In three successive years trials were made of measures for the control of parasitic gastro-enteritis in calves, based on the knowledge that the second generation of the worms is the cause of disease and that it becomes available on the herbage in July. A comparison was made between calves which remained on the same pasture throughout the season, calves which were moved in the middle of July to pasture which had not been contaminated since the previous autumn and calves which were given a dose of anthelmintic when moved to such clean pasture. A fourth group consisted of calves which received anthelmintic treatment every week while remaining on infected ground.

Aphelenchoides besseyi Christie, 1942 is recorded for the first time on rice in Mali and Upper Volta, the morphology is discussed and the description of the species emended. Boehmeria nivea Gaud. (Ramie) is reported as a new host for A. besseyi. A. siddiqii n.sp. is described from Foeniculum vulgare Mill, in Sudan. A key is given to the species of Aphelenchoides with a star tipped tail.

1. 8515 specimens of the common periwinkle, Littorina littorea (L.), from four localities on the North Yorkshire coast were examined for larval Digenea during 1966 and 1907. Four species were found, namely Cryptocotyle lingua (Creplin, 1825), Himasthla leptosoma (Creplin, 1829), Cercaria lebouri Stunkard, 1932 and Cercaria A, the incidence of infection with which correlated with the presence of sea bird and wader final hosts.

2. 5878 of all L. littorea examined were from one locality of relatively high incidence of infection where there were seasonal changes in incidence, being greatest during the autumn and early winter and least during the summer. The incidence of infection was higher in larger than in smaller periwinkles except in infections with an unidentified species, named Cercaria A, where the incidence declined sharply in L. littorea above 25 mm shell length. The ecology of the infections is discussed.

808 cunners, Tautogolabrus adspersus (Walbaum) were obtained from eight sampling stations around the Newfoundland coast, during the periods August-September, 19G7 and July-October, 1908. The fish were examined for metazoan parasites using conventional parasitological techniques. 22 species of parasites (10 trematode; 5 cestode; 6 nematode; 1 acanthocephalan) were recovered. This number excludes metacercariae of Cryptocotyle lingua (Creplin, 1825). 19 are new host records. Details of infections with the various species are given, each species being discussed and/or described individually. No leeches were found on this host despite the fact that it lives in. close proximity to other fish species that are heavily infested and an experiment performed to determine if leeches would move from one host species to another gave negative results.

Investigations are described in which lambs were given either 1,000 or 5,000 3rd stage infected larvae of T. axei at 2, G, or 10 weeks age and were subsequently challenged with 200,000 3rd stage larvae at either 5 or 7 months of age. The immunity acquired following primary infection was manifest by a reduction in the numbers and size of the worms developing after challenge infection.

Gavage administration of cambendazole at 50 mg/kg was found to eliminate a 7 hour Trichinella spiralis infection in mice. Cambendazole was also found to be highly active against the muscle phase of trichinosis. Partial activity was also indicated against migratory larvae and adult worms. Cambendazole appears to have a sterilising effect on adult T. spiralis. It is postulated that cambendazole has potential therapeutic value.

A rapid technique for the assessment of a larval population on herbage is presented. Factors influencing the reliability of this technique and the problems encountered whilst trying to estimate efficiency of recovery rate are discussed.