1. Rana clamitans of New York and R. pipiens from the middle part of the United States, were found to be infected by a Myxosporidian, apparently identical with Leptotheca ohlmacheri (Gurley) Labbé, found by Ohlmacher in the kidney of Bufo lentiginosus.

2. The Myxosporidian was found only in the space between Bowman's capsule and the glomerulus of the Malpighian body and in the uriniferous tubules of the kidneys of the host, no other organ being infected.

3. The mature spore contains two independent uninucleate sporoplasms which fuse into one prior to the germination in the posterior region of the stomach or duodenum of a new host.

4. The germination of the spore was observed in hanging drop preparations with the digestive fluid.

5. The youngest stage found in the lumen of the tubule of the kidney, was the uninucleate form.

6. The trophozoites multiply actively by a process of gemmation and probably also by a schizogony of the uninucleate forms.

7. The trophozoites are, as a rule, disporous and the spores develop independently of each other.

8. The vegetative nucleus persists throughout the entire trophic life of the individual.

9. The Myxosporidian does not exercise any fatal effect upon the host.

10. Infection takes place through the mouth. The liberated binucleate amoebulae probably penetrate through the wall of the small intestine, reach the coelom and are carried to the uriniferous tubules through the nephrostomes or blood vessels.

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.

1. Collections of flukes made in several centres in China include 25 species of cercariae.

2. Fourteen of these species are described as new.

3. Details of the excretory system are presented for six of the species described. In two of these instances (echinostome larvae and furcocercarjae) differentiation within thenatural group is demonstrated, while in two other larvae, C. styloidea and C. diophthalmica, proof of relationship and correlation with adult groups is established.

4. C. abbrevicauda shows striking resemblances to the larva described as the cercaria of Paragonimus westermanni and may possibly be regarded as identical with the larval stage of that worm. Moreover, the host genus is the same.

5. The stylet organ is shown to be non-specific and the group of the “xiphidio-cercariae” to be a composite of several natural families.

6. No organs of the cercaria save the cephalic glands and flame-cells have thus far proved satisfactory for differential diagnosis of the larva.

7. Further study along these lines will make it possible to demonstrate natural groups where only artificial groups now exist.

Lambs contract Moniezia infection either at or very soon after birth, since they have been observed to harbour adult worms at 2–3 months old and in one case, to pass proglottids at 4–6 weeks.

The intermediate host, if such exists, must be frequent on the pasture in early spring, otherwise lambs would not be found to harbour adult tapeworms so regularly or in such numbers when slaughtered in early summer. In the small intestine of a lamb from 3–4 months old slaughtered at Aberystwyth, there occurred 75 individuals.

The fact that lambs regularly harbour adult tapeworms before they are weaned suggests the possibility of their contracting the infection from the mother-ewes. No direct evidence in this direction has been obtained, however, and an attempt to produce a larval stage in the udder region of a ewe by feeding to it the eggs of a tapeworm proved abortive.

Hitherto, all attempts to produce the adult tapeworms directly by feeding the eggs to sheep have failed; there is, however, the remote possibility that the eggs require to undergo some kind of maturation process outside the body of the sheep before they will develop. The fact that several species of Moniezia occur in the domestic sheep would seem to require an intermediate stage, which would occur in a corresponding number of intermediate-host species.

The disease seems prevalent in flocks which are singularly free from ectoparasites.

The invertebrates which seem most likely to harbour an intermediate stage are coprophagous insects, etc. (beetles, flies, mites). Attempts to infect species of Aphodius have nevertheless proved fruitless.

Moisture favours the survival of the eggs of Moniezia: eggs kept in water for a period of several months seemed to remain perfectly viable. Nevertheless tapeworm is common among flocks on pastures about Rome which are characteristically dry.

A comprehensive series of experiments under conditions of the most complete control would almost certainly clear up the life-history; on economic grounds alone the problem is urgent.

The overwhelming majority of a quantity of worms collected from slaughter-houses in Aberystwyth, Aberdeen, Beauly (Inverness-shire) and Newcastle-on-Tyne proved to be of the species M. expansa. The only other species found were M. trigonophora and M. alba. The identification was based on anatomical characters and not on externals, which are useless.

The writer intends directing his attention to coprophagous mites as carriers, viz. Gamasus coleoptratorum, G. fimetorum, Macrocheles glaber.

1. Attempts to secure a micro-organism which could induce abortion or sterility in wild rats and which might be used in an anti-rat campaign, more especially when plague threatens a community, have not been successful.

2. An account, however, is given of certain micro-organisms producing pathological conditions in the genito-urinary tract of wild rats.

3. A routine determination of rat parasites including ecto-parasites, helminths, intestinal protozoa and haematozoa has been undertaken.

4. It has led to the discovery of a new species of Hymenolepis and has shown that Heligmosomum braziliense is present in rats in England. It has also demonstrated the occurrence of haemogregarines in the leucocytes of black rats in this country.

5. Work has been done on the incidence of Leptospira icterohaemorrhagiae in Rattus norvegicus and Rattus rattus in England and on the mechanism of its transmission.

6. It has been shown that apparently the guinea pig may act as a carrier of the Leptospira without exhibiting any marked symptoms of the disease which the latter produces. There is also some evidence to prove that infection may take place through the alimentary tract.

7. The Leptospira was successfully and easily cultivated in Wenyon's modification of the Noguchi method but in large measure lost its virulence as the result of repeated subcultures. Even after a year, however, it was still capable of producing characteristic symptoms in the guinea pig.

8. General pathological conditions occurring in wild rats have been recorded.

9. A few observations have been made on the seasonal incidence of pregnancy in wild rats.

This gregarine was found inhabiting the alimentary canal, and especially the midgut, of both larvae and imagines of Anobium paniceum. All the larvae examined, and most of the adult beetles, were found to be very heavily infected, and in some of the larvae almost every epithelial cell harboured one or more of the cephalont stages of the parasite (Fig. 1). The lumen of the midgut of these larvae was densely packed with the freely moving sporonts, and a number of newly formed cysts were visible in the hindgut. In the imago only the cephalont stages were observed, and no sporonts or cysts have been found.

When the 26th Madras Light Cavalry were reconstituted at Bangalore in 1903 the regiment was joined by a couple of squadrons of men from an Imperial Service Regiment in the north, and, after these men had been at Bangalore some months, many developed guinea-worms, our wards becoming filled with cases showing the worms in all stages of delivery. It took many days or weeks to wind out the worms and so many were broken in the operation that the number of men rendered unfit for duty became a serious matter. I consequently made enquiries as to methods employed for hastening the exit of the worm, since its rupture during extraction always led to severe suppuration.

In the summer of 1908 one of us (E. N. P.), whilst collecting material in the River Zeravshan in the vicinity of Samarkand (Turkestan), came across a case of adhesive peritonitis in a local fish, Schizothorax intermedius. The abdominal wall of this fish, with a part of the viscera adhering to it, were dissected out and placed in 70 per cent, alcohol where they remained untouched till 1919 when we proceeded to their examination. The results of our investigation are described in this paper. An examination of the excised parts shows a compact accumulation of tissue on the ventral side of the intestinal coils, in the form of a flat patch from which a series of fine strands run to the black peritoneal covering of the lower body-wall. The patch which shows irregular edges is coloured black and is covered with yellowish spots.

It has hitherto been firmly established from experience gained in the studfarms and by experimental investigations (Hertwig, Prince and Lafosse, Frasbot, Pench) that Dourine is transmitted almost exclusively through coitus. Flies take no part in the transmission of the disease (Laveran and Mesnil), however, the possibility of infection through the bite of fleas (Eabino-witsch and Kempner) or ticks, is not excluded, and was proved experimentally (Sieber and Gonder). Experiments conducted on rabbits and dogs (Rouget, Schneider and Buffard, Laveran and Mesnil) have shown that T. equiperdum is capable of penetrating through the intact mucous membrane of the eye and genital organs, but not through the alimentary tract. Manteuffel's experiments have shown that T. equiperdum can even penetrate through the intact skin.

In April of this year (1922) a specimen was sent to the Agricultural Department, Armstrong College, by Mr S. Giles of South Shields, along with a note explaining that it had been found “down in the first spit of the soil” in one of a group of allotments there. It was obviously a specimen of a leech, but the specimen was submitted later, to Mr John Ritchie, the Museum, Perth, who kindly identified the species as Trocheta subviridis, and who mentioned that “this gives so far as I am aware, a more northern habitat than hitherto recorded. See Parasitology, vol. III, p. 182.”

The phenomenon of tumours in the backs of cattle from which in due time grubs emerge has been known from very early times. So, also, has the phenomenon of “gadding,” now known to be due to Warble flies, and it is sufficient to cite the familiar and most graphic account given by Virgil. Since, however, the origin of the grubs in the tumours was entirely unknown and the “gadding” was usually attributed to members of the Tabanidae, allusions to these phenomena earlier than the 18th century have no value except as indicating the antiquity of the pests.

Students of the history of Protozoology are generally agreed that the earliest recorded observations on the Coccidia are those of Hake (1839). Bütschli (1882, p. 490) mentions his work, though he did not see it; and it has been cited by Leuckart (1879), Labbé (1896), and several other writers on the Sporozoa—including myself (1919)—as the first publication in which coccidia are recognizably described.

Melittobia is a chalcid, ectoparasitic upon a number of species of Hymenoptera and upon the pupae of certain flies. The insect was bred in the laboratory and the life-history is described in detail.

A number of experiments were made with regard to possible hosts and as to feeding and reproduction and certain points are of some interest.

For instance, the male apparently does not feed but the female uses her ovipositor with which she punctures the eggs, larvae or pupae of various insects, afterwards sucking the blood which oozes from the puncture. Such eggs, larvae or pupae, in spite of repeated punctures, may continue to develop.

Before beginning oviposition upon the surface of a suitable host, the female punctures the host one or more times with her ovipositor and apparently injects an anaesthetizing fluid, since insect larvae and pupae, upon which eggs have been laid, very rarely develop farther and yet remain fresh for a considerable time extending to many months.

With regard to reproduction, inbreeding appears to be normal, mating usually taking place between two individuals of the same brood and later between the female and one of her own offspring. Virgin females, unable to find a male, lay a few eggs, which always produce males, the first of which to emerge mates with the female.

The female is very prolific and may lay as many as twelve hundred eggs in two or three batches, mating taking place before each batch is laid. The last eggs of a batch are almost invariably male eggs, indicating that the female has exhausted her supply of spermatozoa.

A virgin female, whose eggs are removed so that she cannot rear a mate, may lay as many as ninety eggs during her life-time, her length of life being more than doubled, and such a female will survive through the winter, even withstanding frost, whereas fertilized females apparently all die in October or November at the latest.

All the eggs of a virgin female are apparently capable of developing and all such eggs produce males.

The parasite herein described was found in the intestinal contents of Blatta americana at Calcutta. A single specimen was observed.

LA litérature ne nous offre que des renseignements fort embrouillés sur les Acanthocéphales parasites intestinaux de l'eider (Somateria mollissima L.).Ces parasites furent decouverts par Phipps en 1774–1775 et décrits par lui sous le nom de Sipunculus lendix. Cependant, de la description et surtout des figures de cet auteur on voit bien qu'il ne s'agissait point de Sipunculides mais de vrais Acanthocéphales (Lühe, 1905). Plus tard, d'autres auteurs ont rapporté cette espéce comme synonyme d'Echinorhynchus polymorphus Brems

Ten years ago I made an attempt to summarize briefly the advances which had been made in our knowledge of parasitic worms during the preceding few years. The interval has witnessed much upheaval and interruption of scientific labour, but nevertheless a very considerable amount of work on the subject has been accomplished. The nature of this does not appear to have been influenced to any exceptional extent by the war.

At the request of Prof. G. H. F. Nuttall, F.R.S., the writer has attempted to put together a few notes on methods found useful in obtaining well-preserved specimens for helminthological purposes. Of the large number of methods that have been recommended for the various groups by different authorities, only a limited selection can be given, and preference is given, where possible, to those which are comparatively simple and can be employed in the field or under the limited conditions of a field laboratory, while at the same time experience has shown them to give sufficiently good results for ordinary purposes.

Lazzaro Spallanzani, one of the great natural philosophers of the eighteenth century, was born in 1729 at Scandiano, and was educated in Reggio and in Bologna where he came under the influence of his cousin Laura Bassi who was professor of mathematics and physics there. He was intended for the law but at the age of 28, having taken holy orders, he became professor of Greek, logic and mathematics in the College of Reggio. It was here that he began to interest himself in biological questions and by correspondence he became associated with Charles Bonnet and Haller in Switzerland. In 1760 he accepted a chair in the University of Modena where he remained eight years. This was one of the most fertile periods of his life for in addition to dissertations on Greek inscriptions, on problems in mathematics and physics he produced his epoch-making works on spontaneous generation, on the regeneration of lost parts and on the circulation of the blood. By the end of the Modena period he was elected F.R.S. and was known as one of the foremost scientists of his time. In 1768 he was appointed by the Empress Maria Teresa to be the Conservator of the Museum of natural history in Pavia and he held this post till his death in 1799. In 1776 he published his great Opuscoli di fisica animale e vegetabile and in 1780 Dissertazioni di fisica animale e vegetabile, works which must compel the most captious critic to range the Italian abbate among the greatest experimental philosophers of all time. In these works he dealt exhaustively with the problems of spontaneous generation, and the origin of the animalcules of infusions, the nature and origin of spermatozoa, the effect of stagnant air on animals and vegetables, the death and resurrection of animals, the nature of moulds, digestion and generation.