A new species of Dirofilaria, D. (Nochtiella) linstowi n.sp. is described from the subcutaneous tissues of the Grey langur, Presbytis entellus thersites, in Ceylon. The adult worms differ from the hitherto described African and South-east Asian species in several respects, especially spicule size and ratio, arrangement and number of caudal papillae and dimensions of the microfilariae.

The development of the preinfective stages of S. lupi has been described and illustrated and the details of morphology given for the first time.

The sex of the first stage juveniles can be distinguished by locating the position of the genital primordium. On an average, the first stage juveniles measure 0·39 mm. in length and 0·036 mm. in breadth, early second stage 0·78 and 0·044 mm. and the advanced second stage 1·40 mm. and 0·63 mm. respectively. The second stage juveniles obtained from beetles were not infective to dogs.

By means of the standard Ziehl-Neelsen staining technique for eggs in tissue sections S. intercalatum can be differentiated from its sibling species S. haematobium, S. mattheei and S. bovis, since only S. intercalatum egg shells stain red.

This technique could be of great value in Africa in clinical diagnosis and in determining the geographical limits and host specificity of these schistosomes, which may easily be confused on the basis of egg morphology alone.

The majority of third-stage Ostertagia circumcincta larvae exposed to 0·5% levamisole failed to infect lambs even though the worms regained some activity after repeated washings in balanced saline. A low level of efficiency was recorded against 4·5-day-old O. circumcincta when lambs were treated with levamisole at 7·5 mg per kg. Nine-day-old worms from hosts which received anthelmintic on day 4·5 were at the same stage of development as those from untreated control lambs.

The genus Ashworthius contains the following species: A. pattoni Le Roux, 1930 (genotype) from Tragelaphus scriptus sylvaticus (bush buck), A. sidemi Schulz, 1933 from Cervus nippon hortilorum (Sika deer) and C. elaphus asiaticus (red deer), A. martinagliai Ortlepp, 1935 from Bosclaphus tragocamelus (Nilgai) and A. lerouxi Diaouré, 1964 from Syncerus coffer nanus (dwarf forest buffalo). Pike (1969) revised the genus and redescribed A. lerouxi from Syncerus caffer coffer (African buffalo). He gave accounts of other valid species and amended the generic diagnosis.

Camallanus fotedari n.sp. is described from the intestine of Nemachilus from Kashmir. This is a new host record for the genus. The new species is characterised by the presence of 14–16 pairs of papillae of which 6–8 pairs are precloacal, 2 pairs are adcloacal and 6 pairs are postcloacal. The tail in females is rounded.

The present study pertains to two nematode genera, Pungentus Thome & Swanger, 1936 and Discolaimoides Heyns, 1963 which were collected from around the roots of Juglens regia, the common walnut tree in Kashmir. They are described herein as new species. Discolaimoides is recorded here for the first time from India.

S. fernandoi and S. pillaii are described as new species and are shown to differ specifically from each other and from S. japonensis, the only other species that has been reported as having spines on the spicules.

1. An Athesmia sp. from two species of jackals (Canis adustus Sundervall, 1846, and Canis mesomelas Schreber, 1775) in northern Tanzania is described.

2. While considerable variation in size and internal morphology was observed, these differences do not appear to be significant.

3. There being no constant morphological features to establish a new species, these specimens are for the present considered to be A.foxi Goldberger and Crane, 1911.

4. The difficulties in the identification of Athesmia are discussed and the present position in the genus briefly reviewed.

5. Histopathological studies were carried out with negative results and reference is made to other reports of such studies in the literature.

It is apparent that under the conditions of the observations recorded in this study the host-parasite relationships of the two species of snails and their respective strains of S. haematobium exhibit marked similarity in certain respects but differ in others. Higher cercarial infection rates were obtained in B. globosus than in B. truncalus at relatively low miracidial exposure levels but the daily mean cercarial outputs of each species at the same miracidial exposure level were similar. A higher frequency of production of large numbers of cercariae was recorded for infividual B. globosus than for B. truncatus. The mean cercarial prepatent periods for B. globosus and B. truncatus at a level of 7 miracidia were each 32 days, but infected B. globosus lived appreciably longer than infected B. truncatus. The hourly output of both species exposed to stimuli for the same period of time was broadly similar. Peaks of cercarial production were generally reached earlier by individual B. truncatus (2 weeks) after onset of shedding than by individual B. globosus (4–5 weeks), although erratic shedding was observed for both species.