Velacumantus australis is a common mollusc along the easter and southern coast of Australia. A study of the incidence of larval trematodes in several populations of V. australis showed that the incidence of the various infections varied considerably with time and place. Heterophyids were usually the commonest infection, while schistosomes and echinostomes were frequently absent. In one population, seasonal changes in the incidence of philophthalmids and schistosomes were found to be positively correlated, and seasonal changes in the incidence of philophthalmids and echinostomes were found to be negatively correlated. These results are discussed.

Several female specimens of a new Philometrid nematode were collected by the writer from under the skin of the fish Bagrus bayad (Forskal) in the head region, just lateral to the sides of the mouth opening. The worms could be seen with some difficulty under the skin, and each fish harboured 2–4 worms. About thirty per cent of the fishes examined were infected and the parasite was prevalent from the month of December to the end of February or early March only.

The paper describes findings of three species of nematodes of the genus Oxyspirura parasites of birds in Czechoslovakia: O. (S.) petrowi (Skrjabin, 1929) from Lanius collurio L., O. (S.) rysavyi Baruŝ, 1963 from Oriolus oriolus oriolus and O. (O.) chabaudi n.sp. from Motacilla alba alba L.

On the 17th September, 1964, a Mute Swan, Cygnus olor (Gmelin) was received for examination. It was a male bird, estimated to be about three years old, which had been found at Henley-on-Thames, Oxfordshire, and had been killed on account of a broken wing which had healed badly. It was believed to be of wild stock.

1. Three exceedingly interesting parasites of the super-family Ascaridoidea have been discussed in this paper. A new genus Lappetascaris is described from two different kinds of fish and a new subfamily has been established to include this genus. The latter is based on its peculiar head structures and the cuticle.

2. Thynnascaris inquies (Linton, 1901) n.comb, is reported for the first time since its original description, from the type host of a new locality.

3. Goezia intermedia n.sp. is described and a comparative study of the related species has been carried out.

The genus Citellina was introduced by Prendel (1928) for a new species, C. dispar, which he described from Citellus suslika. Since that date a further nine nominal species have been referred to the genus, thus: C. alatau Spassky, Rijikov and Sudarikov, 1950; C. alpina Jettmar and Anschau, 1951; C. bashiri Akhtar, 1956; C. levini Li, 1933; C. marmotae Manter, 1930; C. petrowi Schulz, 1930; C. schulzi Korneev, 1951; C. skrjabini Merkuscheva, 1955 and C. triradiata (Hall, 1916) Manter, 1930. Descriptions and figures of eight of these species are given by Skrjabin, Schikhobalova and Lagodovskaya (1960), who have missed only C. bashiri and had no description of C. alpina at their disposal.

1. A lower pathogenicity of the Kenya strain of T. spiralis was substantiated in mice as compared with our laboratory strain; infection with a dose of 2,000 larvae from the laboratory strain resulted in the death of all the animals, whereas 7 out of 10 and 6 out of 20 mice infected with the Kenya strain survived.

2. The reason for the lower pathogenicity of the Kenya strain is related to its weaker infectivity; after the infection with 200 larvae of the Kenya strain the number of muscle larvae produced was half (on average 17,595 larvae) that of the laboratory strain (average 32,792 larvae).

The present study of the morphology of a few specimens of W. bancrofti from India reveals no significant differences from previous published descriptions, with the exception of those of Maplestone (1929) and Maplestone & Rao (1939), which were also concerned with Indian specimens. In the writers' opinion, the male tail does not possess caudal alae supported by pedunculated papillae; moreover the grouping of the papillae in the Indian specimens follows the pattern originally outlined by Leiper (1913), and not the conjectured pattern of Maplestone (1929, 1939). The present description confirms that (1) there are 8 circumoral papillae forming 2 circles, an inner and an outer of 4 each, and that there are 2 lateral amphids; (2) there is an unpaired papilla immediately anterior to the cloacal aperture in the male; (3) There are cuticular striations in the male on the ventral surface only, anterior to the cloacal apertur; (4) there is a subterminal triangular piece, heavily cuticularised, at the distal end of the right spicule; (5) the female tail bears numerous minute cuticular bosses and on the left side, posterior to the anus, there is a single phasmid.

For the first time a Habronematid parasite (subfamily Habronematinae) has been recorded from a fish host. The parasite has been assigned to a new species of Cyrnea (Procyrnea).

The genus Philometra was revised by the writer in 1963 and in continuation of these studies a few more new hosts have been recorded for this genus. The genus Philometroides Yamaguti, 1935 has been reported for the first time from the Indo-Pakistan sub-continent and a new species has been added to it.

During a three year survey of the larval trematodes of Llangorse Lake, South Wales, twenty-one species of cercariae have been encountered. The Xiphidio- and Microcercous cercariae are considered in this paper. Three new species of Xiphidiocercariae are described in detail and a fourth cercaria from this group is recorded from Britain for the first time. The further development of one of these cercariae has been considered. A new species of Microcercous cercariae is also described in detail.

Three specimens of this species were collected on one occasion from the lizard Calotes versicolor. The material consists of one male and two females which were found entangled in the connective tissue of the body cavity.

These are thin worms measuring 11·5 mm. long in the male and 18·3 mm. in the female. The maximum body diameter is 0·23 and 0·35 mm. respectively in the male and the female.

During a three year study of the larval trematodes of Llangorse Lake, South Wales, twenty-one species of cercariae have been encountered. The present paper deals with four cercariae of the Gymnocephalous group. Two new species of Agilis cercariae are described in detail; Cercaria Sphaeridiotrema globulus is recorded from Britain for the first time and the occurrence of Cercaria lophocerca noted

A study of several samples of young conical flukes reared from metacercariae obtained by the late Dr. P. L. LeRoux from certain fresh water snails has resulted in the following findings.

It appears that the species which caused the severe intestinal paramphistomiasis amongst sheep described by LeRoux (1930) in South Africa was Paramphistomum microbothrium Fischoeder, not Cotylophoron cotyhphorum (Fischoeder) as was thought at the time and subsequently repeated in all the text books and reviews on paramphistomiasis published afterwards.

In the past two decades, considerable evidence has accumulated in the literature about the differences in the susceptibility of various intermediate hosts of Schistosoma mansoni to different strains of the parasite. Comprehensive studies on this aspect of host-parasite relationship have been published by Files & Cram (1949), Abdel-Malek (1950) and Files (1951). The results of more recent studies have been reported by Wright (1962) and Saoud (1964).

In the present paper, the writer has studied the susceptibility of four intermediate hosts of S. mansoni from Brazil, Puerto Rico, Egypt and Tanganyika to some strains of the parasite.

1. A new species of Oxysomatium (O. minutum) is described from a frog Rana ptychadena mascareniensis.

2. The crested chameleon (C.? cristatus) and Bufo supercilioris are reported as new species of hosts recorded for Africana africana (Gendre, 1909) Travassos, 1920.

3. Strongyluris brevicandata Müller, 1894 and Thelandros sp. are reported from Agama agama agama.

4. Amplicaecum involutum (Gedoelst, 1916) Yorke and Maplestone, 1926 is redescribed from Chamaeleon (?) cristatus which is regarded as a new host record and A. pesteri n.sp. from Bufo superciloris is described to be the smallest species of this genus.

The genus Orientodiscus was proposed by Srivastava (1938) for O. jumnai and O. lobatus from a freshwater fish, Silundia gangeticus from India. Recently, Rhode (1963) added O. fernandoi and O. hendricksoni from freshwater turtles, Trionyx spp., from Malaysia. A large number of trematodes belonging to Orientodiscus were collected from freshwater turtles in Aligarh, India. They represent three new species.

Worms obtained from the peritoneal cavity of a chick experimentally infected with infective larvae from Mansonia crassipes are described as Cardiofilaria nilesi n.sp. Pseudaproctella is considered a synonym of Cardiofdaria. Strom, 1937 and Pseudaproctella andersoni var. major Chabaud, Brygoo and Richards, 1964 is named Cardiofdaria chabaudi n.sp.

In the First Report of the W. H. O. Expert Committee on Bilharziasis (1953) it was stated: “Infection with Schistosoma is often well tolerated and without clinical signs, however this relative benignity appears to vary considerably from country to country, without the cause of these variations being as yet thoroughly understood”. This statement refers to the relative absence of serious manifestations of schistosomiasis as has been reported by various investigators working in Africa, e.g. Ramsay (1934) working in Nigeria, Dixon (1934) and Fisher (1934) in the Congo, Gelfand (1950) in Southern Rhodesia, Mackey (1953) in Tanganyika, Manson-Bahr (1958) in Kenya and Nelson (1959) in Uganda as compared with the situation reported in Egypt and South America.

Three cestodes are described from the black-winged stilt, Himantopus himantopus himantopus from Ghana.

1. Himantocestus blanksoni gen. et sp. nov. (Diploposthidae Poche, 1926) from the duodenum.

2. Infula burhini Burt, 1939 (Dioecocestidae Southwell, 1930) from the duodenum.

3. Thomasitaenia nunguae gen. et sp. nov. (Progynotaeniidae Fuhrmann, 1936) from the rectal caeca.