We tested Szidat's rule (the more primitive the host, the more primitive the parasites it harbours) by analysing the relationships between phylogenetic clade ranks of fleas and their small mammalian hosts in four biogeographic realms (Afrotropics, Neotropics, Nearctic and Palearctic). From the host perspective, we tested the association between host clade rank and the mean clade rank of all fleas collected from this host. From the flea perspective, we tested the relationships between flea clade rank and the mean clade rank of hosts on which this flea was recorded. First, we tested whether the analysis of the relationships between host and flea clade ranks should be controlled for phylogenetic dependence among either host or flea species. Then, we tested for the associations between host and flea clade ranks separately for each realm using either a phylogenetic general least-squares analysis or an ordinary least-squares analysis. In all realms, the mean clade rank of fleas parasitic on a given host increased with an increase of this host's clade rank, and the mean clade rank of hosts recorded on a given flea increased with an increase of this flea's clade rank, suggesting that Szidat's rule, at least to some extent, holds for fleas.

Cystic echinococcosis is a significant parasitic disease in Iran, where a variety of animals act as intermediate hosts. In this study, 25 isolates of Echinococcus granulosus obtained from water buffalo from various parts of Iran were characterized on the basis of the morphology of the metacestode and the adult worm. The characteristics of protoscoleces from the different studied areas were nearly similar. They showed 2 rows of alternating large and small hooks and their shapes were smooth in outline. In contrast to the protoscoleces, the adult rostellar hooks showed a rough outline. The results showed that the total length, the blade lengths of the large and small hooks and the number of hooks are almost similar to those isolated from sheep but significantly different from those isolated from camels. The growth rates of adult E. granulosus (total worm length, segmentation and maturation) of buffalo origin, at 35 and 41 days post-infection of dogs, were nearly comparable to the common sheep strain. The form of the strobila and the morphology of the reproductive system were also similar to those of sheep origin. This suggests that the common sheep strain (G1) of E. granulosus may also use buffaloes as its intermediate host.

A traditional assumption is that schistosome cercariae lose their tails at the onset of penetration. It has, however, recently been demonstrated that, for Schistosoma mansoni, cercarial tails were not invariably being shed as penetration took place and a high proportion of tails entered human skin under experimental conditions. This phenomenon was termed delayed tail loss (DTL). In this paper, we report that DTL also happens with S. japonicum cercariae during penetration of mouse skin. It occurred at all cercarial densities tested, from as few as 10 cercariae/2·25 cm2 of mouse skin up to 200 cercariae. Furthermore, it was demonstrated that there was a density-dependent increase in DTL as cercarial densities increased. No such density-dependent enhancement was shown for percentage attachment over the same cercarial density range.

For many years it has been known that the domestic fowl, together with some other species of birds, is susceptible to experimental infection by trypanosomes of the brucei group. The successful experiments were performed in European laboratories with strains whose virulence had been greatly exalted as the result of long maintenance in small laboratory animals. Infection was induced by inoculation of infected blood into the comb, the peritoneum or a vein. A natural infection of birds with these trypanosomes has, as far as I know, never yet been reported.

In a recent paper (Parasitology, 23, No. 4, 492) I described under the name Microcotyle sciaenae a new species of Microcotyle from the gills of Sciaena antarctica. Dr M. C. Hall, Chief of the Bureau of Animal Industry, Washington, D.C., has kindly pointed out to me that this name is preoccupied by M. sciaenae Goto (1894). I now propose the name M. sciaenicola in place of this homonym.

The micro-glass electrode used in measuring the pH of blood from the stomachs of mosquitoes was a modification of that described by Caldwell (1954). The electrode was made of capillary tubing, drawn from Corning 015 glass, the outer diameter being 0·5–0·75 mm. and the length about 6 cm. As the electrode was used with a Pye Universal pH meter, and not with the electrometer impedance converter circuit used by Caldwell, it was important that the wall of the capillary tube should be very thin, in order that the resistance of the electrode should not exceed 500 MΩ, the maximum electrode resistance permissible with the Pye Universal pH meter.

The present paper is the third of a series dealing with a collection of parasitic worms from fishes off the coast of Iceland. The two previous papers have been concerned with the Cestoda and Digenea respectively (Rees, 1953a, b). There are no existing records of Monogenea, Nematoda or Acanthocephala from fishes off the coast of Iceland. Although this collection is not a large one, it indicates a wider geographical range of parasites already recorded from marine fishes in other parts of the world. There are five new host records.

Lecithaster musteli sp.nov. from the five-bearded rockling, Onos mustelus (L.), at Mumbles Head, Swansea, is described and compared with other species of the genus.

The genus Lecithaster Lühe, 1901 is reviewed. An emended definition of the genus is given with keys, diagnostic features, and brief notes of the nine recognized species. L. gibbosus (Rud.) Lühe, 1901 is briefly redescribed.

L. intermedius Szidat, 1954 is considered to be a synonym of L. gibbosus (Rud.) Lühe, 1901.

I am deeply indebted to Dr B. L. James for his advice and indispensable assistance throughout the work and the preparation of this paper. I am also grateful to Professor E. W. Knight-Jones for his interest and for providing the working facilities, and to Mr S. Prudhoe, British Museum (Natural History), for his advice, for allowing me to examine slides of L. gibbosus and for the use of the library.

During the examination of over 8000 specimens of Ornithodorus moubata, two cases of partial twinning (one male, one female) of the posterior region were noticed, and also a case of suppression of the postanal region in a male. All the freaks were viable, and the partial twins were normally fertile.

1. When sporozoite-induced infections of Plasmodium relictum are treated with atebrin (mepacrine) in doses suppressive to blood-inoculated infections, for periods exceeding that of normal incubation, parasites devoid of pigment appear in the erythrocytes of the peripheral blood. A small proportion of these may develop into schizonts, but the number of merozoites produced is fewer than normal.

2. A similar phenomenon occurs when quinine is substituted for atebrin, but the drug appears to be excreted more rapidly so that the inhibitive effect upon growth is less marked.

3. When plasmoquine is given in the maximum tolerated dose to birds infected with sporozoites, parasites are not seen in the peripheral blood during treatment, though the infection is not sterilized. With smaller doses parasites, including a few small schizonts, are found in the erythrocytes during treatment.

4. Merozoites produced in the erythrocytes during drug treatment are not capable of further multiplication when inoculated into uninfected birds having a similar blood-concentration of drug, so long as treatment continues, though they develop normally when transferred to untreated birds.

5. No indication of drug resistance has been observed.

6. The possible mechanisms by which blood-inoculated infections are eradicated, or resist eradication, are discussed.

We wish to thank Miss Vincent (Mrs Thorpe) and Dr Parr Tate for access to their preliminary unpublished experiments, and the latter for helpful criticism.

Nuttall and Warburton (1911, pp. 105–13) give a detailed account of the systematic survey of the family Ixodidae and recognise nine genera in the family. They consider Aponomma Neumann as a subgenus of Amblyomma Koch, but I consider it a valid genus.

It would appear from the data presented that the favourite location for the common rat fleas of this vicinity, Ceratophyllus fasciatus, Bosc., and Loemopsylla cheopis, Roth., is about the hind quarters of the rat, while Ctenopsyllus musculi (Dugès), Wagner, prefers the region of the head and neck.

The same regional distribution of rat fleas was found in the case of the guinea-pigs.

Squirrel fleas are most numerous on the hind quarters.

These observations, while they are not to be insisted upon as throwing any special light upon the regional distribution of buboes in naturally infected plague rats, are of particular interest in showing the very constant preference of Ct. musculi for the region of the head and neck.

In regard to the other species of fleas it should be borne in mind that the skin areas are not of equal dimensions; that of the head and neck being smallest; that of the hind quarters being the largest; and the skin area of the fore quarters being between these in size.

The techniques of generalized linear modelling were applied to worm burdens of 2268 mice artificially infected with Schistosoma mansoni and treated with oxamniquine and/or praziquantel. Models which maximized the Poisson likelihood were shown to be superior to those assuming either a log Normal or negative binomial error structure. Use of the models to calculate and compare ED values of 8 strains of S. mansoni, detect abnormal dose response and synergism and to pool data from several experiments is illustrated.

This paper describes the terminalia of two abnormal males of the genus Sarcophaga Meigen (Sarcophaga similis Meade and S. hirtipes Wiedemann var. orchidea Böttcher) which appear to throw light on the interrelationships of the inverted, curvilinear and circumverted types of terminalia in Diptera. The specimens resemble certain stages described by Crampton (1944) in his comparative study of the morphology of the terminalia, and may perhaps represent stages in the pupal development of normal calypterate cyclorrhaphous Diptera.

From a study of the pregenital plate in these forms it seems probable that, in Sarcophaga at least, it represents two fused sclerites—probably sternites 7 and 8.

Habitat and material. By the courtesy of Prof. W. M. Tattersall of University College, Cardiff, I have been able to examine what proved to be a new species of Chondracanthus, the material consisting of a female with a male attached anterior to the abdomen as is usual. The host, Malacocephalus laevis, was taken in deep water from S.W. Ireland by the fishing fleet of M. H. Neale, Esq., the eminent Cardiff naturalist, after whom this species is named.

In this, the last paper to be published from the Uganda Institute, after an account of the strain that forms its main subject, the origin of T. rhodesiense will be briefly discussed in the light of the investigations recorded in this series of papers and a few general observations will be made.

A male Malay tiger was brought to the Clifton Zoological Gardens in July, 1908. He was then very thin and fed badly. After a time he settled down in his new quarters, and ate his food with greater relish. He appeared to be in good health and his coat was sleek and fine, but he never jumped or played in the usual way of his species. On February 4th he vomited, and had a severe attack of diarrhoea. His breathing became less abdominal and more thoracic in character, and death occurred two days later.

While studying a collection of roundworm parasites from animals dying in the Philadelphia Zoological Garden, accounts of which appeared in 1929 and 1931, I found ten flukes in it, one of which proved to be new. Two common distomes in the lot, Renifer ellipticus Pratt 1903 and Opisthorchis tenuicollis (Rud. 1819) are from new hosts; the former from an American beaver (Castor canadensis) and the latter from a Canadian lynx (Felis canadensis). The one rare monostome found in the lot is recognised as a new species of the genus Allopyge Johnston 1913 in the family Cyclocoelidae and is named Allopyge undulatus n.sp. It was found in the thoracic air sacs of Lilford's crane (Megalornis grus lilfordi).

Three specimens were examined, the type, female, and two paratypes, male, collected by Mr B. A. Lever, from a small bat in the Russell Islands, Solomon Islands. They were sent to me by Sir Guy A. K. Marshall, whom I wish to thank for allowing me to describe them.