While fixing a number of tapeworms (Anoplocephala perfoliata Goeze) from the small intestine of the horse, I came across a small tri-radiate specimen. This abnormality has previously been described by Neumann (2), but only briefly, and without any account of the internal anatomy. It therefore seemed advisable to compile a short account of the most salient characteristics. For the material I am indebted to Dr C. L. Boulenger, Helminthologist of this Department. I have also to thank Professor L. G. Neumann for obtaining for me a copy of his paper.

The present paper contains the results, other than those already published, of work done in the Department of Agricultural Zoology at the Birmingham University upon the tapeworms of birds. At the commencement, a little over two years ago, the aim was to make a complete investigation of the Cestodes of British birds, both from the standpoint of anatomy and also of life-history, since, as far as I am aware, there exists no adequate description of them. It was found impossible to obtain a regular supply of any one species of tapeworm, hence the work upon one particular species could only be carried on spasmodically. The results, having to wait upon the occurrence of the material, are necessarily incomplete. Circumstances having made it necessary temporarily to postpone the work, it was considered advisable to write up and publish the results so far obtained.

Eight forms, referred to the genus Ascaris, were described by Dr W. Baird between 1853 and 1868, all of which are represented by type-specimens in the British Museum collection. Stossich, in his monograph of the genus Ascaris (1896), mentions six of them, but all these are regarded by him as species inquirendae. Baird's descriptions are in all cases brief, and confined almost entirely to external features, this rendering them inadequate for the requirements of present-day systematic workers. I have, therefore, thought it advisable to undertake a revision of the various types, with a view to deciding more definitely their systematic value, and, where possible, to re-describe those which appeared to me to represent valid species.

Since the appearance in 1901 of Looss' important monograph on the Sclerostomes of Horses and Donkeys in Egypt a much greater interest has been shown in the presence of these and allied Nematodes in other parts of the world, but, although nearly fifteen years have elapsed since that publication, very little addition has been made to our knowledge of this branch of helminthology

Within the last few years several books and numerous papers have been published dealing with various problems relating to the life-histories, and disease-spreading capacities, of house-frequenting and other nonbiting flies. An intimate knowledge of the habits of flies is essential if the most suitable methods are to be devised in order to diminish their numbers, yet it is only too evident that many of the accepted hypotheses are founded on the most superficial observations, and that extensive and carefully planned experiments, with a few notable exceptions, are conspicuously absent.