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.

The African schistosomes fall naturally into two main groups of sibling species, the S. haematobium complex and the S. mansonil S. rodhaini group. Morphological differentiation of the species within each group depends on small differences in the eggs but in many cases there are clear biological differences in definitive and intermediate host specificity and in parasitic site within the host, and these criteria serve to strengthen a classification based on egg morphology. Nevertheless, many authors have disputed the validity

A new nematode, Oryctonema genitalis gen. et sp. nov., which possesses features of both the Rhabditidae and Angiostomatidae, is described from the genital system of the dynastid beetle, Oryctes monoceros O1. in West Africa. Multiplication of O. genitalis occurs in the bursa copulatrix of female beetles and the nematodes sustain themselves for long periods in the numerous aedaegal ducts of the male beetle. The possible influence of these nematodes on host viability is discussed.

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.

The effect of irradiation on the survival, behaviour and immunogenicity of the infective (3rd stage) larvae of O. columbianum was studied. The findings reported are:

1. Irradiation with up to 160,000 r does not significantly alter the survival of the larvae when stored at 4°C and at room temperature (26–32°C) for a period of 42 days.

2. Irradiation at 15.000 r to 40,000 r results in progressively fewer adults developing but more nodules being formed in the intestinal wall. Irradiation at 80,000 r results in the larvae failing to develop and establish in the host.

Chand ler (1925) described Echinochasmus perfoliatns as a common parasite of Indian dogs in Calcutta. Bhalerao (1936) reported its occurrence in cats of Calcutta and Mukteswar and Patnaik (1959) in dogs of Orissa. Maplestone and Bhaduri (1940) reported Echinochasmus sp. from dogs in Calcutta. Gupta and Pand e (19G3) mentioned that Echinochasmus is represented in Indian carnivores by three species: E. perfoliatns, E. corvus (Syn. E. caninum) and E. canai.

Asexual multiplication in Cysticercus pisifortnis (Bloch, 1780) was first described by Moniez (1880). This observation was refuted by Solomon (1934) as being “erroneous or descriptive of an isolated or abnormal phenomenon”. Several years later, Crusz (1948) confirmed the observations of Moniez (1880). Voge (1967) did not mention asexual reproduction in this species in her review on postembryonic development of cestodes.

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.

Plectus murrayi n. sp. is distinguished from other species by possessing 12 lips; stoma, amphid and excretory system are ‘plectoid’ rather than ‘anaplectoid’. Eudorylaimus antarcticus (Steiner, 1916) n. comb. is proposed for Dorylaimus antarcticus Steiner, 1916 and the species is redescribed. Both species were collected from mosses from the McMurdo Sound Region, Antarctica. Anaplectus arenicola Killick, 1964 has only six lips; stoma and excretory system are ‘anaplectoid’.

1. Metacercarial cysts of Echinoparyphium serratum occur in the pericardium of the snail Isidorella brazieri. Each cyst is surrounded by a nucleated, syncytial host capsule containing granules which are presumed to be melanin. The cyst wall consists of two layers and both contain acid and neutral mucopolysaccharide but little or no protein. No modification of the cyst wall coincident with the point of emergence of the metacercaria has been located.

2. Excystment of the metacercaria takes place in two main stages when pepsin is omitted from the initial pretreatment solution: stage I (emergence from the cyst wall through the escape aperture) is an active process (exogenous enzymes are not necessary), and a high percentage of specimens reaching this stage is dependent on the combined effects of a þH of 2, reducing conditions, elevated temperature (37–39°C) and sodium cholate. Temperature and sodium cholate are absolute requirements for this stage as is pretreatment of between þH 2 and 4 when sodium cholate is included with the reductant (sodium dithionite) rather than in the excystment medium with trypsin. The possibility that CO2 is involved has not been established.

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.

Two new species belonging to two different families of the super-family Aphelenchoidea are described. The material was obtained from the roots of tobacco plants, Nicotiana tabacum.

The worms were killed by hot water, fixed in F.A.A. solution, cleared in 1% glycerine alcohol mixture and mounted in pure glycerine.

Small numbers of the nematode species: Spiculopteragia asymmetrica, Apteragia quadrispiculata, Nematodirus filicollis, Capillaria bovis, Cooperia pectinata and Oesophagostomum venulosum, were recovered from the gastro-intestinal tracts of wild Fallow deer killed in Essex. In addition, the larval cyst of the cestode Taenia hydatigena was found in the liver of one animal.

Macrogyrodactylus polypteri Malmberg, 1957* is a viviparous monogenean found on the skin and fins of the African freshwater fish Polypterus senegalus Cuvier. It was first reported by Malmberg (1957) from Gambia. Khalil (1964, 19G9) and Amirthalingam (19C5) recorded it on the same host species and Saoud & Mageed (1969) found it on P. bichir in the Sudan. Prudhoe (1957) described a new genus and species, Neogyrodactylus congolensis, on the skin of Clarias lazera from the Congo but Yamaguti (1963) considered this genus to be a synonym of Macrogyrodactylus. A third species, M. clarii Gussev, 1961 was reported on Clarias sp. from south Ethiopia and Ghana. On the basis of one specimen M. latest Paperna, 1969 was reported on Lates nilotica from Ghana. So far the species of the genus are confined to African freshwater fishes.

Mr. T Petre of the Volta Basin Research Project of the University of Ghana kindly entrusted the writer with some nematodes collected from the freshwater fishes of Ghana. As far as can be found from published literature there is no previous record of nematodes from the freshwater fishes of Ghana. In fact, the helminth parasites of the freshwater fishes of this country are inadequately known and only monogeneans, digenetic trematodes and a single acanthocephalan have so far been reported. This collection represents 3 different species of nematodes from various hosts, one of which is new to science and is named after Mr. Petre to whom I am most grateful

The specimens described herein were collected by one of us (M.A.R.) from the stomach of Rana esculenta in Al-Basrah, Iraq. After fixation in 70% alcohol and staining in Gower's carmine, they were found to be a hitherto undescribed species of the genus Halipegus Looss, 1899 which is named here as Halipegus alhaussaini n.sp. in the honour of the late Professor A. H. Al Haussaini; Formerly Head, Department of Zoology, University of Ain Shams, U.A.R. for his distinguished contributions to the study of zoology in Egypt.

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.

One of the morphological features that has been considered of diagnostic value in distinguishing between different strains of Schistosoma spp. is the number of testes in the male worm. Hsu and Hsu (1957) demonstrated differences in testes number between different strains of Schistosoma japonicum, and Saoud (1966) subsequently showed differences between Schistosoma mansoni from Mwanza and S. mansoni from Egypt and Puerto Rico. Significant differences in testes numbers occurred between S. mansoni from Egypt and Wellcome strains if the worms were reared in hamsters, but not if they were reared in mice (Saoud, 1966).

It has not been easy to study the rate at which female Trichinella spiralis produce their offspring. Phillipson and Kershaw (1961) described a method of repeatedly grinding and washing infected muscle to collect immature larvae so that one could determine the number of larvae born by the time the animal was killed but their method is unsuitable for dealing with the large number of animals that would be needed for a thorough study of this aspect of the infection. We have sought a method of studying this important factor in the host-parasite relationship.