1. Phase-contrast, ultra-violet and fluorescence microscopy have proved useful tools in the study of the embryology of filarial worms.

2. Spermatogenesis in L. carinii has been described for the first time for any filarial worm.

3. The spermatozoa of L. carinii and D. immitis are remarkable in that they contain well defined chromosomes.

4. The development of the ovum to the mature microfilaria has been described for both L. carinii and D. immitis.

5. Staining with acridine orange has demonstrated the cellular distribution of deoxyribonucleic acid (green fluorescence) and ribonucleic acid (red fluorescence) in both living and fixed embryos of each species.

(1) The microfilariae of L. loa, W. bancrofti, B. malayi, D. immitis, D. repens and D. aethiops have been studied in detail, using phasecontrast and ultra-violet microscopy and vital staining techniques.

(2) In these microfilariae the cells of the “oten Mundgebilde” have been renamed “hook-muscle cells” as they appear to be concerned with the movements of the hook.

(3) Two cells have been demonstrated in the nerve ring by means of ultra-violet photomicrography and vital staining with rongalit methylene blue.

1. The developmental stages of D. immitis in the mosquito A. aegypti at 26°C. have been followed in living and fixed preparations, and the fates of the cell groups of the microfilaria have been traced.

2. The larvae spend the first six or seven days inside the distal cells of the Malpighian tubules; during the next six days they inhabit the lumen of the tubules and eventually migrate to the head of the mosquito on the fifteenth to seventeenth day.

3. The “nuclear-column“ cells contribute largely to the formation of the oesophagus of the infective larva.

4. The G cells 1–3 produce the intestine and the G4 cell forms the anal plate and then the rectum.

5. The anal pore ultimately becomes the anus.

During the course of studies on human filariasis and its vectorsin Fiji, in the period 1954–1956, (Symes, 1957) it was desirableto make a few observations on the dog filaria in order that, whenfound in mosquitoes, its larval stages should not be confused withthose of Wuchereria bancrofti from man.

The material for this species consists of a slide of two worms from the intestine of Heterotis niloticus from the Sudan. The strobilae measure 4·8 cm., and 8 cm. in length. The early segments are longer than broad, but the mature segments are broader than long, measuring 900–960µ broad by 400µ long, and are 175 and 274 in number. The superficial segmentation of alternate segments is weak, and the individual segments are distinguished by the repetition of the genitalia. The genital pores are irregularly alternate and are situated at the middle of the lateral margin of the segments.

1. A new genus Sandondla is erected for the cestode Proteocephalus sandoni Lynsdale, 1960, on the basis of the position of the vitellaria in two compact bands posterior to the ovarian lobes, and Sandondla sandoni n.comb. is made the genotype.

2. A new subfamily Sandonellinae is added to the existing 8 subfamilies of the family Proteocephalidae and a key of the 9 subfamilies is given.

1. The females of a new nematode Nilonema gymnarchi gen. et sp. nov. are described from the lung-like air bladder of the Nile fish Gymnarchus niloticus in the Sudan.

2. Nilonema gymnarchi is made the genotype of a new genus Nilonema on the basis of the presence and position of cone-like cuticular protuberances.

(1) The occurrence of outbreaks of Diphyllobothrium in trout and related forms is reviewed.

(2) A survey of the occurrence of Diphyllobothrium in Great Britain has been made. Plerocercoids of Diphyllobothrium have been found in approximately half of the areas from which trout have been examined. Three species of Diphyllobothrium at least have been found to infect trout and related species of freshwater fish in this country.

A study has been made of the form of the larval hooks in the coracidium and procercoid stages of Diphyllobothrium medium, D. ditremum and D. dendriticum obtained from four sources in Great Britain. It has been found that the form of the larval hooks is constant, and that hook types are related to different species. It is concluded that the hooks provide a sound basis for specific identification.

Schistosoma mansoni developing in mouse hosts subjected to frequent, heavy doses of stilbestrol show five effects: their normal survival rate is much reduced; the parasites for the most part remain in the liver past the time at which they normally migrate to mesenteric veins; both sexes develop to sexual maturity more slowly, if at all; a high proportion of the males have accessory gonadal tissue which probably is mainly ovarian; and the male worms average less than two-thirds as long as controls.

Most of our knowledge concerning the larval stages of the Strigeida is based on the studies of Canadian, American and European workers. One of the earliest descriptions of furcocercariae from British freshwaters was by Brown (1926, 1931) who recorded six new species from Cheshire. Later, Harper (1929) described three species and Hesse (1923) one un-named species, all from Scotland. During this period Matheson (1930) recorded the presence of Cercaria pseiidocellata Szidat, 1942 in an artificial lake at Roath Park, Cardiff, after reports of dermatitis from bathers. In 1932 Rees, during a general survey of Glamorgan, recorded an additional two species from the lake. These furcocercarial species were Cercaria X Baylis, 1930 and C. macrosoma which had been previously described by Brown in 1926.

1. Of 40 adult toads, Bufo marinus L., collected from 4 parishes of the Bermuda Islands, 82–5 per cent were infected with the lung worm Rhabdias sphaerocephala Goodey. The average number of worms per infected animal was 10 and the largest number recovered from a single toad was 50.

2. Although some eggs hatch in the lower rectum and cloaca, most do not hatch until they are evacuated and are lying in or on the fresh faecal material on the ground.

The number of cysts used for each replicate in a dilution hatching trial may be reduced to 10. Log. total hatch is used, instead of total hatch itself, and the mean for each dilution determined from the log. values; the logs, of these means, plotted against dilution in the usual way, gives a straight line as in the original Fenwick technique. Reduction of the number of cysts permits the use of commercially available utensils to form an easily handled set-up.

A number of male and female specimens were available for study. They were collected by my colleague Mr. J. McClelland who very kindly made them available for study.

Description: The worm is very small with the largest diameter at the cephalic end and tapers down posteriorly and rather markedly so in the female worm (Fig. 4). The cuticle has fine striations. The bivalve buccal capsule has a number of longitudinal ridges of varying lengths. The number of these ridges are different for the male and female. The head is slightly tilted ventrad. There is a pair of tridents. The ventral trident is small and indistinctly branched. The dorsal trident is large and clearly trifid. The posterior part of the buccal capsule ends in six small projections (Fig. 1).

Through the courtesy of Drs. C. Kulasiri and C. H. Fernando this fine collection of camallanid nematodes from freshwater fishes in Ceylon was placed at my disposal for study.

Camallanid nematodes are rather confusing in a way as several species are often found within a single host. The study is further complicated when only a few specimens of a species of either sex are found. With an extensive collection, however, these nematodes are not troublesome.

The family Camallanidae is examined and two new subfamilies Procamallaninae and Camallaninae are erected for retaining the existing and new genera; the former subfamily for worms with a continuous buccal capsule and the latter for worms with a bivalve buccal capsule. The genus Camallanus s.l. is examined in detail and a revised definition given. Camallanus s.l. is divided into Camallanus s.s., Zeylanema Yeh, 1960, Piscilania gen. nov., and Serpinema gen. nov.

A number of these nematodes were sent to this Department for identification early in 1958 by Dr. J. F. B. Edeson from the Institute for Medical Research at Kuala Lumpur. The specimens were collected from the peritoneal cavity of Macaca irus. Since then, several further collections of the same species have been sent to this Department from time to time. The latter collections came from several laboratories using monkeys caught in Malaya and Siam for the production of poliomyelitis vaccines.

In 1956 the author described five new species of Procamallanus from India and also gave an amended key to the species, originally described by Annereaux (1946). Meanwhile a few more species were reported from India and elsewhere, but as the author had no access to the publications, these species were not included in the key. To clarify certain points the following review is given.

During the tour in Kashmir, two males and four females of the species to be described were collected from the vicinity of the heart and the body cavity of the white cheeked Bulbul, Molpastes leucogenys leucogenys.

These are rather slender worms with attenuated anterior ends. The posterior ends are twisted into 2–3 coils. The cuticle is thin, smooth, nonstriated, but richly furnished with bosses throughout the length of the body.