Studies were made of the fate of irradiated cercariae of Schistosoma mansoni, during their migration as schistosomula in the definitive host, by direct recovery of intact schistosomula from the skin and lungs and of adult worms from the liver of infected mice. Gamma radiation (6000 r) inhibited the migration and maturation of S. mansoni schistosomula to the adult stage. Penetration of irradiated cercariae into host skin proceeded normally and the first site of damage was in the lungs, but the majority of irradiated schistosomula were probably destroyed in the liver. The efiects of gamma radiation compared with those of ultra-violet radiation on cercariae of S. mansoni are discussed.

A new Indian species of Paraphelenchus is described and compared with P. basili Das, 1960, also from India, and with other known species of the genus.

A description is given of stainless steel gauze baskets used to contain cysts for infecting potato plants.

The taxonomic histories of Spirometra and Lueheella are reviewed, and the former is shown to be a junior synonym of the latter. Gatesius probably has priority over both. It is suggested that the International Commission on Zoological Nomenclature be petitioned to exert their Plenary Powers to validate Spirometra and invalidate Lueheella and Gatesius.

The isoenzymatic pattern of glucose 6-phosphate dehydrogenase (abbreviation G6PD) from Ascaris suum has been studied by vertical polyacrylamide gel (PAGE) and horizontal starch gel electrophoresis. After polyacrylamide gel electrophoresis, two stained zones could be identified. One corresponded to tetrazolium oxidase activity; since this zone was stained even in the absence of glucose 6-phosphate (G6P), non-specific staining could be detected. In the other zone of activity, seven regularly-spaced bands were identified by staining in the presence of G6P and NADP as substrates. By using starch gel electrophoresis, different electrophoretic patterns for G6PD have been observed in the muscular sac, intestine and reproductive system from A. suum. The existence of three different alleles of G6PD in the same individual suggests the existence of at least two genes for this enzyme.

The fourth-stage larvae and adults of Ascaris suum were studied as they developed in the pig intestine from 11 to 22 days after infection. This is a period of rapid growth, in which both sexes increase approximately ten-fold in body length. Further examination of females showed the length increase to be positively allometric with respect to body diameter. The genital primordium in early fourth stage is at the same relative position along the length of the body as it is in the newly hatched larva. During development from fourth stage to adulthood the greater growth of the posterior part of the worm causes the relative position of the developing vulva to shift anteriad.

Serine dehydratase was found to be five times more active than threonine dehydratase in the liver-fluke Fasciola indica. The latter was not affected by L-isoleucine. Optimum pH for both enzymes was found to be 9.0 in tris-universal buffer. Seven metallic ions tested did not accelerate the enzyme activity, but produced different effects on two enzymes. Two different enzymes probably exist for the two aminoacids, L-threonine and L-serine.

1. The life-cycle of the fowl tapeworm Davainea proglottina and its various intermediate hosts are described briefly.

2. Studies on the different species of slugs in Great Britain under natural conditions were carried out and a short, simple method of differentiating the species has been presented.

3. A satisfactory method of keeping and breeding these slugs under laboratory conditions is described.

4. Feeding experiments of the different slugs on freshly collected gravid proglottides confirm that the intermediate hosts, as published by Grassi and Rovelli are as follows: Agriolimax agrestis, Limax cinereus, Limax flavus; by Wetzel, Arion empericorum (A. ater), Arion hortensis, Arion circumscriptus and Arion intermedius. In addition to these known intermediate hosts, the writer succeeded in infecting the following species: Agriolimax reticulatus, Agriolimax carvanae, Milax gracilis and Milax sowerbyi which may accordingly serve under natural conditions as intermediate hosts for D. proglottina.

5. The common field or grey slug (Agr. reticulatus) and the garden slug (Arion hortensis) seem to be the most important intermediate hosts for D. proglottina. in Great Britain. Slugs of nearly every age of these two species were experimentally exposed to infection with almost 100% positive results. Both these slugs are the most prevalent and widely distributed species in this country. This fact and the wet climatic conditions which obtain in this country are thus very favourable factors in the propagation of the tapeworm.

6. Slugs of different ages were experimentally infected and it was found that younger ones were more susceptible, but Agriolimax reticulatus of almost all ages became infected.

7. From the last experiment it may be concluded that slugs will feed on the droppings of fowl despite the presence of a sufficient normal diet, in this case clean lettuce.

The feasibility of infecting laboratory rabbits experimentally with the ovine nematode Nematodirus spathiger was examined. Eight-week-old rabbits were dosed either with 5000 or with 17 000 third-stage larvae and killed on days 10, 21 or 42 post-infection. With the lower dose, 20 to 40% of the inoculum were recovered at necropsy. Similar values were recovered at necropsy. Similar values were observed with the 17 000 dose on days 10 and 21 post-infection, but on day 42 the worm population was residual (0·6%). With both dose levels, during the course of infection, the worm populations were mainly composed of fourth-stage larvae and worm egg excretion was low. N. spathiger mainly inhabited the proximal jejunum. The results were compared with N. spathiger infection in sheep to assess the usefulness of the rabbit as an experimental model for Nematodirus infection.

Female ICR mice, 5 to 6 weeks old, were exposed by stomach tube to 25 metacercarial cysts of Echinostoma caproni per mouse. At 14 days post-exposure, mice were fed by stomach tube clorsulon (1000 mg/kg, 25 mg/kg, 500 mg/kg and 100 mg/kg) or rafoxanide (50 mg/kg, 25 mg/kg and 5 mg/kg) dissolved in dimethy lsulphoxide (DMSO) carrier and mebendazole (1000mg/kg and 500 mg/kg) or arprinocid (100 mg/kg and 50 mg/kg) suspended in a2:1 polyethylene glycol (PEG)/DMSO carrier. All drugs were obtained from Meerck In. (Rahway, New Jersey, USA) and only single dose regimes were used. Experimentally infected mice that served as controls received either DMSO or 2:1 PEG/DMSO carriers or were not given the carrier. Mice were necropsied 15v, 16, 18 and 20 days post-exposure to worms. Doses of 100 mg/kg of clorsulon and 50 mg/kg of rafoxanide were 100% effective in eliminating the echinostomes on day 1 post-administration of the anthelmintics. Mebendazole and arprinocid were ineffection in eliminating worms at 1 or 2 days post drug daministration.

Lyophilized eggs of Schistosoma mansoni, when incubated briefly with serum from infected mice, bind antibodies, as made evident by subsequent binding of flurorescein labelled anti-IgG or 125 I-labelled protein A. On the basis of these findings, a radioimmunoassay was devised which employs whole lyophilized eggs (500 or 250 eggs/serum sample) as antigenic particles and 125 I-labelled protein A as a probe for antibody binding. Only 10 μl of serum are required to obtain 90% of the maximal binding. Kinetic studies indicated that 70% of the maximal seropositivity develops in mice between five and six weeks after a light infection, reaches a maximum at eight weeks and fluctuates around a high plateau thereafter. Pre-incubation of the test serum with soluble egg antigen (sea) considerably inhibits antibody binding to the eggs, suggesting that SEA-like antigens participate in the reaction.

A new species of filarial worm, Paronchocerca mansoni, a cardiac parasite of Pica pica sericea (Gould) and Cyanopica cyana interposita Hartert, is reported from Peking, China. The thread-like adults of both species taper towards anterior and posterior ends. The cuticle exhibits superficial rugae, with multiple transverse striations underneath. The lipless mouth is surrounded by 4 paired submedian papillae and one lateral pair of amphids. The posterior end of the body is curved ventrad; the post-anal region is short. The male measures 17 mm. long and 0·14 mm. in diameter; the female, 35·8 mm. long by 0·23 mm. in diameter. In both sexes the anterior muscular oesophagus is short, the posterior glandular portion much longer. In the male, there are two pairs of pre-anal and one pair of post-anal papillae, likewise one pair of subterminal caudal papillae. There are neither caudal alae nor gubernaculum. The longer left spicule and the shorter right one have distinct species-characteristic morphological patterns. In the female, the vulva opens approximately 2·0 mm. from the anterior end. The microfilariae are sheathless; immature ones preponderate in heart blood; mature ones, present in heart blood and exclusively in circulating blood, measure 147 to 184 by 6·0 to 6·5 microns.

The long-term infection with Schistosoma mansoni (Gezira strain—Sudan) was studied in the Nile rat (Arvicanthis niloticus) to investigate the ‘self cure’ phenomenon. The results indicated that while a considerable number of worms and eggs were still recovered by week 28 post-infection, elimination of some of the worms occurred by week 20.

Travassos (1937) in his monograph on Trichostrongylidae Leiper, 1912, deals with Trichostrongyles belonging to 91 genera under 13 subfamilies of which 4 are new. He places Molineus Cameron, 1923, along with 33 other genera in the type subfamily Trichostrongylinae Leiper, 1908. Subsequently Skrjabin and Schulz (1937) erected the subfamily Molineinae with Molineus as type.

Breinlia mackerrasae n.sp. is described from the short-nosed bandicoot Isoodon macrourus. It bears most similarity to B. dentifera, but differs in having larger spicules and in the arrangement of the anal papillae. Female worms from a ‘mumut’ (Peramelidae) are described, but as no males are available, their taxonomic status remains uncertain. These are the first records of Breinlia from peramelid marsupials.

A D-D mixture was tested against the Root-Knot Eelworm, Heterodera marioni (Cornu), in a glasshouse devoted to the growing of tomatoes under commercial conditions in South Wales. The effects of four different rates of application, namely, 0, 200, 300 and 400 lb. per acre injected at a depth of seven inches at staggered points fifteen inches apart were investigated.

Improvements in growth of the tomatoes and reductions in the eelworm manifestations on the roots were produced in proportion to the increases in the dosage rate. Height of the plants, number of flower trusses and yield of fruit were selected for actual measurements of the effects produced on the growth of the tomato plant. All of them showed a graduated response to the injections at 200, 800 and 400 lb. per acre, the yields of marketable tomatoes, for example, being at the three dosage levels, respectively, about 200, 850 and 450 per cent. higher than in the controls.

The nematocidal effects were measured independently by grading the roots into four distinct categories, according to the severity of the pathological manifestations associated with the presence of Heterodera marioni. Judging by the results obtained in this way, D-D reduced the infestation by something like 25, 50 and 75 per cent, when injected at the rate of 200, 800 and 400 lb. per acre respectively. No information regarding the quantity necessary to effect complete extermination is available but it seems that an application exceeding 400 lb. would be imperative for this purpose at least in heavily infected soils where 70 per cent, of the plants are liable to suffer severe infestations.

Adult trematodes identified as Galactosomum ussuriense Oshmarin, 1963 were recorded from the intestine of Sterna hirundo and Larus brunnicephalus from Visakhapatnam, India. The occurrence of metacercaria of this species in inshore and offshore fishes is discussed in relation to the ecology of the snail intermediate host.

C-banding has been performed on Dictyocaulus filaria using both original and modified techniques. The karyotype is reported based on C band observations. The existence of large heterochromatic blocks appears to be the cause of the low chiasmata frequency.

The life history of Grysoma indica n.sp., a psilostome trematode, obtained experimentally in ducklings, after feeding with metacercariae occurring in the snail Thiara tuberculata, is elucidated. Natural infections with cercariae were found in T. tuberculata, collected from a freshwater stream at Visakhapatnam, India. Metacercarial cysts were found in the same and other species of snails in the locality. The new species differs from other species of the genus in the sucker proportions, position of the testes and distribution of the vitelline follicles.