Tremiorchis ranarum nov.gen., nov.sp., was first found in the small intestine and duodenum of thirty-six out of one hundred and two specimens of Rana tigrina examined for the purpose. Subsequently many more frogs have been examined and we have obtained these parasites in one out of every three frogs. Rana tigrina being the commonest species of frog available in Northern India is used as the type for dissection in every laboratory and it appears, therefore, strange that this common Trematode parasite should have remained unknown till now. The number of parasites in a host is very variable. Three hosts were found infected with one parasite each, one had 4, one had 5, one 16, one 18, one 196 and one as many as 204.

Early in 1925 I received from Mr E. Jacobson a mite taken in 1918 from the Passalid beetle Gnaphalocnemis (Eriocnemis) burmeisteri Kaup. on the east coast of Sumatra. It clearly belonged to the genus Megisthanus, and was apparently new. I had described and figured it before I showed it to Mr Stanley Hirst of the British Museum (Natural History), South Kensington. He informed me that he had received both sexes of what he believed to be the same mite, and most kindly offered to hand over to me the material to complete my account of the new species. By the courtesy of Sir Sidney Harmer he was permitted to do this, and I have therefore been able to examine, as regards external features, four female and three male specimens.

p. 151, line 9 Read biramous for uniramous (see Fig. 4).

p. 153, line 15 Delete the words in parenthesis.

p. 276, line 6 Read median for medium.

Among the bird-parasites included in the family Hippoboscidae, are four small closely conneceted genera, in all of which the wings exhibit more or less extensive reduction and are apparently useless for the purpose of flight. In various parts of the world species belonging to one or other of three of these genera, namely Crataerina, v. Olf., Myophthiria, Rond., and Brachypteromyia, Will., infest Swifts (Micropus, Collocalia, etc.) and their nests; while the solitary representative of the fourth genus Stenepteryx, Leach, at present known is similarly parasitic on the House-Martin (Delichon urbica, L.), which, though in no wise related, is closely associated with the Common Swift in the popular mind.

A Ciliate, which seems to be new, has recently been discovered in the caecum of cattle in Cambridge. Out of 8 cattle examined 5 were found to be heavily infected, while in 10 sheep and 4 goats there was no infection. I have given the name Buxtonella to the new genus that has had to be established, as it was through the kindness of Prof. Buxton, Director of this Institute, that I obtained the material in which it was first found. The specific name refers to the grooved ridge or furrow which forms the most conspicuous feature of this species.

In a paper read before the Royal Society of South Africa in September 1914, and published in 1915, I gave a brief description of a Herpetomonas that was found in great numbers in the cloacal mucus of Chamaeleon pumilus on Robben Island, South Africa. The flagellates were present in various stages of development in all the chamaeleons examined, i.e. about a dozen, at different seasons of the year. Attempts to cultivate the flagellates on blood agar failed owing to bacterial contamination of the media, and none were discovered in smear preparations of the lizards' spleen and liver or in blood films. Having found Herpetomonas in certain flies (Scatophaga hottentota) at that time, and it being well known that chamaeleons feed on insects, I concluded that the flagellates present in the lizard were probably derived from insects.

Broadly oval, 5·8 × 3·9 mm., slightly broader at the posterior third; rounded in front, the posterior border more flattened. Integument mammillate and with dorsal depressions and discs, and ventral grooves strongly recalling O. coriaceus (see Fig. 1). Numerous short white hairs scattered over the integument, and notably a ring of close-set clavate hairs round the base of each trochanter. Eyes absent. The half-gorged ♂ measures 6 × 4 mm.

The trematodes described in this paper were collected by Miss Reynolds and myself from Corvus insolens, a Burmese house-crow, specimens of which contained many parasites of different species, all being minute except in two cases. They were obtained by washing the intestines after opening them in luke-warm water in a large glass basin, whence they were removed by means of a pipette, being readily identified owing to their slight movements. Those occurring in the liver were obtained by teasing that organ in luke-warm water. Table I records the results of the examination of five crows for parasites. I am indebted to Miss Reynolds for the help she gave me in placing the material she collected at my disposal.

Sieboldiellina planariarum is a large astomatous ciliate parasitic in the gut of the freshwater Triclad Planaria torva. The writer's attention was first called to it at Cambridge in 1923 whilst demonstrating the structure of Planarians collected from ditches in the neighbourhood.

Habitat and Record. Six females, three of which were adult and of equal size and the rest small and imperfect, of a new species of Naobranchia, easily recognisable as being the only one as yet described in which the cephalothorax is definitely shorter than the trunk, were taken by L. Harrison Matthews on 7 viii. 1923 during his visit to Brazil, at Praia de Icarahy, Rio de Janeiro, on the gills of the Diodontid globe-fish Chilomycterus spinosus.

Leigh-Sharpe (1918, Parasitology, XI. p. 24) states that the alimentary canal of the male has no visible contents and quotes Wilson (1915) to the effect that there is never an anus. He (Leigh-Sharpe) makes three suggestions: (i) that the male never feeds, (ii) that it feeds on the spermatozoa of the dogfish or (iii) on the eggs of the nematode which infests the latter. It is unlikely that the copepod is capable of completely digesting the chitinous case of the eggs in a canal which Wilson (loc. cit.) states to be sparingly furnished with glands; but if there is to be no debris all material taken in must be completely digested and absorbed. If the male never feeds the mouth would degenerate as rapidly as the anus; the mouth and oesophagus are both well developed. That spermatozoa form the food is a suggestion which cannot be disproved except by observation of the living animal.

Habitat and record. The animal under consideration, a copepod of the Family Caligidae, has up to the present received three notices: by Norman and T. Scott (1906), A. Scott (1907), and T. and A. Scott (1913). (For further particulars see References at end of this paper, p. 409.) Norman and Scott stated that “the specimens were taken forty years ago on the dory by Laughrin, and by him sent to A. M. N.” Consequently, the specimens were forty years old before they were described, which would, even in the absence of other reasons, excuse a little scepticism as to the description. Scott gives a bare record of capture, with a copy of Norman and Scott's diagrams. These diagrams and the original of Norman and Scott are republished by Scott and Scott with the addition of a few errors. Considering these facts, and also that no satisfactory description is given of the appendages of the male, or of the maxillae or swimming legs of the female, and that the animal is very common, occurring on nearly every dory, I feel that there is some justification for a further description.

Several visitors to the Molteno Institute having expressed a wish for a description of certain cases in our Museum, and believing that the types of cases I have devised, with the aid of a local carpenter, may appeal to others desiring inexpensive cases or stands for similar purposes, I herewith append an account of them. The cases are intended for the reception of specimens that are not frequently shifted about.

The specimens herein described were obtained from the gills of Somniosus microcephalus Block, at Excursion Inlet, Alaska, in 1909. This shark is also the host of Onchocotyle borealis, the species most closely resembling the new species, and is known in European waters as the Greenland Shark. To quote Goode: “This species, also called by our fishermen the ‘Gurry’ or ‘Ground’ Shark, is a native of the Arctic Seas, but on our coast ranges south to Cape Cod, and in the Eastern Atlantic at least to England, while in the Pacific it has been observed from Puget Sound northward.”

Parasitology has now become a vast subject, and it is impossible for any parasitologist to have a complete knowledge of the classification of all the groups of parasites with which he may be expected, from time to time, to deal. Almost all helminthologists, for example, are obliged to confine their special studies to one of the main groups—one dealing chiefly with Nematodes, another with Trematodes, another with Cestodes, and so on. Even within these large groups many findit impossible to keep in touch with the literature concerning more than one or two special families. But whether the field they attempt to cover be large or small, it is probable that most parasitologists find the name of the host a very valuable clue to the identity of the parasite which they are endeavouring to determine. For some groups more or less comprehensive host-lists have been published from time to time, and authors frequently include such lists even in short memoirs, presumably for the assistance of their fellow-workers. In all probability many workers find it useful to attempt to compile for their own use some kind of host-list.

In a paper published in July 1924, Professor Brumpt has done me good service by criticising certain views of mine on the epidemiology of human trypanosomiasis (Brumpt, 1924).

1. Tick paralysis occurs in man, the dog, and other domesticated animals on the East Coast of Australia.

2. As far as is known, the disease in Australia is only conveyed by the mature female of Ixodes holocyclus. The immature stages and the male of this species of ticks are non-pathogenic.

3. A similar disease, induced in a like manner by females of other species of ticks, has been observed by various authors in South Africa, Canada and Crete.

4. A single tick, as shown by experiment, may cause fatal paralysis in man and the dog in Australia, the death-rate in dogs being very high.

5. The main symptoms of tick paralysis in Australia do not differ materially from those observed in other countries. They begin with loss of coordination commencing in the hind legs in dogs, the fore legs, head and neck becoming subsequently affected. Death in all cases appears to be due to respiratory paralysis.

6. The onset of symptoms has not been observed to occur in less than 5 days from the time the tick or ticks have attached themselves to a dog.

7. Some of the ticks do not produce paralysis and others do, as shown repeatedly from my experiments on dogs. This requires explanation. It does not depend on the time that has elapsed between the tick having moulted and its attacking the dog.

8. Paralysis has never been seen to occur when ticks were removed from dogs before the time when symptoms usually appear.

9. It is impossible to transmit the disease from affected to healthy animals by the inoculation of blood, cerebro-spinal fluid or nervous tissue. Nor can the disease be transmitted by the injection of the body contents of ticks removed from affected animals. The examination of the fluids and organs of affected animals has failed to reveal the presence of pathogenic organisms.

10. It is considered that the causal factor in the production of the disease is a tick-derived toxin, this toxin being secreted by the salivary glands.

11. During the process of engorgement the salivary glands develop greatly, pouring out a maximum amount of secretion during the 2 days before the female tick drops.

12. An emulsion of salivary glands of I. holocyclus proved to be toxic for when injected into a dog (Experiment V, p. 424) it caused fever, vomiting, etc. The salivary secretion contains anticoagulins. As Nuttall and Strickland found for anticoagulins, individual ticks may vary in toxicity.

13. The period which elapses between the attachment of a tick to the host and the first signs of an attack of tick paralysis cannot be regarded in the light of an incubation period; it is dependent on the rate and stage of the tick's engorgement.

14. If it be accepted that the causal agent of the disease is a tick-derived toxin, it remains to be shown how such a toxin is produced.

15. There is some evidence that immunity to the disease may be acquired after recovering from previous attacks.

16. There is no evidence of season having an influence on tick paralysis. It was induced experimentally both in winter (June–August) and summer (November–December) in Sydney.

Reference to the National Insect Collection at Ottawa shows that species of the genus Cuterebra have been collected in various localities of Western Canada at different times. Of these Cuterebra grisea Coq. is distributed throughout Manitoba, Saskatchewan, Alberta, North-West Territories and British Columbia. There is one record each of C. emasculator Fitch (determined by Aldrich as C. fontinella Clark), of which the locality is unknown, and of C. fasciata Swenk, from Peachland, British Columbia. The specimen of C. emasculator bears a note that it had been reared from a chipmunk, Tamias striatus lysteri Richardson. The remaining species, C. americana var. polita Coq., C. similis Johnson and C. tenebrosa Coq. have all been collected in British Columbia. There is but a single record from the Eastern Provinces and that a specimen of C. fasciata from Bathurst, New Brunswick, dated August, 1900. Altogether there are 22 specimens in the National Collection belonging to six species. Of these there are 11 specimens of C. grisea, which would thus appear to be the most prevalent species in Western Canada. The comparative paucity of specimens may be correctly attributed to the peculiarly shy habits of the species, the adults of which, according to information furnished me by Criddle, prefer rather dark situations, such as outbuildings, summer kitchens and the ground burrows of rodents. They occur on the wing from June to September and are probably to be found closely attendant upon the haunts of their rodent hosts. That the percentage of parasitism is not high is concluded from the fact that Parker and Wells (1919), in a careful examination of over a thousand rodents in Montana for possible infestation by the Rocky Mountain spotted fever tick, Dermacentor venustus Banks, found but two that were parasitised, each with one larva of C. tenebrosa.