Study of a species of eelworm closely akin to the eelworm of paper-hanger's paste but differing from it in certain anatomical details has afforded an opportunity for considering the systematic relationships of this interesting worm and its congeners with the result that a new and, to the writer, a more satisfactory grouping is put forward.

In the characters of the head, the structure of the stoma, the shape and build of the oesophagus and the general structure and arrangement of the female gonad as well as in the distribution of the male caudal papillae and the character of the spicules, the genera comprising this group, show obvious resemblances to members of the family Cephalbbidae Chitwood & Chitwood, 1934. The writer therefore proposes their formal inclusion in this family.

Schneider (1866), under the name Leptodera curvicaudata, described and figured certain nematodes obtained from moist soil and decaying matter. The species was removed to the genus Rhabditis by Oerley (1886) and the name became R. curvicaudata (Schneider, 1866) Oerley, 1886. Apart from the original description there appears to be no further record of the species in the literature dealing with this genus of free-living nematodes. The discovery of adult worms which agree well with Schneider's account provides an opportunity for redescribing the species and for giving some account of its very interesting association with flies belonging to the genus Psychoda. The writer is indebted for the material to Mr. G. H. Satchell who is investigating sewage purification problems at the University of Leeds (under a grant made by the Department of Scientific and Industrial Research) and discovered the association between the larvae of the worms and Psychoda flies concerning which further particulars are given later on.

Certain species of the nematode genus Anguillulina which commonly occur in close association with the roots of grasses are known to invade the root cortex and to reproduce therein. Thus Anguillulina pratensis, A. obtusa and A. erythrinae all occur in the roots of Agrostis stolonifera L. in pastures at this Institute. The writer has on a few occasions, also found one or two specimens of the small tapering-tailed species, A. agricola and A. costata, within the root cortex of the same kind of grass but further observations are needed before we can say definitely whether these two species actually parasitize roots and reproduce within the tissues. An occasional specimen of A. intermedia has also been found by the writer once or twice inside root tissues but never in what could be regarded as fresh, sound roots, and in view of Linford's (1937) observations on the ability of this species to feed upon fungal hyphae, it is probably safest to regard it as not a true parasite. The examples found may have entered partly decayed roots in search of fungal hyphae.

Recent re-examination of the paper by Maupas (1900) in which, on pp. 571–575, he describes Aphelenchus agricola de Man, and the figures 2-7 of plate 25 illustrating the same, have confirmed the writer in a view he expressed in an earlier paper (Goodey, 1928, p. 135) that Maupas was correct in identifying: the worms found by him in Algiers with Aphelenchus agricola de Man, 1881 = Aphelenchus avenae Bastian, 1805.

Disease in onions due to the stem eelworm, Anguillulina dipsaci, causing a soft rot of the bulb and a general stunting of the plant, commonly called “bloat,” has been known for many years. Its symptoms and pathology were fairly fully described and figured by Bos (1888–92). More recently a considerable amount of investigation on the disease has been carried out in U.S.A., particularly by Newhall and Chitwood [see Newhall & Chitwood (1940), Chitwood, Newhall & Clement (1940), Newhall (1941) and (1943)]. It is not intended to discuss this work here but merely to indicate that our knowledge of the disease set up both in the seedling plant and in the grown bulb is now fairly full and detailed.

Certain gaps in out knowledge of the bionomics of the disease have, however, remained, particularly those relating to its sporadic incidence in areas where onions have' not previously been grown or have not been grown for many years. One possibility which needed exploration was whether the parasite could be seed-borne. Bos (1889, ṕ. 346) provided a note on this matter. He said that in seed harvested from a diseased crop of onions and sent to him in the spring of 1886, he was able on close examination to see that some of the seed contained eelworms but only in small quantity.

Eelworm disease of tulips was first reported by Bos (1906) in bulbs of the varieties “La Reine” and “Yellow Prince,” grown at Sassenheim in Holland. Westerdijk (1906) dealt a little more fully with the same outbreak, described the typical brown ring symptoms shown by the bulbs and reported on a few preliminary trials designed to determine whether the parasite belonged to the same biological race as that attacking hyacinths.

Theobald (1912) reported the presence of Tylenchus devastatrix in a number of tulip bulbs (variety unnamed) which had been spnt to him from Dublin, Ireland. In a later note Theobald (1924–25) speaks of a tulip grower in Thanet, Kent, having such bad attacks of eelworm in his bulbs that he decided to remove his nursery to clean ground. Whether the stem eelworm was actually found in affected tulip bulbs was, however, not stated.

On 23/3/43 a small experiment was sown with commercial onion seed at Kirton, being one of a series laid down at county oentres in order to study the effect of different times of lifting on the development of wastage in store. Four varieties, which may be designated A, B, R, U, were sown in strips of three rows 10in. apart, in triplicate, the rows being 41 yards long and forming three randomised blocks. The liftings were also in randomised block pattern, 3 × 3, across the length of the rows. Two sub-plots of each variety were taken for convenience, consisting of adjacent six-foot lengths across the three rows, the produce of each sub-plot being put into a separate box immediately on lifting.

Whilst studying the hatching of larvae from cysts of Heterodera rostochiensis in different samples of potato and tomato root excretions, in the hope of ultimately developing a technique for the standardisation of root excretion, the author felt that it might be worth while to publish details of a refinement of Gemmell's (1940) single cyst technique.

When carrying out hatching experiments it would frequently be an advantage to have a quantitative measure of the activity of the root excretion used and search was accordingly made for a stable substance which could be made to a solution of constant known strength and which could be used as the basis for the comparison of the activity of different samples of root excretion. Hurst (Hurst 1937) records that tyrosine in dilute solution, lysine in the form of its picrate as well as picric acid at ·01% concentration caused active hatching to occur and experiments using the above single cyst technique were conducted to investigate these claims. The results with the former two substances were disappointing but dilute picric acid solutions were found to be very active. Since it is hoped to publish a further paper in which the effects of picric acid will be considered quantitatively and in detail it is not proposed to publish data in this article but concentration experiments showed that picric acid is most active at ·02—·01% concentrations, the solutions being made up in distilled water. Several experiments were conducted in which picric acid in these concentrations was compared with water and with root excretion; in all cases picric acid hatches were significantly greater than water hatches although picric acid was not generally as active as root excretion taken from vigorously growing plants.