Gastrodiscoides hominis is unique among the helminthic infections of man in that it is the only common representative of the Amphistome group in the human host; Watsonius watsoni (Conyingham, 1904), another Amphistome, is normally a parasite of monkeys and has been very rarely recorded from man in whom it is evidently an accidental parasite.

As indicated above, this species was collected by the writer from Galago crassicaudatus in Blantyre, Nyasaland. This is a new host record and a new locality record for the species. The measurements that the writer was able to make from his specimens contribute additional information to our knowledge of the size-range of this parasite and provide an example of how one and the same species of nematode may vary in size (but not in morphological details).

The suitability of sheep and cattle as hosts for Fasciola hepatica was compared after infection with metacercariae of ovine or bovine origin. It was found that, irrespective of the host of origin, the prepatent periods and the infectivity in both hosts were similar. The flukes in the sheep grew faster, more uniformly and to a greater size, but the individual parasites in the cattle produced approximately twice as many eggs per day as those in the sheep.

Oxysomatiinae: Sexual dimorphism not marked; mouth with three lips; body delicate; pharynx short and muscular; females with ovaries much reduced, uteri divergent, amphidelph, contain a reduced number of eggs arranged in moniliform manner and towards the centre eggs with well developed larvae or even free larvae may be present; vulva behind middle of body; males with subequal or equal spicules of moderate size; accessory piece present. Parasites of amphibians and reptiles. Type species: R. simples (Travassos, 1925) Travassos, 1927.

A short historical study of this species is followed by a redescription from a male specimen which provides further details of head and bursa and of the structure of the spicules. The spicules are considered to be of considerable taxonomic importance at the generic level. The presence or absence of certain other significant morphological features is confirmed, for example, the presence of a cervical cuticular inflation and the absence of a gubernaculum. A new host and a new geographical locality are recorded. Finally some notes on the genera Troglostrongylus Vevers, 1923 and Bronchostrongylus Cameron, 1931 attempt to explain why the writer considers that the latter genus is superfluous and could be suppressed. A key to the species of the genus Troglostrongylus (sensu lato), a list of species and synonyms, and a bibliography are given. An amended generic diagnosis is proposed.

The cuticle is finely striated and is partially reflected over the lips. The cervical papillae are symmetrically placed and occupy a position just anterior to the junction of the two parts of the oesophagus at about the same level as the nerve ring, some 0·32 mm. from the anterior end. The pseudolips are hemispherical and lateral. Each of the two pseudolips carries two papillae, one towards the latero-dorsal border and one towards the latero-ventral border. An amphid is situated centrally between the two papillae on each pseudolip. Internal to the pseudolips there is a complete denticular crest comprising externo-lateral teeth, interno-lateral teeth, paired submedian teeth and intervening denticles (Fig. 1). The externo-lateral teeth are large and pointed; the interno-lateral teeth, somewhat more posteriorly placed (Fig. 2), are smaller and also pointed. The four pairs of sub-median teeth are easily distinguished by their greater size from the denticles. The four spaces between the sub-median teeth and the externo-lateral teeth are each occupied by six to seven denticles. These denticles are larger in size than the very small denticles of which ten occupy the dorsal and ten occupy the ventral angles of the denticular crest.

In August 1962 Dr. C. Amirthalingham brought to me a dead fish, Polypterus senegalus, on which there were a few worms moving. These were found to be monogenetic trematodes of the gyrodactylid type and were later identified as Macrogyrodactylus polypteri Malmberg, 1956.

On examining a tank where a few Polypterus senegalus—from Jebel Awlia on the White Nile near Khartoum—were kept, it was found to be heavily infested with these worms and each fish was covered with a thick greyish-white fluff on its skin. The trematodes could be seen by the naked eye and were found practically on the whole surface of the fishes.

Some 250 substances were assessed for larvicidal activity against the free-living stages of Haemonchus contortus. Most of them were either plant products or chemical compounds found in plants.

Results indicate that promising chemical types worth further investigation are ketones of low molecular weight, alkyl di– and trisulphides, and organic isothiocyanates. Compounds whose molecular structures include the allyl group (e.g. anethole) and the methylenedioxy ring system are potentially active, safrole being particularly effective. Alkaloids as a group were not very effective, but eserine (physostigmine) was outstandingly active, and nicotine sulphate and arecoline hydrobromide showed pronounced activity. Other substances worthy of mention were phenyl mercuric phthalate, galegine sulphate, 8-hydroxy quinoline, methyl salicylate, 10-allyl phenothiazine, guaiacol, thymol, l-limonene and sabinol.

Most of the plant products tested were essential oils: these generally were active, the lowest activity being noted in those oils rich in sesquiterpenes. Activity in the essential oils could be correlated with that of the known compounds.

Studies on the symptomatology of red-ring disease were carried out by the author (Goberdhan; 1961) on thirty-two trees at La Forest Estate. It was hoped that from this study, methods for detecting the disease at an early stage would have been developed. If this were possible, then therapeutic treatment might be administered to combat the disease and so save a tree from destruction. From these field observations, it appeared unlikely that very early infection could be detected visually, since infection in the stem was found to be well advanced even when only one or more leaves showed signs of rich, gold, yellowing, typical of the disease. The initial time of infection could not be determined nor could the length of time elapsing between infection and the onset of symptons. It was therefore decided to artificially infect young, and apparently healthy palms, to estimate rate of spread of infection, the length of time from infection to appearance of symptoms, and the possible detection of very early infection.

The study of larval trematode parasites of freshwater molluscs is a field which has been much neglected in Great Britain. Renewed interest has appeared in recent years and this, together with the scattered nature of the literature, has prompted the construction of a key which will aid in the identification of cercarial stages emerging from freshwater molluscs.

In many cases it will be noted that the author and date associated with the species may not be that of the original author but will represent the most recent and complete description of the form. A few of, the early descriptions do not contain sufficient detail to allow very precise demarcation from closely related animals but an attempt has been made to separate them in the present text. As far as possible, easily distinguishable morphological features have been employed, but in some cases reference to the excretory formula and floating position in the water is necessary.

1. The structure of the head in four samples of the genus Allodapa from Madagascar birds is described and shown to represent stages in the functional deformation of the pharyngeal portions.

2. All the specimens are considered to belong to Allodapa suctoria (Molin, 1860) s.l. and are described. Their hosts are: Margaroperdix sp. Centropus toulou, Coua caerulea and C. raynandii.

3. The species of the family Subuluridae known from Madagascar hosts are discussed and it is shown that they represent a minor parasite fauna which has most probably been secondarily introduced.

4. It is reported that Subulura prosimiae Baer, 1935 is indistinguishable from Primasubulura distans (Rudolphi, 1819) and that the record of the former species given by Chabaud and Petter (1958), based only on females, is that of a Subulura species and not a Primasubulura.

5. A Subulura species is reported from Coua gigas.

A survey of nematodes from the lower digestive tract of 356 adult domestic fowls indicated that Capillaria obsignata and Ascaridia were more common than was formerly supposed. The incidence of C. candinflata has decreased, whilst that of C. anatis, Heterakis and T. tenuis remains unchanged. These changes may be correlated with the introduction of intensive methods of poultry husbandry.

1. The males and females of a new nematode Cithariniella citharini gen. et sp. nov. are described from the rectum of the Nile fish Citharinus citharus in the Sudan.

2. Cithariniella citharini is made the genotype of a new genus Cithariniella and differentiated from the nearest genus Laurotravassoxyuris Pérez Vigueras, 1938.

The distribution of glycogen in the adult common liver fluke, Fasciola hepatica, was studied by the periodic acid-Schiff reaction. As well as in the yolk cells, the peripheral muscle layers and to a lesser extent the parenchyma, glycogen was detected in fine tonofibrils in the tegument.

The glycogen of the peripheral muscle layers and of the tonofibrils of the tegument is drastically depleted if the flukes are kept for a few hours in Hédon-Fleig with insulin added, as compared to controls without insulin.

The effect of insulin raises the question whether this protein enters the tissues through the surface of the tegument, or conceivably but less likely, through the gut. Furthermore, the mechanism of its action in the parasite's tissues requires investigation

A technique is described for measuring the larvicidal activity of compounds against the free-living stages of bursate nematodes of sheep. Cultures were made in small glass tubes in 2 oz. “pomade” jars, and the larvicidal effects of the compounds were measured by comparing the number of infective larvae which were recovered from treated cultures with the numbers from the control cultures.

This technique provides another in vitro screening method for compounds which may be effective as anthelmintics against bursate nematodes.

While examining a collection of amphistomes from a red lechwe (Onotragus leche), obtained by the late Dr. P. L. LeRoux, one of us (Y. L.-S.) found a few specimens of a species which appeared to be undescribed. On a later trip to Northern Rhodesia Dr. LeRoux made a further collection consisting of several hundred specimens from the same host-species. The worms were recovered from the caecum, which contained up to fifty specimens.

A male specimen of Dirofilaria (Nochliella) repens has been recovered from the skin of the right upper arm of a patient from Colombo, Ceylon who manifested signs and symptoms of bancroftian filariasis and had microfilariae in his peripheral blood. This is the second case of Dirofilaria infection reported from man in Ceylon.

1. A new genus of a spiruroid nematode belonging to the family Thelaziidae is described from the liver of a marine fish, Chorinemus tala from Karachi, Pakistan. The genus is based on the structure of the head, the presence of body papillae, the peculiar female reproductive system, the position of the vulva etc. This is the first record of a nematode from the liver of a fish.

2. The genus Filochona (Saidov, 1954) Yamaguti, 1961 is synonymised with Rhabdochona and the subfamily Filochoninae Yamaguti, 1961 is suppressed.

Mesocoelium monodi Dollfus, 1929 is reported from Rana (Ptychadena) mascareniensis and Agama agama agama in the Cameroons.

Mesocoelium pesteri sp. nov. is described from a hornless chamelon and compared with related species.

Mesocoelium cameroonensis sp. nov. is described from Rana (Ptychadena) oxyrhynchus and compared with related species.