Very little work has been done on the systematic study of entozoic trematodes of Australian fishes. Possibly the earliest contribution to the subject was a work by Kreft (1871), “On Australian Entozoa.” Other contributors to this branch of the subject are Wm Nicoll, S. J. Johnston, and T. Harvey Johnston, their studies being chiefly based on parasites of fishes from Queensland and New South Wales waters. So far as can be ascertained there has been as yet only one contribution to the literature on trematode parasites of fishes of Southern Australian waters, a paper by T. Harvey Johnston recently published.

The descriptions by Bassett-Smith (1898–9), Thompson and Scott (1903) and Wilson (1906) constitute practically all the work which has been done on the interesting group of Copepoda parasitic on fishes along the Ceylonese coast. To this short recorded list the present author has added five new species (1932–4). In a short series of papers, of which this is the first, it is proposed to describe a number of species, some of which are new forms, collected since those dates.

Parasitology, 26, 169–72

For first maxilla read maxillary hook. For second maxilla read first maxilla.

For maxillipede read second maxilla.

For second maxillipede read maxillipede.

Following a brief historical introduction, the results of differential counts, precipitin tests and skin reactions on seven cases of trichinosis 4–9 years after recovery are presented. Eosinophile counts ranging from 2 to 7 per cent. were encountered, but the number of cases studied does not warrant any conclusion being drawn. Positive precipitin tests and intradermal reactions were encountered in cases up to 7 years after infection. The findings are discussed, together with a consideration of the pertinent literature, and the importance of the skin reaction and precipitin tests as aids to diagnosis are emphasised in conjunction with due consideration of the history and symptomatology. It is affirmed that the tests have proved of value in establishing a diagnosis in mild cases.

It is a pleasure to acknowledge our indebtedness to Dr George R. Minot, who made the records of the hospital available to us, and to Dr W. D. Sutliff, whose continued interest and ready co-operation greatly facilitated our work.

The mechanism of feeding in ticks has been fully described in numerous text-books. Briefly, it is believed to be as follows: After the tick has fixed itself on the host's body by means of the denticles on the ventral surface of the hypostome, the chelicerae, or the so-called mandibles, are brought into action, and the “protrusion and retraction of the shaft, together with the extension of the teeth on the digits, results in a saw-like movement which tears a hole in the skin” (Patton and Cragg, 1913). More recently, Sharif (1928) has suggested the possibility that the actual incisions in the skin of the host are, as a rule, made by the cheliceral digits and that through the incisions thus made, the proboscis (i.e. the chelicerae and the hypostome collectively) is pushed into the deeper tissues.

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 family Fellodistomidae Nicoll 1913 comprises two subfamilies, Fellodistominae Nicoll 1909 and Haplocladinae Odhner 1911, which are composed of a large number of genera of small flukes, all parasitic in fishes. The type genus of the family was described by Stafford in 1904 from the gall bladder of a Canadian wolf-fish, Anarrhichas lupus. Subsequently several new genera have been added from European and American fishes, but until now no representative of the family has been reported from India.

The results described above indicate that quinanil and the compound 2 (p-dimethylaminoanil)-β-naphthoquinoline methochloride might be successfully used as selective reagents for the isolation of insect flagellates of the genus Leptomonas.

The actual concentrations, which might be successfully used in the culture media, will show some variation according to whether the flagellate is adapted, at the time, to luxuriant growth in the media used. For example, in preliminary experiments, the Leptomonas from Polietes and Calliphora grew better in Locke serum agar than in bouillon, and quinanil was more toxic in the latter than in the former. In the present experiments the reverse held, but in later ones, not here recorded, where the flagellates have again grown more abundantly in Locke serum agar, growth regularly occurs in 1/6000 concentrations of quinanil in this medium. There is little doubt from other results, not yet published, that some Leptomonas forms can be made to show modification of cultural requirements through adaptation. It is probable therefore that in the attempted isolation of fresh forms from the gut of the insect, several kinds of media might have to be employed.

After this work was completed, in several attempts made to purify laboratory-contaminated cultures, success was attained by following the suggested methods, using quinanil and 2 (p-dimethylaminoanil)-β-naphthoquinoline methochloride. The compound 113 was even less toxic to the Leptomonas forms in media than was the compound 52, but its bactericidal action was correspondingly weaker. The few experiments conducted in the absence of media indicated that this substance might have proved very useful, but unfortunately the material gave out and further supplies were not available. In the preliminary treatment of gut contents, acriflavine, owing to its apparently bacteriostatic action, might prove of some value for destroying organisms of the Bacillus prodigiosus type.

Consideration of the results obtained with gentian violet, brilliant green, and the two anilquinolines, 2 (p-dimethylaminoanil)-6-acetylaminoquinoline methochloride and methosulphate, suggests that these compounds are of no use as selective bactericidal substances permitting the growth of Leptomonas forms. The combined action of two or more of these substances has not yet been studied.

As our results indicate, little success is to be hoped for in this direction with the Leishmania forms, which are extremely susceptible to the toxic effects of all the substances employed. Two points of interest were obtained from these results. It might be noted that Leptomonas ctenocephali reacted in a similar manner to the Leishmania forms but that Leishmania tropica (“Baghdad”) behaved like a Leptomonas form. This strain appeared similar in all respects to the other Leishmania forms, but it was the only one readily acclimatised to media containing no blood. Its morphology also showed some modification after a time.

We are greatly indebted to Dr St John-Brooks, Curator of the National Collection of Type Cultures, and to Prof. S. Adler of the Hebrew University, Jerusalem, for certain of the cultures of Leishmania and Leptomonas used, and also to Dr K. E. Cooper for the gift of the anilquinoline derivatives and for much helpful advice.

One of us (F. C. H.) has also been in receipt of grants from the Medical Research Council, and he would like to take this opportunity of expressing his thanks to that body.

Stages of incomplete division of chains of individuals in the species Herpetomonas bancrofti, as well as the distribution of abnormal cells within long chains, were found to support the writer's earlier view (Holmes, 1931) that successive longitudinal divisions of individuals occur within chains. In this type of division there is alternate splitting of individuals from anterior and from posterior ends of cells. It is concluded that this hitherto unproved type of division of pairs and chains is sufficient to account for the presence of all observed aggregates.

No evidence was found suggesting occurrence of any essentially different type of cell division, such as the transverse fission reported by Franchini (1931, 1931 a) as possibly accounting for formation of chains in H. ganorae.

1. The life history of Merocystis kathae shows that development follows a seasonal course. The youngest stages may appear in the kidney any time between March and June. Growth proceeds and sexual differentiation takes place but mature gametes are not found until November, when the first stages of sporogony also make their appearance. Mature spores containing sporozoites are formed in January and become increasingly common up to May. Degenerating stages of spores are common in summer.

2. The smallest parasites within the cells of the kidney are about 10μ. Growth occurs in the intracellular condition. The karyosome is complex, and contains a chromatinic body; in older parasites no chromatin reaction is given by the nucleus outside the karyosome.

3. Sexual differentiation is not perceptible until growth is almost complete.

4. In the female the intrakaryosomic body emerges, though a large karyosomic remnant remains until after fertilisation. Very fine granules of chromatin reappear in the nucleus, and form a fine network, which incorporates the intrakaryosomic body, and later forms the characteristic prefertilisation ‘cobweb’ nucleus. This network contracts in the mature macrogamete. Meantime the parasite has become free of its host cell, and the cytoplasm stains more intensely.

5. In the male, the elongated karyosome breaks down, generally completely, leaving the centrally placed chromatin body surrounded by a ring (in sectional view), of deeply stained material containing granules of chromatin, into which the central body passes as in the female. The male is released from the host cell, and, as in the female an alteration of the cytoplasmic staining occurs.

6. The nucleus, in the male parasite, moves to the surface, and undergoes repeated divisions until approximately 32 nuclei are formed. Cleavage of the cytoplasm brings about the formation of uninucleate cytomeres; within each of these are produced many nuclei, which lie near the surface, and finally become the microgametes.

7. After the macrogamete is fertilised, a thick membrane is formed outside the zygote. The nucleus assumes the characteristic spindle shape and subsequently divides.

8. Nuclear divisions proceed, until finally a great number of cone-shaped nuclei are found on the surface. This becomes folded and the nuclei sink in, and each is surrounded by a portion of cytoplasm to form a sporoblast. A single nuclear division then occurs, and the two nuclei elongate to form sporozoites each with a small cytoplasmic body.

9. Nuclear divisions are mitotic, but the longitudinal splitting of the chromosomes occurs without contraction. It is probable that ‘amitotic’ appearances are due to the incomplete incorporation of these long chromosomes at the telophase poles, and the multipolar divisions to the subsequent division of such ‘amitotic’ resting nuclei. Six chromosomes can be seen at the anaphase poles, but each is looped back so that it is V or J shaped. This chromosome number is characteristic of the divisions of both microgametogenesis and sporogony.

10. There is good evidence that, as in other Coccidia, reduction division occurs in the zygote, and that this is therefore the only diploid phase.

1. Megasolena estrix Linton 1910 has been incorrectly classified in the Allocreadiidae.

2. The possession of two pairs of longitudinal lymph vessels, a remarkable hermaphroditic sac as well as other minor characters indicate relationship to the Paramphistomidae.

3. Hapladena Linton 1910 possesses these same characters and is considered related to Megasolena.

4. These characters are considered to be of more fundamental taxonomic value than the position of the acetabulum.

5. A new subfamily, Megasoleninae, of the family Opistholebetidae is named and described.

In India larvae of several species of Anopheles(Culicidae, Nematocera, Diptera) are parasitised by two species of fungi which form numerous large-sized spores in the host. These fungi occur in the haemocele of the Anopheles larva, and in heavily infected larvae the fungus can be seen to fill the entire haemocele from the thorax to the last segment of the abdomen. In many instances mycelia and spores occur even within the head of the insect. The fungi were not observed to invade the anal gills of the larva (except in a solitary instance in which spores occurred within the deteriorating anal gills).

The symptoms produced by a green strain of tomato streak virus 1 upon a variety of Solanaceous plants are described. A yellow variant of the streak virus which appears to have arisen during the culturing of the green strain is also described. This variant produces local yellow spots upon all inoculated leaves of White Burley tobacco.

Healthy tobacco plants have been infected with the green strain of the streak virus by spraying them with a virus suspension from an atomiser.

The behaviour of the green and yellow virus strains when, co-existing in the tobacco plant is discussed.

Filtration through graded collodion membranes shows that the two strains have different filtration end-points and that therefore they can be separated by this means. The difference in filterability is considered to be a quantitative effect and cannot yet be assigned to difference in particle size.

Immunity tests have shown that a complete cross-immunity exists between the green and yellow strains of streak themselves, between them and two other strains of streak which produce local lesions and between the green and yellow strains and tobacco virus 1. No immunity was found between the streak viruses and those of tobacco necrosis, tobacco ringspot, tomato spotted wilt and potato virus X.

The yellow strain of streak produced local yellow spots on mature leaves of White Burley tobacco. This suggests that the chlorophyll is actually attacked by the virus, and that the formation of the chlorotic spots is not due merely to the inhibition of plastid formation by the virus.

The question of the origin of the Aphaniptera has been, so far, considered obscure. It is for the supposed complete absence of wings in all stages that these insects have been thought by some authors to constitute a very sharply defined order having no close connection with any other group of insects (Imms, 1934, p. 688; Patton and Cragg, 1913, p. 434). This total absence of wings in an order of insects which has a complete metamorphosis would have given this group a very anomalous position in the insect world, as there is no holometabolous insect known which does not possess wings in any stage of its existence. For this reason Packard's conclusion (1894, p. 331) ‘Indeed, the three-fold division of the thorax referred to should have a priori forbidden the thought of rudimentary wings’, and Patton and Cragg's statement (1913, p. 434) ‘They bear no recognizable traces of wings, and the structure of the thorax makes it very doubtful if they are descended from winged forms at all’, can scarcely be accepted.