Larvae of Heterodera rostochiensis have penetrated S. nigrum, quickly caused necrosis in the invaded roots and usually themselves suffered degeneration, which it is believed has led to their death. In these cases the region of the intestine apparently becomes devoid of food reserves and the subcuticular layers of the body wall degenerate into irregular strands of tissue. Only of the order of 0.5 per cent, completed the second moult in eight weeks, while the same stage was reached in tomatoes in a little over two weeks. Many larvae apparently do not develop at all. Tomato roots react to invasion by becoming swollen, and necrosis is less in evidence than in black nightshade.

A simple apparatus is described in which can be measured the vertical migration of Heterodera rostochiensis larvae in soil and in the presence of the host plant. The migrations upwards and downwards are comparable in extent, but can be inhibited by water-logged soil and greatly reduced if the cysts are exposed to insolation under glass when near the soil surface. In the layer furthermost from the inoculum (8 to 10 inches away), either no cysts are formed or their number constitutes a very small proportion of the total: a fraction of one per cent.

1. Variations in the nematode egg-content of sheep faeces are discussed and data from an experiment to study such variations are presented.

2. Previous work on “within day” variations is confirmed and the “ day to day ” variations are shown to be highly significant.

3. The bearing of these variations on sampling technique is discussed.

By growing potatoes in infested soil in sectional wooden boxes, changes in the population of potato root eelworm have been observed at 5, 9, 13 and 19 weeks after planting, and at 5 two-inch levels in the soil. Results show that most of the increase in population occurred during the last 6 weeks of the experiment and that the normal population changes proceeded more slowly in the topmost level, leading to a lower final population in that level.

1. This paper describes the life-history of Limnaea truncatula under laboratory conditions.

2. Under controlled conditions sexual maturity may be reached in 28 days and egg laying continues for the greater part of the snail's life.

3. Under good environmental conditions each snail may lay as many as 60 eggs in a single day and a total of more than 3,000 in a life approximately a year.

4. Egg laying occurs during every month and at temperatures as low as 10°C. to 11°C. The incubation period of the egg is related to the atmospheric temperature.

5. The longevity of the snail is likely to be related to its rate of growth and to environmental conditions including periods of drought.

6. The snail remains fully active at temperatures as low at 1.5°C.Sustained temperatures much above 20°C. are unfavourable, temperaturesabove 25°C. proving markedly deleterious.

It was found that in six aged horses after treatment with 30 grammes of phenothiazine the faecal egg count fell to zero but had returned to a high level after some live or six weeks. Examination of the faeces at the time of treatment showed that many worms were eliminated. Repetition of the treatment several times produced a similar result on each occasion, but there was a tendency for the egg count not to rise so high as it was before treatment, for fewer worms to be eliminated at each treatment, and for the time before the egg count reached a high level after treatment to lengthen with each successive treatment. Many treatments had to be given over a period of some three years before the egg counts of the horses were reduced permanently to a low level. Post-mortem examination of three of the horses at this stage showed their worm burdens to be low.

1. When potatoes are planted in eelworm infested land, the root diffusate produced results in 70—80 per cent, of the larvae emerging from the cysts in the first 4—5 weeks of growth and this effect is shown up to a distance of 6 in. from the root centre.

2. Moderate or heavy soil infestations of potato root eelworm result in a considerable root invasion prior to potatoes breaking through; several thousand cysts can result from this early attack and can cause severe dislocation of the young root.

This highly distinctive worm was collected in Honde, Southern Rhodesia, on two separate occasions, from hosts designated “house rat” and “native granary rat” which the writer understands could readily be one and the same, since houses and granaries in these areas are built in fairly close proximity. If, however, it is assumed that these buildings are at a distance from each other, it is possible that two different genera and species are concerned; and if such is the case, the “granary” rat might possibly be a field rat. It is regretted that the identification of the host cannot be more explicit.

1. The treatment of clover and teazle seeds with solubilized chlorphenol has been carried out and found to be equally harmless to the seeds, as regards germination, as the ordinary solutions previously described. The mixing of the micellar solution, and its use, is described.

2. The use of chlorphenol in bulb baths for the treatment of narcissus bulbs infested with eelworm is reviewed in the light of the solubilization of chlorphenol. The strength of chlorphenol is reduced from 0.25 per cent, to 0.1 per cent., the percentage of detergent remaining at 0.25 per cent. Mixing of the solution and its use, are described.

3. Advice is given on the handling of chlorphenol.

4. Details are given of the solubilization of several benzene derivatives by means of detergents of the long-chain alkyl sulphate type.

(1) A survey was made of the trematode and nematode parasites of Apodemus sylvaticus, Clethrionomys glareolus and Sorex araneus from the islands of Raasay, Ulva and Scalpay.

(2) The following species have been recorded:—

A. sylvaticus:

Trematodes—

Lyperosomum villa

Brachylaemus recurvum

Nematodes—

Capillaria muris-sylvatici

Heligmosomum glareoli*

Syphacia stroma

1. Heavy intestinal infestation with Plagiorchis (M.) megalorchis Rees, 1952, in four two-week old turkey poults is described. This was presumably the cause of death in the four poults and possibly of nine other birds of the same hatch.

2. The epizootiology of the condition is described.

3. The life-cycle of the parasite has been investigated, using turkey poults as the definitive host.

In reviewing the literature on helminthology one finds that a great deal of attention has been given to the study of the physiology of parasites. Investigations of such a nature are valuable, in that they enable one to approach the problem of anthelmintic treatment in a scientific manner. Most of the early work that was carried out on lungworms in general was concerned either with their life histories or with their morphology, and little work has been done on their physiological characteristics.

1. A detailed morphological study has been made of certain nematodes occurring in the basidiomycetous fungi, Entoloma rhodipolium, Pleurotus corticalus, P. ostreatus, Hygrophorus virgineus and Tricholoma cunifolium.

2. From the first three of these, males and females of two species of eelworms have been obtained which are placed in the genus Iotonchium Cobb, 1920. One of these is Iotonchium fungorum (Butschli, 1878) n. comb., originally described by Butschli under the name of Tylenchus fungorum', the other is a new species which is named I. bifurcatum n. sp.

3. The males of both species have peculiar lobed, dorso-ventrally flattened heads and a poorly developed mouth spear. The bursa is very large, the spicules have posterior prolongations which arc extruded through the cloaca and ventral post-anal papillae are present. A gubernaculum is absent.

Intensive cropping on a commercial scale as practised on fertile land in Europe is hitherto unknown in the Gold Coast apart from the growing of cocoa trees in a wide belt stretching from east to west across the central region of the country. In general, the method of farming is exceedingly primitive, being largely shifting cultivation, that is, the bush is partially cleared and the land is then cultivated by hand-hoes and cropped for a period of three or four years. Normally, no manure of any kind, either organic or inorganic, is applied and the land at the end of this period is allowed to revert to bush. New ground is brought into cultivation in its place, only to be allowed when virtually exhausted of readily available plant food to return to its natural, jungle condition.

1. P.silusiae is shown to be unable to resist desiccation on a microscope slide for periods above half an hour, although larvae within the uterus of the mother can survive for somewhat longer periods.

2. When “protected” by a colloidal gel, the worms are shown to resist desiccation for several months. Such “protected” worms are more resistant to temperature extremes than “non-protected” ones.

8. P. silusiae is immobilized in glucose solutions above 1M strength, although it can resume mobility on dilution of the solution, even after fourteen days in 4 M glucose solution.

4. P. silusiae is shown to be positively chemotactic towards oxygen, in addition the gravid females are negatively geotactic.

5. Drosophila fimcbr is is shown to act as a dispersal agent for P. silusiae.

1. Fasciola indica n. sp. from goats, cattle and buffaloes in Bihar is described and differentiated from F. hepatica and F. gigantica.

2. Specimens of Fasciola from Assam (cattle and buffaloes), Rangoon (cattle), Singapore (pig) were examined and identified as F. indica.

3. F. hepatica is further differentiated from F. gigantica on the basis of the cuticular armature and the disposition of the intestinal branches.

In summarising, therefore, we conclude that a tendency to become dormant during the larval stage, which is so characteristic a feature of the free-living larvae of parasitic nematodes and is an essential requirement in their use of intermediate hosts is not an uncommon occurrence during their life in the final host. Its purpose in each instance is essentially the same, i.e. to carry it through a period in which the environment is unsuited to development; on the ground, for instance, where it waits for a suitable host, as a parasite of an intermediate host, where it waits for a suitable final host, or in a resistant final host where inhibited development serves the parasite in enabling it to wait until some depression of the host's state of resistance allows it to grow to maturity.