1．THE PHYLUM PLATYHELMINTHES 1
(a) Turellaria 2
(b) Trematoda 2
(c) Cestoda 3
(d) Temnocephalida 3
Monogenea,Aspidogastrea and Digenea,the Orders of the Trematoda 5
A．The Order Monogenea 6
B．The Order Aspidogastrea 8
C．The Order Digenea 8
Some Trematode Names and their Derivation 9
2．THE CONTRASTING LIFE HISTORIES OF THE MONOGENEA AND DIGENEA 13
(a) The Life History of a Monogenetic Trematode (Polystoma integerrimum) 14
(b) The Life History of a Digenetic Trematode (Fasciola hepatica) 17
(ⅰ) The Miracidium 17
(ⅱ) The Sporocyst 17
(ⅲ) The Redia 19
(ⅳ) The Cercaria 20
3．THE MORPHOLOGY OF THE MONOGENEA 24
Ⅰ．External Structure 24
(ⅰ) The Anterior Adhesive Apparatus or Prohaptor 26
(ⅱ) The Posterior Adhesive Apparatus or Opisthaptor 26
(ⅲ) The External Apertures 28
Ⅱ．Internal Structure 29
(ⅰ) The Muscular System 29
(ⅱ) The Parenchyma 29
(ⅲ) The Mode of Action of the Suckers 30
(ⅳ) The Nervous System and Sense Organs 31
(ⅴ) The Digestive System 32
(ⅵ) The Excretory System 33
(ⅶ) The Reproductive Systems 33
(ⅷ) The Mode of Formation of the Egg Capsules 35
4．THE STRUCTURE OF ASPIDOGASTER AND THE GENERA OF THE ASPIDOGASTRIDAE The Structure of Aspidogaster conchicola 37
(ⅰ) External Characters 37
(ⅱ) Internal Characters and Integument 38
Species of the Genus Aspidogaster Baer,1827 41
Recent Observations on the Structure of Aspidogaster limacoides 42
Key to the Genera of the Family Aspidogastridae Poche 44
5．THE MORPHOLOGY OF THE DIGENEA 45
Ⅰ．The Suborder Gasterostomata Odhner 45
Ⅱ．The Suborder Prosostomata Odhner 46
A．Some General Types and their Main Characteristics 46
B．The Structure of Prosostomata 51
Ⅰ．External Characters 51
Ⅱ．The Internal Organs 52
(ⅰ) The Muscles and Parenchyma 52
(ⅱ) The Nervous System and Sense Organs 53
(ⅲ) The Digestive System 53
(ⅳ) The EXcretory System 55
(ⅴ) The Lymphatic System 57
(ⅵ) The Hermaphrodite Reproductive System 58
(ⅶ) Abnormalities and Artefacts 63
6．THE TAXONOMY OF THE TREMATODA 64
Ⅰ．The Classification of the Monogenea 64
Key to the Suborders,Superfamilies and Families of the Monogenea 65
Suborder Monopisthocotylea Odhner,1912 66
Superfamily Gyrodactyloidea Johnston ＆ Tiegs,1922 66
Families:Gyrodactylidae Cobbold,1864 67
Dactylogyridae Bychowsky,1933 67
Calceostomatidae Parona ＆ Perugia,1890 68
Superfamily Capsaloidea Price,1936 68
Families:Monocotylidae TAschenberg,1879 69
Capsalidae Baird,1853 69
Acanthocotylidae Price,1936 70
Microbothriidae Price,1936 70
Udonellidae Taschenberg,1879 71
Suborder Polyopisthocotylea Odhner,1912 71
Superfamily Polystomatoidea Price,1936 71
Families:Polystomatidae Gamble,1896 71
Hexabothriidae Price,1942 72
Superfamily Diclidophoroidea Price,1936 72
Families:Mazocraeidae Price,1936 73
Discocotylidae Price,1936 73
Microcotylidae Taschenberg,1879 74
Gastrocotylidae Price,1943 74
Diclidophoridae Fuhrmann,1928 74
Hexostomatidae Price,1936 75
Ⅱ．The Classification of the Digenea 75
Key to Families of Digenea 80
The Main Characters of the Families of the Digenea 82
Ⅰ．Gassterostomata 82
Family Bucephalidae Poche,1907 82
Ⅱ．Prosostomata 83
Families:Fellodistomatidae Odhner,1911 86
Allocreadiiae Stossich,1904 86
Acanthocolpidae Lühe,1909 87
Acanthostomatidae Poche,1926 88
Zoogonidae Odhner,1911 88
Ptychogonimidae Dollfus,1936 88
Azygiiae Odhner,1911 89
Hemiuridae Lühe,1901 89
Halipegidae Poche,1926 90
Accacoeliidae Dollfus,1923 91
Haplosplanchnidae Poche,1926 91
Monorchiidae Odhner,1911 91
Haploporidae Nicoll,1914 92
Didymozoidae Poche,1907 92
Aporocotylidae Odhner,1912 93
Bunoderidae Nicoll,1914 93
Gorgoderidae Looss,1901 93
Plagiorchiidae Lühe,1901 94
Lecithodendriidae Odhner,1910 94
Cephalogonimidae Looss,1899 95
Dicrocoeliidae Odhner,1910 95
Microphallidae Viana,1924 96
Opisthorchiidae Lühe,1901 96
Heterophyidae Odhner,1914 97
Stomylotrematidae Poche,1926 98
Philophthalmidae Looss,1899 98
Orchipedidae Skrjabin,1924 98
Psilostomatidae Odhner,1911 99
Eucotylidae Skrjabin,1924 99
Cathaemasiidae Fuhrmann,1928 99
Troglotrematidae Odhner,1914 99
Cyclocoelidae Kossack,1911 100
Notocotylidae Lühe,1909 100
Brachylaemidae Joyeux ＆ Foley,1930 101
Echinostomatidae Looss,1902 101
Mesotretidae Poche,1926 102
Fasciolidae Railliet,1895 102
Campulidae Odhner,1926 103
Paramphistomatidae Fischoeder,1901 103
Microscaphidiidae Travassos,1922 104
Mesometridae Poche,1926 104
Cyathocotylidae Poche,1926 105
Strigeidae Railliet,1919 105
Diplostomatidae Poirier,1886 105
Clinostomatidae Lühe,1901 106
Schistosomatidae Looss,1899 106
7．THE MONOGENEA OF BRITISH FISHES AND AMPHIBIA 107
Families:Gyrodactylidae 108
Dactylogyridae 109
Calceostomatidae 119
Udonellidae 120
Monocotylidae 123
Microbothriidae 130
Acanthocotylidae 135
Capsalidae 137
Polystomatidae 148
Hexabothriidae 149
Mazocraeidae 156
Discocotylidae 160
Gastrocotylidae 166
Microcotylidae 167
Diclidophoridae 172
Hexostomatidae 181
8．SOME DIGENETIC TREMATODES OF BRITISH AND SOME OTHER FISHES 185
Families:Bucephalidae 190
Allocreadiidae 198
Acanthocolpidae 214
Acanthostomatidae 222
Haploporidae 224
Monorchiidae 229
Haplosplanchnidae 232
Accacoeliidae 232
Fellodistomatidae 238
Zoogonidae 246
Azygiidae 251
Ptychogonimidae 255
Hemiuridae 257
Bunoderidae 273
Gorgoderidae 274
Didymozoidae 278
Aporocotylidae 284
Mesometridae 286
Paramphistomatidae 288
9．SOME COMMON DIGENEA OF AMPHIBIA AND REPTILIA 289
Families:Plagiorchiidae 289
Cephalogonimidae 304
Dicrocoeliidae 305
Lecithodendriidae 307
Gorgoderidae 310
Halipegidae 311
Paramphistomatidae 312
Some Trematodes of Chelonians 313
Pronocephalidae 314
Microscaphidiidae 314
Spirorchiidae 314
Allocreadiidae 315
Zoogonidae 315
Azygiidae 315
Hemiuridae 315
Acanthostomatidae 315
10．SOME TREMATODES OF BIRDS 316
Families:Plagiorchiidae 317
Lecithodendriidae 324
Dicrocoeliidae 325
Microphallidae 329
Opisthorchiidae 335
Heterophyidae 338
Clinostomatidae 342
Orchipedidae 343
Eucotylidae 345
Philophthalmidae 346
Cathaemasiidae 348
Psilostomatidae 348
Echinostomatidae 352
Troglotrematidae 361
Notocotylidae 362
Cyclocoelidae 364
Brachylaemidae 366
Cyathocotylidae 369
Strigeidae 370
Diplostomatidae 373
Schistosomatidae 374
Paramphistomatidae 376
Microscaphidiidae 376
Stomylotrematidae 377
11．SOME TREMATODES OF MAMMALS 378
Families:Plagiorchiidae 378
Mesotretidae 379
Lecithodendriidae 383
Dicrocoeliidae 385
Fasciolidae 386
Campulidae 388
Allocreadiidae 394
Opisthorchiidae 394
Heterophyidae 398
Echinostomatidae 402
Troglotrematidae 404
Notocotylidae 406
Cyathocotylidae 407
Diplostomatidae 409
Schistosomatidae 409
Brachylaemidae 412
Paramphistomatidae 415
12．THE LARVAE OF THE DIGENEA 419
Classification of Cercariae 419
(1) Amphistome cercariae 424
(a) ＇Pigmentata＇ type 424
(b) ＇Diplocotylea＇ type 424
(2) Monostome cercariae 426
(a) ＇Ephemera＇ type 426
(b) ＇Urbanensis＇ type 427
(3) Gymnocephalous cercariae 427
(4) Cystocercous cercariae 429
(a) ＇Cystophorous＇ cercariae 429
(b) ＇Cysticercaria＇ (anchor-tailed cercariae) 432
(c) ＇Macrocerous＇ (Gorgoderine) cercariae 433
(ⅰ) ＇Gorgoderina＇ group 433
(ⅱ) ＇Gorgodera＇ group 434
(5) Trichocercous cercariae 435
(a) having eye-spots 437
(b) lacking eye-spots 437
(6) Echinostome cercariae 438
(a) ＇Echinata＇ group 439
(b) ＇Coronata＇ group 440
(c) ＇Echinatoides＇ group 441
(7) Microcercous cercariae (stumpy tail) 442
(8) Xiphidiocercariae 445
(a) Cercariae Microcotylae 446
(ⅰ) ＇Cellulosa＇ group 446
(ⅱ) ＇Vesiculosa＇ group 447
(ⅲ) ＇Pusilla＇ group 449
(b) Cercariae Virgulae 449
(c) Cercariae Ornatae 450
(d) Cercariae Armatae 451
(9) Furcocercous cercariae 453
(a) Bucephalus group 454
(b) ＇Lophocerca＇ group 456
(c) ＇Ocellata＇ group 459
(d) ＇Strigea＇ and ＇Proalaria＇ groups 460
(e) ＇Vivax＇ group 463
(10) Cercariaea 464
(a) ＇Mutabile＇ group 464
(b) ＇Helicis＇ group 465
(c) ＇Leucochloridium＇ group 465
(d) ＇Gymnophallus＇ group 467
Abnormalities of Larval Development 468
13．THE LIFE HISTORIES OF THE TREMATODA 470
A．Monogenea 470
B．Digenea 472
Ⅰ．One intermediate host only 472
(ⅰ) Cercariae not encysting,but actively penetrating the definitive host 472
(ⅱ) Cercariae encysting on herbage after emergence from the snail host 475
(ⅲ) Cercariae encysting upon the shell of the snail intermediate host 475
(ⅳ) Cercariae encysting in the tissues of the snail intermediate host 476
(ⅴ) Cercariae encysting in the snail,but cysts deposited in ＇slime-balls＇ on herbage 477
Ⅱ．Two intermediate hosts 478
(ⅰ) Both intermediate hosts molluscs 478
(a) Gastropod and lamellibranch (adult flukes in birds) 478
(b) Gastropod and nudibranch (adult flukes in fishes) 480
(ⅱ) First intermediate host a mollusc;second a crustacean 480
(a) Second intermediate host a fresh-water crustacean;devinitive host man 480
(b) Second intermediate host a marine copepod,devinitive host a marine fish 480
(c) Second intermediate host a fresh-water copepod,definitive host a frog 481
(ⅲ) First intermediate host a mollusc;second a larval insect 482
(a) Definitive host a fish 482
(b) Definitive host a frog 484
(c) Definitive host a bat 485
(d) Definitive host a bird 486
(ⅳ) First intermediate host a mollusc;second a fish 486
(a) Definitive host also a fish 486
(b) Definitive host a bird or mammal 487
(ⅴ) First intermediate host a mollusc;second an amphibian 489
(a) Definitive host an amphibian 489
(b) Definitive host a bird 489
(c) Definitive host a mammal 490
The Life Histories of some Trematodes 491
14．REPRODUCTION,GEOGRAPHICAL DISTRIBUTION AND PHYLOGENY 494
Reproduction in the Trematoda 494
Ⅰ．Fecundity 494
Ⅱ．Gametogenesis and development 495
A．Spermatogensis 496
B．Oogenesis 498
(a) Maturation and fertilization 498
(b) Segmentation 499
C．The Miracidium and mother redia 500
D．Rediae of the second generation and cercariae 500
Ⅲ．The germ-cell cycle in Trematoda 501
The Geographical Distribution of the Trematoda 503
The Phylogeny of the Trematoda 507
15．THE BIOLOGY OF THE TREMATODA 511
A．Larvae 511
(a) The hatching of miracidia 511
(b) The emergence of cercariae 511
(c) The movements of cercariae 512
(ⅰ) Swimming 512
(ⅱ) Creeping 513
(ⅲ) Rotation 514
(ⅳ) Forced Movements (Taxes) 514
(d) Encystment 515
(e) The effect of the parasite on the host 518
(ⅰ) General 518
(ⅱ) The problem of sex change 520
(ⅲ) Gigantism and abnormal growth in the host 520
(f) Host-specificity 522
(g) Ecological 523
B．Adults 525
(a) Effect of the parasite on the host 525
(ⅰ) Monogenea 525
(ⅱ) Digenea 526
(b) Immunity 527
(c) Hyperparasitism 529
(d) Nutrition 530
(e) Respiration 531
(f) Growth 532
The Maintenance of Living Trematodes in vitro 535
16．A SHORT HISTORICAL ACCOUNT OF THE TREMATODA 537
APPENDIX 543
Notes on the Collection and Preservation of Trematoda 543
The use of the Camera Lucida 547
The Hosts referred to in the Text by their Common English Names 548
A．Fishes 548
B．Amphibia and Reptilia 551
C．Birds 551
D．Mammals 544
LIST OF LITERATURE 556
INDEX 613
Explanation of Abbreviations used in Table 1 83
Table 1．The General Characters of the Main Families of the Digenea 84
Table 2．Monogenetic Trematodes of certain Fresh-water and Marine Fishes in Europe 110
Table 3．Digenetic Trematodes of certain Fresh-water Marine Fishes in Europe 188
Table 4．Some Common Digenetic Trematodes of Amphibia and Reptilia 290
Table 5．Some Trematodes of Various Birds in Europe 318
Table 6．Some Trematodes of Certain Mammals in Europe 380
Table 7．The Life Histories of some Trematodes 491