Many crops of carrots grown in gardens and on a field scale, during the War, have been infested with a weed which bears a resemblance to Solanum nigrum. It has been identified as Solanum sarachoides Sendtner. The plant is a native of Temperate and Sub-temperate South America. The carrot seeds containing this impurity are said to be of Californian origin.

The plant possesses oval leaves, slightly more wavy than those of British specimens of S. nigrum. They are smooth and dark green in colour, but the stems are covered with short hairs. The habit is procumbent to prostrate and the weed creeps extensively through the dense foliage of the carrot crop. The inflorescences are borne laterally and display minute white flowers. Dark green berries are produced in great profusion each containing about 25 seeds. There is evidence that the plant is becoming established on light soils, in the market gardening districts of Staffordshire, and it is doubtless localised elsewhere.

It was noted that where the weed was growing adjacent to plots of potatoes affected with blight (Phytophthora infestans), that its leaves were also attacked. The lesions resembled those of potato blight and the identity of the fungus was confirmed by Mr. N. C. Preston, of Harper Adams Agricultural College.

Although it may be objected that the present paper deals with a limited population in a circumscribed area, the conclusions drawn are in the main applicable to any zone of endemic Bilharzial infestation. The numbers examined form a considerable series, and the distribution and age and seasonal incidence of the contrasting infections are of some interest. A personal relation with those infected has been, and still is, maintained.

It is a well known fact that Heterodera schachtii in the brown cyst stage can survive in soil for several years in the absence of host plants. Fuchs found living contents in five-year old cysts of the beet strain of this nematode, while eight-year old cysts of the potato strain have been found by the writer still to be infective to the host plant. Thus, the starving out of this parasite by withholding susceptible crops would appear to be impracticable.

We have previously reported on the cestode and trematode parasites of the Sheathbill at Signy Island (Jones & Williams 1967, 1968, 1969) and conclude with an account of the nematodes and Acanthocephala. Our previous reports were based on specimens obtained from 13 Sheathbills collected at Signy Island in July and October, 1965 by Mr. Charles Howie, British Antarctic Survey. In addition to these we have examined a further 12 Sheathbills taken at Signy Island in March, 1967. We are greatly indebted to Mr. E. A. Smith, Senior Biologist, British Antarctic Survey, for arranging the collection and transport of the latter material.

Histochemical techniques were used to study the chemical composition of Mehlis’ gland secretion in Ceylonocotyle scoliocoelium. The results suggest the secretion to be lipoproteinous in nature, containing several hydrolytic and oxidative enzymes. In tests for nine hydrolytic enzymes only seven were detected in relation to gland cells, ihe two enzymes not showing any reactivity being glucose-6-phosphatase and 5-Nucleotidase. Alkaline phosphatase and ATPase have been associated with the permeability and transport of precursors of synthetic material from the surrounding parenchyma and with eliminating the waste products from the gland: ACPase in (i) generating a favourable milieu in the gland for the synthesis of secretory material and (ii) in regulating secretion and its over production; TPPase in elaborating the secretion, esterases in the metabolism of the gland. Intense SDH and MAO activities were related to high synthetic activity of the gland cells. Phenol oxidase—a key enzyme involved in tanning was absent.

Natural populations of the freshwater gastropods Bithynia tentaculata, Gyraulus convexiusculus, Helicorbis coenosus, Indoplanorbis exustus, Lymnaea acuminata, L. luteola and Vivipara bengalensis, were examined from October 1985 to September 1986 at seven transmission sites for paramphistomiasis, fascioliasis and other gastropod-borne infections in Aligarh, northern India. Gastropod diversity and the type and abundance of vegetation were highest at sites containing permanent water bodies. The distributions of H. coenosus and L. acuminata were positively correlated with the type and abundance of vegetation at these sites. Ephemeral water bodies contained B. tentaculata, I. exustus and L. luteola which were resistant to desiccation during the hot season. Aestivation in these gastropods preceded pronounced breeding activity which began with the onset of the monsoon season. Multivariate analysis (by principal components) was used to investigate relationships between each species of gastropod, their site of occurrence and levels of infection with larval helminths. Seasonal variations in numbers and size class structure in these gastropods were found to influence their prevalences of infection with larval helminths. Metacercarial and cysticercoid infections were more prevalent in smaller size classes of B. tentaculata and V. bengalensis, whereas larval paramphistomes were more prevalent in larger size classes of G. convexiusculus, I. exustus and L. luteola. Attempts were made to equate these findings with seasonality in egg shedding by certain species of adult paramphistomes occurring in domestic ruminants.

1. A method of management of sheep at pasture is described which appeared successful in preventing reinfection by nematodes parasitic in the alimentary tract, with the exception of Strongyloides papillostts.

2. A significant depression of liveweight gain was observed, due to a sub-clinical infestation in lambs at pasture.

3. Reseeded pasture sown on land that had carried sheep 11 months before appeared to be worm-free.

Protective immunity of homologous challenge infection was examined in jirds after drug-abbreviated infection with Brugia pahangi. Mebendazole (MBZ) treatment at the early prepatent (5–7 weeks of post infection) or the late prepatent (7–9 weeks of post infection) period was highly effective in causing almost complete eradication of the primary infection. After challenge infection, the worm burden was significantly reduced 19% (31·1 in average) and 77% (9·5) to that of the controls (38·8 and 41·7), respectively. The magnitude of eosinophil response paralleled the degree of protection. No or only a few microfilariae were seen after challenge infection in jirds treated during the prepatent periods. They were also resistant to intravenous challenge with the microfilariae of B. pahangi. MBZ treatment at the patent period was, on the contrary, incomplete against primarily infected adult worms, and was not able to induce either significant protection (30·1 vs 33·1 in control) or eosinophil response to the challenge infection.

A technique is described for the floatation and enumeration of trematode eggs. A special sampling and mixing pipette has been designed. The floatation fluid is a solution of potassium mercuri-iodide (K2HgI4). A modified McMaster egg-count slide, or else a calibrated sliding toppiece apparatus is used for counting the eggs and estimating the number per gramme of faeces. The apparatus is illustrated and described.

In December, 1957, Dr. Zaheer Ahmad, Veterinary-Assistant Surgeon, Baswada, handed over to the writer for specific determination a few specimens of Stephanofilaria which had been collected by him from ear-sores of buffaloes in Baswada (Nizamabad). Since on examination the material was found to consist only of females, it was not possible to identify the species. On consultation of relevant literature, however, it was noted that ear-sore infection associated with Stephanofilaria had been recorded by Gopalkrishnan in 1949 in Assam and later referred to by Menon (1952) in connexion with the treatment of “Contagious Ottorrhoea“ in buffaloes in Travancore.

Fly load of Onchocerca volvulus microfilariae and their early development in Simulium ochraceum were examined at intervals of 10, 30 and 60 min after ingestion and then hourly up to 72 hours. Many microfilariae ingested were damaged by the cibarial armature of the vector, limiting the fly load, but some of these damaged microfilariae were able to penetrate the gut before they died. Thus, the mean number of the living parasites per fly in the head and thorax decreased gradually with elapse of time after ingestion. The parasites ingested by S. ochraceum did not develop beyond the microfilarial stages during the first 24 hours; thereafter only thoracic forms (lst-stage larvae) were found to be alive. The high mortality of the infected fly might be caused by the high intakes of microfilariae and also by normal and/or partly wounded microfilariae invading various organs. The numbers of microfilaria ingested from different biting sites were usually high in comparison with the densities observed in each site; this indicates that the microfilariae might be attracted by the biting females.

1. 24: rats were infected with 5,000 N. brasiliensis larvae and were examined hourly from 12 to 24 hours after infection for larvae in the blood and the lymph nodes.

2. Larvae were found in small numbers in the blood and the lymph nodes; the maximum number of positive blood samples occurring sooner after infection than the maximum number of positive lymph nodes.

3. These results were discussed particularly in relation to the timing of the skin to lung migration, and it was concluded that the larvae of N. brasiliensis migrate mainly in the blood but also in the lymph.

A description of Neoparadiplostomum magnitesticulatum gen. et sp. nov. and Neoparadiplostomum kafuensis gen. et sp. nov. is given. The material was obtained from the intestine of Crocodilus niloticus, Kafue River, Northern Rhodesia.

The genus Neoparadiplostomum which is proposed as new is closely related to all the other genera of the subfamily Proterodiplos-tomatinae, but differs from them in the nature of the paraprostate and the arrangement of the sexual ducts.

A catalogue is given of some known strigeid (Trematoda) parasites from the African Continent.

This report is the third in a series by the authors on the digenetic trematodes of marine fishes from Ghana, and was supported in part by a State University of New York Faculty Research Fellowship (FRF 68–40–003) awarded to the senior author. Specimens have been deposited in the U.S. National Museum Helminthological Collection as indicated. All measurements are in microns.

In a previous paper published in 1937 Carroll & McMahon discussed the possibility of effecting control of potato root eelworm (Heterodera schachtii) by means of trap cropping with potatoes. During the past two seasons further experiments, designed with the same object in view, have been carried out. The additional information obtained from these experiments and from the experience of the past two years is presented in the present paper.

1. The morphology of the adult worms and the microfilariae are described of a new species of filarial worm, Dipetalonema manson-bahri.

2. Dehpsylla crassipes Jordon, 192G, a flea specific to Pedetes surdasler, was found in nature to contain infective larvae which are believed to be those of D. manson-bahri.

3. In the laboratory full development of D. manson-bahri was observed in Ctenocephalides felis and Xenopsylla cheopis.

Moaciria chondropythonis sp. n., from cysts in the wall of the oesophageal/stomach junction of Chondropython viridis originally from New Guinea but kept in captivity at the Zoological Society of London for three months is described and figured. It is distinguished from the other species of the genus by the number and arrangement of the caudal papillae and by its larger size.

The classification of the Trematode family Opisthorchiidæ presents some difficulties to the systematist. These difficulties arise partly from the fact that a number of the existing species appear to lack any real morphological characters by which they can be differentiated, slight variations in measurements, together with a difference in host, having been considered sufficient to justify the making of new species. This view has resulted in the placing of undue importance on somewhat minor differences when they do occur in other species, such differences being considered sufficient for creating new genera.

The systematist is further confronted with the difficulty of forming definite opinions on the systematic position of some of the species made by earlier workers. Their descriptions and figures are often inadequate owing to the fact that characters which, in the past, were considered of minor importance are now given much closer attention. Examples of the confusion which has arisen from such a position will be referred to in this paper.

Spinicauda regiensis n. sp. is described from a captive ball python, Python regius. The new species differs from all other species of Spinicauda by the presence of a papilla in the precloacal sucker of the male.

Diagnosis of intestinal parasites through examination of fresh faecal samples is hampered by its unpleasantness and the urgent need to detect all parasitic forms. In this paper, we compared the standard Kato–Katz (KK) technique with a traditional fixation method, the merthiolate–iodine–formalin (MIF) method. Two hundred and twenty-seven faecal samples from individuals living in a rural setting in Venezuela with high to moderate prevalences of Ascaris lumbricoides (Al), Trichuris trichiura (Tt) and hookworm infections were examined. The ‘gold standard’ used here was derived from the combination of the outcomes from both methods. KK performed better at detecting Tt, and showed higher sensitivity and negative predictive value for both Tt and Al, probably due to a higher capacity of KK to detect low parasite loads. Both methods showed an almost perfect agreement using the Kappa index. MIF provided a higher median of parasitic loads for low and total egg counts for the three helminths. Differentiating fertile from infertile eggs of Al did not affect the results; infertile eggs were present only at low and intermediate parasitic loads, but absent at high loads. KK was not able to detect high loads of any of the helminths. MIF allowed for the detection of other helminths, such as Strongyloides stercoralis, and protozoan infections, for which KK is not specific. In conclusion, MIF is a simple and inexpensive technique that performs competitively with KK in both laboratory and field work on intestinal helminths, particularly in resource-limited settings.