A description is given of a new species of Henneguya (Myxosporidia), named H. tegidiensis sp.nov. It is parasitic in the freshwater fish, Coregonus clupeoides pennantii, from Lake Bala (North Wales), producing in it intramuscular cysts.

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.

1. A key to the laelaptid paraphages of Myriapoda is given.

2. Hypoaspis (Hypoaspis) spirostrepti Oudms is transferred to the subgenus Jululadaps. J. rotundatus Berl. is regarded as a synonym of this species.

3. Hypoaspis (Hypoaspis) indicus Vitzth. is regarded as a synonym of Julolaelaps luctator Berl.

4. Hypoaspis (Coleolaelaps) amazon is figured.

5. The subgenus Julolaelaps is defined and a key given to the species. The type species is figured.

6. Three new species are described, namely Hypoaspis (Julolaelaps) peritremalis, H. (J.) myriapodalis and H. (J.) pararotundatus.

7. A list of all the known species of Laelaptidae occurring on millipedes is given.

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.

Laboratory studies on the embryonic and larval development of Haemonchus contortus under constant temperatures of 0·0°, 7·2°, 11°, 14·4°, 21·7° and 37° C., and varying moisture conditions were carried out. Reports of preliminary studies on Ostertagia spp., Trichostrongylus spp. and Oesophagostomum venulosum are included.

Observations showed that eggs in the same culture may behave in several ways: (1) eggs may develop at different rates; (2) eggs may exhibit intermittent stages of active and inhibited development; and (3) eggs may fail to develop and die at any stage from unknown causes.

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.

The anatomy of Köllikeria filicollis (Rudolphi, 1819), Cobbold, 1860 (Trematoda: Digenea) is described in detail.

An account is given of the integument and musculature of the worm and the structure of the cyst in which it is found, followed by a discussion of the body wall in other digenetic trematodes. The alimentary canal, excretory system, nervous system and genitalia are also described.

The study shows that the sexes are not entirely separate in all members of the genus Köllikeria as hitherto believed.

The systematic position of K. filicollis is discussed and a specific diagnosis is given for the species.

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).

The external features, the excretory, nervous and genital systems of Phyllobothrium sinuosiceps sp.nov. (Cestoda: Tetraphyllidea) from Hexanchus griseus are described in detail, particular attention being given to the genitalia.

The species is compared with Phyllobothrium dohrnii, a well-known cestode.

The systematic position of P. sinuosiceps is discussed and the differences between P. sinuosiceps, P. lactuca and P. radioductum are tabulated.

The simple arrangement of the nervous and excretory systems, the specialized features of the genitalia and host distribution suggest that P. sinuosiceps may be one of the most primitive species belonging to the family Phyllobothriidae.

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 life cycle and pathogenicity are described of a pure strain of Eimeria isolated from turkey poults in Great Britain and identified as E. meleagrimitis.

There were three schizogony cycles followed by a sexual generation.

The coccidium produced a high mortality and loss of weight in young poults.

An age resistance developed by the time the poults were 8–10 weeks of age.

The pathology of the infection is described.

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.

1. Two species of Allantonematidae were found parasitizing five of twelve species of Drosophila collected at Rothamsted Experimental Station, Harpenden, Herts, England.

2. H. aoronymphium sp.nov. was found in 20·8 % of D. phalerata and 4·3 % of D. kuntzei examined. Parasitylenchus diplogenus sp.nov. was found in about 5 % of D. subobscura, D. obscura, and D. silvestris examined.

3. The type species and taxonomy of the genus Parasitylenchus are discussed.

4. The life history of H. aoronymphium is typical of most allantonematids except that the female is fertilized when she is a fourth-stage larva. P. diplogenus has two sexual generations per cycle.

5. Both nematodes have a precocious development of the male and a retarded development of the female genital system. Both destroy host gonads.

6. The specificity of the nematodes is not a result of dissimilar ovipositing habits of the hosts, but shows a similarity to the taxonomic assignment of the hosts to subgenera.

Bacteria-free cultures of E. histolytica have been inhibited by specific and related antibodies in the antisera produced in rabbits. Maximal culture-inhibiting antibodies were produced when the rabbits were immunized with frozen and thawed, formalin-treated trophozoites injected intravenously. Human sera from subjects with current or past histories of amoebiasis also inhibited growth of amoebae in vitro.

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.

The new species described here, found in the collections of the Chicago Natural History Museum, was forwarded to me by Harry Hoogstraal, NAMRU-3, Cairo, Egypt, for description. All measurements are given in millimetres.

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.

Neodiplostomum intermedium n.sp. from the small intestine of the allied rat, Rattus assimilis, is described. It can be separated from other species of Neodiplostomum by the following combination of characters: genital cone absent; vitellaria form two ventro-lateral bands in hindbody without terminal masses; anterior testis nearly symmetric, as wide as posterior testis. It is proposed that Fibricola be made a subgenus of Neodiplostomum containing the species in Fibricola and the species, N. intermedium described herein, because N. intermedium is intermediate between Neodiplostomum(Neodiplostomum) and Fibricola. Further evidence is given in favour of the invalidation of the subfamily Alariinae.