The following list, compiled during my tenure of a grant given by the Nuffield Foundation to the Wildfowl Trust, Slimbridge, Gloucestershire, records species of Protozoa, helminths and Arthropoda found in anatid birds, either by the authors of the papers listed in the References, or by others to whose work these authors refer. It will be seen that there are, after the names of all the parasites, numbers which indicate, by reference to the corresponding numbers in the References, the authors and publications in which the species concerned are recorded. Thus Cotylurus brevis (142, 145*) means that this trematode was recorded from Aix galericulata, the Mandarin Duck, by Dubois (1953) and that Dubois & Rausch (1950a) reported an experimental infection of this duck with it.

The post-cercarial development of G. crumenifer (Creplin) has been experimentally elucidated.

Gyraulus convexiusculus (Hutton) serves as the intermediate host under natural conditions.

The adult stage of the fluke was raised experimentally in ruminants, the time taken by the parasite to attain maturity being 118 days in the kid and 114 in the buffalo calf.

Cercaria chungathi Peter & Srivastava, 1955, has been established to be the larva of Gastrothylax crumenifer. The cercaria, the redial parthenita and the metacercaria have been described.

The authors are grateful to the Director, Indian Veterinary Research Institute, for his keen interest in these studies.

A description is given of two new Cephaline gregarines from Indian crickets collected at Lucknow and Jalaun, United Provinces.

One of these, Stenophora gryllodes-sigillatae sp.nov., from the gut of Gryllodes sigillatus, has solitary slender trophozoites up to 194μ long. Its epimerite is rounded in young forms and absent or represented by its remnant in adults. The nucleus has two chromosomes. Cysts are rounded, invested in a very thin membrane and without sporoducts.

The second, Bulbocephalus indicus sp.nov., from the gut of Liogryllus bimaculatus, is characterized by solitary elongated sporadins; the neck is short and a bulbous epimerite is always present. The body, measuring up to 175μ in length and up to 30μ in breadth, presents a striated appearance. Cysts are oval, covered by a very thin membrane, and have no sporoducts.

The author is very grateful to Dr S. M. Das, under whose able guidance this work was carried out. His thanks are also due to the Department of Zoology, University of Lucknow, for providing the laboratory facilities.

In November 1953, about one-half per cent of Lymnaea luteola taken from a pond in Alfred Park, Allahabad, were infected with an echinostome cercaria. The first collections of these cercariae were made by Dr Onkar Nath Srivastava, who was surveying cercarial infections in the snails and who kindly gave me the echinostome material. Additional material was obtained by numerous subsequent collections. After the cercaria was described it was possible to undertake a limited number of experiments in an attempt to discover other stages of the life cycle. It was found that Lymnaea luteola is both the first and the second intermediate host of a new species of Echninoparyphium. The adult of this new species, for which the name E. bagulai is proposed, matures in the intestine of the domestic duck, Anas poecilorhyncha. When this duck was experimentally infected with cercariae, the adult trematode was recovered from the intestine of this duck 21 days after its infection.

The excretory systems of Gastrothylax crumenifer, Fischoederius elongatus and F. cobboldi have been described. In all three species it shows the characteristic, more or less H-shaped, pattern of the amphistome excretory system.

The difference between the systems in the three species lies in the nature of the branches of the anterior portions of the longitudinal excretory ducts, in the transverse excretory ducts and the branches received by them and in the number of flame cells at the ends of the capillaries.

The main longitudinal excretory ducts run internal to the intestinal caeca in G. crumenifer and F. cobboldi, while in F. elongatus they run almost external to the caeca and maintain this position even in the posterior half of the body, where the caeca are not present.

1. Neodiplostomum intermedium Pearson is recorded from four new hosts; as an adult from the water rat, Hydromys chrysogaster Geoffroy, and as a metacercaria (diplostomulum), from tadpole and adult of an undescribed tree frog, Hyla sp., tadpole of (Hyla latopalmata (Günther) Mixophyes fasciolatus Günther and frog of an unidentified leptodactylid.

2. The life cycle of Neodiplostomum intermedium was followed experimentally; the hosts were: Pettancylus assimilis (Petterd), a fresh-water limpet, as first intermediate host; tadpole of Hyla pearsoni Copland as second intermediate host; Hyla caerulea (Shaw) a tree frog, and Hemisphaerodon gerrardi Peters, the pinktongued skink, as paratenic hosts; and Rattus assimilis (Gould) and laboratory rats as definitive hosts.

3. Descriptions are given of the morphology of the miracidium, mother sporocyst, daughter sporocyst, cercaria, and diplostomulum, with special reference to the structure of the miracidium and of the cercarial tail.

4. Observations are given on the embryology of the miracidium, hatching of the egg, transformation of the miracidium into the mother sporocyst with special reference to the germinal cells, the route and manner of escape of cercariae from the snail host, the development of the diplostomulum with special reference to the reserve excretory system, and the movements of diplostomula during metamorphosis of the tadpole host.

5. The haploid chromosome number is ten, as determined from squashes of testes. One paratype and a series of experimental adults have been compared with and found different from Neodiplostomum (Fibricola) sarcophilus n.comb. The orthography and formal proposing of the names of the species of Fibricola transferred to Neodiplostomum by Pearson (1959b) are corrected.

The writer wishes to thank Dr M. J. Mackerras, Queensland Institute for Medical Research, for generously supplying water rats; Professor J. F. A. Sprent, University of Queensland Veterinary School, for his criticism of the manuscript; Mr K. Webber and his sons for their assistance in catching rats and for permission to collect snails, frogs and tadpoles from their streams; and Mr R. J. Ballantyne for technical assistance. This study was supported by a grant from the Rural Credits Fund of the Commonwealth Bank of Australia.

1. It has been shown that there is a difference between the resistance of male and female mice to infection with Nematospiroides dubius.

2. More parasites were harboured, during both the larval and adult parasitic phases, by male mice.

3. These worms were found to occupy a similar relative length of the intestine between the stomach and the caecum in male and female mice infected for either 5 or 10 days.

4. The relative length of the intestine infected on the fifth day was significantly greater than that infected on the tenth day.

This investigation was carried out during the tenure of a Research Studentship from the Department of Scientific and Industrial Research. I should like to thank Professor I. Chester Jones, in whose department the work was done, for the facilities provided and Dr E. T. B. Francis for his helpful and critical supervision.

1. Histological data are given about the location and frequency of the different stages of the life history of D. folliculorum in the pilo-sebaceous apparatus of man. These data are examined statistically and the relative durations of each stage and their movements in the follicle are deduced from them.

2. A method of in vitro culture is described and data are given about the longevity of the various stages of the life history.

3. Experiments on the behaviour of the different motile stages of the mite are described. It is concluded that the deutonymph is the distributive stage, and that distribution occurs over the skin surface.

4. The life history is reconstructed by a synthesis of the evidence presented. The life-cycle lasts approximately 14½ days, the life span of each stage of it being: ovum 60 hr., larva 36 hr., protonymph 72 hr., deutonymph 60 hr., adult 120 hr. Interval between copulation and oviposition 12 hr.

This work was largely carried out in the Department of Pathology of the Institute of Dermatology, London, and I wish to thank the Director of Pathology, Dr J. O. Oliver, for making available to me the facilities of his department, and for his advice and interest during the progress of the work. The photographs were prepared by Mr R. H. Lunnan of the Photographic Department of the Institute of Dermatology. I am indebted to the Dean of the Institute of Dermatology for permission to publish the photographs.

I am grateful to Mr T. E. Hughes of the Department of Zoology, Birkbeck College, University of London, for his advice at all times, and to Miss Hilda Davies of the Department of Statistics, University of Sheffield, for help with statistical methods and to Mr W. Moseley, who prepared the text figures.

Finally, I wish to express my thanks to Professor I. Chester Jones and Dr E. T. B. Francis of the Department of Zoology, University of Sheffield, for reading the manuscript and for their help in its preparation.

1. Echinobothrium brachysoma Pintner and E. affine Diesing have been found in the spiral valve of Raja clavata L. off the coast of Britain.

2. The spiral valve is lined by tubular crypts into which the scolices of the worms are thrust, the strobila, with one gravid proglottid, being free in the lumen.

3. The functional morphology of the scolex of E. brachysoma has been described. That of E. affine appears to be similar.

4. The scolex adheres, mainly, by the apical hooks which can be raised by inner and outer elevator muscles attached to their roots and closely associated with the rostellum.

5. The rostellum can be protruded by the contraction of a dorsal and a ventral protractor muscle. Movements of the rostellum elongate the scolex in a dorsoventral direction, forcing the apical hooks against the crypt wall and supporting them.

6. The peduncle hooks are not often embedded in the epithelium. Both series of hooks damage the epithelial lining of the crypt.

7. The remaining musculature, excretory and nervous systems are described.

8. The genitalia are essentially the same in both species. The number of testes varies from one proglottid to another in the same worm. In E. brachysoma the mid-ventral genital atrium is near the posterior end which affects the course of the vagina. The eggs in both species include two yolk cells which are similar to those of the Digenea and Pseudophyllidea.

The species of Astomatous ciliates of the genus Metaradiophrya dealt with in the present paper inhabit the intestine of three species of earthworms. They are, together with their hosts, as follows:

The three trematode specimens described in this paper were collected by the senior author at the Marine Biological Station, Ghardaga, Red Sea; they are deposited in the collections of the Department of Parasitology, Ein-Shams University, Cairo, U.A.R.

Dr H. E. Hinton, who is working upon the larva of a chironomid, Polypedilum vanderplanki Hinton (1951), found in dried mud from shallow rock pools at Anara, alt. 2500 ft., about 20 miles south-east of Kaduna in Northern Nigeria, noticed that there were nematodes in this dried mud which revived when placed in water and very kindly sent me the material to examine from Hinton

The following new species are described:

Pterygosoma sinaita sp.nov. (♀, ♂ nymph) off Agama sinaita, A. mutabilis and A. inermis.

P. adramitana sp.nov. (♀, ♂) off A. adramitana.

P. mutabilis sp.nov. (♀, ♂ nymph) off A. mutabilis, A. pallida, A. jayakari and A. inermis.

P. singularis sp.nov. (♀) off A. colonorum.

P. caucasica sp.nov. (♀, ♂ deutonymph, protonymph and larva) off A. caucasica.

P. foliosetis sp.nov. (♀, nymph) off Charasia dorsalis.

Descriptions are also included of the hitherto unrecorded male, nymph and larva of Geckobia hemidactylus Lawrence, 1936, from Hemidactylus mercatorius Gray from Ascension Island.

1. The coccidial parasites (Eimeria acervulina and E. mitis) cause a recrudescence in chicks harbouring chronic infection with Plasmodium juxtanucleare.

2. E. acervulina causes higher levels of parasitaemia in P. juxtanucleare infections in chicks if the coccidial infection is produced during the prepatent period of malaria, but it does not affect the length of patent and prepatent periods or raise the mortality rate among infected chicks.

3. E. acervulina induces a severe fatal relapse in chicks harbouring latent P. gallinaceum infections.

I wish to express my sincere thanks to Professor P.C.C. Garnham who supervised this work, and Dr R. Lainson who helped in identification, isolation of the coccidial parasites and the establishment of infection in clean laboratory-bred chicks.

In a paper recently published in Parasitology (Baker, 1960), I referred to the description of trypanosomes from the fish Malapterurus electricus and Labeo macrostoma by Rodhain (1908). Most regrettably, I was unaware until after my paper was printed of the existence of a later publication by Rodhain (1942) in which these trypanosomes were named Trypanosoma malopteruri (sic.) and T. gandéi, respectively. Rodhain's descriptions are rather brief, and it is difficult to compare them with those of earlier authors, which are often also lacking in detail: however, in the light of present knowledge of the morphological variability of these large trypanosomes and their wide host-ranges (in the few cases in which these are known), there seems to be no sure ground for regarding T. malopteruri and T. gandéi as valid species: possibly both are synonyms of T. toddi Bouet (1909), if it be assumed that Bouet saw only the larger forms of a pleomorphic species.

No differences in susceptibility or parasite distribution of avirulent Toxoplasma was observed between biotin-, pantothenic acid-, nicotinic acid-, riboflavin- and heat-labile vitamins-deficient chicks and their controls. Ordinary diet supplemented with cod-liver oil did not have any effect either. Avirulent Toxoplasma were readily isolated from the brains of all the animals at the end of 1 month.

We are grateful to Professor P. C. C. Garnham for his interest.