1. A description is given of the egg of Gasterophilus intestinalis.

2. The chorion has been shown to consist of a number of tanned protein and lipoprotein layers.

3. The waterproofing of the egg is shown to be dependent on a primary wax layer on the inner membrane of the endochorion and a secondary layer on the vitelline membrane.

4. The respiratory requirements of the egg are supplied from a free-air space between the inner membrane and the tanned protein layer of the endochorion which communicates with the atmosphere by specialized pore canals opening into the follicular grooves.

Thanks are due to Dr P. Tate for suggesting the subject of this work and for his advice and encouragement during its progress.

The microsporidian parasite Hamiltosporidium tvaerminnensis can infect Daphnia magna both horizontally (through environmental spores) and vertically (through parthenogenetic and sexually produced eggs). The spores of H. tvaerminnensis come in three distinguishable morphologies, which are thought to have different roles in the transmission of the parasite. In this study, we examined the role of the two most common spore morphologies (i.e. oval-shaped spores and pear-shaped spores) in horizontal transmission of H. tvaerminnensis. To this end, we infected hosts with solutions consisting of either mostly oval- or mostly pear-shaped spores, and quantified infection rates, parasite-induced host mortality and mean number of parasite spores produced per host. We found that spore morphology by itself did not influence infection rates and parasite-induced host mortality. Instead, host clone and parasite isolate interacted with spore morphology in shaping infection outcome and mortality. Thus, there appear to be strong genotype-by-genotype (G × G) interactions in this system. While there is no dispute that H. tvaerminnensis can transmit both vertically and horizontally, our findings do not support theoretical predictions that different spore morphologies hold different roles in horizontal transmission of H. tvaerminnensis.

In March 1932, while examining the gut contents of Bufo melanostictus, I came across a species of coccidian in two specimens. On consulting the literature, I found that while five species of Eimeria have been recorded from the intestinal region of anurous amphibians, none of them corresponds with the one I have observed. Moreover, I notice that for no one of these five species has the whole life history been described.

The present investigation was primarily undertaken by Mr G. Merriman at the suggestion of Professor Nuttall, but was discontinued at a very early stage owing to Mr Merriman's departure for Africa. The object of the investigation was:

(1) To determine if immature stages of ticks whose mouth-parts have been mutilated or torn off by the forcible removal of the parasite from the host possess the power of regeneration. In nature, many immature ticks must be injured in this manner, and it seemed of interest to determine if they could regenerate the lost parts, thus helping them in the struggle for existence.

(2) To determine if the small legs occasionally observed in nymphal and adult ticks are due to mechanical injury followed by regeneration. A very striking example of such a tick is the type specimen of Amblyomma scaevola Oudemanns (♂), in which four legs are markedly under-developed. In the large quantity of tick material that has been received at the Quick Laboratory, individuals with one or more miniature legs have been observed repeatedly.

As animals we have been a remarkably successful species; but also as animals we are vulnerable to environmental, in particular climate change. Such change is accelerating as a result of human activity, and global warming may already be taking place. Although we can foresee the trends, we cannot yet be specific about the results. Change usually proceeds by steps rather than gradients. But warming would probably include new risks to human health and contribute to an increase in human displacement. Of course climate change is only one among other complex problems facing human society, but it is closely related to them all, including population increase, environmental degradation and loss of biodiversity. We cannot prevent global warming but we can anticipate and mitigate some of its worst effects. Peoples and governments still need persuading of the need for action and of the magnitude of the issue at stake.

The follwing descriptions relate to two new species of the genera Haemaphysalis and Amblyomma, respectibely, and to a new variety of Amblyomma variegatum:

Haemaphysalis silacea sp. n. ♀, from South Africa (370).

Amblyomma variegatum var. n. nocens, ♂, from South Africa (371).

Amblyomma fiebrigi sp. n. ♂ and ♀, from South America (6).

Recently, we introduced an epoxy group to mebendazole by a reaction with epichlorohydrin and obtained two isoforms, mebendazole C1 (M-C1) and mebendazole C2 (M-C2). The in vitro effects of mebendazole derivatives at different concentrations on Echinococcus multilocularis protoscoleces and metacestodes as well as cytotoxicity in rat hepatoma (RH) cells were examined. The results demonstrated that the solubility of the two derivatives was greatly improved compared to mebendazole. The mortality of protoscoleces in vitro reached to 70–80% after 7 days of exposure to mebendazole or M-C2, and M-C2 showed higher parasiticidal effects than mebendazole (P > 0.05). The parasiticidal effect of M-C1 was low, even at a concentration of 30 µm. The percentage of damaged metacestodes that were treated with mebendazole and M-C2 in vitro at different concentrations were similar, and M-C1 exhibited insignificant effects on metacestodes. Significant morphological changes on protoscoleces and metacestodes were observed after treatment with mebendazole and M-C2. In addition, the introduction of an epoxy group to mebendazole also reduced its cytotoxicity in RH cells. Our results demonstrate that the introduction of an epoxy group not only improved the solubility of mebendazole, but also increased its parasiticidal effects on E. multilocularis and reduced its cytotoxicity in RH cells.

Cochliomyia hominivorax larvae cause myiasis in animals and humans. To register a commercial product to control this dipteran is necessary to experiment on animals. The in vitro test was standardized to evaluate the larvicidal efficacy of commercial topical products. Five formulations were analysed in vitro and in vivo. For the in vitro test, a colony was formed and three replicates (n = 200) of each larval stage (L1, L2 and L3) were treated. The viability of the larvae was evaluated after 5 and 30 min, and at 1, 2, 6, 12, 24, 48, 60 and 72 h post-treatment (HPT). For the in vivo test, 30 bovines divided into six groups were castrated to achieve natural infestation with C. hominivorax. Animals in the treated groups received the product. Myiasis and efficacy were evaluated 12, 24, 36, 48, 60 and 72 HPT. Four formulations tested in the in vitro test achieved 100% efficacy at 24 HPT. In the in vivo experiment only one achieved 100% efficacy at 24 HPT. However, all products achieved the maximum efficacy by the end of study. The in vitro test developed here could be adopted to evaluate the efficacy of topical products for the control of C. hominivorax larvae.

Sexual transmission occurs commonly in microparasites such as viruses and bacteria, but this is an unusual transmission route for macroparasites. Here we present evidence which suggests that a nematode parasite of Wood Mice (Apodemus sylvaticus) may be sexually transmitted and we have classified the nematode using molecular data. Wood Mice were collected annually in the course of work on their reproductive physiology. Larval nematodes were found in the epididymides of 19·6% of males. It seems likely that they would be transmitted to females at ejaculation. To identify these larval nematodes, which we were unable to do using morphological features, we sequenced the 18S rDNA. Sequence comparisons with the molecular phylogeny of Blaxter et al. (1998) demonstrated that they were bursate nematodes (Order Strongylida). The relationships between strongylid taxa were poorly resolved by 18S rDNA. However, both distance and parsimony analyses grouped the nematode with the superfamily Metastrongylidea in a clade containing Filaroides and Angiostrongylus sp. Importantly, the sequences were distinct from those of Heligmosomoides polygyrus and Angiostrongylus dujardini, two common strongylid nematodes of Apodemus. We were therefore unable positively to identify these worms by matching their sequences with those from morphologically identifiable adult strongylid nematodes infecting Apodemus. These results demonstrate that an as yet unidentified strongylid is quite commonly found in large numbers in the male reproductive tract of Wood Mice. Further work is required to understand the biology and transmission dynamics of this interesting system.

Antibodies at gastrointestinal mucosal membranes play a vital role in immunological protection against a range of pathogens, including helminths. Gastrointestinal health is central to efficient livestock production, and such infections cause significant losses. Fecal samples were taken from 114 cattle, across three beef farms, with matched blood samples taken from 22 of those animals. To achieve fecal antibody detection, a novel fecal supernatant was extracted. Fecal supernatant and serum samples were then analysed, using adapted enzyme-linked immunosorbent assay protocols, for levels of total immunoglobulin (Ig)A, IgG, IgM, and Teladorsagia circumcincta-specific IgA, IgG, IgM and IgE (in the absence of reagents for cattle-specific nematode species). Fecal nematode egg counts were conducted on all fecal samples. Assays performed successfully and showed that IgA was the predominant antibody in fecal samples, whereas IgG was predominant in serum. Total IgA in feces and serum correlated within individuals (0.581, P = 0.005), but other Ig types did not. Results support the hypothesis that the tested protocols are an effective method for the non-invasive assessment of cattle immunology. The method could be used as part of animal health assessments, although further work is required to interpret the relationship between results and levels of infection and immunity.

Echinoparyphium serratum sp.nov., with 37 collar spines, is described from experimentally infected ducklings and chickens. It appears to be most closely related to E. aconiatum but differs from it in having smaller eggs, fewer tegument spines, almost confluent vitellaria in the post-testicular region, and the inner margin of the ventral sucker is serrated. The natural host is unknown but thought to be a bird.

Bile composition may account for the markedly different recovery percentages of adult worms from the two experimental hosts.

Miracidia hatch between 9 and 11 days at 22 °C. Experimental infections of snails with miracidia have not been obtained.

Rediae occur naturally in Isidorella brazieri Smith, and free-swimming cercariae encyst in the pericardium of the same species of snail.

This latter part of the life-cycle is based on strong circumstantial evidence. A few cysts were occasionally found in the pericardium of Lenameria sp. but the enclosed metacercariae were dead.

The cercaria can be distinguished from Cercaria echinata, the cercaria of E. aconiatum, and C. equispinosa in having cystogenous gland cells containing granular material only, and the inner margin of the ventral sucker serrated.

I would like to record my sincere thanks to Professor J. D. Smyth for his advice, and comments on the manuscript.

The paper records the description of the morphology and taxonomy of a new genus and species of a Heterotrichous ciliate (family Clevelandellidae) found in the gut of the non-xylophagous termite Capritermes incola Wasm. (Termitidae) from Dharwar (India).

When fresh-water snails are examined microscopically, specimens are occasionally encountered that are infested with the cercariae of more than one species. Sometimes these cercariae are easily differentiated. A snail may harbour numerous eye-spotted amphistomes and a few distomes without eye-spots, or furcocercous forms may be associated with cercariae possessing undivided tails. In some collections of semi-stagnant water, however, the same individual snail may be found infested with at least two distinct schistosomes. In 1916, I found Physopsis africana (in an overflow pool along the course of the Umsindusi river at Pietermaritzburg) heavily infested with two distinct schistosomes, and it was not uncommon, as Dr E. E. Warren also observed, for the two forms to develop in the same host. One of these cercariae I named Cercaria secobii, the other was probably the cercaria of Schistosoma haematobium. Soparkar (1921 a and b) has moreover noted a double infection of Planorbis exustus near Bombay.

A new species of larval trematode, C. projecta, infects Helisoma antrosa. The very small distome cercaria is ontogenetically young, showing no traces of reproductive anlagen even after excystment. It belongs to the cystophorous cercariae, and has a vesicular tail into which the body of the cercaria withdraws when mature. In this encysted state the cercaria is expelled from the snail and awaits ingestion by the next host. The redia is a large, elongate sac, without “feet,” possessing a small pharynx, short intestine and an excretory system consisting of a longitudinal channel and at least sixty flame cells on each side of the body. Excystment is caused by mechanical pressure which releases a force within the cyst, which projects the cercaria very rapidly through a long cuticular tube, the excretory projection, to a considerable distance away from the cyst. Various complex appendages of the tail vesicle along with parts of the excretory system play a large part in this process of excystment. As postulated, the purpose of this type of excystment is to throw the larva away from its cyst, to prevent it from being regurgitated from the body with the empty cyst.

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.