In a revision of the genus Setaria s.l. the author gives a review of the literature on the systematics of this group. The genus Setaria s.l. is divided into three genera. Hyraconema n.g. monotypic for H. loveridgei (Sandground, 1928), a primitive worm of the hyracoids; Setaria Viborg, 1795, monotypic for S. equina (Abildg., 1789) the common parasite of equine animals; and Artionema n.g. for the remaining species, all of which occur in artiodactyls. Artionema africana n.sp. is the genotype. A. africana is found in Tragelaphus spp. and cattle in various parts of continental Africa. The other new species A. hartwichi n.sp. is found in the European deer, Capreolus and Alces on continental Europe. The paper includes a discussion on host parasite relationship, phylogeny and the evolution of taxonomic characters in speciation. In the Subfamily Setariinae Yorke and Maplestone, 1926, the author recognizes five genera as follows: Skrjabinofilaria Trav., 1925; Hyraconema gen. nov., Setaria Viborg, 1795, Papillosetaria Vevers, 1923 and Artionema gen. nov. The paper ends with a host list.

Anafilaroides rostratus Gerichter, 1949 a nematode found in the lungs of cats in Palestine and Ceylon, and its first stage larvae are described. Studies on the biology of the first stage larvae indicate that it is easily destroyed by adverse conditions.

Thelazia ugandensis n.sp. is described from a hooded vulture. It differs from the other known species in the length of the spicules, length of the gubernaculum and the number and position of male caudal papillae.

Seven specimens of this new species were collected from the intestine of a freshwater turtle, Trionyx triungnis (═T. nilotica) in the Sudan.

These are lanceolate worms which gradually taper to rounded ends, with a length of 2⋅5–2⋅9 mm. and a width of 0⋅6–0⋅9 mm. The cuticle is invested with scales, dense in the anterior half of the worm, but becoming more and more sparse towards the caudal end. The oral sucker is large, measuring 0⋅23–0⋅27 mm. in diameter and is about one and a half times the diameter of the ventral sucker which measures 0⋅14–0⋅17 mm. in diameter. Both suckers lie in the anterior half of the body. The mouth is subterminal and leads to a pharynx which is stout, 0⋅7–0⋅8 mm. by 0⋅11–0⋅12 mm., and leads to a long oesophagus of 0⋅25–0⋅32 mm. in length. The caeca terminate at the posterior border of the posterior testis or slightly anterior to it.

The first stage larva of Anafilaroides rostratus develops, after penetration into the foot of certain molluscs, Laevicaulis alte Fer. Mariella dussumieri Gray, Achatina fulica (Fer.) and Helix aspersa Müller. Two moults occur in the foot of these molluscs in 20–56 days depending on the temperature. After each moult the cuticle is shed. The details of development are described. The infective larvae are found in the foot of these molluscs. Natural infection was found in L. alte.

Mice and chickens can act as auxiliary hosts. Probably rats, other rodents and birds can also act in the same capacity.

The study of the development of the parasite in the cats is not complete. On ingestion the infective larvae penetrate the stomach wall and reach the lung where the third and the fourth moults occur. Exact times of the occurrence of the moults have not been definitely established. All moults are however completed by the 46th day; from then until the 58th day, immature helminths are found in the lungs. Fully gravid females are found on the 74th day, and larvae are first seen on the 78th day. The worms continue to produce larvae for more than 255 days after maturity. The duration of the life of the adult is probably considerably longer than one year.

1. A new species of the genus Ptychobothrium Loennberg 1889, recovered from the intestine of the Hying fish Cypselttrus poecthpterus Cuv. and Val., off the coast of Waltair, is described.

2. Ptychobothrium cypseluri n.sp. differs from P. bclottes (Dujardin, 1845), the only other known species of the genus, in the nature of the ovary, uterus and the number of testes.

The family Filaroididae Schulz, 1951 is defined and reclassified into five subfamilies, viz.: Filaroidinae Skrjabin, 1933; Angiostrongylinae Bohm and Gebauer, 1934; Vogeloidinae Dougherty, 1951; Oslerinae Khera, 1954; and Marsupostrongylinae subfam. nov. Definitions of the last two sub-families are given and the familial relationships of the Filaroididae are discussed. All species in the Filaroididae are listed and a key is given to its sub-families and genera.

As the interesting and complex family the Proteocephalidae is represented by several forms not only from the Sudan but from various parts of the world, a brief summary of it is made below.

Four worms were recovered from the intestine of a Scaly Anteater, Manis temminckii, examined in this Department in August, 1958. They appear to represent a new species for which I propose the name Inermicapsifer rhodesiensis.

1. A new species, Ganeo bufonis, from a toad, Bufo viridis, in Kashmir, is described. This is the first species of the genus recorded from a toad; it differs from the known species in having both the vitelline glands confined to one side. The uterine coils do not extend into the post-caecal area; the excretory bladder is without any median stem and the metraterm is present.

2. Ganeo tigrinum Mehra and Negi, 1928 is also recorded for the first time from Bufo viridis. Ganeo kumaonensis Pande, 1937 and Ganeo lingnanensis Li, 1938 are both regarded as synonyms of Ganeo tigrinum.

3. A revised generic diagnosis and a key to the species of the genus Ganeo Klein, 1905 are given.

Eleven cestode specimens were collected from the intestine of Prinops plumata which was brought into the Department for examination. They appear to be a new species for which the name Anomotaenia prinopsia is given.

The seasonal availability of sheep nematode infective larvae under normal farm conditions was investigated by exposing lambs reared worm free for two weekly periods in the fields. Data were collected in the form of populations found at post mortem examination.

It was found that Nematodirus spp. were acquired in greatest numbers in the autumn after the date by which lambs normally have acquired resistance to superinfection. The conclusion was that self-augmentation of Nematodirus parasitism in lambs resulting from eggs the lambs conveyed to the ground was of minor significance and that eggs reaching the ground in one season are the source of parasitism in lambs in the following spring.

It was found that greatest numbers of Haemonchus conlortus were acquired in summer. Heavy contamination of pasture with eggs of this species by ewes in the spring did not result in large populations in their lambs. It was concluded that the extent of parasitism in lambs in the late summer and autumn was contingent on there being favourable conditions at that time of the year for the development of infective larvae.

1. A new species, Cosmocerca kashmirensis n.sp. from the toad, Bufo viridis, in Kashmir, is described. The new species has 19 plectanes in the male tail, of which 3 plectanes are simple rosettes and resemble the compound caudal papillae of the genus Cosmocercoides.

2. The existing species of the genus Cosmocerca Diesing, 1861 are listed and briefly described.

Description: The specimens were collected from three Bartailed Godwits shot in the winters of 1956 and 1957. The description below applies mainly to the first infestation found. There are certain differences between the infestations which are noted later. There were up to 150 individuals in each infestation, varying from immature worms consisting of a scolex and a few proglottides to mature strobilas containing some 300 segments and reaching a length of 75 mm. The maximum breadth of the strobila is 1·8 mm. The onset of maturity is accompanied by a marked increase in the breadth of the strobila and the mature proglottides are broader than long.

Previously uninfected eleven month old sheep were used as indicators of the availability of the infective larvae of sheep nematodes in early spring. Ostertagia and Nematodirus species were acquired in much larger numbers than other species. It is concluded, since the order of parasitism found in the experimental sheep resembled that found in spring born flock lambs in early life, that the relative specific incidence is the latter is due to the numbers of available infective larvae and not to any factor associated with the stage of development of the lambs.

A new technique for the recovery of Trichostrongyle larvae from soil and pasture samples is described.

The technique is based on the difference in density of larvae and debris under the influence of a stream of water flowing upwards at a gradually decreasing flow rate.

The results from trials with known numbers of larvae gave an average recovery of 74% from pasture, and of 78% from soil.

Sheep reared worm free were used as indicators of the availability of sheep nematode infective larvae during the summer on pasture grazed by ordinary flock ewes and their lambs.

Data were collected in terms of worms found in the test sheep at post mortem examination after periods of three weeks' exposure in the field.

Haemonchus contortus infective larvae were given to previously uninfected weaned and unweaned romney lambs. Difference in susceptibility between the groups was not found.