The parasite was found in the bile ducts of three sperm whales, which were caught in the 1957–58 whaling season.

As specimens were found independently in bile ducts of three whales this position in the host appears to be the natural habitat. All the worms were in pieces and incomplete. The pieces, in each case, totalled approximately 18 metres, 0·9 metres and 21 metres respectively. The holotype (length 18 metres) was probably complete except for a few terminal proglottids because it consisted of two very long pieces and one short piece which could be fitted together. The type material has been deposited in the British Museum (Natural History) Registered No. 1961·12·12·1 (Holotype) and 1961·12·12·1 (Para types).

1. The recovery of nearly 400 specimens of Fasciola hepatica from experimental infections of the mouse, representing 20 stages covering the period from the first day of infection to maturity at 37 days, has made possible for the first time a study of growth and maturation. Flukes have reached the bile duct on the 32nd day of infection, and in two instances reached this final location on the 29th and 24th days.

This new species is described from material consisting of four males and six females said to have been recovered from the intestine of Rhinoceros bicornis in Kenya and sent to the writer through the courtesy of Mr. M. C. Round, B.Sc, of Veterinary Research Laboratory, Department of Veterinary Services, Kabete, Kenya.

The specimens on which this new genus and species are based were collected by Mrs. R. H. McConnell from the intestine of Cichlasoma festivum (Heckel, 1840) at Sofia, Georgetown, British Guiana. Since oxyurid parasites of fish are very unusual the possibility of the present specimens having been taken with food must be considered but this appears to be ruled out by the relatively good condition of the specimens and their location in the host. Oxyurid parasites are notoriously difficult to preserve in a good condition and the present specimens, although somewhat contracted, are in a much better condition than many other oxyurids I have received at various times which had been collected during parasitological surveys.

1. Two new species, Spironoura sudanensis sp. nov. and Spironoura hexapapillata sp. nov. are described from freshwater fishes in the Sudan.

2. The genus Velariocephalus Singh, 1958 is considered to be a synonym of the genus Spironoura Leidy, 185G.

Seven species of pharyngeal, longifurcate, distome furcocercariae are recorded from London (U.K.).

C. letifera Fuhr. is recorded for the first time from Britain. Two new species are described in detail.

Three new species of cercariae of the ‘Vivax’ type are described from London (U.K.) and the classification of this group of cercariae is discussed.

The life-cycle of one of the cercariae is studied and different stages are described in detail.

Cercaria essexensis Khan, 1960 is shown to encyst in freshwater snails and to develop into a new species of Hypoderaeum when fed to pigeons, chickens and ducklings. Different stages in the life history, except the redia and the cercaria which have been described before, are described.

Measured dosages of larvated eggs of the caecal nematode, Heterakis gallinarum and the small intestinal nematode, Ascaridia galli were fed to domestic chickens, in order to study the distribution of the numbers of worms developing and the influence on the worms and the chicks of the treatments in the experiments. These treatments are summarised in Table 1, p. 110.

Chronic respiratory disease, accidentally acquired by the groups of chicks in varying degrees appeared to have no influence on the course of the worm infections and the ensuing blackhead (Table 2, p. 112).

Following ingestion of eggs of Heterakis, blackhead occurred in three of four groups of chicks, apparently in varying degrees, possibly related to the size of the egg dosage and to differences in susceptibility to Heterakis (Table 1, p. 110). The chicks inthe group which did not contract blackhead were considerably older than those of the other groups.

Big variations have been reported in the extent of occurrence of the so-called “histotropic or tissue phase” (“dormant larvae”) especially in intestinal nematodes. In several species these variations were found by some authors, not by others, and also not always by the same author. From this fact, and from the well known retardation of growth of larvae during their stay in the tissue, it was concluded that it does not represent a phase in the sense of a behavioural pattern innate to the parasite, but rather a phenomenon dependent upon the degree of resistance in the host.

Amongst cestodes collected from birds in the Lake Kariba district, Southern Rhodesia, was a dioecious species of the genus Gyrocoelia Fuhrmann, 1800, obtained from a darter, Anhinga rufa.

Ortlepp (1037) described, from a single poor specimen, a new species in this genus, which he termed G. kiewietti. Ortlepp thought that his specimen was functionally monoecious, the ovary and vitellaria appearing after the testes had disappeared. Although the present material is definitely functionally dioecious, it is thought that it is the same species as Ortlepp found as the number, size and arrangement of the rostellar hooks are very similar.

Several specimens of this species were collected by one of us (M.B.B.) from the intestine of a Mistle Thrush, Turdus viscivorus viscivorus (L.) examined at Silwood Park, the field station of the Imperial College of Science and Technology. Detailed examination of this material has only recently been made, and it appears to represent a new species for which the name Anomotaenia caenodex is proposed.

Observations, limited to one year, on autumn born and spring born lambs and weaners indicated that very few infective larvae of bursate nematodes, with the exception of those of Nematodims spp., were ingested after the middle of spring, with the result that at least until they were eight months old, and probably older, spring born lambs were comparatively lightly infested.

These observations also suggested that retarded larvae, especially the histotropic stages, are the cause of the “summer rise” in weaners and that they also cause the “parturition rise” in autumn lambing ewes, and can be the cause of increased worm egg production in wethers.

It seems probable that the “summer rise” of sheep in the southern part of Western Australia is comparable to the “spring rise” of sheep in the United Kingdom and elsewhere.

Strongylus (Dicerocola) tremletti sp.nov. is described from the black rhinoceros, Diceros bicornis L. from Kenya.

The affinities of S. (D.) tremletti sp.nov. with the other species of the genus Strongylus Müller, 1780 are discussed and the subgenus Dicerocola subgen.nov. is erected to contain it.

The species of Strongylus in Kenya are noted and original drawings of S. (D.) asini Boulenger, 1920 are included.

The absorption spectra of haemoglobins from A. glabratus and P. corneus and from B. (P.) globosus and B. (B.) tropicus angolensis were established. There was no difference between the spectra of snails which transmit Schistosoma mansoni or S. haematobium and the spectra from related insusceptible species.

The snail haemoglobins produced absorption spectra which differed from mammalian pigments only in the position of a single peak.

Snail blood occasionally produced additional small peaks in the ultra-violet region, which may have been due to blood proteins other than the respiratory pigment.

One male specimen was collected from the liver of a short tailed wallaby, Macropus brachyurus, which died in the Zoological Gardens, London on 26th September 1960. It is a slender worm 82 mm. in length and 0·41 mm. in maximum width. The anterior extremity is rounded. There is a small buccal cavity and at the base of this there is a prominent cuticularised ring. The cephalic end bears four pairs of submedian papillae and a pair of amphids. The en face view was not studied because of the lack of specimens. The cuticle is transversely striated all over the body and there are bosses like small slightly curved markings on it.

These trematodes were collected from the large intestine of a black-necked stork which had died in the Zoological Gardens, London. All the specimens present are damaged and there is only one piece showing the anterior part containing the head collar. It was not possible to determine the exact length of the specimens, but they are long and slender and measure at least 18 mm. in length. The body is almost uniform in width except in the regions of the ventral sucker and the testes where it is broader. The cuticle is thickly covered with spines in the anterior region of the body from the posterior border of the head collar to the posterior rim of the ventral sucker. On the dorsal surface the spines form a semicircle around the region of the ventral sucker and extend on either side of it. On the ventral surface very few spines are present on the sides of the sucker. The size of these spines varies a lot; in the anterior part they are very small, their size increasing towards the posterior region up to the end of the oesophagus from where it decreases again till the last row of spines which are very small.

Liga brevis (von Linstow, 1884) Dubinina, 1953, is recorded for the first time in the British Isles.

Detailed descriptions are given of the external features, integument and musculature, excretory system, nervous system and reproductive system of Liga brevis.

The relationship of Liga brevis to other species of the genus Liga Weinland, 1857, settstt Ransom, 1909, is discussed and new information on the relationship of the genital ducts to the longitudinal excretory vessels in Liga facile (Meggitt, 1927) Szpotańiska, 1931, is given. The systematic position of Liga brevicollis (Fuhrmann, 1907) Sandeman, 1959, is discussed. The value of some of the morphological characters used to differentiate the species of Liga is discussed.

A table showing the more important morphological and ecological features of thirteen species ascribed to Liga Weinland, 1857, sensu Ransom, 1909, is given.

A number of filariid worms were obtained from the connective tissues of the muscles of two Malayan amphibians. These include 22 males and 40 females from Bufo asper Boulenger from Taiping, Perak; 2 males and 2 females from Bufo asper, from Gunong Pulai, Johore; and 1 male and 4 females from Rana cancrivora, Gravenhorst from Thomson Road, Singapore. On examination these were found to be a new species of Icosiella for which the name Icosiella innominata sp. nov. is now proposed. A tentative key has also been drawn up for the species of the genus.