It has been stated that in the stomach of the bed-bug the spirochaetes of relapsing-fever may frequently be observed to lose their normal regular curves and become more or less “worm-like.” This is of interest to those who oppose the view that spirochaetes are rigid spirals, a view which, after gradual abandonment by most observers, has lately been again advanced by Novy and Knapp in their study on S. recurrentis.

It is presumed that the majority of investigators who dissect anopheline mosquitoes for the purpose of detecting the parasites associated with malarial fever are not concerned with the finer details of anatomical relationships. Nor do they take the time to completely isolate the two acinus glands with the accompanying normal six lobes. This latter is assumed not essential in a search for protozoan organisms, as the sporozoites may be found in the torn portions of the acinus material as well as in the muscular tissue and mounting fluid in which the dissection is made.

1. Hymenolepis diminuta is shown to be quite frequent in the rat, Rattus rattus, of Colombo; and reasons are suggested for its apparent rarity in man.

2. An extremely low incidence of H. nana in rats was found. It is suggested that this cestode will not be found to parasitize man in Ceylon as long as its murine infection continues to be low.

3. Raillietina madagascariensis is not uncommon in rats in Ceylon; but, until its vector has been detected, the possibility that it may infest man in Ceylon cannot profitably be discussed.

4. Instances of variation in the arrangement of genital pores in R. madagascariensis, and in the general anatomy of H. diminuta were detected.

I am grateful to Dr G. A. R. Perera, Medical Officer of Health, Colombo Municipal Council, for supplying the rats used in this study; to Drs V. Sivalingam and L. G. Jayawardena of this Institute for helpful criticism, and to Dr A. C. J. Weera-koon of the University of Ceylon for revising my manuscript.

The genus Neoaplectana now contains eleven species of nematodes. All are associated with insects. A brief review of the history of the genus is given. An undescribed species referred to as DD-136 is compared with one other species in the genus Neoaplectana. It is very similar to the description given for N. carpocapsae Weiser, and it is concluded that it is probably this species.

A tumour among the gill filaments of Trigla gurnardus bears a female Medesicaste with the head and neck buried in its apex, and a male Medesicaste completely embedded in its base. The two sexes of the parasite are connected by a conjugation tube, external to the tumour, down which tube the spermatophores presumably pass. The appendages of the copepod are described.

Cis Bidentatus, which acts as host to this gregarine, is a small fungus-eating beetle. Almost all the beetles examined proved to be infected, but the parasites were never very numerous in each host. As a rule the infected beetles contained from four to eight of the sporont associations, and sometimes a few of the cephalont stages or cysts. The adult gregarines may be seen by transparency through the wall of the mesenteron: they lie either straight or else bent in the form of a U, but always with their long axis parallel to the sides of the gut. They are restricted to the posterior region of the midgut, and are never distributed along its whole length.

A description is given of a new species of paruterinid Cestode, belonging to the subfamily Paruterinae Fuhrmann, 1907, of the family Dilepididae Fuhrmann, 1907, to which the name Lallum magniparuterina gen. et sp.nov. is given. It is parasitic in the intestine of the common teal, Nettion crecca Linn.

1. A short note is given on Pterygosoma hystrix Lawrence, 1935, amplifying the original description and extending the known range of variation.

2. The hitherto undescribed male, larva, protonymph and deutonymph of Pterygosoma gerrhosauri Law, 1935, are described and figured.

3. The protonymph and deutonymph of Pterygosoma bicolor Law, 1935, are described and figured, together with a record of variation in the female.

Previous records and descriptions of the fungus known as Acladium castellanii, a human pathogen in the south-east of Asia and Europe and in Brazil, are cited and an account is given of its morphology when studied in culture on organic media.

It is concluded that it is closely related to, and perhaps merely a strain of, the widely distributed Sporotrichum schencki, the commonest cause of human and equine sporotrichosis, and that the term acladiosis as denominating a distinct disease should be deleted.

References to dipterous parasites of Diptera are rare in the literature. Bombyliids of the genera Villa and Thyridanthrax have been reared from the puparia of Glossina; Hemipenthes morio L., from the tachinid Parasetigena segregata Rond., and the sarcophagid Sarcophaga affinis Fall.; Argyramoeba varia F. from the tachinid Sturmia inconspicua Mg. The phorid Hypocera incrassata Mg. was found by H. M. Morris in dead and unhealthy larvae of Bibio marci L. Only one larva of Hypocera was obtained from each specimen of Bibio, and the account given by Morris suggests that this species is a true parasite. The evidence is, however, not absolutely conclusive and further study of this interesting species is desirable. The same thing must be said of E. E. Edwards' record of Aphiochaeta brevicostalis Wood, as a parasite of Tipula sp.

Schistosomiasis is a chronic debilitating disease which accounts for considerable human mortality and morbidity and is second only to malaria in its prevalence and severity. Despite several years of concentrated effort to combat the disease with molluscicides and chemotherapy, schistosomiasis is still spreading, and it is thought that 500 million people are currently exposed to infection (larotski & Davis, 1981).

From the small intestine of a lynx, Lynx canadensis, killed in the vicinity of Minneapolis, Minnesota, four strobilae and two fragments of an undescribed taenioid cestode were recovered. The largest of these tapeworms, which is the only one containing segments in all stages of development, measures 31 cm. in length and contains 253 proglottids; the other three strobilae measure 8, 26 and 30 mm. in length, respectively. The two fragments, one consisting of three and the other of eight ripe proglottids, apparently are segments from the largest one of these four strobilae.

Testes in the male early acanthella of Moniliformis dubius are cellular. The testes in the middle and late acanthellae and cystacanth stage also contain individual cells but these are embedded in a compact supporting syncytium which also forms the boundary of the testis. The testes are embedded in the cytoplasmic wall of the ligament sac in the early acanthella but after this stage they become exposed in the cavity of the sac when the surfaces of the testes become covered by a surface coat. Certain cells adjacent to testes primordia in the early acanthella appeared to have formed rudiments of vasa efferentia in the middle acanthella.

Vesiculated protoscoleces (VP) were produced by culturing freshly collected protoscoleces from Echinococcus granulosus horse liver hydatids in RPMI 1640 monophasic medium at 37°C for 18 days. Half of the VP were used as such, the other half used after killing them by freeze—thawing. Nine-day-old chicken heart fragments (CHF) were cultured in MEM at 37°C for 72 h. Subsequently, CHF were put together with live and dead VP, respectively, for up to 53 days, on a semisolid medium consisting of agar, Ringer's and MEM. Time-dependent histological observations revealed that dead VP were surrounded by CHF cells. Dead VP tissue was eventually internalized and disintegrated in about 1 week. Live VP penetrated into the CHF tissue and further developed into small hydatid cysts, located within the boundaries of the experimental ‘host’ tissue. The amorphous-looking contact region PAP-stained positively only with anti-E. granulosus serum and not with anti-CHF serum; it was considered identical to the normal laminated layer. The invasion of VP in CHF tissue proved to be different from a tumour or a bacterial invasion: it was concluded that the confrontation of VP and CHF had resulted in an ‘in vitro cohabitation’ rather than in an ‘in vitro infecion’.

In making the examination of a series of 400 rats, Heligmosomum brasiliense was found in 6 per cent. of those examined. The rats were all of the one species, Epimys norvegicus, and were chiefly from London and suburbs; the exceptions being one from Berkshire, one from Hampshire and two from Hertfordshire.

The ultrastructure of the developing excretory system of Prosorhynchoides gracilescens and Prosorhynchus squamatus cercariae is described. The development pattern was similar in both species. In early embryos the two main collecting tubes were composed of a layer of cells which were wrapped around the lumen. Later, the tubes fused and the excretory epithelium of the fusion zone and that of the lateral caudal ducts became a syncytium. The collecting tubes in the cercarial body retained their cellular organization. As the tails grew, additional excretory pores were formed in the tail stem where thickened portions of the caudal duct epithelium contacted the surface tegument. Following this, the distal portions of the lateral caudal ducts lost contact with the primary excretory pores and progressively degenerated. Excretory atrium development started with differentiation of secretory active cytons peripheral to the fusion zone. These cells gave rise to cytoplasmic extensions that penetrated the fusion zone wall to eventually form a continuous cytoplasmic layer. This layer eventually replaced some of the fusion zone excretory epithelium and became the lining of the excretory atrium. The anterior end of the fusion zone differentiated into an excretory bladder and a short posterior portion gave rise to the caudal vesicle.