In the blood of the above mammals there was found in varying proportions those enigmatical bodies recently described by Theiler as Protozoa under the name Anaplasma marginale, but more generally known as “marginal points” or “coccus-like bodiees.”

A comparison of the descriptions of the morphological characteristics of Filaria loa by previous authors shows differences which are explained by the study of our uninjured specimens. We have prepared a table (q.v.) which shows the results of the work of various observers together with our own. We believe that most of the drawings so far published are somewhat misleading; we have, therefore, drawn the essential parts as seen through the microscope with an entire diameter and a portion of a longitudinal section in focus. The drawings are not composite or schematic but have been made on a large scale with accuracy in the measurements so as to represent the different parts in proper proportion (see Plate).

This method is especially applicable to the blood and body fluids of Invertebrates in which true clotting does not occur, and in which the proportion of proteid substances in the serum is not high.

In this brief note it is not my intention to enter into detailed criticism, but merely to express my surprise and that of other proto-zoologists, that the personal opinions of the Recorder should be allowed insertion in the Zoological Record (1909) which is also the International Catalogue of Zoological Scientific Literature. Against this procedure I beg to record an emphatic protest.

Although in nature Sleeping Sickness is chiefly transmitted by Glossina palpalis, the possibility of other modes of infection has been suggested by various authors.

In a recent paper (Journal of Parasitology, 1910, III. pp. 245—54) I described a new trichomonad (Trichomastixc trichopterorum) and a spirochaete from the hind-gut of certain trichopterous larvae. I also mentioned the occurrence along with these parasites of another peculiar flagellate, which, at the time, I was disposed to consider as closely related to Macrostoma caulleryi, Alexeieff.

Although the literature on ticks is very extensive, we have failed to find any satisfactory description therein of the process of copulation. Most authors state that the male mouthparts are introduced into the female genital orifice, or vulva, and that this constitutes copulation, leaving it to the reader's imagination to determine how the seminal secretion gains access to the female generative organs. The mechanism of copulation, in other words, remains to be described, and we propose, in this paper, to give an account of what we have observed in Ornithodorus moubata. We shall describe the process in Ixodidae in a later paper, but may state here that, as far as our knowledge goes, it is essentially the same as in moubata, that is, impregnation takes place by means of spermatophores.

A consideration of the facts presented in the foregoing pages appears to warrant certain conclusions which must, however, be regarded in part as provisional and subject to revision when our knowledge of the various species of ticks has become more extended. The views here expressed may prove of practical use in the study of the Ixodidae.

The Argasidae represent the relatively primitive type of ticks because they are less constantly parasitic than are the Ixodidae. Their nymphs and adults are rapid feeders and chiefly infest the habitat of their hosts. In certain Argasidae (O. moubata and O. savignyi) the disadvantage of their possessing an “active” larval stage has resulted in the development of an “inactive” larva, i.e. the young nymph being the first to suck blood. In O. megnini we have a considerable adaptation brought about by the difficulty there must be in the tick entering the small aperture of the ear more than once. Owing to the Argasidae infesting the habitats of their hosts, their resistance to prolonged starvation and their rapid feeding habits, they do not need to bring forth a large progeny, because there is less loss of life in the various stages, as compared to Ixodidae, prior to their attaining maturity.

The Ixodidae are more highly specialized parasites than the preceding. The majority are parasitic on hosts having no fixed habitat and consequently all stages, as a rule, occur upon the host. In the genus Ixodes we find an adaptation of certain species according to the habits of the hosts upon which they are parasitic. In the species which usually occur upon wandering hosts both sexes are found upon the host, whereas in other species which occur on hosts possessing more or less fixed habitats the males are rarely or never found upon the host. The males of species of Ixodes, both sexes of which occur upon the host, are characterized, as a rule, by the possession of hypostomes with prominent teeth, the reverse being the case in forms wherein the males do not occur upon the host. Where species occur upon a wandering host it is essential, for their propagation in nature, that both sexes should be carried about upon the host.

In the course of an inquiry into the relation between the bionomics of certain insects and epidemic disease upon which I am engaged, the following question suggested itself to me. In the event of a larva becoming bacterially contaminated by means of its food, is it possible that the resulting pupa and imago will still be infected? The only previous work bearing upon this question with which I am acquainted is that of Faichnie, who writes:

The embryo of Filaria loa has never been fully studied or described and for this reason the hypothesis put forward by manson, that the Filaria diurna is the larva of Filaria loa, remains unproven. when manson suggested this connection he had at hand some sketches of embryos which leuckart had made and sent to him. as these sketches were not of sufficient aid to establish the identity of the embryos with the larvae found by him in the blood, and as no metamorphosis takes place in the larvae while circulating in the blood, it is reasonable to suppose that they must have been rather crude sketches. however, the hypothesis came to be accepted because it was well supported by the fact that the two worms have the same geographical distribution and also by the occasional discovery of both in the same host. at the same time that this hypothesis was advanced, manson changed the name from Filaria sanguinis hominis major to Filaria sanguinis hominis diurna and said that the species was practically indistinguishable on morphological grounds from the well-known Filaria sanguinis hominis of Lewis (Filaria nocturna, Manson) i.e.Filaria bancrofti. this fact made it all the more necessary to observe embryos taken from an adult female Filaria loa before venturing to state the origin of the larvae found in the blood.