1. Parvatrema homoeotecnum sp.nov. from the oystercatcher, Haematopus ostralegus occidentalis Neumann at Aberystwyth is described and compared with other species of the genus.

2. The life cycle of this species is unique. The larval stages occur in the gastropod, Littorina saxatilis (Olivi) subsp. tenebrosa (Montagu) and include germinal sacs which have a structure and development similar to an adult digenean. There are no free-living stages and only one intermediate host.

3. The significance of this unique life cycle is discussed.

4. The family Gymnophallidae Morozov, 1955, is reviewed. Emended definitions are given for the family, subfamilies and genera. Keys, diagnostic features and brief notes of the species are included.

I am very grateful to Dr Gwendolen Rees, who suggested the investigation which led to the discovery of this species, for her advice and indispensable assistance throughout the work and the preparation of this paper. I am also grateful to the late Professor T. A. Stephenson for his interest and for the provision of working facilities; to Mr W. A. Ballantine, Mr A. H. Clarke, Jr., Mr C. Curtis, Miss G. P. F. Evans, Dr V. Fretter, Professor L. A. Harvey, Mr D. H. Jones and Dr J. Lewis who sent me specimens of Littorina saxatilis; to Professor R. M. Cable and Emerit. Professor G. R. La Rue for helpful suggestions; to Mr J. R. Hirst and Mr D. Hemingway Jones for photographic and technical assistance and to the Department of Scientific and Industrial Research for a grant which made the work possible.

A new halarachnid mite, Zumptiella coreaensis, is described from female and male specimens obtained from the nasal cavities of the Korean squirrel, Sciurus vulgaris coreae, collected from Korea. A key to the species of the genus Zumptiella is presented.

Earlier schemes of classification of the family Heterophyidae have been based in large part on such features as shape of body, presence of oral spines, number and position of testes, and distribution of vitellaria (Witenberg, 1929; Ciurea, 1933; Mueller & Van Cleave, 1932). Price (1940a) was the first to make extensive use of features of the ventrogenital complex (ventral sucker, gonotyl, genital pore, terminal male duct) and excretory bladder, and produced the first reasonable classification of both the family Heterophyidae and the superfamily Opisthorchioidea. In despite of the obvious significance of the rationale of Price's approach, later authors (Morozov, 1952, 1955; Yamaguti, 1958) have largely ignored the ventrogenital complex and recently discovered life-history data, and have used much the same sorts of features as earlier authors.

The morphology of Paramphistomum sukumum sp.nov. from Bos indicus in the Lake Region of Tanganyika, East Africa, is described and illustrated.

A list is given showing the incidence of nine species of the family Paramphistomatidae and three species of the family Gastrothylacidae found in cattle in the Sukumaland area of the Lake Region of Tanganyika.

In the present paper seven species of cymothoid isopods parasitic on the marine fishes of the Kerala coast are described. A preliminary diagnosis of three of them was published earlier (Pillai, 1954). Full descriptions of all the species are given below. The larval stages described were in all cases taken from the brood pouch. The present work forms part of a thesis for which the author was awarded the Ph.D. Degree by the Kerala University.

Koga (1922) recorded for the first time the occurrence of metacercariae belonging to the genus Phyllodistomum Braun, 1899, in the freshwater shrimp, Palaemon nipponensis from Japan. Later Yogota (1922), Hirata (1928) and Asada (1928) recorded that shrimps in Japan were infected by larvae of several species of Phyllodistomum.

A survey of endoparasites of the Red Kangaroo (Megaleia rufa (Desmarest)) has been carried out in three geographically distinct areas of south-eastern Australia.

During a period covering 22 months, 464 kangaroos of different sexes and ages were collected. Alimentary canals and tracheae of all of them and blood and organ smears from 333 were examined for parasites.

A list of endoparasites of the Red Kangaroo encountered during the study and of others reported earlier is given. This includes three species of blood protozoa, two species of coccidia (Eimeria spp.), two species of cestode and twenty-one species of nematodes.

The numbers of some nematode species are analysed in relation to season, sex of host and age of host as expressed by length of tibia.

Two different patterns of age susceptibility of the Red Kangaroo to nematodes are recorded and it is suggested that these may be dependent upon the presence or absence of direct contact of the parasite with host tissue.

Distribution of nematodes in the stomach of the Red Kangaroo has been studied. Different species were found to occupy separate niches within the stomach.

A statistical test aimed at showing the correlation between severity of infection with some nematodes and condition of host expressed by the ratio: body weight — stomach content/tibia length showed only a very weak negative correlation.

Alimentary canals of 100 sheep and thirty-five wild rabbits sampled simultaneously in the same area were found to be infected with only small numbers of worms.

No parasites injurious to domestic stock were found in the kangaroos examined.

During the present century oogenesis and maturation have been extensively studied in the Digenea. The earlier observations, however, were based on limited methods of histological and cytological techniques and were concerned principally with the general features of the germ-cells and with their chromosomes. Consequently, until recently, little information has emerged regarding the extra-nuclear components of oogonia and oocytes and the changes that these cells undergo during oogenesis. The earlier work on the Digenea is reviewed by Cable (1931), Anderson (1935), Rees (1939), and more recent research is cited in the present paper.

Factors governing the response of the Oriental rat flea, X. cheopis, to the white rat and to three murids were studied in an olfactometer.

Starved females aged 5–10 days were attracted to white rats, whereas starved younger females were repelled or indifferent. Starved males, 1–10 days old, were either indifferent or were repelled.

No clear-cut attraction of 7- and 8-day-old starved females towards the murids Meriones tristrami, Acomys dimidiatus and Microtus guentheri was observed.

Starved females increased their weight during the first 8 days of life by 12·0%, while starved males lost 2·2%. Females kept in a vessel with a white rat showed a 115·2% weight gain, while males under the same conditions gained only 18·8% (Table 5).

The authors wish to thank Dr F. G. A. M. Smit, of the British Museum (Natural History), Tring, Hertfordshire (England), for his valuable help in the preparation of the manuscript for this paper.

The genus Azygia was erected by Looss (1899) for Fasciola tereticollis Rud. (1802) ( = Fasciola lucii Mueller, 1776) from the stomach of Esox lucius in Europe. Other species of the genus were described a few years later, namely, Azygia loossi by Marshall & Gilbert (1905) from Micropterus salmoides, Lucius lucius and Amia calva; A. volgensis by von Linstow (1907) from Lucioperca sandra; A. sebago by Ward (1910) from Salmo sebago and A. bulbosa, and A. acuminata by Goldberger (1911) from Amia calva.

Male specimens found with females of Spinitectus oviflagellis Fourment, 1884, in the intestine of Gadus merlangus have been described and compared with two other males of Spinitectus. Considering the differences they are regarded as males of S. oviflagellis.

1.Studies on the histological changes during digestion in Argas persicus reveal that the ingestion of blood is accompanied by the destruction of the existing gut epithelial cells.

2.The blood remains unlysed for 2–3 days while a new epithelium develops which contains cells that secrete a saliva-fast PAS-positive colloid that causes haemolysis.

3.Other epithelial cells remove the freed erythrocytic nuclei by phagocytosis.

4.Most of the gut cells then absorb protein from the lumen and intracellular digestion takes place leaving pure haematin granules as the waste product of the digestion of haemoglobin.

5.After the initial rapid phase of digestion only relatively few cells show signs of absorptive and digestive activity.

6.Absorption of protein is accompanied by increased alkaline phosphatase activity in the microvilli of the cell border; this activity is lost once absorption finishes and digestion begins.

7.Strong aminopeptidase activity can be demonstrated at the border of some of the protein vacuoles.

8.In vitro tests show that the gut proteinase is active only in the acid range with peaks at pH 2·6 and 3·8 and has a Km of 0·32 % with bovine serum albumin as substrate.

9.In vivo data show that digestion, after haemolysis has occurred, takes place in two phases; the first is rapid and lasts approximately 1–2 weeks and is followed by the second phase which is slow and remains constant until the next blood feed.

10.The proportion of the blood meal which remains after the rapid phase of digestion is determined by the sex and developmental stage of the tick and within each category it is constant and serves, in the absence of significant fat and glycogen reserves, as a food reserve.

1.The morphology of Protopolystoma xenopi from Uganda is compared with specimens previously described by Williams. The chief differences are the slightly greater maximum size, the presence of a second pair of anchors on the opisthaptor, and the absence of a second large oviducal chamber in the uterus.

2. Encapsulation of the egg is described from living worms. A thin, plastic membrane forms around the ovum and yolk cells within the ootype before all the yolk cells have passed into the ootype. The remaining yolk cells pass from the ovo-vitelline duct into the sac formed by this membrane, which is attached to the distal walls of the ootype.

3. Eggs are produced at the rate of 4–15 eggs/worm/24 hr. They hatch in 24–27 days at 24–26° C. The opisthaptor of the larva bears sixteen hooklets and two pairs of anchors, which are in the same positions as in the adult.

4. One larva with one pair of suckers was obtained from the alimentary canal or kidney of a metamorphosing Xenopus tadpole. About sixty other tadpoles were examined for P. xenopi but none was found.

5. Twelve P. xenopi were recovered from the kidneys of a small frog that had been infected experimentally 10 days previously.

6. When naturally infected small frogs from Kajansi Fish Farm were examined, immature P. xenopi were found in the kidney of one frog, in the urinary ducts of two frogs, and in the bladder of one frog. The infection rate was much lower than that in mature Xenopus. Immature P. xenopi were also found in the kidneys of mature Xenopus mülleri.

7. P. xenopi matures more rapidly than its host. A frog weighing only 2·9 g. contained a nearly mature worm in the bladder, while one weighing 4·2 g. contained two mature worms, shedding eggs. Eggs are shed throughout the year. The life cycle of P. xenopi is therefore not regulated by that of its host.

Experiments on the larval development of Fasciola gigantica carried out under natural conditions have shown that at temperatures of 16° C. or less the rediae did not produce cercariae. The first-generation rediae, developed from the sporocyst, and all the rediae of subsequent generations produced only daughter rediae and did not change over to the production of cercariae as long as the low temperatures of the cold season lasted.

As soon as the cold season ended and the temperature of the water in the aquaria containing the infected snails rose to a mean maximum of 20° C. all the rediae switched from redial to cercarial production.

The histological anatomy of the female reproductive system of an oxyuroid nematode, Aspiculuris tetraptera, Schulz, has been described.

The process of egg-shell formation in this animal has been followed in detail while the structural and chemical characteristics of the egg-shell have been studied by histochemical and other methods. It is shown that there are three layers: a lipoprotein layer, a ‘chitinous’ layer and the so-called vitelline (glycosidal) membrane. Evidence is presented for the exogenous origin of the lipoprotein layer: this being formed by the cells of the upper uterus which are shown to be secretory.

The question of quinone-tanning in the egg-shell of A. tetraptera and in other oxyuroids and ascarids is considered. It is shown that neither a polyphenol oxidase nor a high concentration of phenolic substances (apart from protein tyrosine) exists in this system. The significance of these and other observations is discussed in relation to the mechanism of tanning as elucidated in insects and trematodes.

I have to acknowledge with gratitude the support of many during these investigations. To Dr P. Tate for his encouragement and provision of facilities at the Molteno Institute; to Dr D. L. Lee, for much useful discussion and permission to refer to some of his unpublished electron micrographs of nematodes; to Professor J. D. Smyth, who kindly read through the manuscript; to the Cambridge Philosophical Society for a grant that made possible the translation of Fauré-Frémiet's classical study on Ascaris; and to the Department of Technical Cooperation for financial assistance.

The genus Neoaplectana now contains eleven species of nematodes. All are associated with insects. A brief review of the history of the genus is given. An undescribed species referred to as DD-136 is compared with one other species in the genus Neoaplectana. It is very similar to the description given for N. carpocapsae Weiser, and it is concluded that it is probably this species.

The Mochlus fernandi lizards (Scincidae) from the Kivu province (Congo) around Lwiro, Katana, are infected with a broad leaf-like monomorphic trypanosome, Trypanosoma mochli. The high moisture requirements of M. fernandi, which resemble European salamanders, and the morphological similarity of T. mochli to amphibian trypanosomes point to an aquatic transmission and vector for this species.

The morphology of the adult blood fluke Schistosoma edwardiense sp.nov. from Hippopotamus amphibius L. is described and compared with that of other species of Schistosoma.

I wish to acknowledge the receipt of a research grant from Makerere University College towards expenses incurred during this work. I should like to thank Captain F. Poppleton, Warden of the Queen Elizabeth National Park, Dr R. M. Laws, Nuffield Unit for Tropical Animal Ecology, and Dr W. M. Longhurst, University of California, for helping me to get specimens from the hippopotami, also Mr L. Rugema, histologist, for sectioning the worms.

The collection of large numbers of nematodes from Macropus rufus from Toganmain and Wilcannia in New South Wales and Cunnamulla in Queensland and from M. canguru from Cunnamulla has made possible the revision of five species and the description of three new species. The work is divided into two sections:

(1) Strongylina. Filarinema flagrifer Mönnig, Zoniolaimus setifer Cobb, Z. cobbi Kung, Rugopharynx australis (Mönnig) and Papillostrongylus labiatus Johnston & Mawson are re-described: Pharyngostrongylus alpha Johnston & Mawson and P. beta Johnston & Mawson are recognized as synonyms of R. australis; Filarinema moennigi sp.nov. is described from Macropus rufus.

(2) Oxyurina. Macropoxyuris longigularis gen.nov., sp.nov., and M. brevigularis gen.nov., sp.nov., are described from M. canguru. Re-examination of paratype material of oxyurids previously recorded from marsupials has made possible the presentation of more detailed descriptions, and the following nomenclatural changes become necessary: Oxyuris (s.l.) acuticaudata Johnston & Mawson is a synonym of Austroxyuris finlaysoni Johnston & Mawson: Syphacia trichosuri Johnston & Mawson is considered as Oxyuris (s.l.) trichosuri; two new genera are proposed, Potoroxyuris, for Oxyuris (s.l.) potoroo Johnston & Mawson, and Paraustroxyuris for Passalurus parvus Johnston & Mawson. Figures are given of Passalurus ambiguus (Duj.).

The material studied was made available by the generosity of Dr R. Mykytowycz of the C.S.I.R.O. Division of Wildlife Research, Canberra, to whom I am most grateful.

I am also indebted to Dr R. J. Ortlepp, Division of Veterinary Services, Onderstepoort, South Africa, for the gift of a sample of Rugopharynx australis, to Dr M. J. Mackerras, then of the Queensland Institute of Medical Research, for material from Macropus canguru from centres in south eastern Queensland, and to Dr G. B. Sharman of the C.S.I.R.O. Division of Wildlife Research for information on the correct names of the host species.

1. The envelope surrounding Polymorphus minutus during its development in Gammarus pulex has been found to be a capsule produced by a wound healing haemocytic reaction of the host. The haemocytic reaction is stimulated when the parasite stretches the connective tissue serosa of the host's gut.

2. The capsule is a thin, acellular structure, consisting of a protein-carbohydrate complex like that constituting host connective tissue. This material is produced and deposited by the haemocytes.

3. The ability of the haemocytes to produce this protein-carbohydrate material is considered to be the mechanism which ensures the growth of the capsule during the subsequent development of the parasite in the haemocoel.

4. A second layer appears within the capsule just before the parasite reaches the cystacanth stage. This layer is believed to be produced by the parasite.

5. The relevant literature is reviewed, and it appears that the envelopes surrounding all developing Acanthocephala, which have been studied to date, are probably capsules originating in the manner described above.

I am very grateful to Dr P. Tate for advice and encouragement during this work, and to Dr George Salt, F.R.S., for helpful discussions and criticism of the manuscript.