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.

The material on which this article is based was sent to Dr. R. T. Leiper, C.M.G., F.R.S., by Mr. L. R. Hutson, Veterinary Officer, Antigua, to both of whom my thanks are due. Most of the cestodes had already been described by Prof. J. G. Baer and recorded by him in 1940. The rest of the collection consists mainly of nematodes but there are, however, representatives of all three groups of helminths—Trematoda, Cestoda and Acanthocephala as well as the Nematoda. The hosts were all described by the local popular names and I am much indebted to Mr. Kinnear, of the Natural History Museum, London, for identifying them.

The only trematode in the collection is the Strigeid, Apharyngostrigca cornu Goeze, 1800, which had been removed from the large gut of a Yellow crowned night heron, Nycticorax violaceous. It has already been recorded from a number of birds belonging to the Ciconidae and to the Ardeidae but not from this particular host. It is not uncommon in Europe and the United States but has not been reported in the British West Indies before. There are two specimens both attached to the mucous membrane but they were easily removed and seemed to have caused no pathological changes. They are mature and contain eggs and the vitellaria are strongly developed, obscuring most of the other organs.

In the following article is described an interesting parasitic condition which is difficult to interpret. The small intestine of an Hadada, Geronticus hagedash, was brought back from the West Coast of Africa by Major T. A. Cockburn, M.D., R.A.M.C, who kindly passed it to me for further examination. The bird is a member of the family Plataleidae, living in wooded districts in West Africa in the neighbourhood of water and feeding on invertebrates, mainly annelids and small crustaceans which it finds at the bottom of ponds and streams in the mud.

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.

Many crops of carrots grown in gardens and on a field scale, during the War, have been infested with a weed which bears a resemblance to Solanum nigrum. It has been identified as Solanum sarachoides Sendtner. The plant is a native of Temperate and Sub-temperate South America. The carrot seeds containing this impurity are said to be of Californian origin.

The plant possesses oval leaves, slightly more wavy than those of British specimens of S. nigrum. They are smooth and dark green in colour, but the stems are covered with short hairs. The habit is procumbent to prostrate and the weed creeps extensively through the dense foliage of the carrot crop. The inflorescences are borne laterally and display minute white flowers. Dark green berries are produced in great profusion each containing about 25 seeds. There is evidence that the plant is becoming established on light soils, in the market gardening districts of Staffordshire, and it is doubtless localised elsewhere.

It was noted that where the weed was growing adjacent to plots of potatoes affected with blight (Phytophthora infestans), that its leaves were also attacked. The lesions resembled those of potato blight and the identity of the fungus was confirmed by Mr. N. C. Preston, of Harper Adams Agricultural College.

Up to the present time, so far as the writer is aware, there has been no previous British record of galls on a moss caused by a nematode although cecidologists have reported galls of nematode origin on 52 species of moss on the continent of Europe (see Goodey, 1940). Except in the case of Hypnum cupressiforme L. and Thuidium delicatulum (L.) Hedw., in which the causal parasite is Anguillulina askenasyi (Bütschli, 1873), the specific identity of the worms affecting the other 50 species has not been determined though it is probable that in all cases they belong to the genus Anguillulina.