While carrying out an intensive survey of the helminths parasitic in domestic animals at Aberystwyth, an opportunity was Afforded the writer to examine the dogs and cats taken to the local police station for destruction by the lethal chamber process. These animals comprised the unclaimed “strays,” the incurably wounded or maimed, the vicious and the aged. Healthy but unwanted animals, also, were occasionally destroyed.

In the extensive literature devoted to this worm axe many anatomical descriptions, the earlier of which are, according to modern standards, vague and superficial. But among recent authors de Man (1910) has given a full and illustrated account with detailed measurements of some forty specimens, an account to which it might seem difficult to add anything of importance. However, the present writer is preparing a paper on the bionomics of the worm, and therefore considers a brief anatomical description to be desirable, particularly as de Man's paper may not be easily accessible to those interested

It is well known that free-living nematodes are of frequent occurrence in various kinds of rotting organic materials both animal and vegetable under natural conditions. In a recent investigation of the nematodes occurring in a variety of substances such as pig-manure, sheep droppings taken from pastures, soil from a chicken run, decaying leaves from a drain, etc., the writer has made use of the Baermann method (Cort and others 1922) with a good deal of success. Amongst several interesting forms obtained from samples taken from a heap of pigmanure were six worms, four females and two males, belonging to the genus Aphelenchus, which at once attracted attention by reason of certain peculiarities in their appearance. They closely resemble Aphelenchus tenuicaudatus de Man (1895) in certain anatomical features, but differ on certain points, and the writer regards them as belonging to a hitherto undescribed species.