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).

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.

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.

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.

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.

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.

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.

Buckley and Fairley (1950) working in England found segments of a species of Bertiella passed by an eight year old girl who had lived in Kenya for 14 months during 1946–47. Since only the terminal segments were available for study, a specific identification could not be made, though the authors thought that it was probably Bertiella studeri (Blanchard, 1891). Nelson (1963) has found that baboons in Kenya are commonly infected with species of Bertiella.

Seven males and three females, identified as Trichostrongylus hamatus Daubney, 1933 were recovered from the abomasum of a steinbok shot at Deloraine Estates in the Kenya Highlands. No other Trichostrongylus species was present. The species was originally described by Daubney (1933) from Ovis aries also from the Kenya Highlands. The specimens from the steinbok were examined and compared with the original description of the species. Figs. 1–4 show drawings of the spicules and part of the bursa. Table I gives the measurements of Daubney's specimens compared with those of the present specimens.

Stephanofilaria dinniki sp. nov. is described from cutaneous lesions of the black rhinoceros, Diceros bicornis L. The species differs from the others of the genus mainly in the length of the left spicule in the male; the short distance of the vulva from the anterior end in the female; and the curved tails in both sexes.

1. A new trematode Tremajoannes buckleyi gen. et sp. nov., is described from the bats Pteronotus davyi fulvus and Mormoops megalophylla from Colombia, Central America. A comparison between Tremajoannes gen. nov. and the other related genera of the family Lecithodendriidae is given.

2. Primatotrema Premvati, 1958 is considered as a synonym of Phaneropsolus Looss, 1899, accordingly Primatotrema macacae should be Phaneropsolus macacae (Premvati, 1958), n.comb.

3. Phaneropsolus magnitesticulatus Ryšavý et al., 1960 is considered as a synonym of P. macacae (Premvati, 1958).

4. Phaneropsolus orbicularis (Diesing, 1850) Braun, 1901 is reported from a new host and redescribed.

1. Chabertiella pesteri gen. and sp. nov. from the giraffe (Giraffe camelopardalis) is described.

2. Chabertia rishati Akhtar, 1937 is synonymized with Chabertia ovina (Gmelin, 1790) Railliet and Henry, 1909.

1—A description is given of Buckleyuris buckleyi n.sp. from the steinbok, which is a new host for the genus.

2—The genus Salamia Sarwar, 1959 is synonymised with the genus Buckleyuris Sarwar, 1959.

3—A key of the different species of the genus is given.

1. Four worms were recovered from the subcutaneous connective tissue of a leopard. Of these two males and one female were identified as Filaria martis Gmelin, 1790 with the measurements given and a female described as a new species under the name Filaria russelli.

2. This finding is the first record of the genus Filaria Mueller, 1787 in a leopard.

Two experiments are described in which antibodies against A. suum were detected in the circulation of infected pigs by means of the conglutinating complement absorption test. The pattern and nature of the antibody response was studied. In 21 out of 24 cases the sera antibody titres rose after test doses of infective eggs were given, and on 18 of these occasions a rise in titre was observed within seven days. Following infection two peaks of antibody were detected. At three to four weeks the antibody content of the serum reached its highest concentration, and a further rise was apparent between the 37th and 56th days.

The phenomenon of “self-cure” was demonstrated following reinfection. This was manifested by a depression of the egg count and the elimination of Ascaris worms from the intestine, with a concomitant rise in the antibody content of the serum.

In three out of five pigs which were initially infected, the infection became patent between the 51st and 58th days. On only one occasion out of thirteen were any superimposed larvae able to reach maturity.

Pigs which had been previously infected exhibited resistance to a challenge dose. This was shown by (1) the absence of clinical signs, (2) a resistance to larval migration, and (3) an inhibition of larval growth. In this demonstration of an active acquired immunity to A. suum infection in pigs, a correlation between resistance and high sera titres was observed.

It was possible to make a more critical study of immunity against A. suum by infecting pathogen-free, colostrum-deprived pigs produced by hysterectomy.

By means of the conglutinating complement absorption test, using a saline extract of worm as antigen, antibodies were first demonstrated in the circulation of three experimentally-infected pigs between the 10th and 13th days of infection, and were detected in the sera of two of them for at least 97 days.

The infections did not become patent, and no acquired immunity was shown by the pigs against a reinfection 97 days later. There was no evidence of an age immunity against migrant larvae.

A rise in serum antibody was observed, within seven days of infection, in six pigs aged between 10 weeks and 11 months, following a test dose of 500,000 eggs. Three suckling pigs, aged three weeks, did not respond serologically within seven days to the same test dose.

Following the oral administration of third- and fourth-stage A. suum larvae, which had previously completed nine or ten days somatic migration in guineapigs, rabbits or a pig, six out of eight pigs showed a rise of serum antibody titre, as measured by the conglutinating complement absorption test using a saline extract of Ascaris worm as antigen. Four of these pigs had negative titres before infection, and in these animals antibodies were first detected between the 14th and 20th days. Maximum serum antibody concentration was reached between the 14th and 34th days of infection, and antibodies were detected for at least as long as 68 days.

Larvae were recovered from the faeces on the 23rd and 29th days of infection, and in two pigs out of eight the larvae reached maturity, eggs first being seen in the faeces on the 42nd day.

The results suggest that (1) Ascaris larvae, on their return to the intestine, release antigenic substances which are then absorbed by the gut wall to stimulate the production of antibodies; (2) the secondary antibody rise, which occurs about the sixth or seventh week of an infection with Ascaris eggs, is due to the absorption of this larval antigen; and (3) the moulting process (fourth moult) is not only an important stage for stimulating this further antibody production, but is also the time when maturing larvae are affected by the immune mechanisms of the host.

On reinfection with Ascaris eggs the phenomenon of “self-cure” was noticed. A fall in the faecal egg count, which became negative on the 21st day, was accompanied by a sharp rise in antibody titre. An increase in the number of infertile eggs in the faeces, rising from 11% on the day of reinfection to 100% on the 14th day, was also observed.