An extract of the snail Bulinus (Physopsis) africanus, the intermediate host of Schistosoma haematobium, was used as the antigen in haemagglutination tests in a survey of the prevalence of anti-snail antibodies in various population groups. It was found that sera from known bilharzia-infected individuals and randomly selected individuals from bilhanda endemic areas had significantly higher incidences as well as higher titres of antibodies to this snail antigen than non-infected individuals and individuals from non-endemic areas.

Infection of dogs with E. granulosus is recorded for the first time in the State of Kuwait and observations on 204 dogs from different suburbs showed an infection rate of 23.039%. Cattle, sheep, goats and camels killed for public consumption in the period 6th April to 6th May, 1975, in a slaughter house were inspected and the rate of infection with E. granulosus cysts was recorded. The possible methods of transmission from animals and dogs to man is discussed.

By means of scanning electron microscopy, stalked protrusions were observed arising from the outer surface of intact brood capsules of Echinococcus granulosus. Histological studies showed these protrusions to be developing protoscoleces. However, complete development is not attained and the protoscoleces eventually die. It is suggested that external development is a result of overcrowding within the brood capsule.

The bionomics of the free-living larvae of Dictyocaulus filaria on pasture, and the transmission of infection between lambs, were studied during different seasons of the year m North-East England.

The rate of development of first-stage larvae to the third stage took 4–9 days in late spring and summer, 1½–4 weeks in autumn and 5½–7 weeks in winter. The proportion of first-stage larvae developing to the third stage ranged from 10–28% in autumn and winter, and 2–25% in spring and summer. The rate of mortality of the third-stage larvae was approximately logarithmic in nature, although the survival time was shorter in spring and summer than in autumn and winter. Third-stage larvae were able to survive from autumn until the spring of the following year in sufficient numbers to perpetuate transmission but not to cause clinical disease.

Infection with the cyclophyllidean tapeworm Mesocestoides sp.is recorded in British wild red foxes (Vulpes vulpes crucigera) from Scotland and South East England. Previously, the occurrence of this parasite in Great Britain has been rarely reported, but the results of the present study indicate that vulpine infection may be common.

A hclminthological survey of 149 house rats in Jodhpur during the year 1975 revealed infection with 8 helminth species: 4 cestodes, Vampirolepis fraterna, Hymenolepis diminuta, Mathevotaenia symmetrica and Taenia taenlaeformis (larval stage); 3 nematodes, Aspiculuris pakistanica, Rictularia ratti and Syphacia sp. and one acanthocephalan, Moniliformis sp. Vampirolepis fratema, H. diminuta and A.pakistanica were most common, R.ratti and M. symmetrica less frequent, and T. taeniaeformis, Syphacia sp. and Moniliformis sp. of occasional occurrence. Multiple infections were more frequent among male than female hosts.

The development of Breinlia booliati is described in its natural host, Rattus sabanus and in an inbred strain of laboratory albino rat. The growth of the parasite is similar in both the rat hosts. The third moult occurs between six—eight days and the final moult between 24–28 days. Larvae were recovered initially from the skin and carcass. After five weeks, developing stages were seen only in the thoracic and abdominal cavities, the site of development of the adult worms. Worms became sexually mature by 11–12 weeks and there was considerable growth in length of the female worms after this stage.

In attempting to define the south western limits of the distribution of Schistosoma margrebowiei and S. leiperi and investigating their apparent limited distribution in relation to their snail hosts it was found that there was little overlap in the distribution of S. margrebowiei and S. leiperi and that of the human parasites S. haematobium and S. mansoni, and no overlap with S. mattheei within the area surveyed. It is suggested that the presence of either or both lechwe schistosomes prevented the development of the human parasites and in addition, prevented the development of S. mattheei in certain areas inhabited or surrounded by certain Kobus spp.

The life-cycle of Apatemon (A.) gracilis was completed in the laboratory. The snail host is Lymnaeaperegra (Müller). The cercaria is redescribed from a wide range of material. Metacercariae were found in naturally infected rainbow trout (Salmo gairdneri Richardson), three-spined sticklebacks (Gasterosteus aculeatiis L.) and stone loach (Nemacheilus barbatulus (L.)) from Scotland and in three-spined sticklebacks from Iceland. In trout, most metacercariae were found in the pericardial cavity, in sticklebacks, the eye, and in loach, the body cavity. In infection experiments, cercariae from naturally infected Scottish snails developed in threespined sticklebacks, rainbow trout and brown trout (Salmo trutta L.). Under experimental conditions cercariae did not penetrate stone loach, although this species is naturally infected with A gracilis. The phenomenon of fish host specificity is briefly discussed. Development of the metacercaria is described. Excystation of metacercarial cysts with pepsin and trypsin solutions is unlike that reported for any other digenean; the contents of the cyst appear to be under pressure. In pepsin, layers of the cyst wall peel back from one end. When transferred to trypsin, one pole of the cyst ruptures and the worm is forcibly expelled.

13 species of ccstodcs from 13 species of Philippine birds are reported from Palawan Island. Raillietina (R.) palawanensis n. sp., from Chalcophaps i. indica, has three or four testes, and a cirrus pouch 93 to 108 µm long, 28 to 45 µm wide, and its egg capsules are 10 to 12 µm long, seven to nine µm wide, each containing four to six eggs. Raillietina (R.) passeriformicola n. sp., from Gracula religiosa palawanensis, has seven to nine testes, and a cirrus pouch 134 to 170 µm long, 47 to 68 µm wide. Its egg capsules are 79 to 115 µm wide, containing 7 to 12 eggs each. Raillietina (R.) fischthali n. sp., from Ducula aenea palawanensis, has 12 to 15 testes, and a cirrus pouch 130 to 150 µm long, 52 to 72 µm wide. Its egg capsules are 130 to 200 µmi wide each containing 50 to 70 eggs. Raillietina (R.) johri Ortlepp, 1938, is redescribed. Anonchotaenia chauhani Mukherjee, 1965 is shown to be a junior synonym of A. gaugl Singh, 1952.