From time to time the writers have noted some items pertaining to nematode taxonomy that appeared to require some clarification. In this connexion the following brief notes have been assembled and are presented with the hope that they may prove useful.

Studies were carried out in mice and a monkey (paratenic hosts) and pathological lesions in mice have been described in liver, lung and brain with Toxocara larvae moving actively in the tissues causing damage (haemorrhages and necrosis) with encystment. In both mice and monkey there is essentially an eosinophilic response with lymphocytes and neutrophils also showing rise in the peripheral blood a few days after infection. In mice lymphocytes are the predominant tissue inflammatory cell.

Deaths due to infection with Streptocara crassicauda (Creplin, 1829) occurred in three ornamental flocks of water fowl in Hampshire. On two occasions larvae of the worm were found in Gammarus sp. in the running water to which the flocks had access. Lesions were almost entirely in the oesophagus and pharynx, and death was usually due to necrosis, and consequent impaction, of the oesophagus It appears that the worm is capable of establishing itself in southern England.

Orientatractis leiperi n.sp. (Atractidae) is described, from the intestine of a South American tortoise. It is characterised by a cephalic armature of remarkable symmetry and complexity and by the presence of 3 tripartite structures in the anterior end of the oesophagus.

Inhibition of development in the larvae of Ostertagia spp. infecting tracer lambs under field conditions shows a seasonal pattern (Connan, 1968) somewhat similar to that seen in O. ostertagi infections in calves (Anderson, Armour, Jennings, Ritchie and Urquhart, 1965). This finding also agrees with the seasonal appearance of dormant larvae in ewes (Soulsby, 1966; Connan, 1968) and one year old sheep (Parnell, 1962; James and Johnstone, 1967).

1. Eggs of Contracaecum osculatum, extracted from grey seal faeces, have been hatched in the laboratory at different temperatures and the morphology and behaviour of the larvae described.

2. Artificial exsheathment of the second stage larva from the first stage cuticle has been demonstrated.

3. In attempting to establish the first intermediate host of the life cycle, two species of harpacticoid copepods have been successfully infected but no significant developments reported.

The development of the reproductive system of O. circumcincta is described and the developmental cycle divided into phases. It is suggested that these defined phases can be used to give an accurate profile of a worm population. The population of worms found in the experimentally infected lambs is defined in terms of these phases, linear measurements and, in the mature female worms, the presence or absence of the vulval flap.

The course of infection of chickens experimentally infected with C. nilesi suggested an immune response against the microfilariae. Autopsy findings of 6 experimentally infected chickens are given. In a chicken which received 32 infective larvae, when the peripheral blood was microfilaria negative for a period of 10 days, autopsy revealed 2 live active female and 3 live active male adult worms. These, when implanted in a clean 3 week old experimental chicken, produced a peripheral microfilaraemia for a further 63 days. When no peripheral microfilariae were detected for a period of 17 days, the recipient chicken was autopsied and microfilariae were found in the lung impression smears, although none of the implanted adult worms were found.

The morphology, structure and nocturnal subperiodicity of the microfilariae are described.

Experiments were carried out on the migration, distribution, longevity and pathogenicity of larvae of Aelurostrongylus abstrusus in Helix aspersa. Snails placed in contact with several hundred thousands of first stage larvae, were examined from one to 24 hours until two years after infection. Larvae were first noted in the snails 4 hours after first contact and it was concluded that the migratory phase lasted for approximately 48 hours. Larvae were restricted to the deeper layers of the sole and to adjacent organs while the greatest number recovered from any snail was 1437. Larvae were at first surrounded by an accumulation of macrophage-like cells; this reaction declined and disappeared until by 12–24 months after infection only a single layered connective tissue capsule separated the parasites from the host tissue; sometimes even that structure was lacking. Larvae isolated from snails up to two years after the initial infection, were able to produce parasitic pneumonia in experimental cats. To study possible pathogenic effects of larvae on snails, a group of the latter were kept in constant contact with first stage larvae. One snail died at 15, three at 17, three at 19 and five at 27 days after initial contact, but despite the different exposure periods there was little variation in the number of larvae recovered from each snail. In addition, only third stage larvae were isolated from the last five survivors, which suggested that there was an immunological response by the snails. The importance of these results is discussed.

The presence of five nematodes previously unknown in the British pig population is reported i.e. Globocephalus urosubulatus, Oesophagostomum quadrispinulatum and three species of Trichostrongylus. T. vitrinus is recorded for the first time from Sus scrofa domestica. The gastro-intestinal strongylates were encountered most frequently in older animals and were especially numerous in the spring and early summer, whilst the incidence of Ascaris suum and Trichuris suis declined with the increasing age of the host.

Annulospira oculata gen. et sp. nov., belonging to the family Thelaziidae is reported from the orbital cavity of a parrot. It has coarsely annulated cuticle, well developed buccal capsule, narrow caudal alae, pedunculated cloacal papillae and a gubernaculum.

The Indian gerbil, Tatera indica indica, was collected in the arid western Rajasthan at Bikaner during the first weeks of July, August and September 1968. From sixty gerbils a large number of nematodes belonging to the genera Streptopharagus Blanc, 1912, Rictularia Froelich, 1802 and Trichuris Roederer, 1761, together with a few cestodes, were recovered from the stomach and intestine. The Streptopharagus sp. described below, vastly outnumbered the other worms and appears to be a new species.

Four new genera (each containing one new species) belonging to the order Rhabditida have been described from Jodhpur Sewer. Mesodiplogasteroides n.g. (subfamily Diplogasterinae) is distinguished from the closely allied genus Butlerius by the absence of setose papillae on the head and the presence of a rudimentary bursa in male. Operculorhabditis n.g. (subfamily Rhabditinae) is characterized by the presence of a flap-like, deciduous, cuticular operculum covering the vulva which is well posterior. Praeputirhabditis n.g. (subfamily Rhabditinae) is unique in possessing prepuce-like loose cuticle through which the tail can be protruded. Saprorhabditis n.g. (sub-family Protorhabditinae) has neither a glottoid apparatus nor a median oesophageal bulb but possesses an oesophageal collar. The genus Matthesonema is transferred to the subfamily Rhabditinae. Rhabditis (Rhabditella) octopleura is being recorded for the first time from India.

Some confusion exists as to the correct identity of Ostertagia trifurcata. The relevant literature is reviewed, and it is concluded that the observations of Sarwar (1954, 1956) pertaining to the identity of O. trifurcata are correct; that is that the genital cone possessed papillae. Teladorsagia davtiani is therefore a synonym of O. trifurcata and O. pinnata a valid species.

Aporocotyle argentinensis n.sp. from the bulbus arteriosus of Merluccius hubbsi is described and figured and compared with the other four known species of the genus. Of 240 hake caught at 12 localities off the coast of Argentina, 54 were infected with a total of 83 flukes, 33 fish with one fluke each, 15 with 2 flukes each, 4 with 3 flukes each, and 2 with 4 flukes each. The incidence of infection at individual localities varied from 0% to 45%. The phylogeny of Aporocotyle in hake is discussed; of the three species occurring in hake, A. spinosicanalis appears to be the most highly evolved.

Self insemination appears to be the normal process of sperm transfer in Echinococus granulosus and has been observed in both terminal and subterminal proglottids of worms from dogs.

Cross fertilization between adjacent proglottids or between proglottids of different strobila was not observed.

In some instances, the genital pore was found occluded by a ‘plug’ of material which may represent an antige–antibody precipitate.

The implications of self-insemination in relation to in vitro studies and to the genetics of ‘strain’ production in the genus Echinococcus are discussed.

1. The infective stage larvae of Bunostomum trigonocephalum (Rudolphi, 1808) penetrate the intact skin and undergo skin-lung migration in the mouse and skin-lung-intestine migration in the guineapig. After percutaneous infection in guineapigs, they moult in the lungs to the fourth stage and to the fifth stage in the intestine. Relatively few of them undergo this partial development in the guineapig and they are stunted in growth.

2. In the abnormal hosts, the penetrating larvae cause extensive tissue disorganisation. The histopathology of the skin and lungs is described. There is a cellular reaction to the parasites.

3. In guineapigs, the infective stage larvae reach the lungs after per os infection but they are few in number do no persist for more than six days.

Adult Clonorchis sinensis were taken from the bile ducts of infected rabbits and incubated in Ringer's fluid. The soluble metabolic products secreted by the living flukes during incubation were found to include carbohydrate and protein. Enzyme activities of protease, carbohydrases and esterase, but not of lipase, were detected in the samples.

Samples with a nitrogen content of 3 μg/ml or more reacted as antigen in immunodiffusion tests in gel against sera of rabbits infected with C. sinensis or immunised against whole fluke extract.

The demonstration of enzymes in the metabolic products, the reactions of the samples as antigen and the correlation of antigenic activity with the nitrogen content of the samples suggests that the enzymes detected are effective antigens in clonorchiasis, although complete identity was not demonstrated in this study.

The enzymes investigated were those associated with digestion; intracellular enzymes which have less opportunity to elicit antibody production were not investigated.

The work has demonstrated that one of the more important areas of Scotland where Dicrocoelium dendriticum is endemic carried infected colonies of Helicella itala which live in association with the ant Formica fusca. Workers of the ant were shown to acquire typical metacercarial cysts after the ingestion of slime balls, and the cysts gave rise to mature lancet flukes in sheep and hamsters, eggs appearing in the faeces after 56 and 48 days respectively. Higher egg counts were obtained from hamsters to which more cysts were administered. This is the first occasion on which an ant intermediate host has been demonstrated for Dicrocoelium in Britain.