The genus Dujardinia was proposed by Gedoelst (1916) for the reception of a form considered to be identical with Ascaris helicina Molin, 1860. In the same paper another species, Ascaris nigra, was described by Gedoelst, who mentions that it has close affinities with A. helicina, but does not actually refer it to Dujardinia. The present writer (1920) assigned Ascaris halicoris Owen, 1833, to this genus. More recent work renders it somewhat doubtful whether this species really belongs to Dujardinia, for reasons which will be pointed out later, and though for the present it is retained, it must be regarded as a somewhat aberrant form.

Examination of scrapings from the gingival space at the base of the teeth of 50 coolies in the District Hospital, Kuala Lumpur, Federated Malay States, revealed the presence of the following parasitic protozoa: Entamoeba gingivalis (Gros, 1849) Brumpt, 1913, and a species of Trichomonas. Most of the coolies were patients in the malaria wards, and in no case was the patient in hospital for any kind of mouth affection. Since a fair body of evidence has already accumulated against the pathogenicity of E. gingivalis, and none for it, no special consideration was given to this point (Goodrich and Moseley, 1916). A very cursory review of the dental condition of these patients produced nothing in conflict with such evidence. Some of these coolies keep their mouths very clean: most of them cleanse their teeth daily, but they use no disinfectant. The Indians make use of charcoal and the Chinese of powdered cuttle-bone. The habit of chewing sirih, very prevalent among the Indians, seems to be without effect on the mouth protozoa. Both species were found in mouths deeply stained with the betel juice, and on one occasion together with a wad of the chewing mixture.

For the opportunity of studying this collection of round-worms from Zanzibar I am greatly indebted to Mr W. Mansfield-Aders, Economic Biologist to the Zanzibar Government.

When Prof. E. Hindle took over the direction of the Biological Laboratory of the Egyptian Government School of Medicine, Cairo, he found there a large collection of parasitic worms, most of which had been accumulated by Prof. Looss while in charge of the Laboratory for a number of years prior to the Great War. As a large proportion of this material was unnamed, and as the named portion of it contained many specimens possibly of considerable value as original types or co-types, which had been in a neglected condition for some time, it was thought advisable to send duplicates of the collection to England, in order that part of it might be kept there in safer custody. It was also felt to be desirable that arrangements should be made for the examination and determination of the contents of the unnamed part of the collection.

In May 1921 and again in February 1923 a specimen of the copepod Acartia clausi Giesbrecht, from which was emerging a parasitic trematode, occurred in the townets. The first, taken between Rame Head and the Mewstone, outside Plymouth Sound, was a full grown female Acartia, nearly dead, which had the skin broken between the first and second segments of the metasome where the trematode was emerging. The second, taken close to the shore from near the mouth of the Cattewater, was a full grown male which was alive but the skin was broken between the cephalosome and metasome where the trematode was emerging in a similar way to the first.

The following is a continuation of the foregoing Report (Parasitology, xv, pp. 1–13). As in the first part, the numbers are those given to the original tubes at Cambridge.

The problem of sperm disinfection in mammals is not only interesting from the biological standpoint. It is of practical value especially in the horse-breeding industry.

The bursate nematodes here described have been obtained from three sources: (a) Dr F. W. O'Connor permitted me to deal with his valuable collection from Samoa and the Ellice and Gilbert Islands; (b) Sir Arthur Keith and Mr Burne allowed me to collect and examine certain Strongylata parasitising a gorilla whose body had been placed at the disposal of the College of Surgeons, and to compare them with Cobbold's type material from the ostrich; I am much indebted to these gentlemen for their aid; (c) my own Indian collection, supplemented by a gift from Professor Gedoelst, has furnished the remainder of the material.

As in Parts I and II of this Report (Parasitology, xv, pp. 1–23) the numbers are those given to the original tubes at Cambridge.

The economic importance of Trematode infections of mammals has been, and is still, felt even in this country. Epidemic liver-rot in cattle and sheep is probably one of the most serious epidemic diseases with which veterinarians have had to deal and its ravages have, on occasion, been severe. Bilharziasis in cattle is possibly of considerably less importance and, so far as I am aware, has never become endemic in this country. As pathogenic agents the Amphistomes are of third-rate importance.

In 1918 Southwell and Baini Prashad1 published a description of an unsegmented Cestode parasite—Ilisha parthenogenetica—which they discovered in the “mesentery” of the common edible Indian Shad, Hilsa ilisha. This minute parasite, according to these authors, “appears to be of very great systematic importance, and…further reproduces itself in a manner not before known amongst the Cestoda.” In justification of these general remarks, they make, among others, the following statements: (1) the parasite, though of the well-known Piestocystis larva type, becomes sexually mature and resides in a cyst formed from the tissues of the mesentery; (2) these cysts are so numerous in every individual fish examined that the mesentery becomes transformed into “a massive liver-like organ in which the various coils of the intestine appeared merely as tubes embedded therein”; (3) though two lateral main excretory canals are described, yet there is no terminal excretory aperture: the excretory system “is closed in all stages of [the parasite's] life-history”; (4) the whole of the parenchyma is “filled up with enormous numbers of minute egg-cells. Besides the eggs, morulae and other higher stages in the development of the young were also present in the intima.” In other words, the egg-cells “develop in the body of the parent to form young worms identical in structure and appearance with the parent”; (5) the young worms “escape through a temporary aperture which is formed in the middle of the rostellum, anteriorly,” and, when the old cyst has been ruptured, they become “scattered in the mesentery, the [new] cyst not having been secreted at this stage.”

Trypanosoma melophagium Flu, 1908, is a parasite of European domestic sheep (Ovis aries L.), in the blood of which it occurs in very scanty numbers and can be detected by the cultural method. In England it has been found in 80 per cent, of sheep examined.

The infection is of fairly short duration and does not produce an immunity in sheep, since the latter can easily be re-infected. In all probability T. melophagium produces no pathological effect in sheep, and is incapable of infecting laboratory animals.

Morphologically the sheep-trypanosome is closely allied to the cattle-trypanosome, T. theileri.

The intermediate host of T. melophagium is the sheep-ked, Melophagus ovinus L., in the alimentary canal of which it passes through a definite cycle of development ending in the production of infective forms (metacyclic trypanosomes) in the hind-gut of the insect.

The mode of transmission is contammative, the sheep acquiring an infection by ingesting the ked. Infection of sheep did not result from the bite of the ked, through abrasions of the skin, or from inoculation of cultures of the trypanosome.

T. melophagium is easily cultivated at 30° C. Its evolution in cultures is similar to that in the invertebrate host.

In January, 1921, I published in Parasitology (Vol. xn. No. 4, p. 337) a brief description of what appeared and still appears to me to be a new species of Porocephalus, and I commented upon the fact that this species exhibited “the most marked form of sexual dimorphism yet discovered in the Linguatulidae” and is therefore of some interest. Two writers have recently questioned the validity of this new species. Alcock1 suggests the possibility of my female specimen of Porocephalus pomeroyi being an individual abnormality, and Sambon2 unhesitatingly decides that its peculiar form is merely due to “constriction” and deformity, and records the species as a synonym of his “Armillifer annulatus” —the Pentastoma (Porocephalus) annulatum of Baird, 1853.

In a recent contribution to Parasitology (present volume, p. 26) a short description of the male of this species was given. The type-material consisted of a single male from the Silurid fish, Heterobranchus anguillaris, from Cairo. Through the kindness of Dr W. N. F. Woodland, of the Wellcome Bureau of Scientific Research, the writer has recently had the opportunity of examining further material belonging evidently to the same species, the host being Synodontis eupterus and the locality Khartoum. This material consists of several males, one mature and two immature females, all mounted as microscopic preparations in glycerine-jelly. A few further details may now be added to the description of the species.

A short description is given of an important disease of sheep (Scrapie, Traber-krankheit, La Tremblante), believed to be caused by a heavy infection with Sarcocystis tenella, probably of increased virulence.

The itchiness and paresis, the congenital transmission by the mother, the non-contagiousness, the long incubation period, etc., are readily explained on this view and a method of control of the disease based on this theory has been highly successful.

The sarcocyst has been shown to be transmitted from sheep to sheep by intrauterine infection and by means of the milk.

The minute structure of the sarcocyst is described and it has been shown in particular that the sickle-shaped spores are surrounded by a capsule. Under certain conditions, as in 1 per cent, glucose water and in the centre of the ripe cyst, these spores swell out and become globular, eventually bursting and scattering small chromatin granules. The further evolution of these granules is dealt with.

The spread by means of milk and by the intestinal route is discussed1.

Most of the published descriptions of R. prowazeki in lice have dealt with the minute round, oval, diplococcal or dumb-bell forms found by Ricketts and Wilder (1910), Sergent, Foley and Vialatte (1914), da Rocha-Lima (1916), and others.