Patrick Alfred Buxton was born in Hyde Park Street, Paddington, on 24 March 1892, and died at his home in Gerrards Cross, Bucks, on 13 December 1955. His father was Alfred Fowell Buxton, a busy banker and one time chairman of the London County Council, his mother was Violet Jex-Blake.

A general morphological account of Multiceps smythi n.sp. from the local dogs in Dublin is given. This new species is characterized by forty-four rostellar hooks arranged in two rows of alternating crowns. Testes 286–310 in a single segment, occupying all parts of the segment in between the longitudinal excretory vessels, except the poral, posterior portion of the segment. Vagina opening posterior to the cirrus sac. Receptaculum seminis present. Uterus with 16–19 lateral branches on each side. Onchosphere enclosed in an embryophore, which is itself enclosed in a thin-walled capsule which has a bulge on one side containing fatty globules. The histological structure of Mehlis' gland and of the vitelline glands is also described.

1. The morphology and histochemistry of the genitalia concerned in the formation of the egg in Multiceps smyihi n.sp. are described.

2. The vitelline cells are devoid of the phenolic protein globules, which occur in the vitelline cells of the Pseudophyllidea; this result is correlated with the absence of a true external egg-shell.

3. The hardened embryophore (often mistakenly termed the egg-shell) gives none of the reactions of sclerotin (tanned protein) or chitin, but gives a strong P.F.A.S. reaction for disulphide bonds, suggesting that it is a ‘keratin’ type of protein.

4. The cells of Mehlis' gland secrete a material which is intensely P.A.S.-positive and is not digested by saliva, α-amylase or hyaluronidase. This suggests that it may be secreting a mucopolysaccharide or muco- or glycoprotein.

The manner by which Kuhnia scombri (Kuhn, 1829) Sproston, 1945, attaches itself to the gills of Scomber scombrus L. is described.

The parasite lies between the primary gill lamellae with its posterior attachment organs ‘upstream’ with respect to the gill ventilating current of the host.

The adhesive mechanism consists of two sets of organs which become attached to the secondary lamellae: a pair of hooks, provided with powerful muscles, perforates three or four secondary lamellae; and each of the members of four pairs of hinged clamps, operated by its own extrinsic muscle, grasps one or two secondary lamellae.

The description of the adhesive mechanism given differs substantially from that given by Sproston. Sproston's classification of the Diclidophoroidea, being based mainly on her interpretation of the structure of the clamps of Kuhnia, is therefore open to criticism.

During an examination of fishes for the parasitic crustaceans, fourteen specimens of Argulus belonging to two different species, viz. A. indicus Weber, 1892 (eight specimens) and A. siamensis Wilson, 1926 (six specimens) were collected from the fish, Ophiocephalus marulius Hamilton, taken from a canal in the environs of the village Champahati, District 24 Parganas, West Bengal. Out of seven fishes so obtained only three were found to be infected with the copepod parasites. While examining these copepods, the attention of the writer was drawn to a viviparous monogenetic trematode infecting only one species of Argulus, viz. A. indicus. It was rather unfortunate that the piscine host could not be examined at that stage for the helminthic infection. About one hundred specimens of this trematode were collected from the ventral surfaces of the copepods.

The validity of the subgenus Hyalommina is discussed and reaffirmed.

Hyalommina is differentiated from Hyalomma by the absence of the subanal plates in the males and by the humped tarsi and the more or less hexagonal basis capituli in both sexes.

The male and the female of H. rhipicephaloides Neumann, 1901 are re-described. The larva and nymph of H. rhipicepholoides are described for the first time.

The Indian species H. hussaini Sharif, 1928 and H. kumari Sharif, 1928 are re-described. H. hussaini var. brevipunctata Sharif, 1928 is considered as a species inquirenda.

H. lewisi Schulze, 1936 is synonymized with Hyalomma truncatum K., 1844 (Feldman-Muhsam, 1954).

Three species of the genus Nematodirus have been described from sheep in Britain: N. spathiger, N. filicollis and N. battus.

The infective larva of N. spathiger has been described by Monnig (1931), and in more detail by Dikmans & Andrews (1933). The infective larva of N. filicollis was described and figured by Boulenger (1915). A brief description was also given by Morgan (1930), while Maupas & Seurat (1913) figured the larva but gave no description or measurements. In the present paper, the infective larva of N. battus is described and compared with those of the other two species. However, as in the course of this study certain discrepancies were observed in the published description of the larva of N. filicollis, a redescription of the larva of this species is also given.

Toxoplasma ‘Nicolle et Manceaux’ has been examined in the electron microscope in thin sections of infected tissue cultures. The intracellular forms, single or in rosette formations, show that the parasite has no flagella, cilia or other organelles for locomotion. It is covered by a double membrane which is especially well denned at the two poles. A ring-like formation, often slightly protruding, can be seen at one end of the parasite, and in connexion with this, long, homogeneous, dark-stained inclusions of still unknown nature. At the opposite pole a distinct opening has been found.

Mitochondria and strands of an endoplasmic reticulum are also present in the cytoplasm and a fine striation in the region of the periplast. No dividing forms have been observed. Near the nucleus, in the region of what may correspond to the centrosome and the Golgi apparatus, a few extremely fine granules and a spiral-like formation of fine striae or tubules have been observed.

This work has been partly supported by the National Research Council of Brazil. The cost of reproduction of figures was defrayed by the Institute de Biofísica da Universidade do Brasil.

1. The phosphatases present in the adult and cysticercus stages of Taenia pisiformis have been investigated using histochemical and biochemical methods.

2. Histochemical tests failed to demonstrate the sites of enzyme activity in the cysticercus.

3. In the adult, the acid phosphatase is confined to the cuticle. Alkaline phosphatase occurs in the cuticle, subcuticular cells and the membranes bounding the ovary and vitelline tubules.

4. The histochemical distribution is uneven along the length of the worm, both acid and alkaline phosphatase being predominant hi the region of ‘mature’ proglottides. The scolex was negative to both tests.

5. Biochemical tests have demonstrated distinct acid and alkaline phosphatases in the cysticercus and adult stages. In the cysticercus the acid enzyme is predominant and in the adult it is the alkaline, implying a change in relative magnitude during the completion of the life cycle.

6. pH-activity curves have been obtained for the enzymes of both stages.

7. The results are discussed in relation to recent findings in the field of cestode enzymology, and it is suggested that these phosphatases may be associated with active transport of materials across the cuticle and ovarian and vitelline membranes.

1. Histochemical and biochemical studies have demonstrated the presence and distribution of phosphatases in Cysticercus tenuicollis and adult Moniezia expansa.

2. Biochemical tests have differentiated the following types of optimum phosphatase activity: Cysticercus tenuicollis, acid phosphatase, pH 5·0 (approx.); alkaline phosphatase, pH 10·0 (approx.); Moniezia expansa, acid plaosphatase, pH 5·5 (approx.); alkaline phosphatase, pH 7·0–8·0 and pH 10·0–11·0.

3. Attempts to locate the enzymes by normal histochemical methods were unsuccessful in the case of Cysticercus tenuicollis. In adult Moniezia, acid and alkaline phosphatase (both types) occurred in the cuticle. Alkaline phosphatase (pH 10·0–11·0) only was present in the tunicae enclosing the ovary, vitelline gland and testes. This enzyme was also the only one present in the interproglottidal glands, in the wall of the developing uterus and in the subcuticular cells.

4. Tests for all types of phosphatase activity showed that cuticular activity in Moniezia originated in the walls of an extensive branched system of channels. This system was demonstrable in the cuticle of fixed and unfixed material.

5. Incubation experiments with entire living Moniezia showed that substrates external to the body were capable of being broken down. Similar tests with Cysticercus tenuicollis showed that at least some of the alkaline phosphatase activity recorded by the biochemical tests was located in the cuticle.

1. Studies on two Microsporidia, Nosema helminthorum Moniez and N. locustae Canning, have shown that the polar filament serves to conduct the sporoplasm out of the spore.

2. The filament is a solid structure and the sporoplasm is either attached to or is a continuation of it. The filament is first extruded as a tightly coiled mass and, as this uncoils, it drags the sporoplasm out of the spore.

3. The sporoplasm, which is either uninucleate or binucleate, takes the form of a girdle of protoplasm, which lies on the inner side of the spore membrane and surrounds the coiled polar filament. There is no polar capsule.

This work was carried out with a strain of trypanosomes isolated by inoculation into domestic rabbits of fleas naturally infected from wild rabbits in Hertfordshire.

The course of infection was studied in experimentally infected normal and splenectomized rabbits, in which the incubation period varied from 5 to 12 days. After recovery from the infection, rabbits became immune to re-infection. Immune rabbit serum had no protective action against Trypanosoma lewisi.

Attempts to infect other animals with the rabbit trypanosome produced negative results.

Young rabbits proved to be more susceptible to infection with this trypanosome, and their parasitaemia lasted longer than in adult rabbits, but the parasite was found to be non-pathogenic to these animals.

It was demonstrated that this trypanosome multiplies in the spleen, where the stages of division are confined to the capillaries. Multiplication follows the inoculation of metacyclic trypanosomes from infected fleas or blood forms. It proceeds by division of the nucleus and kinetoplast into four, followed by fission of the cytoplasm, giving rise to four small daughter individuals. These are transformed into trypanosome forms, which are shed into the peripheral blood, where they change into the typical adult trypanosomes.

The development in the intermediate host takes place in the gut of the rabbit flea, Spilopsyllus cuniculi, with the production of metacyclic trypanosomes in the hind-gut (posterior station).

The nomenclature and synonymy of the rabbit trypanosome are discussed, and it is concluded that its valid name is Trypanosoma nabiasi Railliet, 1895.

Species of the genus Pennella are of interest because they parasitize widely different hosts such as cetacea, flying fish, pipe fishes, sword fishes, etc. In 1917 Wilson listed fourteen valid species and nine more have been added since. Of these P. exocoeti (Holten) and P. blainvilli (Le Sueur) have been recorded as parasites of flying fishes, the former probably in Exocoetus speculiger from which Leigh-Sharpe (1928) and Deboutteville & Nunes-Ruivote (1954) recorded the species, while the latter was found on E. volitans. The present paper deals with four parasites collected from four different species of flying fishes of Madras. The types will be deposited in the Indian museum, Calcutta.

1. A fork-tailed cercaria Cercaria diplostomi phoxini (Faust) has been found to develop in sporocysts in 3·9 % of Lymnaea pereger var. ovata (Drapanaud) in Fron Goch Pool near Aberystwyth.

2. The cercaria is described in detail. The arrangement of spines on the body is characteristic and there is a double row of seventy-two spines on the ventral sucker. The flame cell formula is given.

3. The cercaria is compared with seven closely related types.

4. Infestation experiments show that Cercaria diplostomi phoxini develops into Diplostomulum phoxini in the brain of the minnow.

5. The early stage of infestation of the brain of the minnow is described and compared with an infestation of long standing.

In a collection of parasitic mites from Palestine sent by Prof. O. Theodor, Hebrew University, Jerusalem, the author found several larval mites which prove to be new species, one in the genus Euschöngastia the other two in the genus Trombicula. These are described and figured in the present paper along with a new species of the genus Blankaartia taken on a bird in Uganda and sent for identification by G. H. E. Hopkins, O.B.E. (formerly Senior Medical Entomologist, Kampala). The author wishes to acknowledge his thanks to the above donors for having given him the opportunity to examine these specimens.

1. The male of Rhipicephalus humeralis is redescribed and the female and immature stages are described for the first time. The synonymy of the species is discussed and the various stages are compared with those of R. pulchellus.

2. Details of the life cycle under laboratory conditions are given.

3. The host list and distribution of the species are given.

1. A series of experiments is described in which the transmission of cattle lung-worm infection has been investigated in relation to four different pasture conditions—long grass, short grass produced by gangmowing, grazing by sheep and grazing by resistant cattle.

2. The methods of study of value in this type of field investigation are discussed. It is suggested that the results can be usefully expressed as a series of coefficients which summarize the factors involved in the process of transmission. The methods of calculation of these coefficients are described.

Lavoipierre & Griffiths (1951) described the female, and Lavoipierre (1953) described the male, of Knemidokoptes pilae found on a budgerigar. Later, Oldham & Beresford (1954) and Evans & Browning (1955), respectively, added Psittacula nipalensis and Upupa epops to the host-list of this species. The present author (1956) has also mentioned the occurrence of Knemidokoptes pilae on a budgerigar and a parrakeet, Palaeornis torquatus, and an unknown species of the genus Ara may now be added to the list.

Some time ago Mr E. Wilson, of the Marine Laboratory, Aberdeen, brought to notice the abnormal appearance of the cranial cartilage in a plaice (Pleuronectes platessa L.) which had been tagged (in St Andrews Bay) and subsequently recaptured (24 miles south-south-east of Arbroath). The fish was a 44·5 cm. long female, 6 years old, with mature ovary and in good condition generally. The cartilage, exposed by the opening of the cranium to remove the otoliths, seemed hypertrophied and full of whitish splotches giving it a mottled appearance. These ‘splotches’ were formed by irregular, vein-like branching canals, in many places along their length swelling into cyst-like, subspherical cavities up to 3 mm. in diameter. They were filled by a mass of soft substance which was found to be an accumulation of Cnidosporidian spores. Small granules of the substance were also found inside the otic capsules. It is possible, however, that these granules were displaced into the capsules during the opening of the cranium.

The external structure of the capitulum of all stages of Dermacentor parumapertus is described in detail. The capitulum is divisible into an extra-basis and basis regions. The former consists of a dorsally grooved hypostome or food channel overlapped by a labral membrane, along its whole length. The salivary channel lies above the labral membrane, being bordered laterally by the meso-ventral margins of the outer cheliceral sheaths. Within the basis a vertical wall separates the base of the palpal cavity from the rest of the basis. This wall is produced backwards to form a wing or ala on either side of the pharynx and to it are attached dilator and constrictor muscles. Opening of the fore-part of the pharynx, i.e. where it is in the form of a V-shaped depression overlapped by a wedge, is effected by ventral and ventro-lateral dilator muscles, and closure by the elasticity of the pharyngeal walls.

The pharynx, oesophagus and salivary glands are described.