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 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.

The present study was conducted to evaluate the anti-parasitic activity of a pure compound from Streptomyces sp. HL-2-14 against fish parasite Ichthyophthirius multifiliis, and elucidate its chemical structure. By electron ionization mass spectrometry (ESI-MS) and nuclear magnetic resonance spectrum (1H NMR and 13C NMR), the compound was identified as amphotericin B (AmB). The in vitro trials revealed that AmB can effectively kill the theronts and tomonts of I. multifiliis with the median lethal concentration (LC50) of 0·8 mg L−1 at 30 min for the theronts and 4·3 mg L−1 at 2 h for the tomonts, respectively. AmB at 5 mg L−1 significantly reduced I. multifiliis infectivity prevalence and intensity on grass carp (Ctenopharyngodon idella), and consequently decreased fish mortality, from 100% in control group to 30% in treated group. The 72 h acute toxicity (LC50) of AmB on grass carp was 20·6 mg L−1, but fish mortality was occurred when exposure to 13·0 mg L−1. These results indicated that AmB was effective in the therapy of I. multifiliis infection, but the safety concentration margin is relatively narrow. Further efforts aiming to decrease the toxicity and improve the therapeutic profile remain to be needed.

The development of T. lewisi in the blood of the rat is accompanied by a division of the nucleus which is more like an amitosis than a mitosis.

The division of the blepharoplast, always preceded by the division of a karyosome-like granule, might be called a promitosis (sensu: Nägler, 1909).

It is not proved that autogamy or parthenogenesis takes place in rats' blood or in cultures. The evidence brought forward by Prowazek and by Moore, Breinl and Hindle proves only the existence of chromidia; neither are Schilling's recent proofs suggestive.

Under abnormal conditions hypertrophy takes place affecting the nucleus and the blepharoplast, with subsequent formation of chromidia and final fragmentation. Similar stages found in the rat-louse have been described as sexual cells.

Considering these results in connection with previous observations of Strickland and myself, we may conclude that as yet nothing whatever indicates the occurrence of any sexual process in the life-cycle of T. levrisi, both in the vertebrate and invertebrate hosts.

Owing to the courtesy of Dr G. M. Vevers I have had the opportunity of examining a marine Ichthyobdellid leech, taken by Dr F. A. Phillipps from the cloaca of a shark, 7 feet long, caught between the islands of Aore and Santu, New Hebrides. The leech resembles Pontobdella superficially in being covered by warty tubercles. It possesses, however, certain peculiarities described below which justify its recognition not only as a new species but also as a representative of a new genus.

A new species of Trypanosoma, T. (Megatrypanum) hoarei, is described from shrews of the genus Sorex (S. trowbridgii, S. vagrans, S. ornatus, and S. palustris) in California. Four body types are found in adult populations of T. hoarei, two common and two rare, as well as intermediate stages, indicating a tendency to-ward polymorphism in this species. Multiplication is discontinuous, with a reproductive and growth period characterized by moderate numbers of diverse and bizarre developmental forms in the blood and high coefficients of variation for total length (20–30 %), succeeded by an adult phase with few trypanosomes in the blood and lower coefficients of variation for total length (7–12 %). The method and site of multiplication in T. hoarei is unknown but evidence indicates that reproduction by multiple fission or binary fission of amastigote forms may occur in tissue capillaries, with the production of large, rounded amastigote individuals. The latter develop, without intervention of epimastigote stages, into large, rounded trypomastigote individuals from which a wide variety of other developmental forms proceed, including certain distinctive, very long ribbon-like trypanosomes. A review of the literature on mole and shrew trypanosomes suggests that T. hoarei of Sorex, T. petrodromi from Petrodrorrms, and T. talpae from Talpa are related, primitive insectivore forms, clearly distinguishable from the lewisi-type trypanosomes also found in insectivores.

On the skin of the dorsal surface, and particularly on the dorsal fins of Scyllium canicula at Plymouth, occurs a parasite which appears to be identical with Paracotyle caniculae Johnstone 1911. In British waters it was first noticed by Scott (1906) who queried it as a species of Epibdella. Johnstone (1911) gave an account of the species but his specimens were immature, being in the male phase of their development and considerably smaller than those found at Plymouth.

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.

Experimental studies on the dynamics of infection of Lymnaea truncatula by the miracidia of Fasciola hepatica show that there is a linear relationship between the net rate of attachment of miracidia to snail epithelium and the density of infective stages. The probability of a snail remaining uninfected after exposure to a single miracidium varies with the size class of the snail. Under the conditions of the experiment (temperature, 15° C; exposure period, 30 min; water volume, 8 ml), the probability was 0·46–0·48, 0·27–0·26 and 0·13–0·19 for snail size classes, 0·5–2·9, 3·0-5·9 and 6·0-8·9 mm respectively.

The oocysts studied were concentrated from the contents of the colon and caecum of the cottontail rabbit. The concentration method of Benbrook (1929) has been found to serve best.

Here we report on the infection of captive crested geckos Correlophus ciliatus Guichenot (Reptilia: Diplodactylidae), with adults of the ascaridoid nematode, Hexametra angusticaecoides Chabaud & Brygoo, 1960 (Ascarididae). A population of captive crested geckoes became ill and died within a short period of time. Nematodes were recovered from the crested geckoes examined from within the coelomic cavity, penetrating various organs and migrating through subcutaneous tissues, as well as emerging through the geckos' skin. One gecko was treated with levamisole following surgical excision of nematodes from under the skin; this gecko survived. The potential source of the nematode infection in the captive geckoes is discussed. It is most likely that wild-caught Madagascan mossy geckoes, Uroplatus sikorae Boettger (Reptilia: Gekkonidae), introduced the infection to the colony. Molecular sequences of the nematodes are the first produced for the members of this genus. A redescription of the species and its genetic characterization based on the internal transcribed spacer sequence data is provided, suggesting some of the morphological criteria that have been used in the past to distinguish between Hexametra spp. may have been intraspecific morphological variations.

Most animals are concurrently infected with multiple parasites, and interactions among them may influence both disease dynamics and host fitness. However, the sublethal costs of parasite infections are difficult to measure and the effects of concomitant infections with multiple parasite species on individual physiology and fitness are poorly described for wild hosts. To understand the costs of co-infection, we investigated the relationships among 189 European eel (Anguilla anguilla) from Mar Menor, parasites (richness and intensity) and eel's ‘health status’ (fluctuant asymmetry, splenic somatic index and the scaled mass index) by partial least squares regression. We found a positive relationship with 44% of the health status variance explained by parasites. Contracaecum sp. (Nematoda: Anisakidae) was the strongest predictor variable (44·72%) followed by Bucephalus anguillae (Platyhelminthes: Bucephalidae), (29·26%), considered the two most relevant parasites in the analysis. Subsequently, 15·67 and 12·01% of the response variables block were explained by parasite richness and Deropristis inflata (Platyhelminthes: Deropristiidae), respectively. Thus, the presence of multiple parasitic exposures with little effect on condition, strongly suggests that eels from Mar Menor tolerate multiparasitism.

In June 1935 we observed in the intestine of an Indian squirrel, Sciurus sp.1, a coccidium which, since it has tetrazoic tetra-sporocystid oocysts, must be placed in the genus Wenyonella recently created by Hoare (1933).2

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.