassidulinidae, 403 Castanellidae, 425 Castanidium, 425 murrayi, 425 Cat, 277, 358, 472, 474, 475 Catabolic products, 103-106 Cat-bird 497 Catenoid colony, 146 Catfish, 568 Catostomus, 285 commersonii, 528 Cattle, 278, 299, 310, 364, 470, 502, 504, 505, 577, 591, 605, 606, 607, 655, 656, 657, 658, 659 Caudal cirri, 49, 50 Caulicola, 691 vulvata, 690, 691 Caulleryella, 460 pipientis, 459, 460-461 Causey, 71 Cavia aperea, 606, 607, 659 porcella, 606, 607 Cell, 5 Cell-aggregates, Protozoa as, 6 Cell-anus, 74, 92 Cell-organs, 50 Cellobiase, 91 Cellulase, 91 Cellulose, 25, 38, 91, 148 Cenolarus, 423 primordialis, 422 •Central capsule, 61, 171, 417 motor mass, 54, 55, 56, 60 spindle, 134 Centrechinus antillarum, 605, 640 Centriole, 67, 130, 131, 132, 133, 134 Centrodesmose, 131 Centropyxis, 386 aculeata, 178, 386, 386 Centrosome, 133 Centrosphere, 135 Cepedea, 34, 548 cantabrigensis, 548 fioridensis, 548 hawaiensis, 548 obovoidea, 548 Cepedella, 554-555 hepatica, 555 Cephalin, 430 Cephalina, 431, 440-462 Cephaloidophora, 442 nigrofusca, 442 Olivia, 442, 443 Cephaloidophoridae, 440, 442 Cephalothamnium, 288 cyclopum, 288 Ceratiomyxa 341 fruticulosa, 339 Ceratiomyxidae, 340 Ceratium, 11, 100, 144, 146, 259 fuzus, 258, 259 hirundinella, 21, 176, 177, 258, 259 longipes, 258, 259 tripos, 258, 259 var. atlantica, 259 Ceratodinium, 254 asymetricum, 252, 254 Ceratomyxa, 521 hopkinsi, 521, 522 mesospora, 521, 522 Ceratomyxidae, 521-522 Ceratophyllus fasciatus, 274, 279 Ceratopogon, 542 solstitialis, 454, 460 Ceratospora, 439 mirabilis, 439 Cercaria tenax, 13 Cercomonas, 20, 291 crassicauda, 21, 46, 290, 292 longicauda, 21, 139, 290, 291 Cerithium rupestre, 457 Certesia, 677 quadrinucleata, 677, 678 Cervus canadensis, 659 Cestracion zygaena, 521 Cestus veneris, 635 Cetonia, 299 Chaenea, 573 limicola, 573 Chaetodipterus faber, 521 Chaetogaster, 554 Chaetognatha, 371, 554 Chaetospira, 672 miilleri, 671, 672 Chagas, 138, 350 Chagas' disease, 277 Chagasella, 480 hartmanni, 480 Chalkley, 17, 141, 143, 713 Challengeridae, 424 Challengeron, 425 wyvillei, 425 Chambers, 19 Chang, 358 Chaos chaos, 11 Chara, 341 Charon, 607 equi, 606, 607 Chatton, 57, 66, 130, 180, 254, 623, 630 Cheissin, 555, 625 Chelydra sepentina, 365 Chemical composition of water on Protozoa, 20-22 stimuli, 116 Chemicals on cysts, 359 Chen, 137, 365, 497 Chicken, 266, 313, 364, 367, 472, 497 Chill and fever, 484, 489 Chilodinium, 254 cruciatum, 252, 254 738 PROTOZOOLOGY Chilodochona, 682 quennerstedti, 681, 682 Chilodon, 588 Chilodo'nella, 11, 18, 37, 69, 70, 117, 588 caudata, 589 cucullulus, 21, 62, 104, 122, 123, lU, 589 cyprini, 589, 590 fluviatilis, 589 hyalina, 590 longipharynx, 590 rotunda, 590 uncinata, 122, 129, 141, 166, 181, 182, 589-590 Chilodontopsis, 585 vorax, 586, 587 Chilomastigidae, 293, 298-299 Chilomastix, 14, 298 beltencourti, 299 caprae, 299 cuniculi, 299 gallinarum, 139, 299 intestinalis, 299 mesnili, 15, 25, 298-299 Chilomonas, 65, 70, 88, 118, 136, 194, 214 oblonga, 215 Paramecium, 23, 94 96, 97, 103, 176, 214, 713 Chilophrya, 569-570 labiata, 570, 571 utahensis, 570 Chilostomellidae, 404 Chimpanzee, 639 Chiridota, 438 laevis, 438 Chironomus plumosus, 30 Chitin, 40, 41, 65, 148 Chiton caprearum, 457 Chlamydoblepharis, 222 Chalmydobotrys, 228 stellata, 229 Chalmydococcus, 218 Chlamydodon, 56, 588 ynnemosyne, 587, 588 Chlamydodontidae, 585, 588-590 Chlamydomonadidae, 217-222 Chlamydomonas, 38, 46, 78, 79, 80, 139, 150, 151, 182, 194, 217-218, 220 angulosa, 218 debaryana, 176, 178 epiphytica, 218, 219 eugametos, 184 globosa, 218, 219 gracilis, 218, 219 monadina, 218, 219 paradoxa, 184 pauper a, 184 pseudoparadoxa, 184 Chlamydomyxa, 333 montana, 332, 333 Chlamydophrys, 382 stercorea, 21, 382, 383 Chloraster 224 gyrans, 223, 224 Chlorasteridae, 217, 224 Chlorella, 25 Chlorine on cysts, 359 Chlorogonium, 194, 220 elongatum, 23 euchlorum, 23, 220, 221 teragamum, 23 Chloromonadina, 78, 200, 243-244 Chloromyxidae, 523, 526 Chloromyxum, 526 leydigi, 140, 145, 146, 52 4, 526 trijugum, 524, 526 Chlorophyll, 78, 92, 194 Chloroplast, 78 Choanocystis, 414 lepidula, 414, 415 Choanocystella, 436 tentaculata, 435, 436 Choanocystoides, 436 cosiaricensis, 435, 436 Choanomphalus, 627, 628 Choanophrya, 86, 708 infundibulifera, 708 Chondriosomes, 70-72, 99 Chondropus, 333 viridis, 333 Chonotricha, 24, 145, 196, 551, 681- 682 Chorophilus triseriatus, 548 Christensen, 470 Chromatin, 34, 35, 36, 37, 122, 123, 124, 546 Idio-, 37 Tropho-, 37 Chromatin test, 35 Chromatoid body, 355 Chromatophore, 6, 38, 78-79, 92, 194, 195 Chromidia, 37-38, 374 Chromidina, 555 elegans, 555, 556 Chromomeres, 123 Chromosomes, 131, 132, 133, 135, 136, 137, 138, 139-142, 165, 166, 467 Chromulina, 47, 70, 201, 202 pascheri, 202, 203 Chromulinidae, 201-205 Chrysamoeba, 194, 203 radians, 203, 204 Chrysapsis, 203 sagene, 202, 203 Chrysarachnion, 194, 210 insidians, 210, 211 Chrysemys elegans, 365 picta bellii, 705, 706 AUTHOR AND SUBJECT INDEX 739 Chrysidella, 25, 215 schaudinni, 214, 215 Chrysidiastrum, 210 catenatum, 210 Chrysocapsa, 212 paludosa, 209, 212 Chrysocapsina, 201, 210-212 Chrysococcus, 203 ornatus, 202, 203 Chrysomyia macellaria, 361 Chrysomonadina, 78, 100, 194, 195, 200-212 Chrysopyxis, 203 cyathus, 202, 203 Chrysophaerella, 204 longispina, 202, 204 Chrysothylakion, 195, 210 vorax, 210, 211 Chytriodinium, 256 parasiticum, 255, 256 Cienkowski, 333 Cilia, 41, 47-52, 111-113, 193, 545 Ciliary field, 50 flagella, 45, 46 movement, 111-113 zone, 50 Ciliata, 5, 12, 20, 193, 196, 545-693, 715 Cilioflagellata, 245 Ciliophora, 38, 47, 65, 73, 101, 122, 144, 193, 545-709 Ciliophryidae, 407, 409 Ciliophrys, 409 infusionum, 409, 4^1 marina, 409 Cinetochilum, 615 margaritaceum, 21, 614, 615 Cingulum, 257 Circoporidae, 425 Circoporus, 425 odahedrus, 425 Circular cytostomal fibrils, 59 Circum-oesophageal ring, 54 -pharyngeal ring, 54, 55 Cirri, 49, 56, 57, 668 Cirrus fiber, 49, 50, 56 Citharichthys xanthostigmus, 521 Cladomonas, 146, 286 fruticulosa, 286 Cladonema radiatum, 631 Cladophora 689 Cladothrix pelomyxae, 349 Cladotricha, 670 koltzowii, 669, 670 Claff, 90, 94, 148, 712 Claparede, 12 Clark, 103, 170 Clathrella, 412 foreli, 412, 413 Clathrellidae, 407, 412 Clathrostoma, 598 viminale, 597, 598 Clathrostomidae, 593, 598 Clathrulina, 44, 414 elegans, 414, 415 Chathrulinidae, 407, 414 Clausia, 554 Clausocalanus arcuicornis, 254 furcatus, 254, 635 Cleaning glass-wares, 719 Clegg, 15 Cletodes longicaudatus, 697, 703 Cleveland, 8, 25, 30, 35, 66, 91, 103, 131, 134, 144, 311, 324, 355, 601, 718 Clevelandella, 648 panesthiae, 648 Clevelandellidae, 636, 648-649 Clevelandia, 648 Cliff swallow, 497 Climacostomum, 75, 647 virens, 21, 647, 650 Cliola vigilax, 530 CHtellis arenarius, 533 Clupea pilchardus, 528 Clymenella torquata, 256, 685 Clypeolina, 389 marginata, 387, 389 Cnidosporidia, 64, 93, 196, 427, 515- 543 Coatney, 500 Coccidia, 15, 196, 428, 464-482 Coccidiosis, 9, 471, 472, 474 Coccidium, 470 oviforme, 470 Coccolith, 41 Coccolithidae, 40, 201, 208-209 Coccomonas, 220 orbicularis, 220, 221 Coccomyxa, 528 morovi, 527, 528 Coccomyxidae, 526, 528 Cocconema, 541 Coccospora, 541 slavinae, 541 Coccosporidae, 537, 541 Cochliatoxum, 663 periachlu7ti, 662, 663 Cochliopodium, 143, 144, 382 bilimbosum, 382, 383 Cochlodinium, 253 atromaculatum, 252, 253 Cockroaches, 290, 313, 320, 321, 352, 353, 357, 361, 367, 438, 444, 513, 640, 644 Codonella, 654 cratera, 653, 654 Codonocladium, 269 Codonoeca, 271 inclinata, 271 Codonosigopsis, 270 Codosiga, 269 disjuncta, 269 utriculus, 269 Codosigidae, 268-270 740 PROTOZOOLOGY Coelenterata, 285, 370, 554, 613, 620, 630, 631, 632, 679, 692, 696, 699, 703, 709 Coelodendridae, 425 Coelodendrum, 425 ramosissimum, 425 Coelosporidium, 513 blattellae, 513 peri'planetae, 512, 513 Coelozoic Protozoa, 26, 93 Coenobiiim, 225 Coggeshall, 19, 29, 490 Cohn, 12 Cohnilembidae, 608, 620-621 Cohnilembus, 620 caeci, 620, 621 fusiformis, 620, 621 Colacium, 146, 237 vesiculosum, 136, 238 Coleorhynchus, 455 heros, 453, 455 Colepismatophila, 447 ivatsonae, 446, 447 Colepidae, 560, 565-566 Coleps, 11, 38, 50, 86, 196, 565 bicuspis, 565, 566 elongatus, 565, 566 heteracanthus, 566 hirtus, 565, 566 odospinus, 565, 566 spiralis, 565, 566 Collared Protozoa, 41, 270, 271 Collecting canals, 74-76 Collection of Protozoa, 710-711 Collin, 51, 145, 197 Collinella, 592 gundii, 5.91, 592 Collinia, 552 CoUodictyon, 296-297 triciliatum, 139, 296, 297 Collosphaera, 423 Collosphaeridae, 423 Colonial Protozoa, 6, 33, 145-147 Colony, 145-147 arboroid, 146 catenoid, 146 dendritic, 146 discoid, 146-147 gregaloid, 147 linear, 146 spheroid, 147 Color of Protozoa, 38, 235 water due to Protozoa, 247, 253, 260, 565 Colpidium, 23, 128, 611-612 campylum, 21, 23, 95, 98, 127, 611, 612 colpoda, 19, 48, 86, 127, 168, 609, 611, 612 striatum, 91, 97, 98, 612 Colpoda, 11, 37, 601 aspera, 21 calif ornica, 601, 602 Colpoda — continued cucullus, 21, 23, 148, 601, 602 duodenaria, 602 inflata, 601, 602 steini, 30, 601 Colpodidae, 593, 601-603 Colponema, 291 loxodes, 290, 291 Columba livia, 500 Columbella rustica, 457 Colymbetes, 455 Comatula mediterranea, 628 Cometoides, 452 capitatus, 450, 452 Commensal, 24-25 Commensalism, 24-25 Compact nucleus, 35-37 Concentration of cysts, 722 Conchophthiridae, 623-624 Conchophthirus, 56, 73, 74, 623 anodontae, 127, 136, 137, 141, 623- 624, 625 caryoclada, 624, 625 curtus, 127, 624 magna, 127, 624 mytili, 65, 127, 128, 141, 624 Concrement vacuole, 77, 576 Condylostoma, 645 patens, 645 vorticella, 645, 646 Condylostomidae, 636, 645 Cone-nosed bug, 277 Congo red, 90, 720 Conjugation, 13, 129, 154-161, 162, 163, 164, 165, 166, 167, 169, 181, 184, 185, 186, 187, 188 Connal, 474 Connell, 56, 127 Contractile canal, 76, 96 vacuole, 69, 73-76, 102, 103-104, 108 Conus mediterraneus, 457 Copepoda, 254, 256, 299, 537, 539, 541, 542, 554, 630, 697, 700, 708 Copromastix, 298 prowazeki, 296, 298 Copromonas, 241 subtilis, 151, 241 Coprozoic Protozoa, 21, 298 Coptotermes formosanus, 319, 326 Corbierea, 222 Cordylophora lacustris, 696 Coria, 18, 95, 712, 715 Corky scab of potatoes, 342 Coronympha, 315 clevelandi, 315, 316 Corycaeus venustus, 256 Corycella, 451 armata, 450, 451 Corycia, 381-382 coronata, 380, 382 Corythion, 391 pulchellum, 390, 391 AUTHOR AND SUBJECT INDEX 741 Costa, 62, 293 Costia, 29, 297 necatrix, 26, 296, 297 pyrifortnis, 297 Cothurnia, 691 annulata, 690, 691 canlhocamipti, 690, 691 Cougourdella, 542 magna, 541, 542 Coverglasses, 719 Cow bird, 497 Craig, 356, 357 Cranotheridium, 562 taeniatum, 561, 562 Crappie, 27 Craspedotella pileolus, 261, 262 Craspedothorax, 595 Craspidochilus cinereus, 511 Craterocystis, 436 papua, 435, 436 Crenilabrus nielops, 513 ocellatus, 513 paro, 513 Crepidula plana, 650 Crescent, 493 Cresta, 293, 303, 304 Cribraria, 340 aurantiaca, 339 Cribariidae 339 Crickets, 290 Criodrilus, 626 Cristigera, 619 media, 618, 619 phoenix, 618, 619 Crithidia, 273, 280, 281 euryophthalmi, 280 gerridis, 281 hyalommae, 281 Crobylura, 572 pelagica, 572, 573 Cross-striation in cilia, 48 Crossing over, 183-184 Cruciferous plants, 341 Crucinympha, 304 Crumenula, 236 ova, 237, 238 Crustacea, 440, 442, 444, 445, 455, 456, 457, 466, 468, 539, 552, 590, 630, 632, 633, 634, 635, 682, 689, 691, 692, 696, 698, 699, 700, 708 Cruzella, 289 Cryptobia, 284-285 barren, 285 cyprini, 285 grobbeni, 285 helicis, 285 Cryptobiidae, 268, 284-28S Cryptocercus punctulatus, 25, 303, 313, 320, 323, 324, 326 Cryptochilidium, 613 echi, e>\Z,614 Cryptochilum, 616 Cryptochrysis, 215 commutata, 214, 215 Cryptodifflugia, 381 oviformis, 380, 381 Cryptoglena, 237 pigra, 237, 238 Cryptomonadina, 65, 78, 194, 200, 213-216, 245 Cryptomonadidae, 213, 214-215 Cryptomonas, 100, 118, 136, 194, 214, 215 ovata, 214 Cryptopharynx, 588 setigerus, 588, 589 Cryptops hortensis, 447 Cryptosporidium, 475 muris, 475, 4'^6 parvum, 475 Cryptotermes dudleyi, 302, 311 grassii, 315 hermsi, 304, 306, 315 longicollis, 316 Crystals, 96, 104-105, 345 Ctedoctema, 619 acanthocrypta, 619, 620 Ctenocephaius canis, 281, 452 Ctenodactylus gundi, 505, 591 Ctenophores, 635 Ctenostomata, 20, 636, 665-667 Cubitermes, 353 Cucujus, 451 Cucurbitella, 386 mespiliformis, 385, 386 Culex, 7, 8, 490, 495, 496, 497, 539 fatigans, 15 pipiens, 461, 486 Cultivation of Free-living Protozoa, 711-715 Parasitic Protozoa, 15, 283-284, 355, 715-719 Cultures, Bacteria-free, 712 Mixed, 712 Cunhaia, 659 curvata, 659, 611 Current and Protozoa. 115 Curtis, 600 Cushman, 40, 398 Cutler, 15 Cyathodiniidae, 593, 606-607 Cyathodinium, 606 conicum, 606 piriformis, 606, 607 Cyathomonas, 65, 215 truncata, 214, 215 Cyclidium, 21, 619 glaucoma, 48 litomesum, 618, 619 Cyclochaeta, 692 domergui, 692, 693 spongillae, 692, 693 Cyclogramma, 64, 585 trichocystis, 585, 587 742 PROTOZOOLOGY Cyclonexis, 33, 147, 208 annularis, 207, 208 Cyclonympha, 326 Cycloposthiidae, 652, 659-663 Cycloposthium, 61, 660 bipalmatum, 660, 661 dentiferum, 660, 661 Cyclops, 288, 299, 687, 703, 708 fuscus, 537 minutus, 692 ornatus, 708 Cyclosis, 11, 87-89 Cyclospora, 475 caryolytica, 475, 476 Cyclostoma elegans, 692 Cyclotrichium, 565 meunieri, 92, 545, 564, 565 Cynoscion regalis, 525 Cyphoderia, 21, 390 ampulla, 176, 390-391 Cyphon pallidulus, 446 Cypridium, 586 Cyprinus, 285, 590 Cypris, 687 Cyrtoidae, 423 Cyrtolophosis, 615 mucicola, 615, 616 Cyrtophora, 195, 203-204 pedicellata, 202, 204 Cyst, 147-149, 355, 358-359, 361, 721 -carrier, 357 -passer 357 Cystidium, 423 princeps, 423 Cystobia, 440 irregularis, 439, 440 Cystocephalus, 451 algerianus, 450, 451 Cystodiniidae, 248-249 Cystodinium, 248 steini, 247, 248 Cystodiscus immersus, 527 Cystoflagellata, 246, 261-262 Cytogamy, 163 Cytomere, 500, 502 Cytopharynx, 51, 54, 62, 86 Cytoplasm, 38-41, 186 Cytopyge, 74, 92 Cytosome, 33, 38-41 Cytosomic division, 143-145 binary fission, 143-144 budding, 145 multiple division, 144-145 plasmotomy, 145 schizogony, 145, 147 Cytostome, 51, 86-87 Cytozoic Protozoa, 26, 28, 93 Czurda, 79 Da Cunha, 644 Da Fonseca, 297 Dacne rufifrons, 445 Dactylochlamys, 20, 567 pisciformis, 566, 567 Dactylophoridae, 441, 447—449 DactylophoFus, 447 robustus, 447, 448 Dactylophrya, 703 roscovita, 703, 704 Dactylosaccus, 378 vermiformis, 377, 378 Dactylosoma, 505 ranarum, 504, 505 Dallasia, 611 Dallinger, 18 Dallingeria, 294 drysdali, 294 Daniel, 141, 143 Darkfield microscope, 720 Darling, 509 Dasyhelea obscura, 440, 543 Dasypis novemcinctus, 277 Dasytricha, 606 ruminantium, 606 Davaine 14 Davis, 297, 313, 520, 524, 696 Dawson, 91, 168 De Bary, 335 De Garis, 186 Debaisieux, 130, 517 Deer mouse, Canadian, 279 Defecation process, 92 Degeneration, 39 Dellinger, 107 Deltotrichonympha, 326 operculata, 326 Dembowski, 115 Dendritic colony, 146 Dencrocoelum lacteum, 617 Dendrocometes, 699 paradoxus, 698, 699 Dendrocometidae, 695, 699 Dendromonas, 288 virgaria, 288 Dendrorhynchus, 447 system, 447-448 Dendrosoma, 696, 700 radians, 696, 697 Dendrosomidae, 695 Dendrosomides, 696 paguri, 696, 697 Dennis, 503 Derepyxis, 205 amphora, 205, 206 ollula, 206 Dermacenter reticulatus, 505 Dermestes lardarius, 454 Dero limosa, 479 Deschiens, 19 Desmarella, 269 irregularis, 270 moniliformis, 269 Desmose, 131, 134 Deutomerite, 429 AUTHOR AND SUBJECT INDEX 743 Devescovina, 66, 303 lernniscata, 304, 303 Devescovinidae, 293, 303-307 Dewey, 90 Dexiotricha, 615 Dexiotrichides, 615 centralis, 615, 616 Diadeyna setosum, 640 Diaphoropodon, 389 mobile, 387, 389 Dia-ptomus castor, 539 Diastole, 73, 74 Diatom, 333 Dichilum, 613 cuneiforme, 613, 614 Dicnidea, 536, 542 Dicotylus, 617 Dictyophimus, 424 hertwigi, 423 Dictyosteliidae, 341 Didelphys virginiana, 277 Didesmis, 577 quadrata, 576, 577 Didiniidae, 560, 563-565 Didinium, 54, 65, 87, 104, 563 balbianii, 563, 564 nasutum, 24, 129, 141, 165, 563, 564 Didymiidae, 338 Didymium, 339 effusum, 338 Didymophyes, 442 gigantea, 442-443 Didymophyidae, 440, 442-443 Dientamoeba, 367 fragilis, 25, 140, 266, 360, 361, 368 Diesing, 12 Difflugia, 37, 170, 384 arcula, 385 constricta, 385-386 corona, 178, 386 lobostoma, 385 oblonga, 384-385 jiyriformis, 384 spiralis, 107 urceolata, 385 Difflugiella, 381 apiculata, 380, 381 Difflugiidae, 374, 384-389 Digestion, 90-92 Dileptus, 56, 63, 582-583 americanus, 583-584 anser, 37, 63, 64, 123, 171, 583, 485 Diller, 127, 163, 165, 615 Dimastigamoeba, 344 bistadialis, 139, 344 gruberi, 21, 344 Dimastigamoebidae, 51, 343, 344-345 Dimorpha, 136, 195, 265 mutans, 265 Dimorphism, 395 Dinamoeba, 348 mirabilis, 347, 348 Dinenympha, 69, 70, 136, 302 fimbriata, 139, 302, 303 gracilis, 302, 303 Dinenymphidae, 294, 302-303 Dinobryon, 47, 100, 146, 208 divergens, 208 sertularia, 207, 208 Dinoflagellata, 47, 78, 196, 200, 245- 262 Dinomonas, 287 vorax, 286, 287 Dinophysidae, 257, 261 Dinophysis, 261 acuta, 260, 261 Diophrys, 677 appendiculata, 126, 677, 678 Diphasia attenuata, 703 Diphasic amoebae, 344, 714 Diplochlamys, 384 leidyi, 383, 384 Diploconidae, 421 Diploconus, 421 Diplocystidae, 431, 437-438 Diplocystis, 437 schneideri, 140, 166, 437, 438 Diplodinium, 656 dentatum, 656, 658 ecaudatum, 54, 659 Diplogromia, 374 Diploid, 139-141, 165-166 Diplomita, 286 socialis, 286, 287 Diplomonadina, 33, 34, 293, 311-315 Diplophrys, 377 archeri, 377 Diploplastron, 657 affine, 657, 658 Diplopoda, 442, 446 Diplosiga, 270 francei, 269, 270 socialis, 269, 270 Diplosigopsis, 270 affinis, 270, 271 Diplostauron, 220 pentagonium, 219, 220 Direct nuclear division, 122-130 Discoid colony, 146-147 Discoidae, 423 Discolith, 208 Discornorpha, 665-666 pectinata, 666 Discomorphidae, 665-666 Discophrya, 706 elongata, 706, 707 Discophryidae, 695, 706-708 Discorbis, 403 opercularis, 395 petalUformis, 396, 397 Discorhynchus, 453 truncatus, 453 Discosphaera tubifer, 209 Disematostoma, 74, 608-609 butschlii, 609, 610 744 PROTOZOOLOGY Dissodinium, 261 lunula, 260, 261 Dissosteria Carolina, 444 Distephanus speculum, 195, 209 Distigma, 47, 242 proteus, 240, 242 Ditoxum, 663 funinucleum, 662, 663 Ditrichomonas, 308 Division, 5, 122-147 cytosomic, 143-147 nuclear, 122-142 Dixippus morosus, 30 Dobell, 5, 11, 13, 29, 130, 131, 151, 166, 179, 266, 297, 308, 309, 310, 355, 358, 361, 363, 368, 467, 717 Dobellia, 469 binucleata, 469 Dobelliidae, 465, 469 Dobellina, 368-369 mesnili, 369-370 Doflein, 13, 42, 101, 136, 143, 145 Dog, 277, 278, 282, 357, 364, 472, 474, 475, 505 Dogiel, 61, 77, 655 Dogielella, 69, 70, 554 minuta, 553, 554 sphaerii, 553, 554 Virginia, 553, 554 Dolichodinium, 259 lineatum, 258, 259 Donax, 468 trunculus. 513 vittatus, 685 Donkey, 277, 278 Donovan, 15 d'Orbigny, 12 Dorisiella, 475 scolelepidis, 475, 4'^6 Dorsal motor strand, 54 Dosinia exoleta, 629 Doudoroff, 18 Dourine, 9, 278 Doyle, 72, 84, 87, 105 Drbohlav, 15, 355, 717 Drehkrankheit, 521, 529 Drepanoceras, 595 Drepanomonas, 595 dentata, 594, 595 Drew, 28, 358 Drosophila, 542 confusa, 282 Duboscq, 67, 70, 131, 196 Duboscqia, 539 legeri, 5SS, 539 Duboscqella, 256 tintinnicola, 255, 256 Ducks, 313, 501, 510 Dufour, 14 Dujardin, 11, 12 Duniaiella carolinensis, 497 Dunkerley, 144 Dusi, 96, 97 Dutton, 15 Dysdercus ruficollis, 480 Dysentery amoeba, 356 Dysmorphococcus, 225 variabilis, 223, 225 Dysteria, 586 calkinsi, 586, 587 lanceolata, 586 Dysteriidae, 585, 586-587 E Earthworm, 432, 433, 434, 460, 552, 557, 558, 559, 625 Eaton, 29 Ebalia turnefacta, 682 Echinodermata, 439, 440, 554, 597, 603, 604, 605, 613, 621, 628, 634, 640, 649 Echinomera, 447 niagalhaesi, 447, 448 Echinometra lucunter, 605 Echinometris subangularis, 605, 640 Echinospora, 477 labbei, 476, 477 Echinus esculentus, 604 lividus, 613 Ecology, 17-31 Ectocommensals, 24, 29 Ectoparasites, 25-26, 29 Ectoplasm, 38, 39 Edgar, 99 Edwards, 87, 350 Eel-grass, 329 Eels, 280 Effect of parasites on hosts, 25-29 Efimoff, 19 Ehrenberg, 12 Eichhorn, 11 Eimer, l4 Eimeria, 870 acervulina, 471, 472 anseris, 472 arloingi, 470 canis, 4^1, 472 caviae, 472 clupearum, 4^1, 473 cylindrica, 470 debliecki, 471 dispersa, 473 ellipsoidalis, 470 falciformis, 471, 472 faurei, 469, 470 felina, 472 gadi, 100, 473 intricata, 471 labbeana, 473 maxima, 471, 472 meleagridis, 472 meleagrimitis, 472 mitis, 471, ^72 miyairii, 472 necatrix, 472 nieschulzi, 98, 472 AUTHOR AND SUBJECT INDEX 745 Eimeria — continued oxyspora, 473 perforans, 469, 470 praecox, 472 prevoti, 471, 473 ranae, 471, 473 ranarum, 4^1, 473 sardinae, 471, 473 scabra, 471 schubergi, 136, 152, 464, 465, 470 separata, 472 smithi, 470 sizedae, 13, 14, ^6,9, 470 tenella, 99, ^7i, 472 truncata, 472 wenyoni, 473 zurni, 470 Eimeridea, 464-477 Eimeriidae, 465, 470-477 Eisenia foetida, 558 lonnbergi, 558, 625 Elaeorhanis, 44, 410 cincta, 410, ^^-^ Elaster, 414 greeffii, 414, 4^.5 Electrical stimuli, 118 Eleodes, 450 Elephant, 278 Eleutheria dichotoma, 554 Elliott, 96, 97, 98, 218 Ellipsoidina, 403 Ellipsoidinidae, 403 Elliptio complanatus, 624 Ellis, 11, 65 Ellobiophrya, 685 donacis, 685, 686 Ellobiopsis, 256 chattoni, 255, 256 Elphidium, 11, 42, 86, 402 crispa, 396, 397-398 strigilata, 43 Elytroplastron, 657-658 bubali, 658, 660 Embadomonas, 290 Emetin hydrochloride, 359 Emys orbicularis, 480 Enchelydium, 561 fusidens, 561, 562 Enchelyodon, 574 californicus, 574 Enchelyomorpha, 567 vermicularis, 566, 567 Enchelys, 572 auduboni, 572 curvilata, 572, 573 Encystment 147-149, 324, 355, 430, 458, 600-601, 603 Endamoeba, 30, 351-352, 354 blattae, 25, 70, 122, 124, 127, 154, 352-353 disperata, 140, 353 granosa, 353 lutea, 353 Endamoeba — continued majestus, 353 pellucida, 353 sabulosa, 353 simulans, 353 suggrandis, 353 thomsoni, 353 vs Entamoeba, 351 Endamoebidae, 343, 351-370 Endocommensalism, 25, 30 Endocrines and Protozoa, 94-96 Endolimax, 366-367 blattae, 367 gregariniformis, 367 nana, 25, 360, 361, 367 ranarum, 367 Endomixis, 128-129, 169 Endoparasites, 26-29, 30 Endoplasm, 38, 39, 87 Endoskeleton, 55, 61, 62, 64, 65 Endosome, 34, 36, 37, 123, 136 Endosphaera, 705 engelmanni, 21, 685, 705, 707 Engelmann, 56, 62, 88 English sparrow, 475, 495, 497 Enoploplastron, 659 triloricatum, 659, 660 Enrique, 166 Entamoeba, 90, 179, 351, 353 apis, 365 barreti, 365, 716 bovis, 364 brasiliensis, 353, 365 buccalis, 363 caprae, 364 caviae, 364 cobayae, 364 coli, 14, 25, 140, 360, 361-363, 723 cuniculi, 364 debliecki, 364 equi, 364 gallinarum, 364 gingivalis, 14, 70, 140, 363-364 gedoelsti, 364 histolytica, 8, 14, 15, 19, 26, 87, 93, 140, 179, 354-361, 716, 717 intestinalis, 364 invadens, 365, 716 minchini, 365 muris, 364 ovis, 364 polecki, 364 ranarutn, 365 terrapinae, 365 testudinis, 365 venaticum, 364 Enterocystis, 432 ensis, 432, 435 Enteromonas, 297-298 hominis, 296, 297, 298 Entodinium, 654, 655 bursa, 655, 656 caudatum, 655, 656 746 PROTOZOOLOGY Entodiscus, 603-604 borealis, 604-605 indoviitus, 604 Entorhipidiidae, 593, 603 Entorhipidium, 56, 603 echini, 603, 60 J^ Entosiphon, 242 ovatum, 242 sulcatum, 138, 240, 242 Entz, 296, 370 Envelope, 39-40 Enzymes in Protozoa, 70, 72, 90, 93, 335 Eodinium, 655 lobatum, 656, 658 Eosin test, 357, 358 Epalcidae, 665 Epalxis, 665 mirabilis, 665, 666 Epeorus torrentium, 540 Ephelota, 709 coronata, 700, 708, 709 gemmipara, 700, 703, 708, 709 plana, 708, 709 Ephelotidae, 86, 695, 709 Ephemera vulgata, 542 Ephestia kuhniella, 460 Epiclintes, 673 pluvialis, 673 Epicone, 245 Epidinium, 659 caudatum, 659, 660 ecaudatum, 54, 55, 659, 660 Epimerite, 65, 430 Epiplastron, 659 africanum, 659, 660 Epistylidae, 683, 686-687 Epistylis, 580, 686, 696, 700 cambari, 686, 687 fugitans, 686, 687 plicatiHs, 686 Epitheca, 245 Erdmann, 128 Eremoplastron, 657 bovis, 657, 658 Eriphia spinifrons, 457 Ervilia, 586 Erythroblast, 495, 502 Erythrocytic schizogony, 485, 487, 488 Erythropsis, 249-251 cornuta, 250, 251 Eschaneustyla, 75, 670 brachytona, 669, 670 Esox, 527, 530 lucius, 280 reiiculatus, 280 Espejoia, 612 mucicola, 612, 614 Espundia, 284 Eucamptocerca, 586 longa, 586, 587 Euchaeta japonica, 699 Euchlanis, 513 Euchrysomonadina, 201-209 Euciliata, 34, 100, 136, 196, 547, 551-693 Eucomonympha, 326 imla, 325, 326 Eucomonymphidae, 326 Eucryptomonadina, 213-216 Eudiplodinium, 657 maggii, 657, 658 Eudorina, 80, 1, 00147, 220, 230 elegans, 117, 151, 153, 168, 229, 230, 330 Euglena, 11, 18, 21, 38, 46, 47, 80, 117, 194, 233-235 acus, 68, 233, 234, 235 deses, 23, 68, 234-235 gracilis, 23, 70, 91, 94, 96, 98, 99, 138, 194, 234, 235 oxyuris, 234 pisciformis, 23, 96, 139, 233, 234 rubra, 78, 79, 235 sanguinea, 78, 99, 233, 234 spirogyra, 68, 233-234 vermiformis, 235 viridis, 136, 139, 233, 234 Euglenamorpha, 239 hegneri, 238, 239 Euglenidae, 232-239 Euglenoid, 232 Euglenoidina, 36, 70, 78, 200, 232-243 Euglypha, 40, 42, 131, 136, 143, 389 acanthophora, 148, 389 alveolata, 20, 389 cristata, 389, 390 mucronata, 389-390 Euglyphidae, 374, 389-392 Eugregarinina, 428, 429-457 Eulophomonas, 321 kalotermitis, 321 Eumycetozoa, 338-341 Eunicea crassa, 679 Eupagurus berhardus, 635 cuanensis, 696 excavatus, 696 Euphorbia, 281 Euphorbiaceae, 281 Euplotes, 21, 37, 56, 123, 676 aediculatus, 676-677 carinatus, 677, 678 charon, 104, 677, 678 eurystomus, 49, 50, 57, 125, 126, 675, 676 longipes, 129 patella, 22, 56, 57, 58, 104, 141, 156, 157, 159, 186, 675, 676 plumipes, 677 tvoodruffi, 125, 675, 676 Euplotidae, 668, 676-677 Euplotidium, 677 agitatum, 677, 678 Eupoterion, 56, 127, 626 pernix, 626, 627 AUTHOR AND SUBJECT INDEX 747 Eurychilum, 613 actiniae, 613, 614 Euryophthalmus convivus, 280, 281 Eurypanopeus depressus, 457 Euryphagous Protozoa, 24 Eurysporea, 521-523 Eusattus, 450 Eutaenia, 299 Eutreptia, 238-239 marina, 238, 239 viridis, 238, 239 Eutreptiella, 238 Eutrichomastix, 299 axostylis, 300 batrachorum, 300 serpentis, 139, 299, 300 Eutyphoeus foveatus, 434 peguanus, 434 rarus, 434 spinulosus, 434 Evans, 603 Evolution, 5, 193-197 Excretion, 103-106 Excystment, 218, 355, 356, 363 Exflagellation, 489 Exoerythrocytic schizogony, 487 Exoskeleton, 10, 39-41, 61 Exuviaella, 247 apora, 248 marina, 247 Eye-spot, 79, 80 Fabrea, 647 salina, 92, 647, 650 Factors for distribution, 17, 148 encystment, 147-148 excystment, 218 Faeces, collection of, 711 Faecal examination, 721-722 Fair, 358 Fannia canicularis, 361 Fantham, 364 Fat, 91, 100 Faure-Fremiet, 72 Feo, 309 Ferments, 70, 72, 90, 93, 335 Feulgen's nucleal reaction, 35, 37, 38, 68, 122, 726 Fibrillar structures, 52-61 Fiebiger, 473 Filopodia, 42, 44 Finch, 475 Fingers and toes, 341 Finley, 21, 22, 103 Fischerina, 400 helix, 399 Fischerinidae, 400 Fish, 280, 285, 297, 301, 313, 370, 473, 480, 510, 513, 521, 523, 524, 525, 526, 527, 528, 529, 530, 531, 535, 538, 539, 540, 549, 568, 590, 685, 692, 696 Fixatives Acetic-formaldehyde, 727 Bouin, 724 Carnoy, 724 Flemming, 724 Osmiun tetroxide, 724 Schaudinn, 723-724 Sublimate-acetic, 724 Flagellata, 12 Flagella, 41, 45-47, 51, 86, 110-111, 193 ciliary, 45, 46 whip, 45, 46 Flather, 95 Flavohacterium trifolium, 350 Fleas, 274, 279, 281, 452 Flies, 357, 361, 448, 500, 542 Foaina, 304 nana, 304-306 Foettingeria, 630 acliniarum, 630, 632 Foettingeriidae, 630-635 Folliculina, 647 moebiusi, 647, 650 produda, 647, 650 FoUiculinidae, 636, 647-648 Fonsecaia, 442 polymorpha, 442, 443 Fontana's staining, 727 Food capture, 42, 47, 51, 84-87 vacuoles, 24, 77-78, 87-90 Foraminifera, 10, 12, 25, 33, 40, 90, 91, 106, 145, 171, 176, 193, 215, 329, 374, 394-405 Forde, 15 Forma, 654 Fossil Protozoa, 10, 193, 394, 417 Fowls, 266, 299, 364, 367, 472, 473. 510 Fox, 277 Free-living Protozoa, 17-24 Frenzelina, 388 . reniformis, 387, 388 Fresh preparations, 719-722 Frisch, 22 Fritillaria pellucida, 256 Frogs, 25, 239, 279, 299, 301, 313, 365, 367, 473, 475, 476, 480, 505, 521, 527, 528, 547, 548, 555, 640, 645, 692 Frontal cirri, 49, 50, 51 membrane, 51 Frontonia, 20, 74, 608 branchiostomae, 608, 609 leucas, 63, 64, 598, 608, 609 Frontoniidae, 608-617 Frye, 179, 358, 361, 718 Fulica atra, 473 Fuligo, 338 septica, 338 Fulton, 692 Furcilla, 221 lobosa, 221 748 PROTOZOOLOGY Furcula, 61 Furgason, 178, 610 Fusiforniis lophomonadis, 321 Fusulina, 399 Fusulinidae, 399 Gadus, 528 aeglefinis, 473 morrhua, 473 virens, 473 Galleria mellonella, 30 Gallinula chloropus, 473 Gallus domesticus, 497 Gametes, 150, 182, 465, 467, 478, 481, 484 Gametocytes, 465, 467, 478, 481, 484, 489 Gammarus, 539, 584, 681, 682, 692 locusta, 682 pulex, 682, 699 puteanus, 699 Gamocystis, 444 tenax, 44-3, 444 Ganymedes, 440 anaspides, 439, 440 Ganymedidae, 431, 440 Gastrophryne, 547 Gastrosteus aculeatus, 539 Gastrostyla, 23, 674 muscorum, 673, 674 Gastrula, 6 Gaylord, 18 Geese, 472 Geiman, 361, 365, 716 Geitler, 223 Gelatinous substance, 40, 41 Gelei, 48, 57, 727 Geleiella, 683 Gemmules, 145, 522, 624 Geneiorhynchus, 455 aeschnae, 453, 455 Genes, 34, 182, 183, 184, 185 Genetics, 176-188 Genotypes, 179 Geographical distribution of Proto- zoa, 17, 24 Geophiles, 448 Gerda, 685 Gerris, 281 Giardia, 313 intestinalis, 13, 139, 313, 314 lamhlia, 313 muris, 139, 314 Gibbula adamsoni, 457 divaricata, 457 rarilineata, 457 Giese, 38, 643 Gigantism, 94, 95, 643 Gigantochloris, 220 permaxima, 219, 220 Gigantomonas, 61, 306-307 herculea, 307 Gilmore, 509 Glaser, 18, 712, 715 Glaucoma, 30, 99, 128, 180, 611 ficaria, 23 pyriformis, 29, 91, 97 scintillans, 23, 127, 611 vorax, 610 Glenodiniopsis, 248 Glenodinium, 100, 248 cinctum, 247, 249 edax, 247, 249 neglectum, 247, 249 pulvisculum, 247, 249 uliginosum, 247, 249 Globigerina, 404 bulloides, 404 Globigerinidae, 404 Globorotalia, 404 Globorotaliidae, 404 Gloeomonas, 220 ovalis, 219, 220 Glossatella, 685 iintinnahulum, 685, 686 Glossina morsitans, 276 palpalis, 274, 275 tachinoides, 274, 275 Glossosiphonia complanata, 449 Gluge, 14 Glugea, 539 anomala, 537, 539 hertwigi, 535, 537, 539 mulleri, 539 Glugea cyst, 28, 635, 637, 539 Glycera, 439 Glycogenous substance, 25, 26, 37, 98-99, 355, 366, 721 Glyptotermes, 304, 306 parvulus, 306 Gnats, 370 Goat, 299, 364, 470, 471, 655, 656, 657 Goebel, 151 Goethard, 251 Goldfish, 280, 285 Goldfuss, 11 Golgi, 14, 57 Golgi apparatus, 67, 68-70, 71, 720 Goniodoma, 259 acuminata, 259, 260 Gonium, 33, 147, 228 formosum, 227, 228 pectorale, 227, 228 sociale, 227, 228 Gonocyte, 254 Gonospora, 438 minchini, 437, 438, 439 Gonostomum, 670 strenuum, 669, 670 Gonvaulax, 100, 259-260 apiculata, 260, 261 polyedra, 260 Gonyostomum, 243 semen, 243 Goodrich, 429, 449 AUTHOR AND SUBJECT INDEX 749 Gorilla, 663 Granata, 136 Grass6, 67, 70, 131, 321 Grassi, 489 Gravity on Protozoa, 115 Gray, HI Greeley, 19 Greenwood, 88, 89 Gregaloid colony, 147 Gregarina, 53, 70, 443-444 blattarum, 140, 166, US, 444 locustae, 443, 444 oviceps, 443, 444 Gregarines, 14, 65, 70, 429 Gregarinida, 54, 99, 145, 428-462, 466 Gregarinidae, 440, 443-445 Gregory, 165 Gromia, 85, 86, 374-375, 398 fluvialis, 375, 376 nigricans, 375, 376 ovoidea, 375, 376 Gromiidae, 374-378 Gros, 14, 364 Gross, 251 Grosse-AUerman, 170 Grouse, 266 Growth factors, 98 Growth stimulants, 98 Gruber, 170, 575, 602 Gruberia, 643 calkinsi, 642, 643 Gruby, 14 Gruithuisen, 11 Guinea pig, 299, 364, 480, 606, 607, 659 Gryllotalpa gryllotalpa, 290 Gryllus abbreviatus, 444, 445 americanus, 444 pennsylvanicus, 445 Gunda segmentata, 556 Gurleya, 539 richardi, 537, 539 Guthrie, 600 Guttuliniidae, 341 Guyenotia, 533 sphaerulosa, 532, 533 Gymnodiniidac, 248, 251-254 Gymnodinioidae, 248-257 Gymnodinioides, 632, 635 calkinsi, 633 Gymnodinium, 78, 100, 249, 251 aeruginosum, 252, 253 agile, 252, 253 palustre, 252, 253 rotundatum, 252, 253 Gymnonympha, 324 Gymnophrys, 333 Gymnospore, 455 Gymnostomata, 62, 551, 560-592 Gynotermone, 151 Gyrinus natalor, 451 Gyrocoris, 640 Gyrodinium, 249, 253 biconicum, 252, 253 hyalinum, 252, 253 Gyromonas, 314 ambulans, 312, 314 Haas, 567 Habitats of Protozoa, 17-31 free-living, 17-24 coprozoic, 20-21 katharobic, 20 mesosaprobic, 20 oligosaprobic, 20 polysaprobic, 20 sapropelic, 20 Haeckel, 5, 12, 33, 53 Haemaphy sails leachi, 503 Haematin, 98 Haematochrome, 78-79, 80, 218 Haematococcus, 11, 218 pluvialis, 78, 98, 101, 139, 218, 219 Haemoglobinuric fever, 502, 504 Haemogregarina, 480 siepanowi, 480, 481 Haemogregarinidae, 196, 477, 480- 482 Haemoproteidae, 486, 499-502 Haemoproteus, 15, 488, 500 colujnbae, 499, 500 lophortyx, 500 Haemosporidia, 196, 428, 484-506 Haemozoin, 105-106, 489 Hahnert, 714 Hake, 14 Hakansson, 179 Halberstaedter, 117 Hale, 19 Halibut, 520, 524 wormy, 520, 524 Halkyardia, 403 radiata, 404 Halkyardiidae, 403 Hall, 24, 71, 93, 97, 98, 136, 138, 144, 241 Hallezia, 703 brachypoda, 703, 704 Halteria, 21, 652 grandinella, 652, 653 var. chlorelligera, 652, 653 cirrifera, 652, 653 Halteriidae, 652-653 Halteridium, 500 Hanging-drop preparation, 719-720 Hantkenina, 403 alabamensis, 402 Hantkeninidae, 403 Haploid, 139-141, 154, 165-166 Haplosporidia, 507, 510-513 Haplosporidian cyst, 513 Haplosporidium, 511 chitonis, 511, 512 heterocirri, 512 750 PROTOZOOLOGY Haplosporidium — continued limnodrili, 136, 511, 512 nemertis, 512 scolopli, 512 vejdovskii, 512 Haplozoon, 146, 256 clymenellae, 255, 256 Haptophrya, 65, 555 michiganensis, 76, 555, 656 virginiensis, 555 Haptophryidae, 552, 555-557 Hardcastle, 470 Hardin, 22, 272 Hardy, 357 Harpadicus gracilis, 635 Harpalus pennsylvanicus erythropus, 444 Harris, 11 Harting, 11 Hartmann, M., 138, 161, 168,3 50, 351 Hartmannella, 131, 350 hyalina, 350 Hartmannula, 587 entzi, 587 Harvey, 95 Hastatella, 683 aesculacantha, 684 Hatt, 455, 456, 457 Hauschka, 166, 479 Hayes, 37, 64, 125 Hedriocystis, 414 reticulata, 414, 4^5 Hegner, 8, 170, 178, 495, 638, 714 Heidenhain, 37 Heidt, 99 Heinsius, 251 Heleopera, 388 petricola, 387, 388 Helicosporidia, 515, 542-543 Helicosporidium, 543 parasiticum, 543 Helicostoma, 621 buddenbrocki, 620, 621 Heliochona, 682 scheuteni, 681, 682 sessilis, 681, 682 Heliozoa, 12, 20, 33, 40, 42, 73, 406- 415 Helix, 14, 285, 479 Helodrilus caliginosus, 434, 552 foetidus, 432, 433, 434 longus, 432, 434 Helops striatus, 451 Hemicycliostyla, 670 sphagni, 669, 670 Hemidactylium scutatum, 555 Hemidinium, 253 nasutum, 252, 253 Hemiophrys, 580 Hemispeira, 628 asteriasi, 627, 628 Hemispeiropsis, 628 comatulae, 628 Hemitubifex benedii, 533 Hemixis, 165 Henderson, 353 Henlea leptodera, 437 Henneguy, 647 Henneguya, 530 exilis, 520, 529, 530 mictospora, 531 psorosperniica, 529, 530 Henry, 471, 472 Hentschelia, 449 thalassemae, 448, 449 Hepatozoon, 480-482 muris, 479, 482 Heredity, 176-188 Herf, 103 Hericia hericia, 543 Herman. 501, 506 Herpetomonas, 273, 282 drosophilae, 281, 282 muscae-domesticae, 282 muscarum, 281, 282 Herpetophrya, 554 astomata, 554 Herpobdella atomaria, 479 Herrings, 473 Hertel, 117 Hertwig, 37, 164 Heterakis gallinae, 266 Heteranthera dubia, 342 Heterocirrus viridis, 512 Heterodinium, 259 scrippsi, 258, 259 Heterohelicidae, 402 Heteronema, 242 acus, 20, 240, 242 mutabile, 240, 242 Heterophrys, 410 glabrescens, 411 myriopoda, 410, 411 Heterophryidae, 407, 410-411 Heterotricha, 636-650 Heterotrophic nutrition, 84-92 Hewer, 72 Hewitt, 495 Hexacontium, 422 aster acanthion, 422 Hexaconus, 421 serratus, 421 Hexactinomyxon, 533 psammoryctis, 532, 533 Hexalaspidae, 421 Hexamastix, 300 batrachorum., 300, 301 termopsis, 300 Hexamita, 312 cryptocerci, 312, 313 iriflata, 20, 46, 312 intestinalis, 312-313 meleagridis, 313 periplanetae, 313 salmonis, 139, 312, 313 Hexamitidae, 312-315 AUTHOR AND SUBJECT INDEX 751 Hickson, 546 Hieronymus, 151 Hill, 11 Hippocampus, 528 Hirmocystis, 444 harpali, 444, 446 termitis, 444, 4-4-6 Histiobalantium, 619 natans, 619, 620 semisetatum, 619, 620 Histiona, 270 zachariasi, 271 Histological changes, 26, 27, 28 Histomonas, 266 meleagridis, 265, 266, 368 History of Protozoology, 10-16 Histozoic Protozoa, 26 Histrio, 668 Hoare, 179, 364 Hodotermes mossambicus, 307 Hogue, 309, 715 Hold-fast organellae, 65-66 Holmes, 282 Holomastigotes, 70, 318 elongatum, 318, 819 Holomastigotidae, 318-320 Holomastigotoides, 319 hartmanni, 319 Holophrya, 23, 567 simplex, 567, 570 Holophryidae, 560, 567-576 Holophryoides, 577 ovalis, 577, 578 Holophytic nutrition, 5, 84, 92-93, 99, 194 Holosticha, 673 hymenophora, 673 vernalis, 673 Holothuria, 440, 628 nigra, 440 Holotricha, 47, 196, 551-635 Holozoic nutrition, 5, 84-92, 194 Homalogastra, 617 setosa, 616, 617 Homalozoon, 562 vermiculare, 561, 562 Homarus gammarus, 457 Homotrema, 405 Homotremidae, 405 Honey bees, 365, 537 Hopkins, 104 Hoplonympha, 322 natator, 322 Hoplonymphidae, 322-324 Hoplitophrya, 557 secans, 558 Hormones in Protozoa, 151 Horning, 71, 72 Horse, 277, 278, 299, 364, 510, 577, 578, 605, 607, 660, 661, 663, 705 Horuvdth, 729 Hosts, 25 Howland, 38, 90, 103 Huff, 487, 501, 502 Hulpieu, 103 Human Protozoa, see Man Hutchinson, 9 Huygens, 11 Hyaline cap, 39, 108, 110 layer, 39, 110 Hyalobryon, 22, 146, 208 ramosum, 207, 208 Hyalodiscus, 334 rubicundus, 332, 334 Hyalogonium, 194, 221-222 klebsi, 221, 222 Hyaloklossia, 468 pelseneeri, 468 Hyalomma aegyptium, 281 Hyalosphenia, 44, 381 papilio, 380, 381 Hyalospira, 635 caridinae, 635 Hyalospora, 444 affinis, 444 Hybopsis kentuckiensis, 530 Hybridization, 182-184, 185-186 Hydaticus, 455 Hydatina, 513 Hydra, 25-26, 370, 672 Hydractinia echinata, 620 Hydramoeba, 29, 30, 351, 370 hydroxena, 25, 140, 369, 370 Hydrogen-ion concentration, 22-24, 90, 98, 102, 252 Hydrophilus piceus, 455, 707 Hydroporus palustris, 480 Hydrostatic organellae, 54, 87, 100 Hydrous, 452 ceraboides, 451 Hydrurus, 146, 210-211 foetidus, 79, 209, 212 Hyla, 547, 692 pickeringi, 548 regilla, 548 versicolor, 160, 547, 645 Hyman, 109 Hymenomonas, 205 roseola, 205, 206 Hymenostomata, 551, 608-621 Hyperammina, 395, 398 subnodosa, 397, 398 Hyperamminidae, 398 Hypermastigina, 25, 45, 61, 85, 91, 103, 131, 195, 263, 318-326 Hyperparasitism, 538 Hypocoma, 629 acinetarum, 627, 629 cardii, 629 patellarum, 627, 629 Hypocomidae, 623, 629 Hypocomides, 629 zyrphaeae, 629 Hypocone, 245 Hypostomata, 560, 585-592 Hypothallus, 337 752 PROTOZOOLOGY Hypotheca, 245 Hypotricha, 50, 636, 668-679 Hypotrichidium, 670 conicum, 670, 671 Hysterocineta, 625 eiseniae, 625 Hysterocinetidae, 623, 624-626 I Ichthyophthirius, 29, 54, 99, 567-568 multifiliis, 26, 568-569 Ichthyosporidium, 513 giganteum, 510-.5ii, 513 hertwigi, 513 Ictalurus furcatus, 528 pundatus, 520, 530 Idiochromatin, 37 Idionympha, 324 perissa, 323, 324 Iduna, 586 Idyaea furcata, 631 Ileonema, 52, 196, 574 ciliata, 574, 575 disper, 574, 575 Immortality, 167 Immunity, 28-29, 491 Incidence of Entamoeba histolytica, 356-357 Incubation period of malaria, 488- 489 Independent assortment, 182, 183 Indirect nuclear division, 130-142 Infusoria, 11 Inman, 117 Insects, 267, 280, 282, 290, 299, 361, 365, 370, 430, 432, 438, 440, 443, 444, 445, 446, 447, 450, 451, 452, 453, 454, 455, 459, 460, 461, 462, 477, 480, 537, 539, 540, 542, 543, 617 Intoshellina, 65, 557 poljanskyi, 556, 557 Intoshellinidae, 552, 557-559 lodamoeba, 99, 365-366 butschlii, 25, 360, 361, 366, 723 suis, 366 williamsi, 366 Iodine cyst, 366 lodinophilous vacuole, 99, 516 Irritability, 113-118 Isogametes, 150, 154 Isogamy, 150, 151 Isolation pedigree cultures, 167, 168, 178 Isopoda, 630 Isoptera, 8 Isospora, 473 higemina, J^Tl, 474 /ei?s, 475, U76 hominis, 471, 473-474 lacazei, 475 lieberkuhni, 475, 4-76 Isospora — continued rivolta, 471, 475 suis, 475 Isotricha, 605 intestinalis, 54, 606 prostoma, 54, 606 Isotrichidae, 593, 605-606 Isselina, 555 Ivanic, 122 Ixodes ricinus, 504 Jacobson, 57 Jahn, 18, 93, 103, 235, 236 James, 29, 486, 487, 490 Jameson, 166 Janda, 30 Janicki, 66, 315 Janickiella, 304 Janus green B, 71, 104, 720 red, 71 Jarrina, 473 paludosa, 471, 473 Jennings, 7, 106, 114, 115, 116, 117, 118, 154, 157, 169, 170, 178, 181, 184, 187, 642 Jensen, 115 Jepps, 179 Jirovec, 30, 57 Joblot, 11 Joenia, 322 annectens, 321, 322 Joenina, 322 pulchella, 322 Joenopsis, 322 polytricha, 322 John, 718 Johnson, D. F., 79 Johnson, L. P., 24, 233, 235 Johnson, W. H., 97, 603 Jollos, 37, 179 Joseph, 117 Joyet-Lavergne, 70, 72 Juncus, 342 K Kahl, 51, 64, 65, 569, 571, 572, 575, 585, 597, 615, 643, 644, 652, 691 Kahlia, 670 acrobates, 670, 671 Kala azar, 15, 282, 283 Kalmus, 103 Kalotermes, 304 brevicollis, 310 clevelandi, 315 emersoni, 315 flavicollis, 321, 322 hubbardi, 306 insularis, 306 minor, 324 simplicicornis, 320, 323, 324 Karyolysus, 482 lacertarum, 479, 482 AUTHOR AND SUBJECT INDEX 753 Karyomastigont, 302, 315 Karyophore, 54, 605, 648 Karyosome, 34 Katharobic Protozoa, 20 Kean, 509 Keilin, 542 Kent, 687, 691 Kentrochona, 682 nebaliae, 681, 682 Kentrochonopsis, 682 Kentrophoros, 582 fasciolatum, 581, 582 Kephyrion, 203 ovum, 202, 203 Kepner, 350 Kerona, 11, 672 polyporum, 25, 672, 673 Keronopsis, 672 rubra, 672, 673 Keramosphaera, 401 Keramosphaeridae, 400 Kessel, 358, 359 Khainsky, 89 Khawkinea, 80, 194, 236 halli, 98, 236 ocellata, 236 Kidder, 56, 57, 65, 74, 90, 94, 127, 129, 136, 148, 168, 552, 611, 612, 615, 624, 626, 715 Kilbourne, 14 Kimball, 7, 123, 156, 157, 184, 186, 187 Kinetonucleus, 67 King, 76 Kingsbury, 72 Kinoplasm, 53, 54 Kirby, 62, 67, 87, 92, 131, 136, 293, 296, 303, 304, 306, 307, 311, 588, 597, 598, 640, 647 Kirbyella, 302 Kissing bug, 277 Kitching, 103 Kite, 38 Klebs, 18, 194 Klein, 48, 50, 57, 65, 729 Kloss, 14 Klossia, 479 helicina, 14, 479 Klossiella, 480 cohayae, 480 muris, 4-79, 480 Knop's solution, 714 Kpch, 364 Kofoid, 38, 47, 66, 67, 130, 131, 132, 144, 246, 251, 260, 261, 277, 654, 655 Kofoidella, 554 eleutheriae, 553, 554 Kofoidia, 324 loriculata, 324, 3£5 Kofoidiidae, 324 Kofoidina, 441 ovata, 441 Kolkwitz, 20 Kolliker, 14 Koltzoff, 53 Konsuloff, 546 Korschikoffia, 221 guitula, 221 Kreyella, 595 Krijgsman, 111, 287 Kruger, 64, 65 Kudo, 8, 36, 54, 123, 127, 144, 350, 457, 568 Kuenen, 357, 358, 359 Kuhn, 19 Kumm, 29 Kunstler, 62, 293 Kusch, 29 Kylin, 78 Labyrinthomyxa, 330 sauvageaui, 330, 331 Labyrinthula, 329 cienkowskii, 329, 331 macrocystis, 329-330 Labyrinthulidae, 329-330 Lacerta, 290 muralis, 482 Lachmann, 12 Lachmannella, 65, 556 recurva, 556 Lackey, 20, 138 Lacrymaria, 20, 572 coronata, 572, 573 lagenula, 572, 573 olor, 21, 572, 573 Lada, 626 Ladopsis, 625 Laelaps echidninus, 482 Lagena, 402 striata, 402 Lagenaria cougourda, 542 Lagenidae, 401 Lagenoeca, 271 ovata, 271 Lagenophryidae, 690, 691-692 Lagenophrys, 691 labiata, 690, 692 patina, 690, 692 vaginicola, 690, 692 Lagynophrya, 567 mutans, 567, 570 Laidlaw, 717 Lamblia, 313 Lambornella, 612 stegomyiae, 609, 612 Laminaria lejolisii, 330 Lampoxanthium, 421 pandora, 421, 422 Lamprodrilus, 558, 559 Lampropeltis getulus, 365 Lampsilis cariosa, 624 radiata, 624 Landacre, 218 754 PROTOZOOLOGY Lankester, 38 Lankesterella, 476 minima, 476-477 Lankesteria, 438 culicis, 429, 430-431, 438 Larcoidae, 423 Lasea rubra, 457 Lauterborn, 20 Laveran, 14, 28, 180 Laverania malariae, 492 Lebour, 248 Lecanophrya, 700 drosera, 700, 701 Lechriopyla, 56, 61, 597 mystax, 597 Lecudina, 441 pellucida, 441, US Lecudinidae, 440, 441-442 Lecythion, 449 thalassemae, 448, 449 Lecythium, 42, 377 hyalinum, 377 Leeches, 279, 449, 476, 479, 480 Leewenhoek, 10-11, 13 Legendrea, 562 heller ophon, 561, 562 Leger, 196, 501, 502 Legerella, 480 hydropori, 4^9, 480 Legeria, 455 agilis, 453, 455 Leidy, 12 Leidyana, 445 erratica, 445, 446 Leidyanidae, 441, 445 Leidyonella, 324 Leidyopsis, 324 Leishman, 15 Leishmania, 8, 15, 26, 28, 33, 273, 282-283, 716 brasiliensis, 71, 284 donovani, 26, 98, 283-284 infantum, 283 tropica, 98, 102, 282, 284 Leishmaniasis, 28, 282, 283, 284 Lembadion, 610 bullinum, 609, 610 Lembus, 620 Lentospora, 528 Lepidosiren paradoxa, 529 Lepismatophila, 446 thermobiae, 446, 447 Lepocinclis, 236 Lepomis, 531 humilis, 523 Leptochlamys, 382 ampullacea, 382, 383 Leptodactylidae, 8 Leptodactylus, 527 Leptodiscus medusoides, 261, 262 Leptomonas, 273, 281 denocephali, 281 Leptopharynx, 595 Leptospironympha, 320 eupora, 319, 320 Leptotheca, 521 ohlmacheri, 164, 521, 522 Lepus cuniculus, 279 domesticus, 279 Lernaeophrya, 696 capitata, 696, 697 Lesquereusia, 44, 381 spiralis, 380, 381 Leucine, 105 Leuciscus ruiilus, 530 Leuckart, 14 Leucocytozoon, 488, 500 anatis, 500, 501 simondi, 500-502 Leucophrys, 610 patella, 157, 609, 610-611 Leucosin, 100 Leucotermes flaviceps, 320 Levine, 639 Levinsohn, 90 Lewis, 14 Libinia dubia, 442 Liceidae, 340 Licnophora 649 conklini, 650 macfarlandi, 649, 650 Lichnophoridae, 636, 649-650 Lieberkiihn, 53 Lieberkuhnia, 42, 85, 86, 376 wagneri, 21, 376, 377 Liesche, 142 Life-cycle of Actipylea, 418, 419 Adelea ovata, 478 Aggregata eberthi, 466-467 Apostomea, 630, 631 Avian Plasmodium, 488 Babesia bigemina, 503-504 Chromulina, 201 Chrysomonadina, 201 Coccidia, 464-465,* 466-467, 478, 481 • _ Discorbis petalliformis, 396, 397 Eimeria schubergi, 464-465 Elphidium crispa, 396, 397-398 Entamoeba histolytica, 355 Eudorina elegans, 151, 153 Eugregarinina, 429, 430-431 Foraminifera, 395-398, 401 Gregarinida, 4^9, 430-431, 457-458 Haemogregarina stepanowi, 480, 481 Haemoproteus columbae, 499 Haemosporidia, 484-486, 499, 501, 503 Haplosporidia, 510-511 Helicosporidia, 542-543 Ichthiosporidium giganteum, 510- 511 Lankesteria culicis, 429, 430-431 Leucocytozoon simondi, 501 I AUTHOR AND SUBJECT INDEX 755 Life-cycle of — continued Microsporidia, 149, 535-536 Mycetozoa, 335-337 Myxosporidia, 517-520 Nydotherus cordiformis, 160, 161 Pandorina morum, 151, 153 Peneroplis pertusus, 401 Phytomonadina, 151, 152, 153 Plasmodium of bird, 488 Plasmodium vivax, 484-486 Radiolaria, 418-419 Schizocystis gregarinoides, 457-458 Schizogregarinaria, 457-458 Sphaeromyxa sabrazesi, 517-520 Spirillina vivipara, 395-396 Spirophrya subparasitica, 631 Stempellia magna, 535-536 Stephanosphaera pluvialis, 151, 152 Tetramitus rostratus, 295 Thelohania legeri, 149 Trypanosoma gambiense, 274-275 lewisi, 274 Light stimuli, 117 Light on Protozoa, 19-20, 38 Ligniera, 342 Lillie, 171 Lilly, 94, 97 Limax amoebae, 29, 44, 45, 109 Limax marginatus, 475 Limnodrilus, 541 arenarius, 557 claparedeanus, ,542 hoffmeisteri, 533 udekemianus, 511, 532, 533 Lin, 359 Lindner, 600 Linear colony, 146 Lineus bilineatus, 512 Linkage, 183 Liocephalus liopygue, 439 Lionotus, 21, 70, 580 fasciola, 18, 21, 157, 580, 581 Lipoid substance, 48, 69, 71 Liponyssus saurarum, 482 Lipotropha, 461 macrospora, 461 Lister, 395 Lithobius forficatus, 449, 464, 470, 477 mutabilis, 477 Lithocircus, 423 magnificus, 423 Lithocolla, 409 globosa, 410, 4^1 Lithocollidae, 407, 409-410 Lithocystis, 438 brachycercus, 438, 439 Littorina rudis, 555 Litmus, 88, 90 Lituola, 399 nautiloidea, 399 Lituolidae, 398 Lizard, 477, 482 Lobitermes longicoUis, 311 Lobomonas, 219 rostrata, 219, 220 Lobopodia, 42, 44 Lobster, 459, 466 Locke's solution, 717 Locomotor organellae, 41-52 Loefer, 22, 24, 93 Lohner, 102 Losch, 14, 356 Loftusia, 399 Loftusiidae, 399 Loligo, 555 Longitudinal body fibrils, 58-61 flagellum, 245, 246 Long-lasting modification, 180-181 Looper, 25, 370, 409 Lophius piscatoris, 535 Lophocephalus, 451 insignis, 450, 451 Lophomonadidae, 320-322 Lophomonas, 62, 320 blattarum, 25, 66, 67, 134, 139, 148, 320-321, 716 striata, 25, 139, 144, 321, 716 Lophortyx, 500 Lophura i. igniti, 498 Lorica, 39-40, 41, 65 Loricata, 683, 690-692 Loripes ladeus, 628 Louttit, 179 Loxocephalus, 127, 613 plagius, 613, 614 Loxodes, 77, 584 magnus, 583, 584 vorax, 583, 584 Loxodidae, 76, 580, 584 Loxophyllum, 580-581 meleagris, 581-582 setigerum, 581, 582 Lucas, 56, 607 Luce, 105 Lucilia, 282, 361 caesar, 361 Lugol's solution, 45, 99, 366, 721 Lumbricus castaneus, 432, 433 rubellus, 432, 434, 558 terrestris, 432, 433, 552, 558 variegatus, 460, 557, 559 Luminescence, 100, 251 Lund, E. E., 56, 57, 58 Lund, E. J., 102, 144 Lung-fish, 529 Luntz, 117 Lwoff, 30, 57, 94, 96, 97, 98, 623, 630 Lycogala, 340 miniatum, 339 Lycogalidae, 340 Lymnaea stagnalis, 703 Lynch, J. E., 56, 61, 596 Lynch, R. S., 364 756 PROTOZOOLOGY Lynchia brunea, 500 capensis, 600 hirsuta, 500 lividicolor, 500 Lytechinus variegatus, 605 M Macacus nemestrinus, 308 rhesus, 19, 309, 310 MacArthur, 30 MacBride, 72 MacCallum, 15 MacDougall, 56, 117, 166, 181, 588 Macfie, 361 Machadoella, 462 iriatomae, 461, 462 Machilis cyUndrica, 444 Mackerel, 473 Mackinnon, 460 MacLennan, 56, 61, 76, 99, 127, 568, 655, 657, 692 Macoma balthica, 624 Macrogamete, 150, 465, 467, 478, 481, 484 Macrogametocyte, 465, 467, 478, 481, 484 Macrohodotermes massambicus, 318 Macromastix, 294 lapsa, 294 Macronucleus, 34, 37, 122-130, 545 Macrospironympha, 320 xylopletha, 319, 320 Macrotrichomonas, 306 pulchra, 305, 306 Magath, 474 Mai de Caderas, 278 Malacophrys, 612 rotans, 609, 612 Malacostraca, 256 Malaria, 27, 486-495 aestivo-autumnal, 492-493 benign tertian, 491-492 malignant tertian, 492-493 mild tertian, 494-495 Ovale tertian, 494-495 quartan, 493-494 subtertian, 492-493 tertian, 491-492 Malarial organisms, 14, 484-499 Mallard duck, 501 Mallomonas, 47, 100, 203 litmosa, 202, 203 Malmsten, 14 Man, Protozoa in, Balantidium coli, 638-639 Chilomastix mesnili, 298-299 Dieniamoeba fragilis, 368 Endolimax nana, 367 Entamoeba coli, 361-363 gingivalis, 363-364 histolytica, 354-361 Enteromonas hominis, 298 Giardia intestinalis, 313 Man, Protozoa in — continued lodamoeba biitschlii, 365-366 Isospora hominis, 473-474 Leishmania brasiliensis, 284 donovani, 283-284 tropica, 284 Plasmodium falciparum, 492-493 malariae, 493-494 ovale, 494-495 vivax, 491-492 Retortamonas intestinalis, 291 Sarcocystis lindemanni, 509-510 Trichomonas elongata, 309 hominis, 308-309 vaginalis, 309 Trypanosoma cruzi, 276-277 gambiense, 273-275 rhodesiense, 275-276 Manifold, 509 Manwell, 674 Manz, 510 Margarita, 340 Margaritidae, 340 Margaropus annulatus, 503 Marginal cirri, 49, 50 Marsson, 20 Marsupiogaster, 242 picta, 240, 243 striata, 240, 242 Martin, 247, 248, 253, 257, 259 Martini, 170 Maryna, 65, 594 socialis, 594 Marynidae, 593, 594-595 Massive nucleus, 35-37, 546 Massartia, 254 nieuportensis, 252, 254 Mast, 11, 39, 44, 65, 72, 76, 80, 87, 90, 91, 94, 105, 109, 110, 117, 713 Mastigamoeba, 20, 264 aspera, 264 hylae, 265 longifilum, 264 • ' , setosa, 264, 265 Mastigamoebidae, 263-267 Mastigella, 265 vitrea, 264, 265 Mastigina, 264 Mastigophora, 6, 12, 38, 73, 117, 193, 198-316, 330 Mastigosphaera, 65, 225, 230 gobii, 230 Mastotermes darwiniensis, 295, 326 Mathis, 501, 502 Mating behavior, 156 types, 7, 122, 155-156, 157, 158, 166, 184, 185, 186 Mattesia, 460 dispora, 460, 461 Maupas, 13, 157, 161, 167 Maupasella, 65, 557 nova, 557, 558 Maurer's dots, 489 AUTHOR AND SUBJECT INDEX 757 McDonald, 56 McGuire, 350 McNeal, 15, 716 Mechanical stimuli, 114-115 Media, culture, 283, 358, 712-719 Medusctta, 425 ansata, 425 Medusettidae, 425 Medusochloris, 224 phiale, 224 _ Megacy clops viridis, 541, 542 Megalospheric generation, 395 proloculum, 395 Meglitsch, 353 Meiosis, 165-166, 467, 468 Melanin, 105 Melanosome, 80, 249 Meleney, 179, 355, 358, 361, 718 Melolontha, 299, 455 Melophagns ovinus, 278 Membrane, cell, 39 nuclear, 34 Membranella, 50, 51, 57 basal plate, 50 fiber, 50, 56, 57 fiber plate, 50, 56, 57 Membranosorus, 342 Mendelian inheritance, 182-186 Menoidium, 241 incurvum, 68, 139, lU, ^40, 241 tortuosum, 241 Menospora, 447 polyacanlha, 447, 448 Menosporidae, 441, 447 Mercier, 154, 353 Merganser, red-breasted, 501 Mergus serrator, 501 Merocystis, 468 kathae, 140, 468, 469 Merogregarina, 459 aviaroucii, 459 Meroselenidium, 462 keilini, 461, 462 Merozoite, 464, 484 Mesenchytraeus flavus, 512 Mesnil, 28 Mesnilella, 559 clavata, 558, 559 rostrata, 558, 559 Mesodinium, 563 acarus, 564 pulex, 21, 564 Mesojoenia, 322 decipiens, 322 Mesosaprobic Protozoa, 20 Mesozoa, 515 Metabolism, 33-34 Metachromatic granules, 101 Metacineta, 700 mystacina, 21, 700, 701 Metacoronympha, 315 senta, 315, 316 Metacystidae, 560, 563 Metacystis, 563 truncata, 563, 564 Metadevescovina, 306 debilis, 66, 139, 305, 306 Metadinium, 657 medium, 657, 658 Metalnikoff, 89 Metalnikov, 168 Metamera, 449 reynoldsi, 449 schubergi, 448, 449 Metaphrya, 552-554 sagittae, 553, 554 Metaradiophrya, 558 asymmetrica, 558 lumhrici, 558 Metazoa, compared with Protozoa, 5, 6 Metcalf, 8, 546, 547 Methyl green, 35, 721 Methylene blue, 720 Metopidae, 636, 640-641 Metopus, 56, 65, 640 circumlahens, 640, 641 es, 102, 161, 163, 640, 641 fuscus, 640, 641 sigmoides, 640 straitus, 640, 641 Meiridium marginatum, 630 Metschnikoff, 89 Metzner, 117 Meyer, 101 Michelson, 601 Microcometes, 376 paludosa, 375, 376 Microcorycia, 384 flava, 383, 384 Microcyst, 337 MicrofoUiculina, 647 limnoriae, 647 Microgamete, 150, 196, 465, 467, 478, 481, 484 Microgametocyte, 465, 467, 478, 481, 484 Microgromia, 376 socialis, 375, 376 Microjoenia, 322 pyriformis, 322 Microlynchia fusilla, 500 Micron, 33 Micronucleus, 34, 122, 129, 136, 546 Micropterus dolomieu, 696 salmoides, 531 Microregma, 196, 572 auduboni, 572-573 Microrhopalodina, 302 Microscopical examination, 719-729 Microspheric generation, 395 proloculum, 395 Microspirotrichonympha, 320 ovalis, 319, 320 porteri, 319, 320 758 PROTOZOOLOGY Microsporidia, 10, 14, 28, 34, 66, 515, 535-542 Microsporidian cyst, 28 Microsporidiosis, 10 Microstomus pacificus, 521 Microtermes hispaniolae, 353 panamaensis, 353 Microthorax, 595 simulans, 594, 595 Microvelia, 281 Miescher's tube, 507, 508 Milam, 29 Miliolidae, 400 Milk weeds, 281, 282 Minchin, 34, 67 Minnows, 27 Mites, 482, 543 Mitosis, 122, 130-142 Mitraspora, 523 elongaia, 523 Mixotricha, 295 paradoxa, 295 Mixotrophic nutrition, 93-94 Mobilia, 683, 692-693 Modifications, long-lasting, 180-181 Modiola modiolus, 626 Moewus, 150, 151, 166, 176, 182, 183 Mole, 475 Molgula manhattensis, 696 Molisch, 19 MoUusca, 285, 350, 457, 466, 467, 475, 479, 511, 513, 555, 576, 601, 618, 623, 624, 625, 626, 627, 628, 629, 650, 685 Monadidae, 268, 287-289 Monas, 21, 47, 111, 112, 287 elongata, 287, 288 guttula, 287, 288 socialis, 46, 287, 288 sociabilis, 287 vestita, 287, 288 Monera, 33, 333 Monkeys, 277, 308, 309, 357, 495 Monocercomonas, 301 bufonis, 300, 301 Monochilum, 613 frontatum, 613, 614 Monocnidea, 536, 537-542 Monocystidae, 431-432 Monocystis, 70, 72, 131, 136, 166, 431 lumhrici, 432, 433 rostrata, 166 ventrosa, 431-432, 433 Monodinium, 563 Monodontophrya, 557 kijenskiji, 556, 557 Monoductidae, 441, 445-447 Monoductus, 445 lunatus, 445-446 Monomastix, 574 Monomonadina, 293 Monophasic amoebae, 345, 714 Monopylea, 420, 423-424 Monosiga, 269 ovata, 269 robusta, 269 Monster formation, 94, 95, 643-644 Moore, 205, 643 Morgan, 171 Morphology of Protozoa, 33-80 Morphonemes, 54 Morris, 353 Mosquitoes, 430, 438, 461, 484, 486, 487, 488, 489, 537, 539, 554, 612 Motella, 528 mustela, 313 tricirrata, 313 Motorium, 54, 55, 66, 60 Mouse, 279, 299, 314, 364, 472, 475, 480, 510 Movement, 106-113 by cilia, 111-113 flagella, 110-111 myonemes, 113 pseudopodia, 106-110 Moxostoma breviceps, 530 Mrazekia, 541 caudata,_ 541 Mrazekiella, 559 intermedia, 558, 559 Mrazekiidae, 537, 541-542 Mule, 277, 278, 578 MiiUer, J., 12 MuUer, O. F., 11, 13, 309 Mailer's law, 418 vesicle, 76-77, 584 Mulsow, 166 Multicilia, 263 lacustris, 263, 264 marina, 263, 264 Multiciliidae, 263 Multifasciculatum, 705 elegans, 705-706 Multiple division, 144-145 Munia oryzivora, 279 Mus musculus, 277 Musca, 282, 582 domestica, 361 Musgrave, 15 Mutations, 117, 181 Mya arenaria, 576 Mycetobia pallipes, 543 Mycetozoa, 34, 89, 90, 145, 195, 329, 335-342 Mycterothrix, 594 erlangeri, 594, 595 Myers, 395, 396, 397 Mylestoma, 666-667 bipartitum, 666, 667 Mylestomidae, 665, 666-667 Myonemes, 52, 53-54, 113 Myophrisks, 54 Myriapoda, 442, 447, 449, 454, 464. 470, 477, 478 Myriophryidae, 407, 414-415 AUTHOR AND SUBJECT INDEX 759 Myriophrys, 414-415 paradoxa, 415 Myriospora, 468 trophoniae, 468 Mytilus edulis, 624, 626 galloprovincialis, 457 minimus, 457 Myxamoeba, 335 Myxidiidae, 526-528 Myxidium, 526-527 immersum, 527 kudoi, 528 liberkiihni, 140, 146, 527 lindoyense, 527 seroUnu7n, 140, .5^5, 527-528 Myxobolidae, 99, 526, 530-531 Myxobolus, 530 conspicuus, 529, 530 intestinalis, 27, 530 orbiculatus, 529, 530 pfeifferi, 141, 520, 5^5, 530 squamosus, 529, 530 Myxochrysis, 196, 205 paradoxa, 204, 205 Myxoflagellate, 337 Myxogasteres, 335 Myxomonas, 306, 307 polymorpha, 307 Myxomycetes, 335 Myxophyllum, 624 steenstrupi, 624^ 625 Myxoproteus, 521 cordiformis, 521 Myxosoma, 528 catostomi, ISO, 162, 528, 529 cerebralis, 520, 529 Myxosomatidae, 526, 528-530 Myxosporidia, 9, 14, 27, 34, 65, 100, 130, 145, 164, 515-531 Myxosporidian cyst, 517 Myxotheca, 42, 378 arenilega, 377, 378 N Nadinella, 388 tenella, 387, 388 Nagana, 9, 14, 277-278 Niigler, 351 Naegleria, 344 Naiadaceae, 329 Nassoidae, 423 Nassonov, 69, 76 Nassula, 70, 585 aurea, 21, 585, 587 Nassulidae, 585-586 Nasutitermes kirbyi, 300 Natrix cyclopion, 365 rhombifer, 365 sipedon, 365 s. sipedon, 365 Natural death, 166 Navicula, 218 Naville, 131, 154, 166, 460, 467, 518 Nebalia bipes, 256 geoffroyi, 633, 682 Nebela, 391 collaris, 391, 392 Necturus, 692 Needham, 712 Negri, 510 Nelson, 718-719 Nematocyst, 66, 257, 258 Nematocystis, 432 vermicularis, 432, 433 Nematodinium, 66, 249 partitum, 249, 250 Nematopsis, 457 legeri, 456, 457 ostrearum, 457 Nemeczek, 720 Nemertinea, 438, 512 Neoactinomyxum, 533 globosum, 532, 533 Neosporidia, 427 Neotermes, 304 connexus, 304 erythraeus, 306 greeni, 306 simplicornis, 302 Neotoma fuscipes macrotis, 277 micropus micro pus, 277 Nepa cinerea, 435, 460, 477 Nephroselmidae, 213, 215-216 Nephroselmis, 215 olvacea, 214, 215 Nereis beaucourdrayi, 441 cultrifera, 441 Neresheimer, 44, 53 Net-plasmodium, 329 Neuromotor system or apparatus, 54-57, 58-61, 113, 659 Neurophanes, 53 Neusina, 400 Neusinidae, 400 Neutral red, 69, 90, 358, 720 Newt, 279 Nicolle, 716 Nicollella, 591 denodactyli, 591, 592 Nigrosin, 721 Nina, 449 gracilis, 140, 429, 430, 448, 449 Nirenstein, 89, 90 Nitocra typica, 700 N N N medium, 716 Noctiluca, 11, 33, 135, 145, 251 miliaris, 251 scintillans, 71, 100, 250, 251 Noctilucidae, 248, 251 Noguchi, 282 Noland, 102, 161, 569, 572, 575, 582, 585, 618, 619, 640 Noller, 477 Non-cellular organisms, 5 Nonionidae, 402 760 PROTOZOOLOGY Nosema, 537 anophelis, 537 apis, 10, 537 bombjjcis, 10, 14, 537 bryozoides, 537 cyclopis, 537 lophii, 635 notabilis, 525, 538 Nosema-disease, 537 Nosematidae, 537-541 Notosolenus, 242 apocamptus, 240, 242 sinuatus, 240, 242 Nolropis blennius, 530 cornutus, 530 gilberti, 530 Novy, 15, 716 Nowikoff, 94 Nucleal reaction, Feulgen's, 35, 37, 38, 68, 122, 726 Nuclear cleft, 125 Nuclear division, 122-142 direct, 122-130 indirect, 130-142 Nuclear influence, 186-188 Nuclear membrane, 34 reorganization, 124-130, 168, 169, 180, 181 stains, 34, 721, 725 Nuclearia, 331 delicatula, 331 simplex, 332 Nucleic acid, 34, 35 Nucleolus, 34 Nucleophaga, 722, 723 Nucleoplasm, 34, 35 Nucleus, 33, 34-37, 103, 186, 351, 546 compact, 35-37 macro-, 34, 35, 37, 546 micro-, 34, 37, 546 vesicular, 34-35 Nutrition, 84-94 autotrophic, 92-93 heterotrophic, 84-92 holophytic, 84, 92-93 holozoic, 84-92 mixotrophic, 93-94 parasitic, 93 phytotrophic, 92-93 sapropelic, 20 saprophytic, 93 saprozoic, 84, 93 zootrophic, 84-92 Nycotobates pennsylvanica, 452 Nyctotherus, 13, 54, 74, 99, 129, 644 cordiformis, 160, 645, 646 ovalis, 25, 36, 37, 54, 125, 644, 646 Obelia commissuralis, 703 geniculata, 703 Ocellus, 80, 249, 250 Ochromonadidae, 201, 206-208 Ochromonas, 199, 206 ludibunda, 206, 207 mutabilis, 206, 207 O'Connor, 297, 357, 358, 359, 361 Odolasium complanatum, 432 Octomitus, 312 Octomyxa, 341 Octopus tetracirrhus, 555 Octosporea, 542 muscae-domesticae, 541, 542 Odor of water due to Protozoa, 100. 205 Oedogonium, 701 Oesophageal fibers, 54 process, 59 Oikomonadidae, 268, 271-272 Oikomonas, 271 termo, 22, 272 Oikopleura dioica, 254 Oil, 91, 100 Oligosaprobic Protozoa, 20 Oligotricha, 636, 652-663 Oncopeltus fasciatics, 282 Onychodactylus, 587 Onychodromopsis, 676 fiexilis, 675, 676 Onychodromus, 674-676 grandis, 157, 675, 676 Oocyst, 152, 465, 475, 484 Oodinium, 254 poucheti, 254, 255 Ookinete, 152, 484, 504 Oospora, 632 Opalina, 13, 34, 54, 72, 113 carolinensis, 548 chorophili, 548 hylaxena, 547, 548 kennicotti, 548 obtrigonoidea, 547, 548 oregonensis, 548 pickeringii, 548 spiralis, 548 Opalinidae, 547-550 Opalinopsidae, 552, 555 Opalinopsis, 555 sepiolae, 555, 556 Opercular fibers, 56 Opercularia, 687 plicatilis, 686, 687 stenostoma, 686, 687 Operculina, 402 ammonoides, 402 Ophelia limacina, 554 Ophiothrix fragilis, 634 Ophisthotrichum, 659 janus, 659 thomasi, 659 Ophiurespira, 634 weilli, 633, 634 Ophrydiidae, 683, 685 Ophrydium, 33, 685 ectatum, 76, 685 AUTHOR AND SUBJECT INDEX 761 Ophrydium — continued sessile, 684, 685 vernalis, 684, 685 Ophryocephalus, 700 capitatum, 700, 701 Ophryocystidae, 458, 459-460 Ophryocystis, 459 mesnili, 459 Ophryodendridae, 695, 698-699 Ophryodendron, 698 belgicum, 698, 699 porcellanum, 698, 699 Ophryoglena, 617 atra, 617 collini, 616, 617 intestinalis, 616, 617 parasitica, 617 pyriformis, 616, 617 Ophryoglenidae, 608, 617 Ophryoscolecidae, 61, 74, 90, 99, 652, 654-659 Ophryoscolecin, 61 Ophryoscolex, 655 bicoronatus, 655, 656 caudatus, 655, 656 quadricoronatus, 655, 656 Ophthalmidiidae, 400 Opisthodon, 580 Opisthonecta, 684-685 henneguyi, 684, 685, 705 Opisthostyla, 687 annulata, 686, 687 Opisthotricha, 668 Opossum, 277 Opsanus beta, 525 tau, 525 Oral basket, 62 membrane, 51 Orang-outang, 639 Orbitoides, 405 Orbitoididae, 405 Orbitolinidae, 400 Orbulina universa, 176 Orcadella, 340 operculata, 339 Orcheobius, 479 herpobdellae, 140, 479 Orchestia agilis, 552, 590 palustris, 590 Orchitophrya, 554 stellarum, 553, 554 Organella, 5 Oriental sore, 284 Origin of parasitism, 29-31 O'Roke, 500, 501 Orthognathotervies wheeleri, 310 Orosphaera, 422 Orosphaeridae, 422 Orthodon, 586 hamatus, 586, 5S7 Orthomorpha, 442 gracilis, 442 Oryctes, 299, 443 nasicornis, 443 Osmerus, 539 Osmiophile structures, 69 Osmium tetroxide, 71 Ostracoda, 630 Ostracodinium, 658-659 dentatum, 659, 660 Ostrea virginica, 350, 457 Oius asio naevius, 497 Ovis orientalis cycloceros, 655 Oxidation, 101-102 Oxygen on Protozoa, 25, 90, 102-103 Oxymonadidae, 294, 301-302 Oxymonas, 301-302 dimorpha, 301, 302 Oxnerella, 409 marilima, 130, 131, 140, 409 Oxyphysis, 261 oxytoxoides, 260, 261 Oxyrrhis, 144, 249 marina, 136, 250 Oxytricha, 20, 50, 56, 668 bifaria, 668, 669 fallax, 18, 141, 159, 165, 668, 669 hymenostoma, 168 ludibunda, 668, 669 setigera, 668, 669 Oxytrichidae, 668-676 Oyster, 350, 457 Owl, 279 Pachygrapsus crassipes, 445 Pace and Belda, 714 Pack, 570 Packchanian, 277 Paedogamy, 162, 164-165, 166, 517 Palacalanus parvus, 254 Palaemonetes, 633 Palatinella, 195, 204 cyrtophora, 202, 204 Paldina vivipara, 706 Palmella stage, 198 Pamphagus, 42, 136, 382 armatus, 20 mutabilis, 380, 382 Pandorina, 80, 100, 147, 229-230 morum, 151, 153, 229, 230 Panesthia javanica, 648, 649 spadica, 648, 649 Panopeus herbesti, 457 Pansporoblast, 517 Pantin, 109 Pantothenic acid, 98 Panzer, 100 Parabasal apparatus, 66-67 body, 47, 66 thread, 66 Parablepharisma, 644 pellitum, 642, 644 Paracalanus, 554 parvus, 256, 635 762 PROTOZOOLOGY Parachaenia, 575-576 myae, 575, 576 Paracineta, 700 limbata, 700, 701 Paraclevelandia, 648-649 brevis, 648, 649 simplex, 129 Paradesmose, 131 Paradevescovina, 304 Paradileptus, 584 conicus, 583, 584 robustus, 583, 584 Paradinium, 256 poucheti, 255, 256 Paraellobiopsis, 256 coutieri, 255, 256 Paraeuplotes, 677-679 tortugensis, 93, 679 Paraeuplotidae, 668, 677-679 ParafoUiculina, 648 violacea, 648, 650 Paraglaucoma, 612 rostrata, 609, 612 Paraglycogen, 61, 55 Paraholosticha, 674 herbicola, 673, 674 Paraisotricha, 605 beckeri, 605, 606 colpoidea, 605, 606 Paraisotrichidae, 77, 593, 605 Paraisotrichopsis, 578 composita, 578 Parajoenia, 61, 304 grassii, 304, 305 Parajulus venustus, 442 Paramaecium, 598 Parameciidae, 593, 598-601 Paramecium, 11, 21, 23, 24, 56, 64, 65, 70, 74, 86, 88, 89, 94, 95, 99, 102, 104, 115, 116, 117, 118, 184, 598 aurelia, 7, 23, 37, 96, 128, 129, 141, 154, 155, 156, 157, 158, 163, 165, 168, 169, 184, 187,598,555 bursaria, 7, 22, 23, 25, 93, 156, 157, 159, 599, 600 calkinsi, 21, 156, 157, 599, 600 caudatum, 17, 18, 19, 22, 23, 37, 63, 64, 89, 90, 94, 96, 102, 104, 105, 115, 122, 123, 129, 154, 155, 156, 161, 163, 168, 178, 179, 186, 187, 598, 599, 600, 601, 715 multimicronucleatum, 18, 22, 23, 58, 59, 60, 74, 75, 76, 129, 156, 598-599 polycaryum, 599, 600 putrinum, 96, 599, 600 trichium, 156, 163, 599, 600 woodruffi, 74, 599, 600 Paramoeba, 371 pigmeniifera, 369, 371 schaudinni, 371 Paramoebidae, 343, 371 Paramylon, 99-100, 430 Paranassula, 585 microstoma, 585, 687 Paraoesophageal fibrils, 59 Parapodophrya, 699 typha, 86, 699, 701 Parapolytoma, 222 satura, 221, 222 Parasite, 25 Parasitic nutrition, 93 Parasitic Protozoa, 24-31 Parasitism, 25-29 Origin of, 29-31 Paraspathidium, 560 trichostomum, 560 Paravorticella, 685 clymenellae, 684, 685 Pareuglypha, 389 Parmulina, 384 cyathus, 383, 384 Parophrys vetulus, 521 Paroxysm, 484, 489 Pascher, 151, 194, 195, 196 Passer domesticus, 475, 495, 497 Passerine birds, 475 Pasteur, 14 Patella caerulea, 629 Patellina, 403 corrugata, 140, 397 Pathological changes in host, 25-29 Patten, 468, 546 Paulinella, 92, 390 chromatophora, 390 Pavillardia, 251 tentaculifera, 251 Pavonina, 403 flabelliformis, 402 Pearson, 568 Pebrine disease, 10, 14, 537 Pecten, 28 maximus, 468 Pectinella, 50 Pedigree culture, 13 Pelamphora, 563 biitschlii, 563 Pelatractus, 563 grandis, 563, 564 Pellicle, 38 Pelodinium, 665 reniforme, 665, 666 Pelomyxa, 34, 90, 91, 99, 100, 145, 348 carolinensis, 11, 42, 349-350, 714 palustris, 20, 91, 348-349 villosa, 349 Penard, 65, 77, 170, 348, 379, 572, 581, 643 Penardia, 333-334 mutabilis, 332, 334 Penardiella, 562 crassa, 661, 562 AUTHOR AND SUBJECT INDEX 763 Peneroplis, 42, 400 pertusus, 41, 215, 394, 401 Peneroplidae, 400 Penfield, 358 Penniculus, 59 Pentatrichomonas, 311 bengalensis, 311 Pentatrichomonoides, 311 scroa, 310, 311 Peranema, 38, 45, 70, 110, 239, 713 granuUfera, 241 trichophoru7n, 71, 111, 138, 239, 240 Perca, 530 fluviatilis, 280 Perezella, 65, 554 pelagica, 553, 554 Perezia, 539 mesnili, 537, 539 Periacineta, 703 huckei, 703, 704 Pericaryon, 635 cesticola, 633, 635 Peridiniidae, 257-261 Peridiniinea, 246, 248-261 Peridinin, 78 Peridinioidae, 248, 257-261 Perdinium, 100, 118, 257-258 divergens, 258, 259 tabulatum, 258 Perioral membrane, 51 Periplaneta americana, 361, 438 Peripylea, 420, 421-423 Perispira, 562 strephosoma, 561, 562 Peristome, 48, 49, 51 Peritricha, 24, 41, 53, 146, 196, 551, 683-693 Peritromidae, 637, 649 Peritromus, 649 californicus, 649, 650 emmae, 649 Permanent preparations, 722-729 Perornyscus maniculatus, 279 Perty, 12, 379 Petalomonas, 241 mediocanellata, 240, 241 Petalostoma minutum, 531 Petrocheliden I. lunifrons, 497 Pfeiffer, 94 Pfeifferinella, 475 ellipsoides, 475, 476 impudica, 475 Phacodiniiim, 644 ■metschnicoffi, 641, 644 Phacotidae, 217, 225 Phacotus, 225 lenticularis, 223, 225 Phacus, 21, 47, 117, 236 acuminata, 236, 238 anacoelus, 236, 238 longicaudus, 236, 238 pleuronectes, 236, 238 pyrum, 139, 236, 238 Phacus — continued triqueter, 236, 238 Phaeocapsina, 213, 216 Phaeodium, 417 Phaeosphaera, 212 gelatinosa, 209, 212 Phaeothamnion confervicolum, 214, 216 Phagocytosis, 29, 455, 457 Phalangiuin cornutum, 454 crassum, 454 opilio, 454 Phalansteriidae, 268 Phalansterium, 268 digitatum, 268, 269 Pharyngeal basket, 62 Phascolodon, 588 vorticella, 587, 588 Pheasant, 473 fire-back, 266, 498 Pheretima barbadensis, 432, 435 beaufortii, 436 hawayana, 435 heterochaeta, 436 rodericensis, 435 sermoivaiana, 436 wendessiana, 436 Phialoides, 455 ornata, 453, 455 Phialonema, 239 Philaster, 621 armata, 620, 621 digitiformis, 620, 621 Philasteridae, 608, 621 Philasterides, 621 Philips, 171 Phlebotomus, 282 argentipes, 283, 284 inter medius, 284 papatasii, 282, 284 sergenti, 284 Phorcus richardi, 457 Phoretrophrya, 633 nebaliae, 632, 633 Phormia, 282 Phormobothrys, 424 Phoront, 630 Phosphorescence, 100, 251 Photorophrya, 634-635 insidiosa, 633, 635 Photosynthesis, 19, 22, 79, 92, 117 Phryganella, 387 acropodia, 387, 388 Phycochrisin, 78 Phycocyanin, 78 Phyllognathus, 443 Phyllomitus, 291 undulans, 290, 291 Phyllomonas, 220 phacoides, 220 Phylogeny of Protozoa, 193-197 Phylloxanthin, 78 Physalophrya, 601 spumosa, 597, 601 764 PROTOZOOLOGY Physaridae, 338 Physematiidae, 421 Physiological solution, 720 Physiology of Protozoa, 84-118 Physomonas, 287 Physophaga, 632 Phytodiniidae, 257, 261 Phytodinium, 261 simplex, 260, 261 Phytomastigina, 6, 18, 20, 52, 73, 148, 194, 195, 200-262, 712 Phytomonadina, 78, 200, 217-230 Phytomonas, 273, 281 davidi, 281 elmassiani, 282 Phytomyxinea, 341 Phytotrophic nutrition, 92-93 Pickard, 56 Pieris brassicae, 539 Pierson, 125 Pig, 278, 364, 366, 471, 472, 475, 510, 639 Pigeon, 473, 500 Pigments, 27, 38, 65, 78-79 Pileocephalus, 429, 452 striatus, 450, 453 Pimelia, 451 Pimelic acid, 98 Pimephales notatus, 530 Pinaciophora, 414 fluviatilis, 413, 414 Pipetta, 423 tuba, 422 Piroplasma, 502 Pisania maculosa, 457 Pithiscus, 222 Pithothorax, 574 ovatus, 573, 574 Pituophis, 299 Placobdella catenigera, 480 marginata, 279, 449, 476 Placocista, 391 spinosa, 391 Placopsilina, 400 cenomana, 399 Placopsilinidae, 400 Placus, 571-572 socialis, 570, 572 Plagiocampa, 196, 569 marina, 569, 570 Plagiophrys, 42, 382 parvipunctala, 380, 382 Plagiopyla, 23, 596 minuta, 597 nasula, 596, 597 Plagiopylidae, 593, 596-598 Plagiopyxis, 386 callida, 386, 387 Plagiospira, 628 crinita, 627, 628 Plagiotricha, 670 Planaria, 692 limacina, 556 Planaria — continued torva, 557 ulvae, 556 Planorbis corneus, 475 Planorbulina, 405 Planorbulinidae, 404 Plant growth substances, 98 Plants, 5, 281, 329, 330, 341, 342 Plasmagel, 39, 108, 109, 110 Plasmalemma, 108, 109, 110 Plasma-membrane, 39 Plasmasol, 39, 108, 109, 110 Plasmodia, 335, 510 Plasmodiidae, 486-499 Plasmodiophora, 341 brassicae, 139, 341 Plasmodium, 7, 8, 26, 28, 33, 118, 145, 151, 179, 486-491, 718 cathemerium, 486, 487, 497, 498 circumflexum, 487, 497, 498 elongatum, 486, 497, 498 falciparum, 27, 28, 489, 490, 491, 492-493, 496 gallinaceum, 487, 497, 498 hexamerium, 497, 498 inconstans, 495 inui, 19 knowlesi, 19, 29 lophurae, 498-499 malariae, 489, 490, 491, 493-494, 496 nucleophilum, 487, 497, 498 oti, 497-498 ovale, 491, 494-495 polare, 497, 498 praecox, 15, 495 relictum, 15, 487, 495, 498 rouxi, 497, 498 tenue, 492 vaughani, 496, 498 vivax, 28, 152, 485, 486, 488, 490, 491-492, 496 Plasmodroma, 193, 198-543 Plasmogamy, 336, 520 Plasmosome, 34 Plasmotomy, 145, 146, 335, 350, 517 Plastin, 34 Platycola, 691 longicollis, 690, 691 Platydorina, 147, 228 caudata, 228, 229 Platyhelminthes, 513, 554, 556, 617, 692 Platynematum, 614 sociale, 21, 614 Platyophrya, 571 lata, 570, 571 Platysporea, 521, 526-531 Platytheca, 272 microspora, 272 Plectoidae, 423 Pleodorina, 230 californica, 230 AUTHOR AND SUBJECT INDEX 765 Pleordorina — continued illinoisensis, 79, 229, 230 Pleurocoptes, 620 hydr actiniae, 620 Pleurocystis, 434 cuenoti, 434, 455 Pleuromonas, 289 jaculans, 289, 290 Pleuronema, 618 anodontae, 618 coronatum, 21, 618 crassum, 618 jaculans, 21 marinum, 618, 619 setigerum, 618 Pleuronematidae, 608, 618-620 Pleurostomata, 560, 580-584 Pleurotricha, 674 lanceolata, 97, 141, 673, 674 Plistophora, 540 longifilis, 535, 540 Simula, 540 Plodia interpunctella, 460 Plumatella fungosa, 537 repens, 537 Pocillomonas, 225 y?os aquae, 223, 225 Podocyathus, 709 diadema, 70S, 709 Podophrya, 699 co/Ziw, 699 elongata, 698, 699 ^xa, ess, 699 gracilis, 698, 699 Podophryidae, 695, 699-700 Pohl, 105 Poisonous substances, 64, 86 Polar capsule, 65, 515 filament, 65-66, 515, 535 Poljansky, 655 Polyblepharides, 224 singularis, 223, 225 Polyblepharididae, 217, 224-225 Polychaetes, 256 Polydora caeca, 552 flava, 552 Polygastricha, 12 Polykrikidae, 248, 257 Polykrikos, 66, 146, 257, 635 barnegatensis, 257 kofoidi, 257, 258 Polymastigidae, 293, 299-301 Polymastigina, 61, 91, 195, 263, 293- 316 Polymastix, 299 melolonthae, 299, 300 Polymnia, 554 nebulosa, 468 Polymonadina, 293, 315-316 Polymorpha, 577 ampulla, 577, 678 Polymorphina, 402 Polymorphinidae, 402 Polymyxa, 342 Polyplastron, 657 multivesiculatum, 61, 657, 660 Polyrhabdina, 441 spionis, 441, 443 Polysaprobic Protozoa, 20, 101 Polyspira, 635 delagei, 634, 635 Polystomella, 402 Polytoma, 11, 182, 194, 222 pascheri, 182, 183, 184 uvella, 46, 93, 97, 139, 166, 182, 183, 221, 222 Polytomella, 80, 118, 224 agillis, 101, 139, 223, 224 caeca, 224 Pomoxis sparoides, 27, 526, 530 Pompholyxophrys, 412 punicea, 412, 4^3 Pontigulasia, 386 vas, 140, 387 Pontosphaera haeckeli, 209 Popoff, 166, 180 Porcellana platycheles, 699 Porifera, 692 Porochrysis, 195, 204-205 aspergillus, 204, 205 Porospora, 456 galloprovincialis, 457 gigantea, 456, 457 Porosporidae, 441, 455-457 Porotermes adamsoni, 311, 320, 322 grandis, 311 Portunus depurator, 466, 634, 682 Posey, 509 Posterior neuromotor chain, 59 Postoesophageal fibrils, 59 Potamilla reniformis, 461, 462 Poteriodendron, 146, 271 petiolatum, 271 Pouchetia, 249 fusus, 249, 250 maxima, 249, 250 Pouchetiidae, 248, 249-251 Powdery scab, 342 Powell, 138 Powers, 92, 565, 604, 605, 640 Prandtl, 165 Pratje, 100 Precystic stage, 355 Prehensile tentacle, 51 Preparations, 719-729 Fresh, 719-722 Permanent, 722-729 blood film, 727-729 smear, 722-727 section, 729 Primite, 430 Pringsheim, 24, 78, 93, 151 Prismatospora, 451 evansi, 450, 451 Proboscidiella, 302 kofoidi, 301, 302 766 PROTOZOOLOGY Procavia brucei, 591 capensis, 591 Proceros, 556 Procryptotermes, 306 Proloculum, 395 megalospheric, 395 microspheric, 395 Prolophomonas, 322 tocopola, 321, 322 Promitosis, 122 Pronoctiluca, 249 tentaculatum, 249, 250 Pronoctilucidae, 248, 249 Prorocentridae, 247-248 Prorocentrinea, 245, 246-248 Prorocentrum, 247 micans, 247 triangulatum, 247 Prorodon, 64, 65, 571 discolor, 21, 570, 571 griseus, 571 utahensis, 570 Prorodonopsis, 577 coli, 577, 578 Prostomata, 560-578 Protanoplophrya, 555 stomata, 555, 556 Protective organellae, 61-65 Proteomyxa, 329-334 Proteromonas, 289 lacertae, 289-290 Proterythropsis, 249 crassicaudata, 249, 250 Proteus, 11, 345 Protista, 6, 12 Protochrysis, 215 phaeophycearum, 214, 216 Protociliata, 25, 48, 73, 93, 100, 145, 196, 365, 547-550 Protocruzia, 644 pigerrima, 641, 644 Protomagalhaesia, 444 serpentula, 443, 444 Protomerite, 429 Protomite, 630 Protomonadina, 195, 263, 268-292 Protomonas, 330 amyli, 330, 331 Protomont, 630 Protoopalina, 34, 549 intestinalis, 141, 549 mitotica, 549 saturnalis, 549 Protophrya, 555 ovicola, 553, 555 Protophyta vs. Protozoa, 5-6 Protoplasm, 12 Protoplasmic movements, 88-90, 106- 113 Protopsis, 249 ochrea, 249, 250 Protoradiophrya, 146, 559 fissispiculata, 658, 559 Protospongia, 147, 270 haeckeli, 269, 270 Protozoa as non-cellular organisms, 5 as unicellular organisms, 5 coining of term, 12 colonial, 6, 145-147 definition of, 5 distinguished from Protophyta, 5-6 Metazoa, 6 ecology of, 17-31 fossil, 10, 193, 394, 417 geographical distribution of, 17, 24 in faeces, 21 thermal waters, 18 parasitic in man, see Man Protozoa, 215, 256, 330, 365, 635, 685, 700 Phylogeny of, 193-197 physiology of, 84-118 reproduction of, 122-172 size of, 33, 94, 95, 643-644 Protozoology in relation to biology, 6-7 cytology, 8 economic entomology, 7-8, 10 evolution, 7 genetics, 7 geography, 8 geology, 10 medicine, 8, 9 phylogeny, 7-8 pisciculture, 9 sanitary science, 9 soil biology, 9-10 veterinary medicine, 8, 9 zoogeography, 8 Protrichocyst, 38, 65, 215 Protrichomonas, 301 legeri, 300, 301 Prowazek, 117, 600 Prowazekella, 289 Prowazekia, 289 Prunoidae, 422 Psammodromus hispanicus, 477 Psammorydes barbatus, 533 Psammosphaera bowmanni, 40 fusca, 40 parva, 40 rustica, 40 Pseudoblepharisma, 644 tenuis, 642, 644 Pseudoboa clelia, 365 Pseudocalanus elongatus, 256 Pseudochitinous substance, 40, 53 Pseudochlamys, 381 patella, 380, 381 Pseudochromosomes, 138 pseudocyst, 430 Pseudodevescovina, 306 uniflagellata, 306, 307 Pseudodifflugia, 143, 389 gracilis, 387, 389 AUTHOR AND SUBJECT INDEX 767 Pseudofolliculina, 647-648 ardica, 648, 650 Pseudogemma, 703-704 pachystyla, 704, 707 Pseudoklossia, 468 pedinis, 468, 469 Pseudolynchia maura, 500 Pseudomallomonas, 203 Pseudomicrothorax, 595 agilis, 594, 595 Pseudopodia, 41~45, 51, 84-86, 106- 110, 114, 193 Pseudoprorodoii, 571 fardus, 62, 570, 571 Pseudospora, 330 eudorini, 330 parasitica, 330 volvocis, 330, SSI Pseudosporidae, 329, 330 Pseudotrichonympha, 326 grassii, 326 Pseudotrypanosoma, 62, 311 giganteum, 310, 311 Psilotricha, 670 acuminata, 670, 671 Pteridomonas, 195, 265-266 pulex, 265, 266 Pterocephalus, 449 Pteromonas, 225 angulosa, 22S, 225 Pterospora, 438-439 maldaneorum, 439 Ptychoptera contaminata, 453 Ptychostomum, 626 bacteriophilum, 625, 626 Pulsating vacuole, 73-76 Pulsella, 47 Purkinje, 12 Pusule, 93, 199, 246 Putter, 102 Pycnothricidae, 585, 590-592 Pycnothrix, 590-591 monocystoides, 591 Pyorrhoea alveolaris, 364 Pyramidochrysis, 203 modesta, 202, 203 Pyramidomonas, 222 Pyramimonas, 222-223, 224 montana, 223 tetrarhynchus, 223 Pyrenoids, 79, 92 Pyrimidine, 96 Pyrocystis, 261 Pyrotheca, 540 incurvata, 541 Pyrsonympha, 69, 70, 302 granulata, 302, SOS vertens, 302, SOS Python, 299 sebae, 365 Pyxicola, 691 a finis, 690, 691 socialis, 690, 691 Pyxidicula, 143, 380 operculata, 380-381 Pyxidium, 687 urceolaium, 686, 687 vernale, 686, 687 Pyxnia, 454 bulbifera, 45 S, 454 Pyxinoides, 445 balani, 445 Quadrula, 392 symmetrica, 392 Quails, 266, 313, 472, 473, 500 Querquedula crecca, 501 discors, 501 Rabbit, 279, 299, 364, 470 Races of Protozoa, 176-179, 355-356 Rachidelus brazili, 365 Radial cytostomal fibrils, 59 Radiating canals, 74-76 Radiolaria, 10, 12, 25, 33, 40, 61, 100, 106, 145, 193, 215, 406, 417-425 Radiophrya, 146, 557 hoplites, 558 Radium rays, 117 Raffaele, 487 Rainey's corpuscles, 507, 608 Raja, 280, 526 oxyrhynchus, 280 Rana, 547 areolata, 548 cantabrigensis, 548 catesbeiana, 548 clamitans, 528 fusca, 300 pipiens, 528 palustris, 555 sphenocephala, 528, 548 Ranatra linearis, 703 Raphidiophrys, 412 pallida, 412, 413 Raphidocystis, 412 tubifera, 412, 413 Ratcliffe, 365, 639, 716 Rats, 277, 279, 296, 299, 314, 357, 364, 472, 482, 510 Reaction of Protozoa to chemical stimuli, 116 current, 115 electrical stimuli, 118 gravity, 115 light, 117 mechanical stimuli, 114-115 radium rays, 117 Rontgen ray, 117 temperature, 117-118 ultraviolet rays, 117 Reconstruction band, 125 Red snow, 18 768 PROTOZOOLOGY Red water, 247, 253, 260, 565 Red-water fever, 502, 504 Red-winged black bird, 497 Redi, 11 Reduction division, 165-166 Reduviid bugs, 277 Rees, 56, 718 Refringent body, 91, 348 Regeneration, 33, 129-130, 144, 169, 170-172 Reichenow, 37, 38, 78, 101, 122, 123, 218, 365, 663 Reindeer, 656, 657, 659 Relation between neuromotor and silverline systems, 58-61 nucleus and cytosome, 33-34, 170- 172, 186-188 Remanella, 64, 77, 584 rugosa, 583, 584 Renn, 329 Reophacidae, 398 Reophax, 398 nodulosus, 397, 398 Reorganization band, 125 Reproduction in Protozoa, 122-170 asexual, 147-149 sexual, 149-170 Reptiles, 290, 299, 365, 473, 477, 480, 482, 705, 706 Reserve food matter, 98-101 Reservoir hosts, 277, 366 Respiration, 101-103 Reticularia, 340 lycoperdon, 339 Reticulariidae, 340 Reticulitermes flaviceps, 325 flavipes, 302, 318, 320, 325, 539 hageni, 319, 322 hesperus, 302, 320, 322, 325 lucifugus, 318, 325, 539 speratus, 318, 325, 326 tibialis, 325 Retortamonas, 290 blattae, 290 gryllotalpae, 290 intestinalis, 290, 291, 715 Reynolds, 25, 30, 178, 287, 370, 601 Rhabdammina, 395, 398 abyssorum, 397 Rhabdocystis, 432 daviformis, 432, 433 Rhabdophrya, 697 trimorpha, 697, 698 Rhabdostyla, 687 vernalis, 686, 687 Rhagadostoma, 571 Rhaphiceros, 659 Rhaphidomonas, 243 Rhinoceros unicornis, 663 Rhipicephalus evertsi, 505 sanguineus, 505 Rhipidodendron, 286 splendidum, 286 Rhithrogena semicolorata, 540 Rhizammina, 398 algaeforrnis, 397, 398 Rhizamminidae, 398 Rhizobium, 350 Rhizocaryum, 65, 552 concavum, 552, 553 Rhizochrysidina, 194, 201, 209-210 Rhizochrysis, 136, 194, 203, 210 scherffeli, 139, 209, 210, 211 Rhizomastigina, 52, 195, 263-267, 343 Rhizomastix, 266-267 gracilis, 265, 267 Rhizoplasma, 333 kaiseri, 332, 333 Rhizoplast, 47, 67, 68 Rhizopoda, 12, 328, 329-405 Rhizopodia, 42, 44 Rhizotrogus, 299, 455 Rhodes, 297 Rhodomonas, 215 lens, 214,215 Rhopalonia, 447 hispida, 447, 448 Rhopalophrya, 574 salina, 87, 574, 575 Rhumbler, 84, 91, 106, 107, 117, 176 Rhyncheta, 708 cyclopum, 708 Rhynchobolus americanus, 442 Rhynchocystidae, 431, 433-434 Rhynchocystis, 433 pilosa, 433-434, 435 porrecta, 434, 435 Rhynchogromia, 374 Rhynchomonas, 289 marina, 289 nasuta, 20, 21, 289, 290 Rhynchonympha, 324 tarda, 139, 324, 325 Rhynchophrya, 707 palpans, 707 Riboflavin, 97 Richardson, 72 Riddle, 96 Ringer's solution, 716, 717, 720 Ringform, 485 Robertson, 56 Robin, 496 Rodhain, 365 Rontgen rays, 117 Rosenhoff, 11 Root, 178, 357, 358, 361 Root hernia, 341 Roskin, 42, 53, 86, 90 Ross, 15 Rossbach, 104 Rostellum, 298, 302 AUTHOR AND SUBJECT INDEX 769 Rotalia, 403 beccarii, 402 Rotaliidae, 403 Rotifera, 513 Roubaud, 361 Roudabush, 500 Roudsky, 180 Rugitermes, 306 Rumjantzew, 38, 99 Rupertia, 405 stabilis, 404 Rupertiidae, 405 Ruppia, 329, 341 Russel, 9 Sabin, 506 Saccammina, 398 sphaerica, 397, 398 Saccamminidae, 398 Saccharomyces cerevisciae, 97 Saccinobaculus, 303 amploaxostylus, 303 Sagartia leucolena, 630 parasitica, 613 Sagenoscene, 424 Sagitta, 554 claparedei, 371 Sagosphaeridae, 424 St. Remy, 509 Salamander, &55 Salinity and Protozoa, 21-22 Salmo irideus, 297 Salmon, 313 Salmonella, 639 Salmonoid fish, 370, 521, 529 Salpa, 254 Salpingoeca, 270 fusiformis, 270, 271 Salvelinus foniinalis, 297 Sand flies, 282 Sanders, 355, 718 Sandon, 24 Sapero, 179 Sapotaceae, 281 Sappinia, 351 diploidea, 351 Saprodinium, 665 dentatum, 665, 666 putrinum, 665, 666 Sapropelic Protozoa, 20, 665-667 Saprophilus, 614 agitatus, 614 muscorum, 614, 615 Saprophytic nutrition, 93 Saprozoic nutrition, 84, 93 Sarcina fJava, 101 Sarcocystine, 28, 508 Sarcocystis, 508 bertrami, 510 lindemanni, 509-510 miescheriana, 507, 510 Sarcocystis — continued muris, 510 rileyi, 510 tenella, 507, 508, 510 Sarcode, 12 Sarcodina, 9, 10, 13, 38, 193, 195, 198, 328-425 Sarcophaga, 282 Sarcosporidia, 14, 28, 65, 507-510 Sarcosporidiotoxin, 28 Sardine, 473 Sassuchin, 101 Satellite, 430 Saunders, 89 Scaphiopus albus, 548 solitarius, 550 Schaeffer, 11, 105, 109, 345, 350 Schaudinn, 13, 15, 85, 91, 131, 136, 427, 464, 486, 489 Schaudinnella 436-437 henleae, 437 Schaudinnellidae, 431, 436-437 Schellackia, 477 bolivari, 477 Scherffel, 194, 195 Schewiakoff, 104, 615 Schiffmann, 94 Schiller, 248 Schizamoeba 30, 370 salmonis, 369, 370 Schizocystidae, 458, 460-462 Schizocystis, 460 gregarinoides, 458, 460 Schizogony, 147, 427, 458, 464, 484 erythrocytic, 487 exoerythrocytic, 487 Schizogregarinaria, 428, 457-462 Schizonts, 147, 149, 427, 484 Schizotrypanum cruzi, 276 Schneider, 171 Schneideria, 454 mucronata, 453, 454 Schroder, 53, 176 Schuberg, 54, 655 Schubotz, 105 Schuffner's dots, 489 Schultzella, 378 diffluens, 375, 378 Schultzellina, 557 mucronata, 55i7, 558 Schumacher, 101 Schwartz, 171 Sciadiophora, 454 phalangii, 458, 454 Sciadostoma, 595 Sclerotia, 335 Scololepis fuliginosa, 441, 475 Scolopendra, 447, 449 cingulata, 449, 478 heros, 454 subspinipes, 449 Scoloplos mulleri. 512 770 PROTOZOOLOGY Scott, 508 Scourfieldia, 220 complanata, 219, 220 Screech owl, 497 Scutigera, 449 Scyphidia, 685 constrida, 684, 685 Scyphidiidae, 683, 685 Scytomonas, 241 piisilla, 21, 240, 241 Secondary nucleus, 37, 38 Secretion, 103-106, 158 Segregation of factors, 182, 183, 185 Selective power of Protozoa, 40 Selenidium, 461 potamillae, 461 Selenococcidiidae, 465, 466 Selenococcidium, 196, 466 intermedium., 466 Senescence, 166, 167, 168 Sensomotor apparatus, 61 Sepia elegans, 555 officinalis, 466 Sepiola rondeletii, 555 Sericostoma, 453 Serinus canaria, 495 Sessilia, 683-692 Seticephalus, 449 elegans, 448, 449 Sewage organisms, 20 Sex factors, 184 reaction types, 7, 122, 155-156, 157, 158, 166, 184, 185, 186 substance, 150-151 Sex-linked inheritance, 184 Sexual fusion, 150-154, 166, 181 Sexual reproduction, 149-170 amphimixis, 150-161 autogamy, 161, 162-164 automixis, 161-165 conjugation, 154-161 paedogamy, 162, 164-165 sexual fusion, 150-154 syngamy, 150-154 Shapiro, 89, 90 Sharp, 54, 654, 659 Sheep, 278, 299, 364, 470, 471, 510, 605, 655, 657, 658, 659 Shell, 39-41, 61, 374, 394-395 Shortt, 283 Shottenfeld, 97 Shumway, 94 Sialia s. sialia, 497 Sida, 687 Siebold, 12, 14 Sieboldiellina, 557 planariarum, 556, 557 Siedlecki, 15 Silica, 40 Silicina, 398 limitata, 397, 398 Silicinidae, 398 Silicofiagellidae, 201, 209 Siliqua patula, 624 Silkworm, 537 Silpha laevigata, 452 thoracica, 452 Silver-impregnation method, 57, 727 Silver line, 57 Silverline system, 57 Simulium, 535, 540 venustum, 502 Sinton, 491 Sinuolinea, 525 dimorpha, 524, 525 Siphonophora, 285 Siphostoma, 528 Sipunculoida, 460, 531 Sipunculus, 438 Size of Protozoa, 33, 545 Skeleton, 61, 106, 193, 406, 417, 418, 419 Slavina appendiculata, 478, 541 Sleeping sickness, 15, 275, 276 Gambian, 15, 275 Rhodesian, 276 Slides, 719 Slime molds, 335 Smear preparations, 722-729 Smelt, 539 Smith, G. M., 223, 226 Smith, T., 14, 266 Snails, 475, 479 Snake, 299, 365, 473 Snyder, 355, 358 Snyderella, 315 tobogae, 316 Sodium chloride on nucleus, 35 on Protozoa, 21-22, 103-104 Soil Protozoa, 9, 24 Sokoloff, 171 Solanum, 342 Solenophrya, 703 inclusa, 703, 704 pera, 703, 704 Sonderia, 597-598 pharyngea, 597, 598 vorax, 597, 598 Sonneborn, 7, 123, 129, 130, 154, 157, 158, 166, 169, 184, 187 Sorodiscus, 341 Sorophora, 338, 341 Sorosphaera, 341 Soule, 102 Spadella hipunctaia, 371 inflata, 371 serratodentata, 371 Sparrow, 279, 475, 495 Spasmostoma, 569 viride, 569, 570 Spathidiella, 561 Spathidiidae, 560-563 Spathidioides, 561 sulcata, 561 Spathidiopsis, 571 AUTHOR AND SUBJECT INDEX 771 Spathidium, 560 spathula, 62, 129, 168, 560, 561 Specht, 102 Spencer, 62, 168, 560 Species, protozoan, 6, 282 Spector, 179, 357 Spermatozopsis, 224 exultans, 223, 224 Sphaenochloris, 221 printzi, 221 Sphaeraetinomyxon, 532-533 gigas, 532, 533 stolci, 532, 533 Sphaerastrum, 42, 410 fockei, 410, 4// Sphaeiella, 218 Sphaerellopsis, 218 fluviatilis, 218, 219 Sphaerium, 618 corneum, 554, 555 Sphaerita, 38, 648, 722, 723 Sphaerocapsa, 421 Sphaerocapsidae, 421 Sphaerocystis, 446 simplex, 446 Sphaeroeca, 270 volvox,^ 269, 270 Sphaeroidae, 422 Sphaeromyxa, 528 balbianii, 140, 145, 146, 527, 528 sabrazesi, 140, 154, 162, 517-520, 527, 528 Sphaerophrya, 699 magna, 700 soliformis, 699, 701 stentoris, 700 Sphaerorhynchus, 451 ophioides, 451 Sphaerospora, 524 polymorpha, 140, 524, 525, 538 tincae, 524, 525 Sphaerosporea, 521, 523-526 Sphaerosporidae, 523, 524-525 Sphaerozoidae, 423 Sphaerozoum, 423 ovodimare, 422 Sphaleromantis, 203 ochracea, 202, 203 Sphenoderia, 392 lenta, 392 Sphenophrya, 628-629 dosiniae, 629 Sphenophryidae, 623, 628-629 Spheroid colony, 147 Spindle fibers, 130, 131, 132, 133, 134 Spionidae, 441 Spiraulax, 261 jolliffei, 260, 261 Spireme ball, 129, 160 Spirillina, 403 vivipara, 140, 395-397 Spirillum voluians, 101 Spirobolus spinigerus, 442 Spirochona, 681-682 gemnipara, 681, 682 Spirochonidae, 681-682 Spirocystis, 459-460 nidula, 459, 460 Spirodinium, 660-661 equi, 661 Spiroglugea, 542 ociospora, 541, 542 Spirogonium, 224 chlorogonioides, 223, 224 Spirogyra, 91, 330 Spirolociilina, 400 limbaia, 399 Spiromonas, 286 augusta, 286 Spironympha, 320 Spirophrya, 630 subparasitica, 631, 632 Spirorhynchus, 640 verrucosus, 640, 641 Spirostomidae, 636, 641-645 Spirostomum, 23, 52, 75, 92, 102, 104, 117, 118, 125, 641-642 ambiguum, 19, 22, 23, 92, 102, 171, 642-643 filum, 642, 643 intermedium, 642, 643 loxodes, 642, 643 minus, 21, 642, 643 teres, 21, 642, 643 Spirotricha, 196, 551, 636-679 Spirotrichonympha, 319 bispira, 144 leidiji, 319 polygyra, 134, 135, 139, 320 pulchella, 319 Spirotrichonymphella, 320 pudibunda, 320 Spirotrichosoma, 320 capitata, 320 Spirozona, 596 caudata, 594, 596 Spirozonidae, 593, 596 Spleen index, 26 Splitting of chromosomes, 137-138 Spondylomorum, 225, 228 quaternarium, 228, 229 Sponge, 692 Spongilla fluviatilis, 692 Spongomonas, 146, 285 xivella, 285, 286 Spongospera, 342 Sporadin, 429 Sporangium, 336 Spore, 149, 427, 515, 535 actinomyxidian, 531 cnidosporidian, 515 haplosporidian, 510 microsporidian, 535 mycetozoan, 337 myxosporidian, 515-516 telosporidian, 430, 465 772 PROTOZOOLOGY Spore membrane, 515, 535 Sporoblast, 465 Sporocytes, 518 Sporogony, 162, 427, 518 Sporokinete, 504 Sporont, 504, 517, 536 monosporoblastic, 517 disporoblastic, 517 Sporophore, 337 Sporoplasm, 515, 516, 535 Sporozoa, 14, 38, 193, 196, 198, 427- 543 Sporozoite, 427, 465, 484 Sprague, 166, 444 Sprat, 473 Squalorophrya, 705 macrostyla, 705, 706 Squirrel, 277 Stabler, 309, 363, 365 Stains, Delafield, 67, 725 Fontana, 727 Giemsa, 725-726, 729 Heidenhain, 725 Mayer, 725 Silver-impregnation, 727 vital, 720 Wright, 729 Stalk, 65 Starling, 496 Stasziecella, 248 Statocyst, 77 Statolith, 77 Staurocyclia, 423 phacostaurus, 422 Staurojoenina, 324 assimilis, 139, 323, 324 Staurojoeninidae, 324 Staurophrya, 697 elegans, 697-698 Steenbok, 659 Stegomyia scutellaris, 612 Stein, 12, 14, 241 Steinecke, 78 Steinella, 65, 555 uncinata, 556 Steinia, 668 Steinina, 452 rotunda, 450, 452 Stemonitidae, 339 Stemonitis, 339 splendens, 338 Stempellia, 539 magna, 535, 536, 539, 5^0 Stenophagous Protozoa, 24 Stenophora, 442 larvata, 442, 443 robusta, 442, 443 Stenophoridae, 440, 442 Stenostomum leucops, 554 Stentor, 11, 33, 41, 50, 52, 65, 75, 118, 125, 180, 645, 700 Stentor — continued amethystinus, 25, 646, 647 coeruleus, 19, 23, 38, 52, 117,141, 171, 645, 646 igneus, 646 miilleri, 645, 646 multiformis, 647 niger, 647 polymorphus, 645, 646 pyriformis, 647 roeseli, 645-646 striatus, 645 Stentoridae, 636, 645-647 Stentorin, 38 Stephanonympha, 315 nelumbium, 315, 316 Stephanoon, 147, 228 askenasii, 228, 229 Stephanopogon, 571 colpoda, 570, 571 Stephanosphaera, 229 pulvialis, 151, 152, 229 Stephoidae, 423 Stern, 131, 136 Stichopus californicus, 649 Stichotricha, 672 secunda, 671, 672 Sticklebacks, 539 Stictospora, 454 provincialis, 453, 455 Stigma, 79, 80 Stigmatogaster gracilis, 447 Stokes, 13, 685 Stokesia, 617 vernalis, 616, 617 Stokesiella, 287 dissimilis, 287, 288 leptostoma, 287, 288 Stole, 91, 170, 349 Stolotermes victoriensis, 320 Stomatophora, 435 coronata, 435 Stomatophoridae, 431, 434-436 Stomatostyle, 605 Strains of Protozoa, 176-179 Stratman-Thomas, 486, 490, 491 Streblomastigidae, 293, 298 Streblomastix, 298 strix, 130, 144, 298, 300 Strelkow, 61, 655 Streptomonas, 287 cordata, 286, 287 Strickland, 602 Strobilidiidae, 652, 653-654 Strobilidlum, 653-654 gyrans, 653, 654 Strombidinopsis, 654 gyrans, 653, 654 Strombidium, 652 calkinsi, 652, 653 Strong, 638 Strongylidium, 672 californicum, 671, 672 AUTHOR AND SUBJECT INDEX 773 Strongylocentrotus franciscanus, 597 droebachiensis, 597, 604 purpuratus, 597, 603 Stump, 387 Sturnus v. vulgaris, 496 Stylobryon, 146, 288 ahhotti, 288 Stylocephalidae, 441, 450-451 Stylocephalus, 450 giganteus, 450 Stylochona, 682 coronata, 681, 682 Stylochrysalis, 206 parasita, 206 Stylocometes, 699 digitatus, 699 Stylocystis, 453 praecox, 450, 453 Stylonychia, 11, 20, 21, 37, 49, 50, 51, 90, 95, 674 mylilus, 674, 675 notophora, 674, 675 pustulate, 23, 97, 104, 126, 141, 157, 159, 167, 674, 675 putrina, 674, 675 Stylopyxis, 208 mucicola, 207, 208 Styloscolex, 558, 559 Succinia, 479 putris, 624 Suctori'a, 12, 34, 51, 136, 145, 193, 196, 545, 695-709 Suctorial tentacle, 51 Sudan III and IV, 721 Sulcoarcus, 578 pellucidulus, 578 Sulcus, 245 Summers, 126, 674, 679 Supportive organellae, 61-65 Surface tension, 106, 107 Surra, 278 Sutherland, 320 Sutural plane, 515 Swaminath, 282 Swarmers, 182, 419 Swellengrebel, 357, 358, 359 Swezey, 663 Swezy, 38, 47, 66, 67, 130, 132, 144, 246 Swingle, 96 Sycia, 441 inspinata, 441, 443 Syllis gracilis, 512 Symbiosis, 25, 92-93, 293, 599, 619, 638, 645, 647, 652, 653, 670 Symmetry, 33 bilateral, 33, 311 radial, 33 universal, 33 Sympetrurn rubicundulum, 451 Synactinomyxon, 533 tubificis, 532, 533 Synapta, 438 Synchaeta, 513 Syncrypta, 205 volvox, 205, 206 Syncryptidae, 201, 205-206 Syncystis, 460 mirabilis, 460, 461 Syndinium, 256 turbo, 139, 255, 256 Syngamy, 150-154, 166 Synkarion, 151 Synophrya, 633-634 hypertrophica, 632, 634 Synura, 47, 100, 205 adamsi, 205, 206 uvella, 205, 206 Systenus, 448, 461 Systole, 73, 74 Syzygy, 430 Tabanid flies, 278 Tachyblaston, 703 ephelotensis, 703, 704 Tachysoma, 669 parvistyla, 669 Tactile organellae, 47, 50 Taeniocystis, 454 mira, 453, 454 Talbott, 659 Taliaferro, 29, 179 Talorchestia longicornis, 590 Tanypus, 453 Tarentola, 290 Tate, 487 Taylor, 50, 56, 57, 104, 113, 602, 712 Teal, blue-winged, 501 Teal duck, 501 Tectin, 40 Teichmann, 28 Tejera, 361 Teleuscolex, 558, 559 Tellina, 468, 628 balthica, 624 Telomyxa, 542 glugeiformis, 541, 542 Telomyxidae, 542 Telosporidia, 196, 427-506 Telotroch, 683 Temperature and Protozoa, 17-19, 117-118, 176, 358, 490 ten Kate, 54, 61 Tenebrio molitor, 459 Tentacles, 51, 86, 695 Tentaculifera, 584, 695 Teratonympha, 326 mirabilis, 323, 326 Teratonymphidae, 326 Teredo, 628 navalis, 628 774 PROTOZOOLOGY Termite Protozoa, 25, 295, 298, 300, 302, 304, 306, 310, 311, 315, 316, 318, 319, 320, 321, 322, 323, 324, 325, 326, 353, 441, 444, 539 Termones, 151 Termopsis angusticollis, 298 Terrapene Carolina, 365 Test, 39-40, 143, 170, 171, 394-395 Testacea, 40, 42, 73, 145, 329, 374- 392, 398, 714 Testudo argentina, 365 calcarata, 365 graeca, 365 Tetrablepharis, 224 multifilis, 223, 224 Tetractinomyxidae, 531 Tetractinomyxon, 531 intermedium, 531, 532 Tetrahymena, 610 geleii, 23, 29, 97, 178, 609, 610, 611 vorax, 23, 94, 95, 176, 610 Tetramastix, 222 Tetramitidae, 293, 296-298 Tetramitus, 296 pyriformis, 296 rostratus, 18, 51, 295, 296 salinus, 296 Tetramyxa, 341 Tetrataxis, 400 palaeotrochus, 399 Tetratoxum, 663 escavatum, 663 parvum, 663 unifasciculatum, 661, 663 Teutophrys, 562 trisula, 563, 564 Texas fever, 9, 14, 502, 504 Textularia, 399 agglutinans, 399 Textulariidae, 399 Thalassema neptuni, 449 Thalassicolla, 419, 421 nucleata, 140, 171, 421, 422 TKalassicollidae, 421 Thalassophysa, 422 Thalassophysidae, 419, 421 Thalassothamnidae, 422 Thalassothamnus, 422 Thaumatomastix, 244 setifera, 243, 244 Thaumatophrya, 706 trold, 706, 707 Thccacineta, 703 cothurnioides, 703, 704 gracilis, 703, 704 Thecamoeba, 374 Thecoplasm, 53 Theileria, 505 parva, 504, 505 Thelohanellus, 530 notatus, 27, 130, 529, 530 Thelohania, 539 legeri, 7, 149, 162, 539, 540 viultispora, 535 opacita, 7, 535, 539, 540 Theobaldia, 490, 495, 497 annulata, 30 Thermal waters and Protozoa, 18 Thermobia domestica, 447 Thiamine, 96, 97 Thiazole, 96 Thigmophrya, 624 macomae, 624 Thigmophryidae, 623, 624 Thigmotricha, 23, 551, 623-629 Thomson, 358 Thoracophrya, 571 Thorakomonas, 220 sabulosa, 219, 220 Thuricola, 691 folliculaia, 21, 690, 691 Thuricolopsis, 691 kellicottiana, 690, 691 Thylaeidium, 638 iruncatum, 637, 638 Thylacomonas, 272 compressa, 272 Tiarella, 628 Tiarina, 566 fusus, 566 Ticks, 281, 482, 503, 504, 505 Tillina, 75, 602 helia, 612 magna, 21, 602 Tiliqua scincoides, 365 Tinea tinea, 525 Tintinnidae, 41, 256, 652, 654 Tintinnidium, 654 fluviatile, 653, 654 semiciliatum, 653, 654 Tintinnopsis, 56, 654 cylindrata, 653, 654 illinoisensis, 663, 654 Tipula, 267, 299, 365 Toads, 301, 521, 527, 528, 547, 548, 549, 550, 645, 692 Tokophrya, 701-702 cyclopum, 145, 702-703 infusionum, 702 Tomite, 630 Tomont, 630 Tonniges, 64 Tontonia, 653 gracillirna, 653 Torodinium, 253-254 robustum, 252, 254 Torpedo, 526 Torquenympha, 322 octoplus, 321, 322 Torrey, 96 Toxicyst, 64 Toxin, 28, 64, 508 Toxoglugea, 542 vibrio, 541, 542 AUTHOR AND SUBJECT INDEX 775 Toxoplasma, 488, 505 gondii, 505-506 Toxoplasmosis, 506 Tracheliidae, 580, 582-584 Trachelius, 582 ovum, 582, 5S3 Trachelocerca, 52, 574-575 phoemcopterus, 575 subviridis, 575 Trachelomonas, 46, 47, 80, 118, 237 hispida, 79, 237, 238 piscatoris, 237, S38 urceolata, 237, 238 vermiculosa, 237, 238 verrucosa, 237, 238 Trachelophyllum, 574 clavatum, 573, 574: Tractella, 47 Tramea lacerta, 451 Transverse fibrils, 59-61 flagellum, 245-246 Traumatiophtora, 635 punctata, 634, 635 Treillard, 30 Tremalith, 208 Trembley, 11 Trentonia, 243 flagellata, 243 Trepomonas, 314 agilis, 20, 21, 312, 314 rotans, 46, 312, 314 Triactinomyxidae, 531-533 Triactinomyxon, 531 duhium, 532 ignotum, 531, 532 legeri, 532 magnum, 532 mrazeki, 532 Triadinium, 661 caudatum, 661 galea, 661 minimum, 661 Triatoma, 277 dimidiata, 462 gerstaeckeri, 277 heidemanni, 277 longipes, 277 megista, 277 protracta, 277 rubida, 277 Tricaudalia, 663 Tricercomitus, 311 termopsidis, 311 Tricercomonas, 297 intestinalis, 298 Trichia, 340 a^/iis, 339 Trichiidae, 340 Trichites, 62, 64 Trichlorididae, 217, 222 Trichloris, 222 paradoxa, 221, 222 Trichocera annulata, 370 hiemalis, 370 regelationis, 370 Trichocyst, 11, 59, 61, 62, 63, 64, 65, 635 Trichodina, 141, 692, 693 pediculus, 692, 693 urinicola, 692, 693 Trichoduboscqia, 539-540 epeori, 540 Trichomastix, 299 Trichomonadidae, 294, 308-311 Trichomonas, 13, 14, 47, 61, 62, 308 buccalis, 309 caviae, 308 elongata, 139, 309, 715 hominis, 308-309, 715 linearis, 310 macacovaginae, 309-310 tenax, 309 termitis, 310 vaginalis, 309, 311, 715 Trichonympha, 324 agilis, 325 campanula, 132, 139, 325 grandis, 139, 326 Trichonymphidae, 324-326 Trichopelma, 595 sphagnetrum, 594, 595 Trichopelmidae, 593, 595 Trichophrya, 696 columbiae, 696, 697 epistylidis, 696, 657 salparum, 696, 65'7 sinuosa, 696 micropteri, 696 Trichorhynchus, 448 pulcher, 448, 449 Trichospira, 596 inversa, 694, 596 Trichospiridae, 593, 596 Trichostomata, 551, 593-607 Trichotaxis, 674 stagnatilis, 673, 674 Trichuris, 368 Trigonomonas, 314 compressa, 312, 315 Triloculina, 400 trigonula, 399 Trimastigamoeba, 344 philippinensis, 344, 345 Trimastigidae, 293, 294-295 Trimastix, 294 marina, 294 Trimyema, 196, 595-596 compressum, 21, 594, 596 Trimyemidae, 593, 595-596 Trinema, 391 enchelys, 24, 391, 392 Tripalmaria, 663 dogieli, 662, 663 Triplagia, 423 primordialis, 423 776 PROTOZOOLOGY Triplumaria, 663 hamertoni, 663 Tripneustes esculentus, 605, 621 Tripylea, 420, 424-425 Triticum, 342 Triton, 301, 685 taeniatus, 301 Tritrichomonas, 310 augusta, 139, 311 batrachorum, 139, 311 brevicollis, 310 fecalis, 30, 311 foetus, 98, 310-311 Triturus, 692 viridescens, 279 Trochammina, 400 inflata, 399 Trochamminidae, 400 Trochilia, 586 palustris, 586, 587 Trochilioides, 586 recta, 21, 586, 587 Trochocochlea articulata, 457 mutahilis, 457 turbinata, 457 Trochodinium, 254 prismaticum, 252, 254 Troglodytella, 56, 663 abrassarti, 662, 663 var. acuminata, 663 gorillae, 663 Trophochromatin, 37 Trophocyte, 254 Trophonia plumosa, 468 Trophont, 630 Trophozoite, 147 Tropidoscyphus, 242 octocostatus, 240, 242 Trout, 313 Truttafario, 313 Trypanodinium, 256 ovicola, 255, 256 Trypanoplasraa, 284 Trypanosoma, 8, 14, 29, 47, 100, 118, 179, 273, 280, 716 americanum, 278 brucei, 14, 180, 277-278 cruzi, 26, 98, 276-277, 716 danilewskyi, 280 diemyclyli, 279, ;?S0 duttoni, 279 equinum, 278 equiperdum, 278 evansi, 278 gambiense, 15, 18, 26, 273-275 giganteum, 280 granulosum, 280 inopinalum, 279, ^SO Zewsz, 14, 28, 102, 179, ;274, ^75, 279 melophagium, 278 nabiasi, 279 nocluae, 279 paddae, 279 Trypanosoma — continued percae, 280 peromysci, 279 rajae, 280 remaki, 280 rhodesiense, 275-276 rotatorium, 47, 279, ^SO theileri, 278 triatomae, 276 Trypanosomatidae, 93, 268, 272-284 Trypanosomiasis, 273, 275, 276, 277 Truttafario, 313 Tschenzoff, 136 Tsetse flies, 14, 274, 278 Tubifex, 438, 541 inflatus, 557 ^M^e^, 531, 532, 533 Tubulina, 340 fragiformis, 339 Tubulinidae, 340 Tunicates, 254, 256, 696 Turbellaria, 556, 557, 617 Turdus, m. migratorius, 496 Turkey, 266, 472 Turner, 57, 125 Turtles, 365, 480, 705, 706 Tuscarora, 425 murrayi, 425 Tuscaroridae, 425 Tussetia, 222 Twist disease, 521, 529 Tyzzer, 266, 361, 472 U Uca pugilator, 442 pugnax, 442 Ulivina, 442 _ rhynchoboli, 442 Ultraviolet rays, 117 Undulating membranes, 47, 4-9, 51 Unicapsula, 524 muscularis, 164, 520, 523, 524 Unicapsulidae, 523, 524 Uradiophora, 444 cuenoti, 444 Urceolaria, 692 mitra, 692, 693 paradoxa, 692, 693 Urceolariidae, 692-693 Urceolus, 47, 239 cyclostomus, 4.6, 239, 24O sabulosus, 239, 24O Urea, 103, 104 Urechis caupo, 442 Uric acid, 104 Urinympha, 324 talea, 139, 323, 324 Urnula, 700 epistylidis, 700, 701 Urocentrum, 615 turbo, 127, 615, 616 Uroglena, 47, 147, 206-207 volvox, 207 AUTHOR AND SUBJECT INDEX 777 Uroglenopsis, 100, 147, 207 americana, 207-208 europaea, 208 Uroleptopsis, 672 citrina, 671, 672 Uroleptus, 72, 671 dis-par, 671 halsetji, 126, 141, 166, 671-672, 675 limnelis, 671 longicaudatus, 671 mobilis, 159, 167, 180 Uronema, 616 marina, 21, 616, 617 pluricaudatum, 616, 617 Uronychia, 171, 677 seiigera, 677, 678 Urophagus, 315 rostratus, 46, 313, 315 Urosoma, 669 caudata, 669 Urospora, 438 chiridotae, 439, 438 Urosporidae, 431, 438-440 Urosporidium, 512 fuliginosum, 512 Urostyla, 37, 672 caudata, 672, 673 grandis, 113, 129, 671, 672 trichogaster, 671, 672 Urotricha, 196, 569 agilis, 569, 670 farcata, 569, 570 labiata, 571 parvula, 569 Urozona, 615 butschlii, 615, 6^6 Usinger, 277 Utricaceae, 281 Uyemura, 18, 176 Vacuolaria, 243 virescens, 139, 243 Vaginicola, 690 annulata, 690 leptostoma, 690 Vaginicolidae, 690-691 Vahlkampfia, 30, 350 Umax, 18, 42, 34.9, 350 patuxent, 349, 350 Valentin, 14 Valvulina, 400 triangularis, 399, 400 Valvulinidae, 399 Vampyrella, 91, 330 lateritia, 330-331 Vampyrellidae, 329, 330-334 Vampyrophrya, 635 pelagica, 633, 634, 635 Van Wagtendonk, 712 Varanus salvator, 365 varius, 365 Variation in Protozoa, 94, 176-188 Vasicola, 563 ciliata, 563, 564 grandis, 563 Vasudevan, 509 Vaucheria, 329 Vectors, 275, 277, 284 Vegetative form or stage, 147 Ventral cirri, 49, 50, 51 Ventral motor strand, 54 Venus fasciata, 628 Verneuilina, 399 propinqua, 399 Verneuilinidae, 399 Veronica, 341 Vertebralina, 400 striata, 399 Verworn, 33, 44, 85, 111, 117, 118, 170, 171 Vesicular nucleus, 34-35 Viability of cysts, 147, 246, 357-361, 603, 639 Vipera aspis, 475 Visscher, 56, 64 Vital stains, 720 Vitamins and Protozoa, 96-98 Vitamin Bi, 97, 98 Bf, 97, 98 Vitrina, 479 Viviparus japonicus, 555 malleatus, 555 Vlk, 45, 46, 47 Volkonsky, 350 Volutin, 101 Volvocidae, 217, 225-230, 330 Volvox, 11, 33, 100, 147, 226-228, 330 aureus, 150, 226, 227 globator, 226, 227 perglobator, 228 spermatosphaera, 226 tertius, 226 weismannia, 226-228 Vorticella, 11, 20, 52, 70, 90, 99, 687 campanula, 687-688 convallaria, 688 microstoma, 688 monilata, 39, 688, 689 nebulifera, 161 picta, 688, 689 Vorticellidae, 683, 687-690 W Wagnerella, 412-413 borealis, 413 Wailes, 259, 261, 696, 699 Wardia, 522 ovinocua, 523, 524 Wardiidae, 521, 522-523 Weatherby, 104 Weismann, 13, 161, 166 Weissenberg, 299 Wenrich, 266, 308, 309, 368, 563, 567 Wenyon, 297, 308, 357, 358, 359, 361, 430 778 PROTOZOOLOGY Wenyonella, 473 africana, ^71, 473 Werbitzki, 180 Wermel, 38, 99, 370 Whelk, 468 Whip-flagellum, 45, A6 Wichterman, 159, 163, 645 Wickware, 501 Wilson, H. v., 350 Wolf son, 19 Wood, 297 Woodcock, 67, 358 Wood rat, 277 Woodroach, 303, 313, 320, 322, 323, 324, 326, 648, 649 Woodruff, 11, 62, 96, 128, 157, 158, 168, 560 Woodruffia, 603 meiabolica, 603 rostrata, 602, 603 Wormy halibut, 520, 524 Wrisberg, 11 Xanthophyll, 78 Xenotis megalotis, 526 Xiphocaridina compressa, 635 Xylophagous Protozoa, 293 Yarborough, 15, 718 Yatren, 359 Yeast, 97 Yellow-throat, Maryland, 497 Yocom, 22, 56, 57 Yonge, 93 Yorke, 358, 359, 719 Young, 329 Zannichellia, 329, 341 Zelleriella, 8, 34, 353, 550 antilliensis, 141, 550 hirsuta, 550 intermedia, 137, 138, 181, 550 scaphiopodos, 548, 550 Zonomyxa, 383 violacea, 383 Zooamylon, 99, 430 Zoochlorellae, 25, 93, 599, 619, 638, 645, 647, 652, 653, 670 Zoomastigina, 20, 73, 195, 263-326 Zoopurpurin, 38 Zootermopsis angusticollis, 300, 311, 325, 441, 444 laticeps, 311, 325 nevadensis, 300, 311, 325, 441, 444 Zoothamnium, 33, 53, 580, 689 adamsi, 689 arbuscula, 689 Zootrophic nutrition, 84-92 Zooxanthellae, 25, 93, 214, 215, 418 Zostera, 329 marina, 329 Zschokkella, 528 hildae, 527, 528 Zuelzer, 38, 103, 117 Zuluta, 54 Zumstein, 94, 194 Zweibaum, 72 Zygocystidae, 431, 434 Zygocystis, 434 ivenrichi, 434, 435 Zygosoma, 441 globosum, 140, 441-442, 443 Zygote, 56, 151, 152, 165, 182 Zyrphaea crispata, 629 This Book (3rd Edition) PROTOZOOLOGY By Richard R. Kudo, D.Sc. was set, printed and bound by The Collegiate Press of Menasha, Wisconsin. The type face is Monotype 8 A and 25J set 10 point on 12 point. The type page is 25 X 44 picas. The page size is 51/2 x 5%. The text paper is 45-lb. White Lexington E.F. The binding is DuPont Fabrikoid; Quality 700; Color 2055; Grain 0-7 (Boiler); Plia. Med.; Finish S.B. The jacket is Ham- mermill Cover, Sepia, Antique Finish. With THOMAS BOOKS careful attention is given to all details of manufacturing and design. It is the Pub- lisher's desire to present books that are satisfactory as to their physical qualities and artistic possibilities and appropriate for their particular use. THOMAS BOOKS will be true to those laws of quality that assure a good name and good will. I