Parasites of marine fishes have attracted, comparatively speaking, but little attention among scientists. This is true especially for the parasites of those fishes which live in the open seas, and are therefore less accessible to investigation than their relatives inhabiting coastal waters. On many occasions, when chance has brought such a parasite to the attention of a research worker, the scarcity of data allowed no more than mere recording of the existence and a brief description of the parasitic species. Now, when investigations into the parasite fauna of marine fishes are being intensified, it is possible to add to our knowledge of such forgotten species of parasites, in order to appreciate more clearly their possible importance to their hosts and, indirectly, to the economics of the stocks of our food fishes.

The genus Myriocladus Okada is considered to be a synonym of the genus Dendrogaster Knipowitsch.

The female and male of a new species, D. tasmaniensis sp.nov. from the sea-star Allostichaster polyplax (Müller and Troschel), are described.

Appendages interpreted as antennae are present in the female, male and ascothoracid larva of the new species.

A brief account is given of the manner in which the larva of D. tasmaniensis sp.nov. enters and escapes from the host.

1. The nomenclature and host specificity of Toxascaris leonina is reviewed and the conclusion reached that this parasite occurs in a wide range of feline and canine hosts. Notice is given of application to the International Commission on Zoological Nomenclature, for the suppression of Ascaris leptoptera Rudolphi 1809 and A. microptera Rudolphi, 1819, which appear to be senior synonyms of Toxascaris leonina. The synonyms and hosts of T. leonina are tabulated.

2. The distribution and growth of the larvae of T. leonina in experimentally infected mice, cats, and dogs is reported. A feline and a canine strain were used for these infections and infection of cats and dogs was produced both by feeding the eggs containing second-stage larvae and by feeding mouse tissues containing third-stage larvae.

Certain species of mites and insects live permanently in the hair coat of mammals and feather coats of birds. The majority lay eggs which are attached either to hairs or feathers, as with lice, or rest on the surface of the skin, as with certain mange mites. However, there appears to be no record in the literature of the eggs of any permanent ectoparasite of birds or mammals which are attached to the skin of its host by means of a distinct stalk. In Fig. 1 may be seen a photograph of the egg of the mite Epidermoptes bilobatus Rivolta, 1876 attached to the skin of a turkey poult. Each egg was attached to the skin by a distinct strap-like stalk which held the egg quite clear of the skin. The manner of attachment of this stalk to the posterior pole of the egg was constant (Fig. 2), in contrast to the attachment to the skin (Fig. 3).

1. The life history of N. battus is described, and a comparative description of the life history of N. filicollis is given.

2. The life histories of these two species are compared with those of N. spathiger and N. helvetianus, two closely related species, and are shown to follow the same basic pattern, with minor variations in timing which appear to be specific in nature, and not related to differences in culture methods or host species.

3. The pathogenesis of Nematodirus species is discussed and related to the migration of larvae into the intestinal mucosa during development.

1. The seasonal incidence of Nematodirus infection in sheep was followed by faecal egg counts, post-mortem examination and pasture larval studies.

2. It was shown that only one generation of adult worms was produced each year and that the life history required a prolonged resting stage on the pasture, which took 12 months to complete.

3. The influence of this type of life cycle on the parasitic disease caused by Nematodirus, and on its control, are discussed.

The Leptomonas described in this paper has been studied principally in the gut contents and faeces of the larva of the fly, Leia sp., and in moisture obtained from the decaying vegetable matter within which the larvae grow and pupate. The incidence of infection of the larvae has been found to be almost 100 %, only one or two very young specimens being found unparasitized among the hundreds studied.

The majority of the parasitic mites described in the following pages were collected in various provinces of Southern Africa by Dr F. Zumpt of the South African Institute for Medical Research at Johannesburg, to whom I tender my hearty thanks. One species was contributed by Mr P. H. Vercammen-Grandjean from a host taken at Bukavu in the Belgian Congo, while a few others were recorded from birds examined by myself at Pietermaritzburg, Natal. Only one species of this group of mites, Harpyrhynchus crista-galli, had previously been taken from a South African bird.

Observations out of doors demonstrated that the viability of embryonated eggs in soil was adversely affected by dryness. This was confirmed in laboratory experiments.

The resistance of embryonated eggs to temperatures below freezing-point was observed both out of doors and in the laboratory.

The rate of development of larvae in the intermediate host was reduced as the temperature fell.

The longevity of the infective larvae appeared to be largely determined by the longevity of the earthworm intermediate host, although they were able to survive for a time when separated from the earthworm's tissues.

The longevity of eggs and larvae under natural conditions and the persistence of infection on a pasture are discussed.

Among the ticks collected by Major E. W. Temple-Boreham from a giraffe at the Talek River, Cis-Mara area of W. Masai, Kenya, in October 1955, were eleven males and eight females which represent an undescribed species of the genus Rhipicephalus. Another female was collected by W. A. Hilton from a giraffe near mile 70 south of Arusha on the Great North Road, Tanganyika, on 10 July 1956, and G. H. Swynnerton collected three males from a giraffe at Nkonko, S. Manyoni district, Tanganyika, on 29 September 1958. The following is a description of these specimens.

Of the two specimens of the little grebe, Podiceps ruficollis Vroeg shot in the environs of district Pilibhit, U.P., one harboured two mature specimens of the genus Schistotaenia Cohn, 1900 and a large number of specimens of the genus Tatria Kowalewski, 1904. Study of these specimens has shown that the former is a new species. So far as the author is aware, this is the first record of amabilid cestodes from India.

The New World iguanid lizards of the genus Sceloporus are parasitized by the scale-mite Geckobiella texana (Banks) 1904. This species has been sufficiently described by Banks (1904, 1906, 1907, 1915), Hirst (1917, 1926), Lawrence (1953) and Lane (1954), while the life history has been worked out by Goodwin (1954).

1. The morphology and life cycle of a new microsporidian, parasitic in the mid-gut epithelium and caeca of the larvae of Scatopse notata, and also present in the pupae and flies, is described.

2. The name Plistophora scatopsi sp.nov. is proposed.

The nervous system of the female of Thelastoma bulhõesi is described. Three granular lobed structures, presumably arcade cells, are present at the anterior end of the female and of the male.

In a recent issue of Parasitology, I have described (Jain, 1959) a new genus of freshwater Tetraonchinae, Sprostonia, from the gill filaments of some Indian fishes. In a personal communication Dr Nora G. Sproston has kindly pointed out to me that the same name has been used by Bychowsky in his monograph on Monogenea (1957), published by the Institute of the Zoological Academy of Sciences of the U.S.S.R., for Sprostonia squatinae (MacCallum, 1921) which he makes genotype and removes it from Trochopodinae to a new subfamily Megalocotylinae in Capsalidae. I therefore change the name of the genus which I have described to Neosprostonia, Sprostonia being preoccupied.

(1) Eight species of furcocercous cercariae have been found during a 3-year study of the trematode larvae harboured by certain fresh-water molluscs in Glamorganshire. Of these four are new species, two have previously been reported from South Wales by Rees (1932) and the remaining two species have been recorded in Europe but not in Britain.

(2) Detailed descriptions are given of the four new species and the last two species which had not been completely described hitherto. The life cycles, as far as are known, of all the the species are outlined; the mollusc hosts are listed and for each cercaria a comparison with related species is given.

(3) C. hamburgensis Komiya has been proved experimentally to be the larva of Apatemon gracilis minor Yam. and according to the law of priority becomes C. a.g. minor.

Human anti-A and anti-B and pig anti-A agglutinins were neutralized by Ascaris lumbricoides materials.

The infection of pigs with A. lumbricoides stimulated the production of anti-A agglutinin but this agglutinin appeared to have no protective action.

Oesophagostomum dentatum infection in pigs did not affect the anti-A agglutinin levels.

During the period extending from February 1955 to January 1956, 192 specimens of deer mice, Peromyscus maniculatus sonoriensis (LeConte), 174 specimens of white tail antelope ground squirrels, Citellus leucurus leucurus (Merriam) and 154 specimens of Ord kangaroo rats, Dipodomys ordii pallidus (Durrant & Setzer), were examined to determine louse-host associations, rate of infestation, frequency of distribution and seasonal fluctuation of louse populations.

Five species of lice were recovered from three species of rodents. The dominant species on the deer mouse was Hoplopleura hesperomydis (Osborn). The dominant species on the white tail antelope ground squirrel was Neohaematopinus citellinus Ferris. The only louse species recovered from the Ord kangaroo rat was Fahrenholzia pinnata K. & F.

Infestation on rodents was recorded on the basis of percentage of hosts infested, number of lice per host and number of lice per infested host. The highest number of lice per host was 27·7 Neohaematopinus citellinus per infested white tail antelope ground squirrel. The lowest value was 2·5 Polyplax auricularis per infested deer mouse.

Approximately 80 % of the rodent sample had less than 25 lice per host. This grouping accounted for about one-half of the total number of recovered lice.

Seasonal fluctuations of louse populations on deer mice, white tail antelope ground squirrels and Ord kangaroo rats were studied over one complete year. There appeared to be some coincidence between rodent activity, temperature and louse populations.

A description is given of the life history and pathogenicity of a species of Eimeria, derived from a single oocyst infection in a coccidia-free bird, and subsequently identified as E. meleagridis.

There are two asexual generations followed by the sexual generation. The first schizogony cycle occurs in the small intestine and the second and sexual generations are restricted to the caeca.

The organism is not pathogenic but the sexual stages produce marked caseous lesions in the caeca. It is immunologically distinct from a pure strain of E. adenoeides and cannot be transmitted to chickens.

1. The incidence, intensity of infection, rate of growth and genital development in Proteocephalus filicollis has been studied by the monthly examination of approximately 60 Gasterosteus aculeatus over a period of 2 years.

2. The existence of an annual cycle, commonly reported for cestode parasites of fish in a temperate climate, is clearly established. The most advanced stages commonly occurring are: plerocercoids (0·25–5mm.) July-November; strobilate worms with genital primordia (58mm.) December-April; mature worms (1 cm.) April-May; gravid (2 cm.) June-July.

3. No tissue phase occurs between the time the procercoid is swallowed and the mature worm develops, but there is a migration from the rectum to the anterior part of the intestine.

4. From a consideration of the seasonal variation in incidence it is deduced that the parasitic population is in dynamic balance and that approximately 1 % of worms present are lost daily.

5. No evidence to support the existence of immunity was found. The lower incidence in 1+ than in 0+ fish was attributed to feeding habits.

6. Other aspects discussed are the interrelationship of proglottid formation and appearance of genital rudiments; the structure of the egg-shell; and the intensity of infection of Cyclops with procercoids as calculated from the numerical distribution of worms in the fish host.

7. Reference is made to intercurrent helminth and protozoan infections and the effect of an epidemic of Ichthyophthirius sp. on the fish population.

I wish to thank Prof. C. M. Yonge for granting every facility for this work. My thanks are also due to Mr Archer, Miss Bell, Mr Berrie, Miss Spence and Miss Wyllie for help in collecting fish, and to Mr Gray who showed me the lochan.