The present paper deals with material examined since the revision of the family (Theodor, 1967) was sent to the press. Material was sent by Mr F. R. Allison from Ghana, by Dr D. Minter, Mr T, S Jones and Mr J. C. Cunningham from East Africa and by Dr F. Zumpt from South Africa and other localities in Africa. The material collected by the Noona Dan Expedition to the Bismarck Archipelago and the Philippines (1961, 1962) was examined. The collection of Nycteribiidae in the Museo Civico di Storia Naturale in Genoa was examined and several new species were found among the material. The types of Stylidia euxesta Speiser in the collection proved different from the species considered as 8. euxesta in the past and to consist of two species. The types of S. euxesta are redescribed.

Records are given of helminth infection found by the dissection of 122 waders belonging to 19 species, some migratory and some resident in Australia. In the examination of the nematodes from these, and some other hosts, the following species were identified and described: Capillaria triloba (Linst.) (Lobibyx novae-hollandiae, Himantopus leucocephalus, Recurvirostra novaehollandiae); Capillaria recurvirostrae sp.nov. (R. novaehollandiae); Amidostomum chevreuxi Seurat (H. leucocephalus); Porrocaecum lobibycis (L. novaehollandiae); Contracaecum spiculigerum (Rud.) (H. leucocephalus); Schistorophus longicornis (Hemp. & Ehr.), and Sciadiocara umbellifera (Molin) (Calidris canutus); Schistorophus limosae sp.nov. and Viktorocara limosae sp.nov. (Limosa lapponica); Viktorocara sp. (Calidris canutus); Echinuria heterobrachiata Wehr (Cladorhynchus leucocephalus, Charadrius alexandrinus, Erolia ruficollis); Chevreuxia australis Johnston & Mawson (Charadrius melanops); Skrjabinoclava horrida (Rud.) (Charadrius rubricollis, C. alexandrinus); Streptocara crassicauda (Creplin) (Ch. alexandrinus); Stello-caronema charadrii sp.nov. (Ch. cucullata); S. glareolae sp.nov. (Glareola isabella); Tetrameres nouveli (Seurat) (Him. leucocephalus, Ch. alexandrinus, Recurvirostra novaehollandiae); T. cladorhynchi sp.nov. (C. leucocephalus); T. calidris sp.nov. (C. canutus); T. lobibycis sp.nov. (L. novaehollandiae); T. scolopacidis sp.nov. (Erolia acuminata, E. ruficollis, Tringa glareola); Pseudaproctella sp. (Lobibyx miles).

I am particularly indebted to the Director, Dr Peter Crowcroft, and the staff of the South Australian Museum; without their help it would have been impossible to obtain many of the parasites. Some birds were presented by Mrs Joan Paton and some by Mr Max Waterman. Specimens from Limosa lapponica were lent by the School of Public Health and Tropical Medicine in Sydney, from Lobibyx novaehollandiae (from Queensland) by Dr John Pearson of the Department of Parasitology of the University of Queensland, and from Lobibyx miles from Dr M. J. Mackerras of the C.S.I.R.O., Division of Entomology, in Canberra. Mr Condon, Curator of Birds in the South Australian Museum, has helped with information on the habits and correct names of the birds, and my colleague, Dr S. J. Edmonds, with names of new species. I also wish to thank Dr W. G. Inglis of the British Museum (Nat. Hist.) who was good enough to read the paper.

The holotype and paratypes of Viktorocara limosae sp.nov. and Schistorophus limosae sp.nov. are in the School of Public Health and Tropical Medicine in Sydney. Other holotypes are in the South Australian Museum, and paratypes in the Helminthological Collection of the Zoology Department of the University of Adelaide.

The life-cycles of the two species of Crepidostomum occurring in a stream in North Wales are investigated. Both species share the same arthropod and definitive hosts, viz. Gammarus pulex and Salmo trutta, respectively, but have different molluscan hosts, viz.: Lymnaea peregra for C. metoecus and Pisidium casertanum for C. farionis.

C. metoecus and C. farionis have annual cycles, hence periodicity of occurrence in their hosts. In C. metoecus the dynamics of occurrence in the three hosts are correlated. The inverse relationship in G. pulex and S. trutta as well as the existence of a time-lag of 3–4 months between the establishment of this worm in G. pulex and in S. trutta are discussed.

Neither premunition nor age-resistance occurs in the parasitization of S. trutta and G. pulex by C. metoecus. The increase in the rate and degree of infestation with the age and length of fish, except in the oldest and longest group, is shown to be due to trophic factors.

C. metoecus is more abundant and widely distributed in the stream than C. farionis. This fact is associated with the occurrence of their molluscan hosts.

Experimental observations were made on the stages in the life-history of C. metoecus, including the mode of emergence of the cercaria, invasion of shrimps and encystment, as well as development of the metacercariae in G. pulex.

More cercariae are shed by day and at higher temperatures, and they live for about 5 days at 8 °C. The metacercaria undergoes considerable development before becoming infective. C. metoecus does extensive damage to L. peregra, has no observed ill-effect on trout, and apparently affects the life-span of shrimps adversely only in cases of very heavy infestations.

The non-parasitization of Cottus gobio by the two flukes is probably due to the prevailing ecological factors.

My thanks are due to Professor H. B. N. Hynes and Dr J. C. Chubb for many helpful criticisms at all stages of this study; to Miss Joan Venn for helping with the sampling programme; and the Commonwealth Scholarship Commission in the United Kingdom for financial support.

Rats were fed on two deficient diets and were infected with N. brasiliensis larvae. They were autopsied at times ranging from 18 hours to 17 days after infection. The effect of the diets on worm burden, sex ratio of the worms and size of larvae and of worms were noted. Significantly more larvae reached the lungs and intestine in rats fed on glucose and filter paper (G.F.P.) and low protein (L.P.) diets than in controls, the highest numbers coming from G.F.P. rats. Neither the migration rate nor the development of the worms was accelerated by the deficient diets. G.F.P. and control rats lost larvae soon after their arrival in the intestine. Adult worms were lost from rats on the deficient diets before they were lost in significant numbers by controls; this was not due to the initially larger worm burdens in the former rats. G.F.P. and control rats lost the bulk of their infections by 17 days; L.P. rats retained about 50% of the worm burden they had on the fourth day. The effect of the deficient diets on the migratory and adult phase of N. brasiliensis, and on susceptibility and resistance is discussed.

This work was done during the tenure of a Science Research Council Studentship. My thanks are due to Dr E. T. B. Francis for his helpful and critical supervision, and to Professor I. Chester Jones, in whose Department the work was carried out, for the facilities he provided.

Amongst parasitic platyhelminthes three Microsporidia are named from cestodes and seven from trematodes. Those in cestodes are Nosema helminthorum Moniez, 1887, Glugea ghigii Guyenot & Naville, 1924 (= Nosema (Plistophora) ghigii Guyenot, Naville & Ponse, 1925) and Stempellia moniezi Jones, 1942. Those in trematodes are Nosema distomi Lutz & Spendore, 1908, Nosema legeri Dollfus, 1912, Nosema echinostomi Brumpt, 1922, Nosema (Plistophora) spelotremae Guyenot, Naville & Ponse, 1925, Glugea encyclometrae Guyenot & Naville, 1924 (= Nosema (Plistophora) encyclometrae Guyenot, Naville & Ponse, 1925), Glugea ghigii Guyenot, Naville & Ponse, 1924 (= Nosema (Plistophora) ghigii Guyenot, Naville & Ponse, 1925) and Nosema dollfusi Sprague, 1964. Other species are recorded but not named.

Three coccidian parasites were found in California Banded King Snakes, Lampropeltis getulus californiae: Isospora crotali, an intestinal Eimeria, and a haemogregarine. Schizogonous stages of the latter occurred predominantly in liver, and were remarkably similar to those described for other blood Coccidia.

Dr Charles E. Shaw of the San Diego Zoological Society identified the snakes, and Dr Gordon Ball, Professor of Zoology at the University of California, Los Angeles, kindly reviewed the manuscript.

An investigation was carried out to discover how the sporocysts of Cercaria doricha obtain nutrients from their host Turritella and how castration of the snail is brought about.

Histological studies of infected molluscan visceral humps showed no trace of toxic or mechanical damage by parasites. There appears to be an inverse relationship between the number of sporocysts and the amount of gonadial tissue.

Biochemical analyses of molluscan tissues indicated that parasitized snails were not depleted of amino acids or purines. The concentration of plasma protein was higher in parasitized snails and the concentration of free amino nitrogen in head–foot muscle showed an increase of 7%. Histochemical investigations indicated that sporocysts do not remove glycogen from the molluscan connective tissue which surrounds them. The sporocysts appear to lack copious secretions of proteinase.

The lack of conditions of starvation in parasitized specimens of Turritella, together with the great similarity of the free amino acid pools of sporocysts and molluscan gonad, suggests that the sporocysts obtain their food supply directly from the gonadial tubules. It is concluded that this is achieved by use of a placenta-like region of the sporocyst wall which is in contact with the gonadial tubule and which appears to be identical with the region of proliferation of the cercariae.

This paper formed part of a thesis for the degree of Doctor of Philosophy in the University of Reading. I wish to thank the Science Research Council and the University of Reading for financial awards, and Professor Alistair Graham for encouragement and guidance during the work.

Small spines of maximum size 0.28 μm × 0.5 μm have been found all over the shells of the eggs of Schistosoma mansoni and S. haematobium. The small spines on S. haematobium eggs are less pointed than those on S. mansoni eggs. They consist of inner and outer parts made up of subunits, and they are continuous with the main part of the shell underneath. S. mansoni eggs still within the blood vessels of the gut have extracellular material between the spines and there is cell debris over them. The scanning electron microscope shows the increased surface area of the egg shell due to the small spines.

I wish to thank many people for their help with this work and in particular Dr F. Hawking, Dr S. R. Smithers and Mrs. L. Ebden.

A combination of histochemical and electron microscope techniques have demonstrated, in Cyathocotyle bushiensis, alkaline phosphatase activity in the matrix of the tegument, in the distal and basal plasma membranes of the tegument, in the wall of the ducts extending from the adhesive organ gland cells and in the wall of the adhesive organ microvilli. Acid phosphatase activity was much stronger and was present in the tegument matrix and in the granular component of the secretion from the adhesive organ gland cells. Strong acid phosphatase activity was also present in the cisternae of the endoplasmic reticulum of the adhesive organ gland cells.

I am greatly indebted to Professor Brough for the excellent facilities available within this department. I also wish to thank Professor J. Sinclair (Department of Mining) for electron microscope facilities extended to me in the early stages of this investigation, and to Mr W. Henderson, Mr T. Davies and Miss M. Williams for their invaluable assistance. The purchase of the Huxley ultramicrotome, coating unit and an AEI EM 6 electron microscope was made possible by a grant from the Science Research Council.

A hypothesis is developed to explain how the nematode propels itself around in the egg before hatching. The normal reactions at the ends of the egg to the pressure exerted by the nematode are each equivalent to a force propelling the nematode around inside the egg and to a displacement force. A diagram of forces that satisfies the requirements for undulatory locomotion has an asymmetrical egg with ends of variable curvature. In such an egg the only effective forces acting on the nematode are the propulsive forces along the longitudinal axis of the nematode and frictional forces between the nematode and egg shell. A steady glide occurs when these two forces are equal. As the nematode moves around the ends of the egg, the muscles in contact with the shell come under tension and owing to the change in curvature of the shell they contract and release the potential energy necessary for propulsion.

Measurements on the shape of eggs, the configurations of actively moving nematodes in the egg, ciné film of eggs and a model of a nematode in an egg do not disprove the hypothesis.

Prior to hatching the surface area of the egg increases and increased force by the head of the nematode at one end of the egg produces a protuberance which eventually bursts under the influence of the mouth stylet which punctures the shell and the pressure from the nematode's head. Propulsive forces within the egg enable the larva to hatch.

Nematodes at a root surface form waves of large amplitude with the result that the head and stylet often meet the root at right angles. The nematode then attaches itself to the root and active use of the mouth stylet makes the initial puncture in the plant's epidermis. Penetration to a depth of 100 μm occurs under the influence of propulsive forces developed by that part of the body outside the root. Thereafter, the section of the body within the root develops the necessary forces and the posterior part outside the root remains almost stationary. The nematode penetrates the root intermittently to a depth of 40–60 μm every 20–40 min corresponding to the penetration of a series of cell walls.

The relationships between egg shape, movement in the egg, mode of hatching and site of hatching present a further interesting problem because it is possible that nematodes that hatch into an environment outside the host require some pre-hatch movement to bring the muscular system to a high level of efficiency. Nematodes that hatch within the host may not need such an adaptation.

Thanks are due to Mr I. R. Dick for his help and useful discussion, to Mr K. W. J. Crocker for technical help and to Miss Colleen Hill who made the drawings.

When serotonin is injected intravenously into certain animals containing microfilariae it causes a sharp short rise in the microfilaria count in the blood, i.e. liberation of microfilariae from the lungs. This happens in the case of Dirofilaria immitis (in dog), D. repens (in dog), Loa loa (in drill), Edesonfilaria malayensis and another Dirofilaria-like microfilaria (in monkey), Monnigofilaria setariosa (in mongoose), and Dipetalonema gracile (in squirrel monkey); but not with Dip. witei (in gerbil) and Litomosoides carinii in cotton rats.

This action (upon D. immitis) is not inhibited by atropine. Administration of reserpine, harmine or harmaline to dogs did not exert any definite action on the microfilaria count of D. immitis. Serotonin had no obvious effect on the in vitro activity of microfilariae of L. loa or E. malayensis. Melatonin had no action in vivo upon any of the above microfilariae.

The action of serotonin upon microfilariae in vivo is similar to that of acetylcholine but it is not identical with it since the sensitivity of Dip. gracile and Dip. witei to the two compounds is different.

Apparently this action is not involved in the production of the 24 h periodicity shown by many microfilariae. It may depend upon disturbance of the normal neuromuscular mechanisms of the microfilariae by which they are retained in the small vessels of the lungs.

Field and laboratory observations on the nature and sequence of the host-finding responses of the hen flea Ceratophyllus gallinae are described. The imago over-winters within the cocoon. Tactile stimuli and a rise in temperature initiate emergence. Emigration from the nest is delayed for a few days by a negatively phototactic response, and begins when this becomes positive. The fleas are negatively geotactic and disperse upwards into the vegetation. Eventually they take up a characteristic posture, oriented towards the light. Jumping is elicited when the light intensity is suddenly reduced, and it is suggested that this enables the fleas to reach their avian host. Those fleas whose jump misses the host fall and form a secondary distribution on the ground. The readiness to jump rises during the first few days after cocoon emergence, then falls again, the rate of fall apparently being partly determined by water loss.

The author is much indebted to the Hon. Miriam Rothschild and Drs E. T. Burtt and M. J. Cotton for valuable advice, and to C. R. Brannigan for a critical discussion of the manuscript. The main part of the research was carried out during tenure of a post-graduate studentship provided by the Department of Scientific and Industrial Research.

The erythrocytes and plasma of a British and Brahman crossbred steer were labelled with 51Cr and 125I respectively. The radioactivity levels were subsequently maintained as constant as feasible by injecting the steers with calculated amounts of the appropriate labelled material on 3 consecutive days. The steers had previously been heavily infested with Boophilus microplus to ensure that all stages in the parasite's life-cycle would be present during the 4-day period, when the steers were being treated with isotopes.

Various stages of B. microplus larvae, nymphs and adults were collected and the uptake of red cells and plasma at each stage assessed by radioassay. In certain calculations, corrections were made for the uptake of blood fractions before the animals were made radioactive.

A relationship between the weight of the tick and its dietary intake was established. At all the stages of larval and nymphal feeding the plasma content of the diet was greater than that of the host blood. However, erythrocytes were detectable even in the earliest larval stages examined. Dropped fully engorged adult females contained more red cells per individual, and generally also more plasma, than engorged ticks removed from the host.

Fully engorged adult females took up as much as twice their own weight of blood components, but in none of the earlier stages did the tick concentrate its blood meal.

No obvious differences could be demonstrated statistically between the behaviour of the parasites on the two hosts. However, indications are that recently attached larvae took up more erythrocytes from the British animal.

We wish to thank Messrs A. K. Duffield, A. J. Short, B. Wilson, and Miss S. J. Shepherd, for skilful technical assistance.

The early (0–18 h) migration of the larva of Ascaris suum in the white mouse was studied.

The eggs hatched in all gut regions posterior to the stomach, the time of maximal release being between 4 and 8 h after infection. The caecum was the site of maximum larval penetration.

Penetrating second-stage larvae produced demonstrable spreading factor reaction with Evan's Blue in the mucosa of the gut. Larvae were located in the venules and lymphatics of the caecum wall as well as in the ileo-colic and hepatic portal veins. Larvae were found in the liver after 9 h and in the lungs 12 h after infection. Larvae were not seen in the muscula externa of the gut and eggs were not found in any region of the body other than the gut lumen.

A similar pattern of larval distribution was seen in the gut wall of the rat and the guinea-pig.

I am greatly indebted to Dr D. A. Erasmus for his encouragement, advice and supervision during this investigation, and also for carrying out the experimental infections. I also wish to thank Professor J. Brough for the provision of excellent laboratory facilities. Many thanks are due to Mr J. H. M. Hughes (Veterinary Officer) and the meat inspectors at Roath Abattoir who provided me with infected material. I wish to acknowledge the financial support of the Pig Industry Development Authority and the Agricultural Research Council.

The development of the feeding lesions of the ixodid tick Boophilus microplus was followed throughout the parasitic life-cycle on cattle of both Zebu and European breeds, using histological techniques.

The feeding lesion of this tick must be the result of an interaction between the tick and its host as it is neither the result of simple mechanical trauma, nor of lysis of the host tissues by salivary secretions of the tick alone, nor is it solely a result of an inflammatory response.

The histological evidence suggests that the diet of the tick in each instar changes as the lesion develops; first, tissue fluids are available, then tissue fluids along with leucocytes which have infiltrated the lesion, and finally these two components along with whole blood.

An early intense infiltration of eosinophils into the area of the mouthparts, typical of an immediate hypersensitive or anaphylactic response, was noted with European cattle on secondary and subsequent exposures to larvae. Hypersensitivity to tick infestation, which has been equated with resistance to infestation, was seen as an extreme of a normal spectrum of sensitization which results in an abnormal susceptibility.

The definitive lesion was similar with all hosts studied. It consisted of a cavity containing leucocytes, predominantly neutrophils, some lymphocytes and erythrocytes in an area of heavily infiltrated collagen.

It is concluded that this host-parasite relationship illustrates the concept of adaptation tolerance as proposed by Sprent (1962).

It is with much pleasure that we acknowledge the continued generous financial support by the Australian Meat Research Committee (formerly the Australian Cattle and Beef Research Committee), which has made possible this project.

Arthur & Chaudhuri (1965) have reviewed the literature dealing with the taxonomic status of Nosomma monstrosum (Nuttall & Warburton, 1908). They have also redescribed the adults and have given the host and geographical distribution of this species. There have, however, been no descriptions or records of immature stages of this species. They are described and illustrated here from laboratory-reared and field-collected material. The parent females of the laboratory-reared material were compared with the female specimen in the Indian Museum collection, reg. no. 2172/17, on which the description of the female was based (Warburton, 1918).

An evaluation programme is presented for determining activity of unknown compounds on Ascaris suum larvae migrating into pulmonary tissues of animals. Data on gross lung lesions due to migrating ascarid larvae were obtained in a series of 44 screening tests consisting of 223 group observations from 1115 mice orally infected with A. suum. Lesion scores were graded in ascending order from 0 to 5 depending upon number and extent of pulmonary haemorrhages. In general, there was no significant difference in lesion scores between untreated mice and mice treated with unknown compounds in their ration. The programme is based on an initial 95% rejection of compounds with a 5% ability to retest compounds in groups of mice.

The grand mean score for 44 tests was 2·88. Ninety per cent confidence limits for means among tests established scores at 2·21 and 3·55, and among groups of mice at 1·76 and 4·00, When the test mean was less than 2·2, the ascarid ova used for infection were considered non-virulent. Compounds selected as active were in groups of mice having a mean lesion score of 1·76 or less. Banminth, Styquin and Tetramisole showed larvicidal activity. A reasonable compromise exists in this system wherein false leads are tolerated to avoid screening out effective materials. The host-parasite relationship is proposed as a valuable tool for anthelmintic evaluation.

The authors wish to thank Mr W. Henry and Mr M. Jackley of this laboratory.

Third-generation rediae and escaped cercariae of Philophthalmus gralli are found primarily in the interacinar spaces on the periphery of the hepatopancreas of its molluscan host, Tarebia granifera. The presence of these stages of P. gralli causes both mechanical and physiological damage to the adjacent host cells. Mechanical damage results from ingestion by rediae and pressure exerted by motile rediae and cercariae. Histochemical tests involving two different substrates L-leucyl-α-naphthylamide and L-leucyl-4-methoxy-β-naphthylamide, have revealed the occurrence of aminopeptidase activity associated with the body surfaces of both rediae and cercariae. This exopeptidase is believed to be responsible for the lysis of the cytoplasm of surrounding host cells during migration and to be associated with extracaecal digestion. The intensity of the enzyme activity is correlated with the ages of the rediae and cercariae. Young rediae did not reveal aminopeptidase activity and cercariae within redial brood chambers revealed little or no activity.

This research was supported in part by a grant from the American Cancer Society.

Splenectomy, either alone or in conjunction with hormonal bursectomy, did not appreciably affect E. tenella infections as measured by oocyst output.

Operated birds became resistant to re-infection as readily as the controls and it seems unlikely that the spleen in chickens plays an essential role in the host's defence against the Eimeria.

Thanks are due to my colleague, Mr P. L. Long, for his advice and interest throughout the work. Mrs J. Simpson gave valuable technical assistance.

Morphological features of the bladder wall of Cysticercus fasciolaris and carbohydrate analysis of the contained fluid are described. The bladder fluid was found to have a higher concentration of glucose than the plasma of the respective host animal. The bladder wall has a prominent duct system with numerous cytoplasmic extensions and interconnections. It is suggested that the bladder may function in the nutrition of the developing cysticercus by providing a reservoir of raw material which may be utilized by the growing strobila.

The authors wish to thank Dr Theodor von Brand for many helpful discussions, and Dr Harley G. Sheffield and Mr Ned M. Etherington for their advice and technical assistance in the preparation of the electron micrographs.