bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on populations of head-lice (Pediculus humanus capitis: Anoplura)
Authors: Buxton P. A. 
Published: June 2009

1. In three previous papers (1936, 1938b, 1940a) the author has discussed the distribution of head-lice among their human hosts, his material being nearly 3000 complete crops of hair. The present paper deals with the strictly entomological side of the inquiry, that is to say, with the study of the populations of head-lice themselves. The total amount of material is the lice from 858 infestations from six places; from each of four places there were less than 100 infestations.2. In about two-thirds of the infestations there were ten lice or less, the proportion of low infestations varying considerably from place to place (Table 1). Infestations over 100 never formed more than 10% of all the infestations in a place.3. In a single head the proportion of the sexes is often far from equal; indeed, in light infestations it is common to find that all the adults are of one sex. Taking all the heads from one place, the total number of males and females differs significantly from equality, an excess of males occurring in one place, of females in another (Table 2). In all heads from one place the coefficient of correlation between the number of males and females is high, about 0·8–0·9. As the density of the louse population, does not generally affect the sex ratio, the correlation is approximately linear. But when the density is unusually high, as it is in some heads from Colombo, the proportion of males rises progressively. This is the only case known, in spite of much searching, in which sex ratio of the louse is affected by an environmental factor.4. In the matter of the number of larvae per female, there are great individual differences between heads, though the coefficient of correlation, worked on all the heads from one place is as high as 0·7 or 0·9. Taking all the heads from one place, the mean number of larvae per female ranges between 5·4 and 10·9; many of the differences between places are significant. I have failed to find any explanation of these differences, and they do not seem to be affected by any environmental factor. The fact that the larvae are always more numerous than the females, indicates that there is a high mortality during the course of larval life; the author has failed to make a more precise estimate of the proportion which die.5. A small part of the material was specially examined, and every larva referred to its instar. In this sample of 502 larvae it was found that the death-rate was higher in the third instar than in the other two, a state of affairs the reverse of what occurs in body-lice reared in boxes.
Further studies on the ultrafiltration of plant viruses
Authors: Smith Kenneth M. , MacClement W. D. 
Published: June 2009

An account is given of ultrafiltration studies with 9 plant viruses. It is shown that 3 of these viruses filter in a consistent manner and appear to have approximately spherical particles. These three areLycopersicum virus4 (tomato bushy stunt virus),Nicotiana virus11 (tobacco necrosis virus) andNicotiana virus12 (tobacco ringspot virus). The filtration end-point of 40 mμ is the same in each case and from this a particle diameter of 13–20 mμ is calculated. There is a peculiarity, however, in the filtration curve of tobacco necrosis virus which shows itself in a “bench” or “shelf” and which suggests either a polydisperse system or some degree of dissymmetry of particle shape.Great difficulty was experienced in filteringNicotiana virus1 (tobacco mosaic virus) and its strains. A value of 13–20 mμ was obtained for the particle diameter of the type virus and this agrees well with measurements obtained by other methods. The filtration results, however, suggest that the infective units are not of the same length and that this variability may be considerable. Similar difficulty was experienced in filteringSolanum virus1 (potato virus X), another rod-shaped virus; the end-point was found to be 100 mμ, from which a particle diameter of 33–50 mμ is calculated. It was not possible to obtain a definite filtration end-point forCucumis virus1 (cucumber mosaic virus), probably because of the low initial concentration of virus in the extracted sap.
The musculature and nervous system of the plerocercoid larva of Dibothriorhynchus grossum (Rud.)
Authors: Rees Gwendolen 
Published: June 2009

1. The structure of the proboscides of the larva of Dibothriorhynchus grossum (Rud.) is described. Each proboscis is provided with four sets of extrinsic muscles, and there is an anterior dorso-ventral muscle mass connected to all four proboscides.2. The musculature of the body and scolex is described.3. The nervous system consists of a brain, two lateral nerve cords, two outer and inner anterior nerves on each side, twenty-five pairs of bothridial nerves to each bothridium, four longitudinal bothridial nerves connecting these latter before their entry into the bothridia, four proboscis nerves arising from the brain, and a series of lateral nerves supplying the lateral regions of the body.4. The so-called ganglia contain no nerve cells, these are present only in the posterior median commissure which is therefore the nerve centre.
The helminths of the intestinal canal of man in Mauritius; and a first record of Trichostrongylus axei locally
Authors: Webb J. Lewis 
Published: June 2009

1. Systematic measurements of all hookworm-like eggs from time faeces of 336 patients in Mauritius led to the finding of 8 per cent Trichostrongyle, 0·9 per cent Ternidens deminutus, and 0·9 per cent Ancylostoma braziliense-like eggs.2. This percentage of Trichostrongyle eggs includes one case from an inhabitant of the French colony, Réunion.3. Hookworm eggs of a very small size, possibly Ancylostoma braziliense were found unassociated with the typical Necator americanus eggs, in the faeces of an inhabitant of Rodriguez; the adult worms appeared drug-resistant.4. A partial eradication of the Trichostrongyles was obtained in one case, and an apparently complete eradication in another, of 6 patients treated with carbon tetrachloride.5. The Trichostrongyles expelled by one of the patients were identified as Trichostrongylus axei (Cobbold, 1879) Railliet & Henry (1909).6. No particular symptoms which could be ascribed to the action of the Trichostrongyles were observed in any of the affected patients.7. Drugs administered orally to a patient passing Ternidens deminutus-like eggs failed to dislodge any of his worms.
The attachment of the monogeneanDiscocotyle sagittataLeuckart to the gills ofSalmo truttaL.
Authors: Llewellyn J. , Owen I. L. 
Published: June 2009

The monogenetic trematodeDiscocotyle sagittataattaches itself to the gills ofSalmo truttawith 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, butDiscocotyleappears to retain a primitive unspecialized character in that the asymmetrical disposition is facultative and not obligatory and permanent as inAxine.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 inPlectanocotyle gurnardi.Scheuring's and Sproston's interpretations of the clamp-closing mechanism ofDiscocotyleas a spring system are wrong.
A comparative account of the tracheal system of larvae of the horse bot-fly,Gasterophilus intestinalis(De Geer), and of some other dipterous larvae
Authors: Tatchell R. J. 
Published: June 2009

1. The tracheal systems of first, second and third instar larvae ofGasterophilus intestinalisare described.2. The homologies of the conical tracheae of the tracheal organ are demonstrated and explain the apparent disappearance of a complete tracheal metamere.3. Anomalies in the tracheal system of the anterior segments ofGasterophilusled to an investigation of the tracheal systems ofDrosophila, Eristalis, Calliphora, ScatopseandAëdes.4. The anterior tracheal system of larval Diptera has been re-interpreted; that of the Cyclorrhapha can be derived from that of the Nematocera without the formation of new tracheae other than a large trachea from the lateral longitudinal trunk to the antero-lateral musculature.
Trematode parasites of snails from Edgbaston Pool: the life history of the strigeidCotylurus brevisDubois & Rausch, 1950
Authors: Nasir P. 
Published: June 2009

1. The life cycle ofCotylurus brevisDubois and Rausch, from the cercaria to the adult, has been investigated for the first time by using laboratory-bred primary, secondary and definitive hosts. The holometabolic metamorphosis with the formation of a tetracotyle stage in a second intermediate host has been described in detail.2. The cercaria ofC. brevisobtained fromLymnaea stagnalisin Edgbaston Pool has been found to be identical withCercaria helvetica XXXIVDubois from Lake Neuchâtel. The total number of flame cells in the cercaria is twenty, as opposed to the fourteen in the cercaria ofCotylurus cornutusRudolphi (= ‘Strigea tarda’ described by Mathias (1925), Harper (1929, 1931) and Wesenberg-Lund (1934)).3. In nature the second intermediate host ofCotylurus brevisisLymnaea stagnalis. Under experimental conditionsL. peregerandL. auriculariawere also found to act as second intermediate hosts, but neitherPlanorbis corneus, P. carinatusnor various leeches could act as second intermediate hosts.4. The tetracotyle stage ofCotylurus brevisis morphologically indistinguishable from the corresponding stage of other species ofCotylurus.
Studies on the physiology of the nematodes of the alimentary canal of sheep
Authors: Davey D. G. 
Published: June 2009

An investigation was made of certain aspects of the physiology of nematodes from the alimentary canal of sheep.Cellulose digestion has apparently no effect on the nematodes.The composition and concentration of a physiological saline solution suitable for Ostertagia circumcincta—and possibly for the other species—was determined.The effect of acidity on the intestinal worms showed that they could not live in the abomasum because the acidity in this chamber would be too great. O. circumcincta could not inhabit the stomach of horses, and carnivores, or the abomasum of cattle, in all of which the acidity reaches a level lethal to this species.A graph is given showing the distribution of the nematodes in the small intestine of the sheep. After a study of the effect of bile salts on the different species its influence in determining this distribution is discussed.A discussion of the evidence relating to the food of nematodes of the alimentary tract led to the conclusion that even species with rudimentary buccal capsules might suck blood; on the other hand, the results from the benzidine tests and spectroscopic examinations indicate that the haemoglobin demonstrated in nematodes is synthesized by them.It was shown that O. circumcincta does not probably feed on abomasal contents. Bacterial difficulties hampering these experiments were overcome by using an apparatus whereby the contents of the abomasum could be percolated over the worms. The latter had been surface-sterilized with acriflavine solution.All attempts to feed the nematodes on serum, defibrinated blood, and blood digests failed. Bacteria again constituted a difficulty, but it is suggested that the failure is not entirely due to them, and that perhaps the tissues of the host must be incorporated into the media.
Further observations upon Entamoeba aulastomi Nöller
Authors: Bishop Ann 
Published: June 2009

1. In Entamoeba aulastomi excystation does not occur in vitro until the glycogen and chromatoids have been absorbed.2. The product of excystation is a quadrinucleate amoeba.3. The amoeba escapes through a minute pore in the cyst wall.4. No evidence of sexual phenomena has been obtained during the metacystic cycle.5. The excysted quadrinucleate amoeba undergoes a series of nuclear and cytoplasmic divisions. These divisions do not necessarily synchronize or alternate with one another, but by them 8 uninucleate amoebulae containing daughter nuclei are ultimately produced from every cyst. Amoebae containing 6, 7 or 8 nuclei may appear in the course of the metacystic development.
The anatomy of Köllikeria filicollis (Rudolphi, 1819), Cobbold, 1860 (Trematoda: Digenea) showing that the sexes are not entirely separate as hitherto believed
Authors: Williams H. Harford 
Published: June 2009

The anatomy of Köllikeria filicollis (Rudolphi, 1819), Cobbold, 1860 (Trematoda: Digenea) is described in detail.An account is given of the integument and musculature of the worm and the structure of the cyst in which it is found, followed by a discussion of the body wall in other digenetic trematodes. The alimentary canal, excretory system, nervous system and genitalia are also described.The study shows that the sexes are not entirely separate in all members of the genus Köllikeria as hitherto believed.The systematic position of K. filicollis is discussed and a specific diagnosis is given for the species.
Taxonomy, life cycle, development, and habits of two new species of Allantonematidae (Nematoda) parasitic in drosophilid flies
Authors: Welch Harold E. 
Published: June 2009

1. Two species of Allantonematidae were found parasitizing five of twelve species of Drosophila collected at Rothamsted Experimental Station, Harpenden, Herts, England.2. H. aoronymphium sp.nov. was found in 20·8 % of D. phalerata and 4·3 % of D. kuntzei examined. Parasitylenchus diplogenus sp.nov. was found in about 5 % of D. subobscura, D. obscura, and D. silvestris examined.3. The type species and taxonomy of the genus Parasitylenchus are discussed.4. The life history of H. aoronymphium is typical of most allantonematids except that the female is fertilized when she is a fourth-stage larva. P. diplogenus has two sexual generations per cycle.5. Both nematodes have a precocious development of the male and a retarded development of the female genital system. Both destroy host gonads.6. The specificity of the nematodes is not a result of dissimilar ovipositing habits of the hosts, but shows a similarity to the taxonomic assignment of the hosts to subgenera.
The life history and development ofToxascaris leonina(von Linstow 1902) in the dog and cat
Authors: Sprent J. F. A. 
Published: June 2009

1. The nomenclature and host specificity ofToxascaris leoninais reviewed and the conclusion reached that this parasite occurs in a wide range of feline and canine hosts. Notice is given of application to the International Commission on Zoological Nomenclature, for the suppression ofAscaris leptopteraRudolphi 1809 andA. micropteraRudolphi, 1819, which appear to be senior synonyms ofToxascaris leonina. The synonyms and hosts ofT. leoninaare tabulated.2. The distribution and growth of the larvae ofT. leoninain experimentally infected mice, cats, and dogs is reported. A feline and a canine strain were used for these infections and infection of cats and dogs was produced both by feeding the eggs containing second-stage larvae and by feeding mouse tissues containing third-stage larvae.
Studies on blood group substances associated withAscaris lumbricoides
Authors: Soulsby E. J. L. , Coombs R. R. A. 
Published: June 2009

Human anti-A and anti-B and pig anti-A agglutinins were neutralized byAscaris lumbricoidesmaterials.The infection of pigs withA. lumbricoidesstimulated the production of anti-A agglutinin but this agglutinin appeared to have no protective action.Oesophagostomum dentatuminfection in pigs did not affect the anti-A agglutinin levels.
Some cytochemical observations on Toxoplasma gondii
Authors: Dasgupta B. , Kulasiri C. 
Published: June 2009

A positive Feulgen reaction has been seen in all stages of Toxoplasma gondii. The intense basophilia seen in the intracellular and the extracellular stages is removable by treatment with ribonuclease. Granules which reacted positively with the periodic acid-Schiff technique were found in abundance in the cytoplasm of the cysts, whereas the same granules were not universally present in the intracellular and the extracellular stages at all days of infection. The cyst wall stained with this technique with varying degree of intensity.It is thought that the variations seen in the individual parasites may be attributed to various causes, for example, strain differences, differences in the reaction of the host to the parasite, differences in the period of infection or to other unknown causes.
On the invasion of the central nervous system by nematodes I. The Incidence and pathological significance of nematodes in the central nervous system
Authors: Sprent J. F. A. 
Published: June 2009

A wide variety of nematode species have been observed to invade the central nervous system. They may be located in the meningeal spaces or may penetrate into the tissues of the brain and spinal cord.The pathological changes resulting from invasion of the central nervous system are influenced by the route of entry, the size and the mobility of the parasite. They may be diffuse or focal and may include haemorrhage, degenerative changes, cellular infiltration and glial proliferation. Such changes may or may not be observed in close association with the parasite.Symptoms indicating involvement of the central nervous system have long been associated with nematode infections outside the central nervous system. The pathogenesis of these symptoms is obscure, but they may possibly be of allergic origin.The direct pathological effects on the central nervous system are mainly the result of trauma and are directly proportional to the size and activity of the parasite. The possibility that nematodes may transport viruses into the central nervous system is briefly discussed.
Studies on the bovine filariid Setaria cervi (Rudolphi, 1819)
Authors: Williams Holman E. 
Published: June 2009

Wild Stomoxys calcitrans flies were dissected in search of developmental larvae of Setaria cervi without success.S. cervi worms were implanted intraperitoneally into rabbits and live microfilariae were recovered from the blood.Morphological descriptions are given of the larvae from the blood of rabbits and of the adult worms taken from slaughtered cattle.
Nematode parasite populations in sheep on lowland farms II. worm egg counts in lambs
Authors: Crofton H. D. 
Published: June 2009

This work started in May 1950 and is part of a wider study of parasite populations on lowland pastures.An account of observations made on ewes has already been given (Crofton, 1954), and the present paper deals with observations made on lambs from the same flocks. It is realized that a proper approach to parasite problems in sheep entails consideration of the flock as a whole, but for convenience, the observations made on different age groups have been described separately. It is for convenience, also, that pasture contamination is only considered briefly here. Later an attempt will be made to consider parasite populations on a lowland farm as a dynamic system of interacting factors.
Dirofilaria aethiops Webber, 1955, a filarial parasite of monkeys II. Maintenance in the laboratory
Authors: Hawking Frank , Webber Winfrith A. F. 
Published: June 2009

1. An account is given of the stages of the life history of Dirofilaria aethiops which take place in the monkey and of the transmission of the infection in the laboratory.2. The microfilariae exhibit nocturnal periodicity in the blood; the number of microfilariae at midday was usually less than 1% of the number at midnight.3. Aëdes aegypti mosquitoes were fed on monkeys during the evening when there were many microfilariae in the blood. Larvae developed in these mosquitoes and they were ultimately transferred to fresh monkeys by injection of a saline suspension of mosquitoes and infective larvae. In this way six Cercopithecus aethiops and one Macaca mulatto, monkey were successfully infected; seven other Cercopithecus aethiops, one Cebus apella, and one Cercocebus monkey were inoculated, but the worms failed to establish themselves.4. In the infected monkeys microfilariae appeared in the blood 11 months after the injection of infective larvae. The number of microfilariae then increased for 8–12 months. Subsequently, it decreased to one-tenth of the maximum in 2 years from the first appearance.5. Post-mortem examination showed that the adult worms live in the fascial tissues on or between the muscle bundles, especially those of the thighs. Tissue reaction to the worms is slight and in these monkeys there was no other pathogenic effect of the infection.6. Adult worms from three of the monkeys were transplanted to two normal monkeys. Microfilariae were found in the blood of one of these and persisted for over 2 years.
A new flagellate of the genus Proteromonas Kunstler, 1883, from an Indian lizard
Authors: Krishnamurthy R. 
Published: June 2009

A new flagellate, Proteromonas hemidactyli sp.nov., is described from the large intestine of the lizard, Hemidactylus brooki, in Hyderabad, India. It is characterized by a long, slender and fusiform body, two similar but subequal flagella, a kidney-shaped sub-blepharoplastic body, a ribbon-like paranuclear body and a vesicular nucleus. A parabasal body is absent.I am extremely grateful to Dr S. S. Qadri, Reader in Zoology, Osmania University, Hyderabad for his guidance and advice during the course of this work. I am thankful to Dr S. Mehdi Ali, Professor of Zoology, Marathwada University, and Dr S. N. Singh, Professor of Zoology, Osmania University, for providing me with laboratory and library facilities. Thanks are also due to the Council of Scientific and Industrial Research, New Delhi, for the award of a fellowship.
Sense organs of monogenean skin parasites ending in a typical cilium
Authors: Lyons Kathleen M. 
Published: June 2009

Single receptors seen with the electron microscope to consist of a terminal cilium embedded in a nerve bulb have been found in the skin parasitic monogeneanGyrodactylussp., adult and larvalEntobdella soleae, Leptocotyle minor(adult) and in the endoparasitic juvenile ofAmphibdella flaviolineata.Their distribution inGyrodactylussp. has been mapped using phase-contrast microscopy, and staining with the indoxyl acetate method for non-specific esterases revealed a nervous connexion between the lateral ventral nerve cord and the ‘tangoreceptor’. The general relationships of the nervous system inGyrodactyluswere investigated by staining with the thiocholine method for cholinesterase. The ‘sensory’ neurone contains vesicles, microtubules and mitochondria and the whole nerve bulb is sealed into the epidermis by means of septate desmosomes. The basal body of the cilium is not greatly modified and there is no obvious rootlet system. The terminal cilium of single receptors inEntobdella soleaehas a 9 + 2 structure. A compound sense organ from the head ofEntobdella soleaehas also been described. The significance of the fibre arrangement in the terminal cilia and the possible roles of these sense organs have been discussed.I should like to thank Dr D. L. Lee for training in electron microscope techniques and for his encouragement, Dr P. Tate for his continued interest and the staff of the Marine Biological Laboratory, Plymouth, especially Mr G. Best and Mr J. E. Green, for their assistance. This work was conducted during tenure of a Science Research Council Fellowship and the Tucker-Price Research Fellowship of Girton College.