The initial pathway of skin penetrating larvae of Strongyloides ratti inside the host is not systemic and could well involve local components of the lymphatic system. The experiments described were an attempt to detect an effect on immunity depending on whether larvae of a challenge infection were committed to a pathway through heavily primed or lightly primed lymph nodes. Female rats were immunised by subcutaneous injection into the right forearm of 1000 heat killed, or 1000 live, third stage larvae of S. ratti. Animals given living parasites were placed on a diet containing 0·1 or 0·2% thiabendazole 48h or 36h after ifection. Challenge infections of <100 larvae (‘exact’ doses) were applied on day 21 to either the right or left flank and, similarly, to controls that had received the anthelmintic but not the priming infection. Heat killed parasites elicited no response at all. Priming with live larvae stimulated a significant immunity (16% and 37% depression in 2 experiments), but there was no difference between rats whose challenge was on the same side as the priming dose and those which had the contralateral treatment. The significance of these results to theories of pathfinding in general, and to practical immunology, is discussed.

The ultrastructure of the spermatid and spermatozoon of Macracanthorhynchus hirudinaceus (Archiacanthocephala) was studied by means of transmission electron microscopy. The flagellum and nucleus in the spermatid gradually expanded simultaneously. The karyoplasm of the spermatid transformed into dense inclusions and a multibarrel structure, which were also found in the spermatozoan body. The multibarrel structure was located close to the flagellum and consisted of many irregular microtubes. The flagellum of the developing spermatozoon was observed in a concavity of the spermatid nucleus. The microtubule arrangement of the flagellum was ″9+2″. No mitochondria or acrosome were observed in spermatozoa.

Promising results in the colorimetric assay of potato-root eelworm hatching factor have been obtained with picric acid and with 3: 5- dinitrobenzoic acid. Both of the reagents are used for the assay of cardiac glycosides with which the hatching factor may have affinities.

1. A precipitate was formed at the oral opening, excretory pore and anal opening of the fourth stage juveniles of O. columbianum in the presence of immune serum in vitro, causing their immobilisation and subsequent death in large numbers. The precipitates failed to appear on these juveniles in normal serum or in saline; nor did they appear on the third stage juveniles on incubation in immune sera. Apparently the excretory-secretory products of the fourth stage juveniles of O. columbianum serve as antigen and play an important role in the stimulation of antibodies in the host.

2. Inactivation of the immune serum did not destroy the precipitin type of antibody, nor was it affected when the immune animals had been treated with cortisone.

3. Immune serum from animals receiving multiple infections showed a higher antibody titre.

4. The possible way in which the antibody acts on the fourth stage juveniles, causing their immobilisation and subsequent death, is discussed.

As a result of complaints received from farmers as to the presence of parasitic worms in sheep, an attempt was made during the period October 1923 to September 1924 (inclusive) to ascertain the distribution and relative abundance of the more usual parasitic worms inhabiting the alimentary canal of sheep in North Wales. Regular collections were made from the following centres:—Pwllheli, Carnarvon, Bangor, Conway and Llandudno, with a few records also from Colwyn Bay, Bethesda, Menai Bridge and Denbigh. All the sheep examined were slaughtered for food purposes, practically the whole being obtained from slaughter houses. Almost all had grazed for considerable periods on the farms in the district mentioned, at elevations varying from sea level to 600 feet.

The humoral response of guinea pigs infected with doses of 500, 1000, and 1500 infective Toxocara canis ova were measured by counterimmunoelectrophoresis and indirect haemmagglutination tests one to five weeks after infection. The antigens used in these measurements were prepared from adult T. canis. Counterimmunoelectrophoresis showed lower titres than haemagglutination method, but it was performed rapidly and with case. The possible use of these techniques for immunodiagnosis of human visceral larval migrans is discussed.

From the researches of Onchi and Nishio it is known that the encysted larva of Heterophyes nocens Onchi et Nishio is found in the Japanese mullet. H. nocens is closely allied to H. heterophyes v. Siebold, which is found commonly in. man, dog and cat in Egypt. It may be assumed that the larva of the Egyptian Heterophyes will be found likewise in certain fishes allied to the mullet. On the homeward voyage from my tour in Europe I examined some specimens of mullet in Port Said, for the purpose of finding the young larva in them, and was fortunate enough to discover encysted larva. I carried back with me some of these fishes fixed by formalin. After returning to Chosen (Korea) I examined the parasite, and found that it certainly belongs to a species of Heterophyes. Its morphological description is given in the present short communication.

Uptake and serosal transfer of the vitamins thiamine, riboflavin and folic acid have been studied in vivo in normal and parasitized rats infected with Hymenolepis diminuta (Cestoda).

Regional differences in intestinal uptake of all three vitamins in both uninfected and parasitized animals were not statistically significant.

In the parasitized intestine mucosal uptake and serosal transfer of thiamine were significantly inhibited, with increased mucosal accumulation of the vitamin as luminal thiamine concentration increased.

Apparent increased riboflavin mucosal uptake in parasitized animals, was not matched by the reduced serosal transfer, suggesting adsorption of the vitamin in the unstirred aqueous layers.

Mucosal uptake of folic acid increased in the parasitized gut; serosal transfer and mucosal accumulation were not affected.

These results, indicating vitamin malabsorption associated with infection by H. diminuta, are consistent with the parasite inhibiting mucosal passive transport mechanisms. This conclusion is supported by the changes in net water fluxes associated with vitamin uptake in the parasitized intestine.

Twenty-three (9%) of 255 domesticated dogs surveyed in Lahore, West Pakistan, were blood positive for microfilariae. Twenty-one (8·2%) had either pure or mixed infections with Acanthocheilonema dracunculoides. Dirofilaria repens microfilariae were present in 4 dogs and one had Dirofilaria immitis microfilariae. A single adult A. dracunculoides was found from the hind leg of an autopsied dog with A. dracunculoides microfilariae. Microfilariae had a diurnal periodicity in this animal. There is only one previous documented report of A. dracunculoides adult worms from a dog in the Indian subcontinent, but it is possible that microfilariae earlier described from India under other names may also have represented this species.

Thirty-eight spotted ground squirrels, Spermophilus spilosoma were examined for endoparasites, and 31 of them were infected with one or more species. Helminths found were Hymenolepis citelli, Citellina triradiata, Physaloptera massino, and Trichuris sp. The protozoan Eimeria larimerensis was also found. Citellina triradiata is redescribed. This is the first report of any helminths from this squirrel.

In order to investigate the experimental transfer of Paragonimus westermani from rodents to rodents following subcutaneous and intraperitoneal routes, 13 rats and 23 mice were inoculated with a total of 115 (1 mature and 114 immature) worms of P. westermani subcutaneously and intraperitoneally. The age of worms before transfer was 25–193 days. The transfer was performed immediately after worm collection from rodents which were killed at various intervals from 4 to 144 days after infection. The location, development and size of worms were recorded. An infection rate of 58% (or 21/36) was demonstrated in rodents after experimental transfer of P. westermani by intraperitoneal and subcutaneous routes. Twenty-seven worms were recovered, giving a worm recovery rate of 23.5%. The rate was significantly higher by the subcutaneous route (34.8%) than by the intraperitoneal route (20.7%) but no difference was found between mice (23.9%) and rats (23.0%). The sizes of worms in the abdominal cavity, pleural cavity and thoracic muscles of mice, and in the leg muscles of rats were much less than in the pleural cavity and lung cysts of rats. A mature worm (7×5 mm) and numerous eggs were found in the uterus and pleural cavity of one rat. It is evidence that these rodents are unfavourable definitive hosts of P. westermani, because the worm size, infectivity, maturation and egg production are usually very low. However, the worms are usually widely distributed in their rodent hosts and remain small in size for a long period. Therefore, these rodents are good paratenic hosts for P. westermani and can play an important role in infecting cats and dogs with P. westermani in the laboratory.

The structure and affinities of the progenctic larva of Echinobothrium reesae Ramadevi, 1969, are described and discussed.

Hexatylus viviparus, a spear-bearing nematode superficially resembling Aiiguillulina dipsaci, was originally described by the writer (1926) from a diseased potato tuber. In a second note published the same year (1926a), further details of its structure were given; the organisms in this case being obtained from a gladiolus corm affected with an internal soft rot.

Since the appearance of these papers the writer has encountered this species on several occasions both in potato tubers and gladiolus corms. The receipt of a gladiolus corm in February, 1937, the brown rotten centre of which contained numerous specimens of the worm, provided further material for detailed observations on the structure of the worms. Some of the decayed central tissues of the corm also served as an inoculum for the cultivation of the nematode, along with a fungus, on slope cultures of a malt extract agar. Subcultures from the original slopes have been made from time to time and on these the worms have been successfully maintained for more than twelve months.

Oxysomatiinae: Sexual dimorphism not marked; mouth with three lips; body delicate; pharynx short and muscular; females with ovaries much reduced, uteri divergent, amphidelph, contain a reduced number of eggs arranged in moniliform manner and towards the centre eggs with well developed larvae or even free larvae may be present; vulva behind middle of body; males with subequal or equal spicules of moderate size; accessory piece present. Parasites of amphibians and reptiles. Type species: R. simples (Travassos, 1925) Travassos, 1927.

In order to characterize GATA transcription factors in Echinococcus granulosus, a PCR-based cloning strategy was developed. Degenerate oligonucleotides were designed for the most conserved sequence in GATA proteins that include 20 amino acids of the zinc domain. A 60 bp fragment was isolated that had high homology among this sequence and those reported in other species. An analogous sequence was obtained by performing the same procedure with DNA from the free living platyhelminth Dugesia tigrina. High stringency Southern blotting experiments confirmed the presence of this sequence in the parasite genome.

A brief description has been given in an earlier paper (Goodey, 1943) of damage to tulip bulbs caused by the stem and bulb eelworm, Anguillulina dipsaci. In April, 1944, an opportunity arose, through the good offices of Mr. J. Oldnall Page, of Spalding, Lincs., of visiting a field in his district, in which eelworm-affected tulips were growing. Two of the varieties inspected were in flower and the other two were in an advanced bud condition. All four varieties exhibited marked symptoms of attack, and in the case of two of them in which there were a considerable number of plants, the damage caused to the blooms would entail a distinct financial loss to the grower. The largest planting consisted of the variety “ Rijnland,” the next largest was the variety “Wonderful.” In addition to these there were smaller plantings of “ William Copland ” and “ Mrs. Farncombe Sanders.” In all four varieties evidences of attack were apparent on leaves, stems and flowers and, in general, the writer can confirm the findings of Chitwood and Machmer (1942) on the symptoms manifested by the growing plant. They mention longitudinal splitting of leaf, flower-stem and corolla. It may be well, however, to attempt a more detailed description of the chief symptoms and types of lesion shown by affected plants: see also the two photographs accompanying this paper.

On the 17th September, 1964, a Mute Swan, Cygnus olor (Gmelin) was received for examination. It was a male bird, estimated to be about three years old, which had been found at Henley-on-Thames, Oxfordshire, and had been killed on account of a broken wing which had healed badly. It was believed to be of wild stock.

1. An Athesmia sp. from two species of jackals (Canis adustus Sundervall, 1846, and Canis mesomelas Schreber, 1775) in northern Tanzania is described.

2. While considerable variation in size and internal morphology was observed, these differences do not appear to be significant.

3. There being no constant morphological features to establish a new species, these specimens are for the present considered to be A.foxi Goldberger and Crane, 1911.

4. The difficulties in the identification of Athesmia are discussed and the present position in the genus briefly reviewed.

5. Histopathological studies were carried out with negative results and reference is made to other reports of such studies in the literature.

Four muscle groups are responsible for the eversion and retraction of the apical denticles and enlarged pseudolabia in Skrjabinoptera goldmanae (Nematoda: Physalopteridae), which occurs in the lizards Chlamydosaurus kingii, Pogona spp. and Varanus gouldii in Australia. These muscles enable the nematode to bury its anterior portion in the gastric submucosa of its hosts. They comprise three sets which are derived from the somatic musculature and are inserted in the oesophagus and associated organs, and a fourth set of muscles which appears to be derived from the muscular oesophagus itself. These accessory muscle groups are described and illustrated, and from this their mode of action in everting and retracting the pseudolabia is derived. Possible selection pressures which led to their evolution are reviewed.

In 1927 and 1928 Hiraishi published some observations which he had made on Ascariasis in swine in the absence of Vitamin A. He claimed that he had been successful in overcoming the resistance of the pigs to the human strain of Ascaris lumbricoides by lowering the vitamin A content of the diet and that he was able to produce much heavier infestations with Ascaris lumbricoides of swine origion in A-avitaminosed pigs. As all other factors were apparently controlled, he draws the conclusion that vitamin A has a direct bearing on the susceptibility of the pig to infestation with round worms. Unfortunately these publications are not readily available in England and only summaries of results have been available to the present writer. But from the data given and in comparison with the effect of the vitamins on Ascaridia (Ackert et alia, 1929 and 1931 a & b) and on hookworm (Foster & Cort, 1931 and 1932), these conclusions would seem to be justified.