A preliminary report on the results of our studies on the comparative efficacy of different culicifuges under laboratory conditions has been published (Roy, Ghosh & Chopra, 1942).

The cercaria is liberated from an unbranched sporocyst by the birth-pore. It is spindle-shaped and possesses a bifid tail. It possesses two suckers, a long oesophagus and a forked gut. The excretory vesicle is Y-shaped with two furcal extensions from its stem. The cuticle is unarmed. There is no stylet or cystogenous organ.

There is no redia.

All stages in the development of the cercaria are found within the sporocyst.

For the purpose of determining the suitability of malaria for some work on experimental epidemiology, it was necessary to study the reciprocal immunity produced between a number of species and strains of avian plasmodia maintained in canaries. Some of this work has been a repetition of that previously described by other authors, but some new observations have been made, involving a number of geographically widely separated species and strains, which seem worth putting on record.

The adults of Rhipicephalus pravus were first described very briefly by Dönitz, in 1910, from specimens collected from buffalo, giraffe and various antelopes on the Masai Steppe in Tanganyika. He did not designate any specific specimens as types. He compared the species with R. oculatus, but stated that the difference in the structure of the eyes of the two forms, which he described in detail, was so marked that he considered it to be specific. He also commented on the fact that the males of R. pravus are often strikingly narrow anteriorly, but added that this is not a decisive character. Zumpt (1942) redescribed the adults in detail from material collected in the Tanganyika highlands (Arusha, Kilimatinde, Kondoa-Irangi, Mkalama, Morogoro and Mpwapwa), in Kenya (Mt. Nyro and Mt. Loroghi) and in Abyssinia (Diredawa). Theiler & Robinson (1953) gave descriptions of adults collected at Fairmount, Edenburg, Orange Free State and of nymphae and larvae bred from them in the laboratory. They also discussed the biology, distribution and synonymy of the species. The following descriptions of the adults, nymph and larva are based on laboratory-bred specimens, the progeny of a female collected at Kima, approximately 90 miles south-east of Nairobi.

To date no experimental infection studies have been conducted in laboratory mice using Mus spp. bartonella strains. Therefore we designed a study to evaluate the in vivo infection characteristics of 2 Bartonella tribocorum strains from wild Mus spp. in laboratory mice with the aim of developing a mouse model that reproduces characteristics of naturally acquired bartonella infections in rodents. Groups of outbred CD1 female mice were subcutaneously inoculated with low doses of 2 mouse bartonella strains (10, 100, and 1000 bacteria/mouse). Blood was collected weekly for 27 weeks to evaluate bacteraemia kinetics in infected mice. Mouse urine collected during weeks 3–6 post-inoculation was also tested for viable bacteria to determine whether urine might serve as a source of bacterial transmission. Mice were susceptible to infection with both strains. Bacteraemias in mice lasted up to 25 weeks, sometimes with abacteraemic intervals, and achieved levels up to 107 cfu/ml of blood. Temporal lags in bacteraemia onset of up to 19 weeks in length were noted at different inoculum doses. No viable bacteria were detected in mouse urine. Bacteraemic mice displayed characteristics of infection similar to those observed in natural rodent hosts during longitudinal field studies. This mouse model of persistent bacteraemia should be suitable for a variety of experimental uses.

When incubated in vitro for 24 h, oncospheres of Hymenolepis diminuta absorb and metabolize radioactive glucose. Between 0 and 12 h post-activation, oncospheres absorb glucose, but glucose is neither metabolized into other carbohydrates nor incorporated into the ethanol-precipitable fraction (which would contain glycogen). Between 12 and 24 h post-activation glucose is incorporated into a number of higher molecular weight carbohydrates that are demonstrable in ethanol extracts of the larvae, as well as the incubation media. Furthermore, measurable amounts of radioactivity are incorporated into the ethanol-precipitable carbohydrate fraction of oncospheres. To determine if these temporal changes in carbohydrate metabolism occurred spontaneously following activation, oncospheres were pre-incubated for 12 h (0–12 h post-activation) in the absence or presence of glucose, and then transferred to media containing radioactive glucose for an additional 12 h (12–24 h post-activation). In these latter experiments, glucose absorption and metabolism between 12 and 24 h post-activation were virtually identical to glucose metabolism in oncospheres that were incubated in radioactive glucose for 0–12 h immediately following activation. Thus, these data do not support the hypothesis that the temporal shift in carbohydrate metabolism occurs spontaneously.

Two species of chondracanthid copepods Acanthochondria platycephali Heegaard, 1940 and Pterochondria alatalongicollis Heegaard, 1940 are described. The latter was described by Heegaard as Acanthochondria platycephali f. alata-longicollis. However, it is placed in a new genus, based on the studies of type specimen and new material. A discussion on the other species of Acanthocondria parasitic on the flathead is given. It is suggested that A. bulbosus Heegaard, 1943, is synonymous with A. tchangi Y¨, 1935, and A. diastema Kabata, 1965, with Pterochondria alatalongicollis.

The adults of Solenopotes tarandi (Mjöberg, 1915) are redescribed and illustrated, and its allied species of Solenopotes are compared. The nymphs of this species are for the first time described and illustrated. Ectoparasite infestation of the barren ground caribou (Rangifer tarandus granti Allen) is also discussed.

Glycosidase activities in the adults and juveniles of the lung fluke Paragonimus ohirai and P. westermani adults were demonstrated histo-chemically. For comparative studies, histochemical examination was also made on the adults of the liver fluke Fasciola hepatica. The enzymes examined were N-acetyl-β-glucosaminidase (EC 3.2.1.30), β-glucuronidase (EC 3.2.1.31), β-galactosidase (EC 3.2.1.23), α-glucosidase (EC 3. 2. 1. 20) and β-glucosidase (EC 3.2.1. 21). The distribution of β-glucosaminidase was similar in juveniles and adults. Strong reaction sites for the enzyme were the caecal brush border, tegument, sub-tegumental cells and testes. In contrast, no staining reaction occurred in the caeca of F. hepatica, although the tegument and parenchymal cells were weakly stained, β-glucuronidase activity was associated only with the luminal surface of the caeca in the juveniles. However, luminal contents also appeared stained and this might suggest that the activity in the caeca is not endogenous. β-galactosidase was localized in the caeca, sub-tegumental cells and tegument in both juveniles and adults. No reaction occurred for the other two enzymes, α- and β-glucosidase.

An account is given of the structure and mode of action of the opisthaptor of the monogenean Pseudobenedenia nototheniae Johnston, 1931, from the skin of the fish Notothenia neglecta, caught in December 1969 at a depth of 40 m offSigny Island (60° 43′ S., 45° 36′ W.), South Orkney Islands. The opisthaptor has a roughly hexagonal central loculus surrounded by a septum which is continuous with six radiating septa. It is armed with 14 marginal hooklets and three pairs of sclerites which function as anchors.The opisthaptor obtains adhesion through gripping the host's skin with the muscular rim, and through close contact by the marginal membrane. These form a water-tight seal, the surface area of which is about one-quarter of that of the ventral surface of the opisthaptor. The seal enables the opisthaptor to function as an underwater sucker. Contraction of muscles associated with the opisthaptor, in particular the extrinsic muscles, can generate a pressure difference across the wall of the opisthaptor some 50 times greater than that required to support the weight of the parasite, thus suggesting that reserves are available to resist dislodging forces such as increased water flow. The instability and tendency to slide of the sucker is counteracted by anchorage from the hooklets and sclerites. The structure and mode of action of the opisthaptor of P. nototheniae are discussed in relation to studies made by other authors on similar adhesive organs.

The immune evasion gene family of malaria parasites encodes variant surface proteins that are expressed at the surface of infected erythrocytes and help the parasite in evading the host immune response by means of antigenic variation. The identification of Plasmodium vivax vir orthologous immune evasion gene family from primate malaria parasites would provide new insight into the evolution of virulence and pathogenesis. Three vir subfamilies viz. vir-B, vir-D and vir-G were successfully PCR amplified from primate malaria parasites, cloned and sequenced. DNA sequence analysis confirmed orthologues of vir-D subfamily in Plasmodium cynomolgi, Plasmodium simium, Plasmodium simiovale and Plasmodium fieldi. The identified vir-D orthologues are 1–9 distinct members of the immune evasion gene family which have 68–83% sequence identity with vir-D and 71·2–98·5% sequence identity within the members identified from primate malaria parasites. The absence of other vir subfamilies among primate malaria parasites reflects the limitations in the experimental approach. This study clearly identified the presence of vir-D like sequences in four species of Plasmodium infecting primates that would be useful in understanding the evolution of virulence in malaria parasites.

There is great heterogeneity in parasite communities among hosts, understanding the nature and drivers of such variations is still a great scientific quest. Here, we analyse the variation in parasite communities by addressing the following questions: (i) What is the beta-diversity component (nestedness or turnover) that most contributes to beta diversity in parasite communities among anuran species? (ii) Does the beta diversity of parasite communities follow a non-random pattern? (iii) Is the dissimilarity in composition of parasite communities related to the phylogenetic or functional dissimilarity among hosts? We found that turnover in parasite assemblages was the main component of beta diversity, but the variation observed both in the total beta diversity and in its components did not differ from the respective null models. The dissimilarity among parasite communities was not related to the phylogenetic species variability or functional dissimilarity among anuran species for most localities. In short, our findings may indicate a process of resource tracking by the parasite species, in which the resource may not necessarily be conserved phylogenetically in their hosts.

The larvae described in this paper were obtained in 1916 by Major C. E. Southon, I.M.S., from a case of intestinal myiasis observed by him in Nairobi (British East Africa). These larvae were sent to Professor J. H. Ashworth and referred to me by Dr G. A. K. Marshall of the Imperial Bureau of Entomology.

While fixing a number of tapeworms (Anoplocephala perfoliata Goeze) from the small intestine of the horse, I came across a small tri-radiate specimen. This abnormality has previously been described by Neumann (2), but only briefly, and without any account of the internal anatomy. It therefore seemed advisable to compile a short account of the most salient characteristics. For the material I am indebted to Dr C. L. Boulenger, Helminthologist of this Department. I have also to thank Professor L. G. Neumann for obtaining for me a copy of his paper.

LA litérature ne nous offre que des renseignements fort embrouillés sur les Acanthocéphales parasites intestinaux de l'eider (Somateria mollissima L.).Ces parasites furent decouverts par Phipps en 1774–1775 et décrits par lui sous le nom de Sipunculus lendix. Cependant, de la description et surtout des figures de cet auteur on voit bien qu'il ne s'agissait point de Sipunculides mais de vrais Acanthocéphales (Lühe, 1905). Plus tard, d'autres auteurs ont rapporté cette espéce comme synonyme d'Echinorhynchus polymorphus Brems

Experiments were conducted in guinea-pigs to elucidate the parameters affecting the development of protective immunity against Schistosoma japonicum induced by a cryopreserved, irradiated schistosomula vaccine such as the number of immunizations, route of injection and the use of adjuvants. Results obtained indicated that the cryopreserved, irradiated schistosomula vaccine was effective by either intradermal or intramuscular injection. One intradermal injection with BCG adjuvant resulted in an average worm reduction of 50·24%, only a little lower than that of a non-cryopreserved, irradiated vaccine, 53·55%, with no statistically significant difference between the two. By intramuscular injection the worm reduction was lower (max. 40%) whether given with or without adjuvants or in 1 or 2 injections.

A description is given of two new Cephaline gregarines from Indian crickets collected at Lucknow and Jalaun, United Provinces.

One of these, Stenophora gryllodes-sigillatae sp.nov., from the gut of Gryllodes sigillatus, has solitary slender trophozoites up to 194μ long. Its epimerite is rounded in young forms and absent or represented by its remnant in adults. The nucleus has two chromosomes. Cysts are rounded, invested in a very thin membrane and without sporoducts.

The second, Bulbocephalus indicus sp.nov., from the gut of Liogryllus bimaculatus, is characterized by solitary elongated sporadins; the neck is short and a bulbous epimerite is always present. The body, measuring up to 175μ in length and up to 30μ in breadth, presents a striated appearance. Cysts are oval, covered by a very thin membrane, and have no sporoducts.

The author is very grateful to Dr S. M. Das, under whose able guidance this work was carried out. His thanks are also due to the Department of Zoology, University of Lucknow, for providing the laboratory facilities.

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.

A positive Feulgen reaction has been seen in all stages of Toxoplasma gondii. The intense basophilia seen in the intracellular and the extracellular stages is removable by treatment with ribonuclease. Granules which reacted positively with the periodic acid-Schiff technique were found in abundance in the cytoplasm of the cysts, whereas the same granules were not universally present in the intracellular and the extracellular stages at all days of infection. The cyst wall stained with this technique with varying degree of intensity.

It is thought that the variations seen in the individual parasites may be attributed to various causes, for example, strain differences, differences in the reaction of the host to the parasite, differences in the period of infection or to other unknown causes.