1. A technique is given for the detailed study of living cercariae in which reference is made to the value of human or horse blood serum as a mounting medium.

2. As a fixative agent for cercariae prior to staining the use of hot lacto phenol solution is recommended.

3. A description is given of three non-furcocercous cercariae obtained from Bullinus contortus in the Sudan.

1. Anopheles amictus in North Queensland is a favourable intermediate host for Wuchereria bancrofti, comparable but perhaps not quite equal to Culex fatigans. The two described varieties of A. amictus were both tested.

2. Experiments with Aëdes vigilax and Culex sitiens show that the former is a rather poor host and the latter a very poor one though infective larvae develop in some mosquitoes.

3. In experiments with Aëdes argenteus none of the sixty-two mosquitoes used proved hospitable.

4. Some observations on the transmission of filariasis in New Britain and on mosquitoes there are mentioned.

Nine attempts to infect kittens directly with E. histolytica macacorurn by means of amoebae (per anum) or cysts (per os) in the faeces of 2 M. sinicus (Polo and Susanna) and 1 M. rhesus (Jacko), were wholly unsuccessful. Four similar experiments with cysts (per os) from another M. sinicus (Bonar) gave 2 positive (Kittens 28 and 31) and 2 negative results.

Attempts to transmit strains of E. histolytica macacorum from one species of Macacus to another have been uniformly successful.

A strain (D.) of E. histolytica, derived from a man suffering from acute amoebic dysentery, has been cultivated in vitro continuously for 5½ years.

(i) The fact has been confirmed that strains of E. histolytica which, when newly isolated, are infective for kittens, may lose this infectivity after continued cultivation in vitro.

1. Three trichomonads have been cultivated and studied, T. hominis, Trichomonas sp. from M. nemestrinus (= R.T. strain), and T. batrachorum from English frogs and toads.

2. A number of strains of T. batrachorum were cultivated over periods varying from two weeks to five months without the appearance of a Eutrichomastix stage.

3. The division process of T. batrachorum has been studied. The new basal fibre arises as an outgrowth from the blepharoplast. The old axostyle is absorbed and new ones are formed from the daughter blepharoplast during the telophase. Six chromosomes appear during the prophase. Spindle fibres do not appear. There is a separation of the daughter blepharoplasts into centro-some and basal granule at the metaphase.

4. Division of T. hominis and Trichomonas sp. from M. nemestrinus is essentially similar to that of T. batrachorum. The number of chromosomes appeared to be five or six. Double individuals were found in the cultures, and in T. hominis individuals containing four or six sets of organellae. Their significance is obscure.

That ducks are subject to infestation by sarcosporidia has long been known. It seems to have been emphasised particularly because ducks afforded one of the first-known instances of the occurrence of these puzzling protozoa in birds. Very few new records have been published until now and no adequate illustrations of the gross features of the infestation have appeared. A general review of the subject and presentation of additional cases, with illustrations, therefore seems desirable.

The histological changes in the gut of Chrysops silacea during the digestion of blood are the same as those described by Cragg in Tabanus.

Digestive enzymes are confined to the posterior half of the mid-gut. They comprise an active invertase, a weak amylase and an active tryptase and peptidase. These results are compared with those in Glossina and Calliphora.

The functions of the crop are discussed.

Little is known about the trematode fauna of India. Hitherto no species has been described from an Indian tortoise except Polystomum kachugae Stewart. In the present paper I describe a new genus Spinometra from a tortoise, and in the systematic account of the family Lepodermatidae I include new observations on other genera which I have studied and which I shall describe in subsequent papers.

1. Experiments on the liberation of cercariae from their snail hosts have shown that under normal conditions C. limbifera (Seifert) and Cercaria “Z” n.sp. emerge during the day-time only, while in C. cambrensis I (Wright) the emergence takes place during the whole twenty-four hours, but considerably more so during the night-time.

Continual darkness causes a decrease in the numbers emerging, and a lowering of the temperature partially or completely checks the escape of the larvae.

In Cercaria “Z” there is a double maximum between 11 a.m. and 4 p.m. in the numbers liberated.

The invasion of L. truncatula by the larval stages of Fasciola hepatica leads to the disintegration of the host's tissues, the appearance of black pigment and the reduction of the liver cells to a thin layer of protoplasm containing the nuclei.

The entry of blood pigment into the tracheal system after a large meal, previously described in Glossina, has been shown to be an artefact of fixation.

The genus Astiotrema Looss is parasitic in reptiles (tortoises and snakes), except Ast. impletum Looss, which is known from a fish Tetradon fahaka. Hitherto three species of this genus have been recorded, two from Egypt and one from Naples (Italy). The present paper contains an account of two more species obtained from tortoises at Allahabad. The allied genus Glypthelmins Stafford is parasitic in Amphibia in North America.

It is presumed that the majority of investigators who dissect anopheline mosquitoes for the purpose of detecting the parasites associated with malarial fever are not concerned with the finer details of anatomical relationships. Nor do they take the time to completely isolate the two acinus glands with the accompanying normal six lobes. This latter is assumed not essential in a search for protozoan organisms, as the sporozoites may be found in the torn portions of the acinus material as well as in the muscular tissue and mounting fluid in which the dissection is made.

1. Embadomonas blattae a new species from the hind gut of Blatta orientalis is described. The flagellate measures 6–9 μ × 5–7 μ and the cysts 5–6 μ × 4–5 μ.

2. An Embadomonas from Rana temporaria, Bufo vulgaris, and Salamandra maculosa has been cultivated and described. I propose to call it E. dobelli. It differs from other known species of this flagellate in shape, and in absence of a definite karyosome. The flagella and their basal granules are duplicated first at division, and a centrodesmose is formed between one of each pair of basal granules. The cytostome disappears and new ones are reorganised after nuclear division is completed. Definite chromosomes were never seen. Double individuals and occasionally individuals with three nuclei were seen.

3. Cysts of E. dobelli were obtained in culture. They are uninucleate. A karyosome is formed; the peripheral chromatin of the nucleus stains intensely and becomes elongated. The lip of the cytostome can often be distinguished, and sometimes the glagella. These cysts are the same as those described originally by Dobell as cysts of Eutrichomastix batrachorum and Trichomonas batrachorum.

4. Cysts of Trichomonas batrachorum have never been found in faeces or in cultures.

It is perhaps well known that the males of the genus Phlebotomus are purely “sexual forms,” i.e. their main function in life being to fertilise the females; they die after having copulated. In laboratory-bred strains of argentipes, it was found that the females were sought by freshly emerged males. I have observed that when a male approaches a female he sways his slender abdomen to and fro laterally and when close to her an unerring lateral swing of his abdomen links the two horizontally through the agency of the male terminalia. The couple remain in this horizontal position facing oppositely with the wings of the male placed ventrally to those of the female for about a minute, after which the insects separate. In several instances a couple in conjunction was seen to move or make short flights in a direction at right angles to their line of linkage.

The description of the species is made from specimens mounted on slides, which were given to me by the late Dr J. Waterston for examination. As all the specimens were flattened and very much distorted by the pressure of the coverslips, it was impossible to determine whether they belonged to one of the known species. Permission having been received for their remounting, the following method was adopted. The slide was placed in xylol and, after the Canada balsam had dissolved, the specimen was transferred to fresh xylol and then to absolute alcohol. In this medium the wings were detached and, after being cleared in oil of cloves, mounted on a slide. The wingless body was passed through spirits of diminishing strengths to water, and then to caustic potash, and boiled. During boiling the specimens become soft and acquire their natural form. If any parts of the body are still distorted after the boiling they may be restored to their natural position with two dissecting needles. This method of remounting gave a very satisfactory result, although the specimens had been mounted more than 10 years. The further manipulation, together with the morphology of the genus, have been described elsewhere (Jobling, 1930).

That parasitic worms may induce bacterial invasion from the intestine has frequently been asserted in explanation of the sporadic occurrence of some bacterial and virus diseases of animals. Weinberg, in 1907, gave an extensive review of the literature dealing with inflammatory conditions of the intestine, due to bacterial invasion associated with parasitic worms. He also gave an account of some original clinical observations. He concluded that, by biting and boring into the intestinal wall, or by wounding it with hooks and suckers, the majority of helminths favour the penetration of microbes, these being carried on the exterior and in the intestine of the worms. In one case, where a fatal septicaemia was associated with the presence of a single individual Trichocephalus, the author's conclusion, that even isolated worms are very dangerous, appears to be rather strained. Records of clinical observations of this kind frequently appear in the literature, but, as a general rule, the evidence showing the agency of the worm is very slender and amounts to little more than the observation of the presence of worms in animals suffering from some bacterial disease.

Four specimens of this trematode were obtained from the small intestine of Kachuga smithii in December 1929. Two of the specimens were not sexually mature; for thought they possessed well-developed testes, ovary and a very small receptaculum seminis, they lacked the uterus and ova. In one of these immature specimens the vitellarian follicles were very feebly developed.

Since I published (1925) a description of this interesting new species of a Caryophyllaeid, Woodland (1926) has suggested that the bodies which I described as post-ovarian vitellaria (1925, p. 233, fig. 2, p.ov.vit.) are in reality ovarian follicles, and that, therefore, the worm is a Lytocestus and not Caryophyllaeus. Southwell in his papers (1928 and 1930) has embodied my original description of this worm and has concluded the description by referring to Woodland's remark regarding the post-ovarian vitellaria, without definitely assigning the species to the genus Lytocestus. With additional material at my disposal, it was possible to re-examine its anatomy, and I have found that the bodies described and figured by me as post-ovarian vitellaria are in reality ovarian follicles. I also take this opportunity of publishing a more complete and, I hope, a more accurate description of its general anatomy.

Three species of furcocercariae are described. By means of direct animal experiment with secondary, intermediate and final hosts I have shown that one species develops into Tetracotyle typica Dies., the larva of Strigea tarda Steenstrup, and a connected detailed account of this life cycle is here given. Of the two other species, both of which are new, I have been able to trace the development of one into Tetracotyle n.sp. in Planorbis crista L., and P. albus Müll. Feeding experiments with this new Tetracotyle using ducklings as final hosts failed, however, to produce the corresponding adult.

Effect of the parasite on the host. The usual results of helminth infection of this nature are observable, namely, marked disruption of liver tissue and in many cases complete parasitic castration of the molluscs infected.

Double infection. In the course of my investigations on larval Trematodes I have met with one example of double infection with sporocysts, viz. Cercaria F.1 and F.2, within one and the same individual of Planorbis albus Müll. This condition was found only on one occasion, Cercaria F.1 being in predominance. Instances of double infection have been recorded by Faust (1971) and Sewell (1922), and from this country by Hesse (1923) and Brown (1926). The condition, however does not appear to be a common one.

Le nombre des espèces d'Hémiptères, hématophages, entomophages ou phytophages, attaquant l'homme, habituellement ou occasionnellement, est assez considérable (voir en particulier E. de Bergevin, Les Hémiptères suceurs de sang, Archives de l'Institut Pasteur d'Algérie, 3, 28–44, 1925, et J. G. Myers, Facultative blood-sucking in phytophagous Hemiptera, Parasitology, 21, 472–80, 1929). A Ia liste déjà longue qui a été établie il convient d'ajouter la Nabis apterus Fabr. (= Nabis lativentris Bohemann) qui jusqu'à présent avait été considéré comme inoffensif pour l'espèce humaine. Or l'année dernière, au mois de septembre, dans une petite localité du canton de Berne (Suisse), un individu de cette espéce est venu se poser pendant Ia nuit sur le cou d'une personne et lui a implanté son rostre dans la peau, cela, non pas pour se défendre, mais, semble-t-il, pour se repaître du sang de sa victime. La piqûre a provoqué une douleur assez violente, analogue à celle d'une guêpe, qui a été suivie de prurit et d'une légère intumescence de la peau. Les effets de la piqûre, probablement atténués par l'application d'ammoniaque, ne se sont fait sentir que quelques heures.

Emended descriptions of the female of Ascaridia hermaphrodita (Froelich 1789) and of the male of Wellcomia evoluta (Linstow 1899) are given. The female of A. hermaphrodita is described in full as a description of it does not appear in the literature. Several corrections are made of errors found in descriptions. Especially noticeable is the illustration of the male tail of W. evoluta by Yorke and Maplestone (1926), p. 197, (fig. 131 E) which they wrongly label “Posterior extremity of female (After Hall).”

Further evidence is furnished upon the probable life-cycle of a species of the genus Eustrongylides in showing that pre-adult stages of E. wenrichi Canavan 1929 have been found encysted in a fish, as well as in a frog and amphiuma (“Congo eel”); the adults of the worm were found in a Canadian goose. Thus confirming Jaegerskiöld in his opinion that fish are the intermediate host and fish-eating aquatic birds are the final hosts of the genus.

Superparasitism is shown to be of fairly common occurrence. Numerous records of new hosts are mentioned. Three worms that previously were found and described by the writer as new were found again. In each case they were encountered in new but closely related hosts to those in which they were previously found.

There are five new species and one new genus described and illustrated in this paper (II): Pharyngostrongylus brevis sp. nov. from a Bernard's kangaroo, Phascolostrongylus turleyi gen. et sp. nov. from a common wombat. Oesophagostomum vigintimembrum sp. nov. from an Arabian camel, Ascaris hippopotami sp. nov. from a hippopotamus and Diplotriaena bifidus sp. nov. from both blue-bearded and pileated jays.

Finally, there are 209 determinations of 39 genera and 69 species, including new ones, from 181 hosts involving 94 different host species.