Artyfechinostomum Lane, 1915 (type A. sufrartyfex Lane, 1915) is a synonym of Paryphostomum Dietz, 1909 (type P. radiatum Dujardin, 1845). While the general morphology of the two forms is similar and places them both in the family Echinostomatidae, other characters clearly place them in different genera of this family. In Artyfechinostomum the cirrus-sac extends far posterior to the acetabulum, and the right and left fields of vitellaria in the post-testicular region are confluent. In Paryphostomum the cirrus-sac is small and anterior to the middle of the acetabulum and the vitellaria in the post-testicular region are not confluent. These differences entitle Artyfechinostomum to be placed in a separate genus. The species Paryphostomum indicum Bhalerao, 1931 and P. mehrai Jain, 1957 are transferred to the genus Artyfechinostomum.

While working on the life cycle of Cercaria mehrai Faruqui, 1930, the author obtained the adults from the intestine of experimentally infected white rats. The trematodes thus obtained were reported as belonging to the genus Paryphostomum Dietz, 1909. In view of the facts that the collar spines are 43 in number, the vitellaria are confluent in the post-testicular region and the cirrus-sac extends far behind the acetabulum, P. mehrai is transferred to the genus Artyfechinostomum Lane, 1915, which is, in author's opinion, a valid genus (Jain, 1959).

Azure A, azure B and Nile blue in both neutral and alkaline solutions were found to be suitable for use as indicator dyes in the Sabin-Feldman test. Toluidine blue, brilliant cresyl blue and thionine were also suitable as neutral solutions. Azure C, phloxine, phloxine B, neutral red, methyl green, pyronine Y, eosin and celestine blue were found to be unsuitable. Azure B and toluidine blue in saline solutions were serviceable up to 5 months after preparation. The significance of these findings is discussed.

This account is based upon the study of forty monogenetic trematodes belonging to the genus Calicotyle Diesing, 1850, found in the following hosts, locality and habitats:

1. The availability of Nematodirus infection to sheep was followed by grazing successive pairs of worm-free lambs on a contaminated plot. It was shown that lambs did not become infected during the summer following pasture contamination in the spring, but became infected when they were grazed on the plot the following spring.

2. The development and hatching of the eggs and larval stages of N. battus and N. filicollis were followed by the periodical examination of infected faeces set out during May-November. The results showed that development to the infective larval stage occurred during the summer, taking normally about 3 months, but that the larvae then remained dormant within the egg membranes until the following spring.

3. Laboratory studies confirmed the hypothesis that the hatching of the infective larvae was a response to a rise in temperature in the spring, following sensitization by exposure to low temperature during the winter. A rise in temperature to 50° F. was necessary before a high percentage hatch occurred.

4. The epidemiology of Nematodirus infection is discussed in relation to these observations.

The monogenetic trematode Discocotyle sagittata attaches itself to the gills of Salmo trutta with its long axis inclined to the long axis of the primary lamella to which it is attached, the direction of inclination being determined by the incidence of the gill-ventilating current of the host. The inclination is to some extent brought about by an asymmetrical disposition of the posterior adhesive organs, but Discocotyle appears to retain a primitive unspecialized character in that the asymmetrical disposition is facultative and not obligatory and permanent as in Axine.

The adhesive apparatus consists of four pairs of clamps and one pair of hooks. The hooks appear to be the persistent posterior hooks of the larva.

Each clamp is operated by an extrinsic muscle-tendon-fair-lead-hinged-jaws system generally similar but possibly less efficient than the corresponding system in Plectanocotyle gurnardi. Scheuring's and Sproston's interpretations of the clamp-closing mechanism of Discocotyle as a spring system are wrong.

Although the majority of rotifers are free-living, there are many records of rotifers parasitizing both plants and animals (Thompson, 1892; Budde, 1925; Remane, 1929). The most marked development of this parasitic habit is found in the genera Balatro, Drilophaga, Zelinkiella and Albertia. In these forms, with the exception of the genus Zelinkiella, attachment to the host is performed by the mastax. Albertia vermicularis Dujardin (1838) has been recorded as a parasite of the intestine and body cavity of earthworms. This author also found specimens in slugs, but he did not indicate the host species involved in either case. This original description was rather incomplete, and it is the object of this paper to expand it by a description of specimens from Allolobophora caliginosa.

1. The staining and morphology of E. parvum were characteristic of the genus Eperythrozoon. The diameter of the organism was approximately 250 mμ.

2. Visible eperythrozoa disappeared in 20 min. from infected blood incubated at 56° C., and in 12 hr. at 37° C. They persisted for several days at room temperature.

3. E. parvum was preserved for short periods at 5° C. and for longer periods at −30 and −79° C.

4. Splenectomized early-weaned piglets were experimentally infected by the parenteral and oral routes, and by means of the pig louse Haematopinus suis.

5. The mean prepatent period of 103 primary infections in splenectomized pigs was 9·7 days. Patent infections sometimes persisted for at least 36 days. One pig remained a carrier of E. parvum for 23 months.

6. A severe anaemia occurred in splenectomized piglets affected with E. parvum, but intact piglets were apparently unaffected.

7. E. parvum was susceptible in vivo to neoarsphenamine and oxytetracycline, but not to sulphadimidine, penicillin or streptomycin.

1. Ten strains of Ornithodoros moubata not fed as adults and never mated were exposed to dry air at 32·2° C. and the effect recorded by measuring the loss of weight and survival rates.

2. Two rates of water-loss were found and O. moubata may be divided into three groups on physiological grounds. Strains found in native huts in South Africa differ from all other tested strains by losing water in dry air at 0·16 mg. per day. All other tested strains lost water at 0·32 mg. (range 0·29–0·4 mg.) per day. The wild strains of the East African warthog and porcupine burrows are distinguished from the East African domestic strains by their ability to withstand prolonged starvation.

3. The initial mean weight of a strain in any of the groups has a considerable effect upon survival in dry air, the percentage survival (in 100 days tested) being directly proportional to the original weight of the ticks. Size of individuals could alone lead to ultimate survival differences of two months in different strains of the same form.

In a literature search for species of Pterygosoma it has been my good fortune to find a figure and Japanese description of Pterygosoma japonicum Kishida, 1927, in Figuraro de Japanaj, Bestej Tokyo, 1927, Hokurykan and Co. Ltd. This species has not been listed by the Zoological Record, and indeed it seems to have been completely overlooked in the West. Hence this re-publication.

The recorded parasites and predators of Meligethes aeneus (F.) and M. viridescens (F.) [Coleoptera: Nitidulidae] are given together with descriptions and illustrations, for the first time, of the post-embryonic stages of the hymenopterous parasites Diospilus capito (Nees) [Braconidae], Isurgus heterocerus (Thoms.) [Ichneumonidae], Isurgus sp. A, and Cryptoserphus parvulus (Nees) [Proctotrupidae]. The egg and first instar of Thersilochus sp. are described and figured, and a species of Zeteticontus mentioned. The antennae, propodea, and ovipositors of the two species of Isurgus are compared and the ovipositors of Diospilus capito, Isurgus sp. A, I. heterocerus and Thersilochus sp. are illustrated.

A protozoan (Gregarine), a larval mite and a nematode, none of which has been identified, are recorded inhabiting Meligethes adults.

A holotrichous ciliate found repeatedly in very large numbers in the body cavity of larval midges (Chironomus plumosus) from Paris and Berlin areas is described as a new species of the genus Tetrahymena, named T. chironomi sp.nov. It appears to represent a true example of facultative parasitism, since parasites released from the host survive in laboratory cultures, and free-living ciliates believed identical have been isolated from fresh-water sources in nature. Over a 3-month period more than 2000 larvae, principally fourth-instar stages, were examined; about 9 % of these were found to be infected with ciliates.

T. chironomi is the thirteenth species to be added to the growing holotrich hymenostome genus Tetrahymena. It is taxonomically distinguishable from other members of the genus on the basis of a combination of characteristics related to its morphology and bionomics. It is one of the smallest species, has 24–27 ciliary meridians and a relatively large, spherical micronucleus, does not exhibit dimorphism or cystic stages in its life cycle, and does not possess a caudal cilium.

1. The character of the scolex, the long filamentous neck and the morphology of the proglottids are features which justify the establishment of a new genus, Penetrocephalus, to accommodate the pseudophyllid species P. ganapatii (= Both-riocephalus ganapatii (Rao, 1954), B. penetratus (Subhapradha, 1955)) from the marine teleost Saurida tumbil Bloch, off Waltair, Bay of Bengal.

2. The anatomy of the female reproductive system is described in detail, and a preliminary interpretation of the histochemistry of egg-shell formation is given.

3. On the basis of histochemical tests it is suggested that Mehlis's gland, which surrounds the cellular ootype, secretes a phospholipid-like material which may aid in the release of shell precursors from the vitelline cells, but it does not form part of the shell. It appears also to be responsible for the synthesis of PAS-positive yolky matter found in these cells in the egg capsule. The functions of Mehlis's gland in helminths are discussed.

4. In a majority of helminths where the egg-shell is a quinone-tanned protein, it is considered that it is solely if not entirely derived from shell globules in the vitelline cells.

Iron-59 (as a ferric chloride solution or as a component of haemoglobin) was introduced into the lumen of the gut of Fasciola hepatica. It was detected by autoradiography in high concentrations in the intestinal epithelium, the cuticular epithelium, the myoblasts and the cells forming the walls of the excretory tubules. Carbon-14, introduced as l-phenylalanine-C-14, was concentrated in the same tissues, with the exception of the intestinal epithelium. These findings are discussed in relation to the function of the respective tissues.

1. The formation of Opalina cysts in Rana temporaria was compared, during September to December, in groups of untreated frogs exposed to normal seasonal fluctuations in temperature, and treated frogs kept at room temperature. Cyst formation was enhanced, to the same degree, in frogs injected with saline or chorionic gonadotrophin (Pregnyl), and, to a higher degree, in frogs injected with frog pituitaries.

2. Observations were made, during September to December, on the state of the testes in Rana temporaria infected with Opalina. The presence of Opalina cysts was most closely correlated with spermiation.

3. Possible factors affecting the formation of opalinid cysts are discussed. It is concluded that the seasonal production of cysts by Opalina is not due to cyclical changes inherent in the protozoa. The factor or factors provoking encystation appear to be correlated with the reproductive cycle of the host, and may be the gonadal hormones.

A new species of Amplicaecum is described from the carpet snake (Morelia argus variegatus) in coastal Queensland. It differs from all previously described species in this genus in that its host is a pythonid snake. It is the largest species yet described, and the spicules are about 3 times as long as in any other species. The genus Amplicaecum is tentatively re-defined and a key is given to the differential features of the recognized species. The view is expressed that before classification of these and related ascaridoids can be adopted, further information is necessary, particularly on (1) the phylogenetic significance of differential features already in use, and (2) on the existence of other more significant differential features.

1. Ixodes auritulus group of ticks and Ixodes percavatus group of ticks are both characterized by having the palpal article I drawn out to a horn anteriorly, but in the percavatus group there is a strong meso-dorsal ‘spur’ on this article, which is lacking in the auritulus group.

2. The mutilated types of I. auritulus and I. percavatus sp. revocata are re-described and electotypes established for both.

3. Variations from I. auritulus sensu stricto are described from Peru and Guatemala, and a revised description given of the male, female and nymph from Snares Island.

4. I. percavatus and I. zumpti sp.nov. have been diagnosed from material from Nightingale Island, Tristan da Cunha. Ticks from Marion Island are identified as a new species, I. pterodromae. Female and nymphs from the Paris Museum originally identified by Neumann as I. auritulus now fall into the percavatus group and are named I. cornuae sp.nov.

André & Colas-Belcour (1942) described the male of Ixodes kerguelenensis as a variety of I. canisuga on the basis of one specimen. Subsequently Zumpt (1952) stated that its status as a full species was unquestionable, for, compared with I. canisuga, the jugular plates on each side of the pregenital plate in I. kerguelenensis are large. The structure of Haller's organ also fully justifies this separation (Arthur, 1956). Zumpt wrote further that: ‘The specimen on which the authors based kerguelenensis was probably fully engorged so that the ventral plates would be widely separated from each other…. The single male from Kerguelen is drawn as having the anal groove diverging, but this is certainly due to a distortion of the engorged tick.’ Through the courtesy of Professor André I was permitted to examine the type. Distortion is not due to engorgement, as Zumpt suggests, but to the mounting of the specimen on a slide under a cover-glass.

Studies on immuno-conglutinin levels in animals infected with T. brucei have shown that immuno-conglutinin appears in rabbits infected with T. brucei ‘M’ variant within 7 days after infection and reaches its peak titre within 30 days. In rabbits infected with the more virulent ‘R’ variant immuno-conglutinin levels rose more rapidly and reached peak titres within 10–14 days after infection.

High levels of immuno-conglutinin are detectable in the sera of rabbits and cats infected with trypanosomes before a significant amount of neutralizing antibody is produced. This difference is most marked in animals infected with the antibody-resistant variant ‘R’ which is more virulent for rabbits.

In animals treated effectively the immuno-conglutinin level dropped to its pre-infection level, while the titre of neutralizing antibody only decreased to a slightly lower level.

No change in the titres of immuno-conglutinin and neutralizing antibody was observed after treatment of animals infected with a drug-resistant strain.

These results are very promising for further field trials and introduce a new approach and method for testing the efficiency of chemotherapy in trypanosomiasis.

Females of Hammerschmidtiella diesingi can survive in the hind-gut of moulting Blatta orientalis. After a period of shrinkage they recover their normal length within 24 hr. in 0·2 and 0·3 m sodium chloride and in 50% sea water, but not in hypotonic media or in hypertonic sucrose. Females of H. diesingi, which have regained their original length in hypertonic media, swell when placed in normally isotonic media; a similar phenomenon occurs with nematodes taken from moulting cockroaches.