1. The anatomy of the genitalia of Gigantocotyle bathycotylc is described.

2. An account is given of gametogenesis, egg-shell formation, and the first two cleavage divisions.

3. The chromosome number is given as n = 6, 2n = 12.

1. Heavy infestations of the coelom-dwelling trematode, Dictyocotyle coeliaca, in rays are reported.

2. Of seven species of skates and rays examined, 16 of 55 specimens of R. naevtis and 81 of 78 specimens of R. naevus and 31 of 73 specimems of R. radiata were infested.

3 The spindle-shaped, three-sided operculate eggs are described and possible modes of exit from the male and female hosts are discussed.

4. A number of immature stages have been found and descriptions are given. Unlike the adults, the opisthaptor projects prominently beyond the posterior margin of the body, but the number and arrangement of the loculi appears to be the same.

5. The systematic position of the trematode is discussed.

A new member of the genus Trichostrongylus Looss, 1905, was collected by the writer from the gastric stomach (abomasum) and the duodenum of an old eland bull in 1981. The animal was shot at a spot amongst the Nega Nega Hills to the east of the Great North Motor Road in the Mazabuka Provincial District.

Eight males and twelve females were collected from the pyloric end of the abomasum which also harboured a large number of Haemonchus mitchelli LeRoux, 1929, and a few specimens of Ostertagia circumcincta (Stadelmann, 1894). Two more males and four females of the new species were encountered amongst a large number of Cooperia spp. including Cooperia neitzi, Mönnig, 1981.

Several specimens of a trichostrongylid, for which the name Paracooperia mazabukae sp. nov. is proposed, were collected from the duodenum of the Oribi (Ourebia ourebi), a small African antelope, in vicinity of the Nega Nega hills in the Mazabuka area, Northern Rhodesia.

Four species of Paracooperia Travassos, 1985, have hitherto been recorded from the small intestine of ruminants. Schwartz (1929) based his description of Cooperia nodulosa on specimens collected from nodules in the mucosa of the small intestine of a carabao (Bubalis bubalis) in the Philippine Islands. Mönnig (1981) described Cooperia serrata, since designated as the type of the genus Paracooperia Travassos, from the springbuck (Antidorcas marsupialis), not Damaliscus albifrons as recorded by Daubney (1988) who records Cooperia serrata Mönnig, 1931, as having been collected frequently from sheep in the Rift Valley and the Athi Plains in Kenya. Daubney notes that the normal host of this helminth has not yet been discovered in Kenya.

1. Syngamus parvus Chapin, 1925, S. gracilis Chapin, 1925, and S. merulae Baylis, 1926, are shown to be synonyms of S. trachea (Montagu, 1811). These conclusions are important in judging the epidemiology of the species.

2. The list of hosts has been critically revised and supplemented with two new hosts, Melanocorypha calandra and Larus canus.

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.

Syngamus trachea is one of the more difficult parasitic worms to dislodge owing to its position in the trachea. Many contrivances such as twisted feathers and spirals of fine wire have been used for the mechanical removal of the worms. In the hands of experts, they may be reasonably effective, but much injury frequently follows their use by amateurs, and the damage is often severe enough to cause the death of the bird. Anthelmintics which may be administered in food and water are seldom excreted by the lungs or are excreted in such low concentration as to be ineffective. Garlic oil and salicylic acid have been used, but are only very slightly effective and cannot therefore be considered as satisfactory treatments. Many so-called gapeworm cures consist largely of substances which stimulate the respiratory musculature and induce a sudden explosive cough.

During the course of some anthelmintic tests carried out during June, 1949, it was necessary continuously to feed 4 per cent, phenothiazine to pheasant poults in the daily mash, which they ate without any obvious distaste and grew reasonably well. The birds were a mixture of several varieties of Phasianus colchicus, including some Formosan and Korean hybrids. These latter birds have a light coloured plumage and it was soon noticed that the feathers were darkening. The change was obvious less than 86 hours after the first experimental feeding. All the birds were therefore examined and it was found that all were similarly affected though it was less obvious among the melanistics and blacknecks, which have a darker plumage. The leg scales too had taken on a distinct dark green hue, and this became more intense as the tests proceeded; the pigmented feathers assumed a fiat brownish colour, while the filoplumes are distinctly red.

1. This paper presents experimental evidence to show that Limnaea truncatula is not the only British snail susceptible to infection with Fasciola hepatica.

2. Of the six British species of Limnaea, five may be infected under laboratory conditions, L. auricularia proving resistant to infection. Full development of the parasite occurs in L. truncatula, L. slagnalis, L. palustris and L. glabra, while development as far as the production of rediae occurred on one occasion in L. pereger. Of the susceptible species L. truncatula may be infected at any age or size, but the other species are susceptible only during the first few days after hatching.

3. F. hepatica appeared to be relatively pathogenic to hosts other than L. truncatula even though the level of infection (as evidenced by the number of rediae which developed) was considerably lower than in the more usual host.

Experiments were conducted in which single cysts and batches of 100 cysts were exposed to the action of potato-root diffusate and the number of larvae liberated at the end of certain intervals of time recorded. Investigation showed that when the hatch at the end of each time interval was expressed as a probit of the total hatch, and plotted against the logarithm of that time, a close approximation to linearity resulted. Statistical analysis confirmed this agreement in the case of single cyst hatching, but disclosed a significant degree of asymmetry in the case of multiple hatching. It was decided that the degree of curvature resulting from this when plotted as a probit line was sufficiently small for it to be ignored.

An experiment was set up to investigate the effect of root diffusates from different varieties of potatoes on natural infestations of cysts in three different soils. A series was included in which no root diffusate at all was used, to obtain an estimate of the degree of spontaneous hatching which occurred. In the absence of diffusate, about 50 per cent, of larvae emerged from the cysts, as compared with 84 per cent, in the case of soils treated with diffusates. Significant differences were detected in the degree of emergence under the action of the different diffusates, that from “Ulster Chieftain” having the greatest effect. Significant differences were also detected between the different soils, larval emergence being lowest in the greensand.

1. “Chlorphenol” and “dichlorphenol”are shown to be highly toxic to eelworms, both in the active and quiescent stages. Comparisons are made between these chemicals and iodine solutions in this respect.

2. Treatments of clover and teazle seed with “chlorphenol” and iodine solutions are described and it is shown that infesting eelworms may be controlled without affecting germination or subsequent growth.

3. The use of “chlorphenol,” with the addition of a wetting agent is recommended for the hot-water treatment of narcissus bulbs, as an additional insurance for the control of the “wool” stage of bulb eelworm.

4. The phytocidal action of “chlorphenol” is discussed and it is shown that such action is not marked.

5. Some preliminary experiments on the use of “chlorphenol” against potato root eelworm are described.