For the material herein dealt with, I am indebted principally to Mr G. A. H. Bedford of the Division of Veterinary Services of South Africa. Other material collected by the writer from bats in the United States National Museum some years ago and a specimen received from Dr C. R. Kellogg of Foochow, China, are also recorded.

In the course of my previous work on the structure of the head and mouth parts of the Streblidae (1929), I encountered some difficulty in identifying the different species of the genus Raymondia. A careful examination of the specimens in the collection of the British Museum and of my own specimens showed that the descriptions and figures given by the authors who studied these insects in the dried condition are not quite adequate. In dried specimens of these minute flies it is often impossible to distinguish clearly the chaetotaxy of the head and the thorax and the characters present in the wings, which are generally interlocked. Moreover, the parts of the male genitalia lying in the abdomen are absolutely inaccessible. When examined in the cleared specimens the genitalia of the different species have been found to possess distinctive characters.

Bhalerao (1926) described a trematode from the common Indian frog, Ranatigrina, which he placed in a new genus Centrovitus and a new species pentadelphi. Mehra and Negi (1926) gave a fuller account of the same form, from the same host and practically the same locality, under the designation Tremiorchis ranarum n.g., n.sp.

This mite was reported by Hirst in 1923 to be causing damage to poultry in Bedfordshire. He states that, although it had previously been found in pigeons, it had not before been recorded as a pest of fowls in this country. In the United States of America it has frequently occurred, and is regarded as a dangerous parasite, but Hirst's record seems to be the only one of its occurrence as a pest in the British Isles.

1. A ciliate occurring in the caecum of about 25 per cent, of the cattle that were examined at Jeanerette, Louisiana, is herein classified as Buxtonella sulcata Jameson (1926) and it is proposed that it be removed from the Class Aspirigera, Family Isotrichidae, and included in the Class Spirigera, Order Heterotrichida.

2. The ciliate is characterised by the position of the cytostome near the permanently open cytopyge and within the peristome which continues from the cytostome around the oral end of the body to the extreme aboral end which during locomotion is anterior.

3. The infections were detected in slaughtered animals by examining faecal material in Syracuse watch glasses under the binocular microscope, this method of faecal diagnosis having advantages over the smear method.

4. By the administration of Epsom salts the ciliates may be obtained from living cattle.

5. A pipette is described and figured for the isolation of Protozoa.

6. Death of Buxtonella sulcata in an unfavourable environment occurred by disruption of the endoplasm through the cytostome.

7. Buxtonella sulcata disappeared from faecal material at room temperature more quickly than balantidia from the pig, but withstood manipulation under the microscope better than the balantidia.

8. The passage of an individual between two obstructions suggested a means of intercellular tissue penetration by ciliates.

9. The oral plug and the centralised neuromotor system described and figured by McDonald in Balantidium coli could not be differentiated by the writer, but McDonald's other morphological observations on the above ciliates were confirmed.

A description of Zalophotrema hepaticum is presented. Study of this species and review of the literature show that the genera assigned to the two families, Fasciolopsidae and Campulidae, may be included in a single family. Furthermore, since Fasciola is the nomenclatorial type of the family to which it belongs, the rules of nomenclature do not permit the substitution of the name Fasciolopsidae for Fasciolidae. Consequently the family Fasciolidae is restored with three sub-families, Fasciolinae, Fasciolopsinae, and Campulinae. A new genus, Synthesium, is erected to contain Distomum tursionis Marchi.

Habitat and Record. By the courtesy of G. Evelyn Hutchinson of Yale University, I have received and examined a new species of Lernaea collected by him on 7. iv. 1928 on a small Barbus, which had lost all its scales and was too young for specific identification, from an alkaline pan in the Transvaal, S. Africa. For the purpose of comparison reference will be made to L. elegans described by me, Parasitology, 1925, 17, 246.

Originally containing only four genera, this family of recent years has been increased by the addition of twelve more and has further been subdivided by Hunter (1927, 1929) into four sub-families: Caryophyllaeinae, Lytocestinae, Pseudolytocestinae, Wenyoninae. Of these, the Lytocestinae and Pseudolytoeestinae have vitellaria either wholly or partly in the cortical parenchyma and differ from each other only in the degree to which these are cortical; a difference hardly of sub-family rank, which should consist of characters of absolute not relative value: the Caryophyllaeinae and Wenyoninae, with vitellaria wholly medullary, differ from each other in the position of the genital pore and the absence of uterine glands, differences again not of sub-family rank. There remain therefore two well-marked sub-families, the Caryophyllaeinae and the Lytocestinae, the differences between which are given in the following table.

Since the description by Linnaeus in 1758 of the very irritating patatta-mite (“patatta-luis”) of Surinam under the name Acarus batatas, this parasite has often been mentioned in the literature, but seldom have attempts been made to learn more about it. Furthermore, many important data have been omitted by authors in their writings, so that it seems desirable to summarise what is known of this mite.

I have examined (a) alcoholic and microscopic specimens of Birula's type-material of O. papillipes preserved in the Zoological Museum of the Academy of Sciences, Leningrad, and (b) hundreds of living ticks from different localities in Turkestan which I determined as O. papillipes. The larger number (b) were chiefly supplied by Dr I. A. Moskwin, who, in my laboratory and at the Infectious Diseases Clinic of our Academy, demonstrated that the spirochaete of Turkestan, relapsing fever, is transmitted by this tick.

The Chalcidoid wasp, Bairamlia fuscipes, was found parasitising the flea Ceratophyllus wickhami in the nest of the North American Grey Squirrel (Sciurus carolinensis) from Gerrard's Cross.

The larval and pupal stages of B. fuscipes were found in the cocoons of C. wickhami, and the adults were crawling about in the squirrel's nest.

The parasites were scarce, only 7 per cent, of the cocoons dissected at intervals during fifteen months were parasitised.

The parasite has not been reared in the laboratory beyond the second instar larva, though full grown larvae have successfully reached maturity under experimental conditions.

B. fuscipes oviposits through the flea cocoon and fixes the egg on the abdomen of a resting larva or pupa. Only one egg has been found in each parasitised cocoon. The larva feeds externally on the flea, fixing itself to the fourth abdominal segment or thereabouts.

Attempts were made to parasitise larvae of Xenopsylla astia, but without success.

The external anatomy of the full grown larva of B. fuscipes is described.

1. The main facts in Brasil's (1907) account of the intracellular schizogony in Selenidium caulleryi from Protula tubularia have been confirmed. Early stages in the sporogony of this species are described now for the first time.

2. Intracellular schizogony is described for the first time in Selenidium mesnili Brasil from Myxicola infundibulum, and here also the early stages in sporogony are noted for the first time.

3. The life histories of Caullery and Mesnil's two unnamed species of Selenidium (now called S. spionis (Köll.) and S. foliatum n.sp.) from Scolelepis fuliginosa have been exhaustively studied. No schizogonic phase has been observed in either. The gametocysts, here described for the first time, are found to develop fully only after escape into the sea. The gametocysts of S. spionis are ovoid, 108μ x 60μ and contain spores with four sporozoites: those of S. foliatum are spherical, 70μ in diameter, and their spores contain eight sporozoites.

4. New or hitherto little known species of Selenidium are recorded from Cirratulus cirratus Müll., Branchiomma vesiculosum Mont., Sabella pavonina Sav., Pomatoceros triqueter L. and Terebella lepidoria Kühl, and the morphological characters of the trophozoites are described.

5. A discussion follows of the value of the diagnostic characters of the genus Selenidium. It is suggested that this genus requires drastic revision and will probably have to be dismembered. Stress is laid, however, on the occurrence in all the gregarines examined, and at all the observed stages of their development, of characteristic chromatic bodies at the anterior end, structures which have hitherto escaped the notice of most observers.