SKULL OF THE BABIRUSSA.
Note especially that the tusk of the upper jaw grows upward from the first. No part of it is directed into the mouth. This tusk is of extraordinary size, and it curves upwards so as to touch, and sometimes even to pierce, the skull. They are, as compared with those of other swine, slender tusks, more especially the under ones. The upper tusk grows through the skin of the upper lip. In old animals, when it is well curved, it must be useless as a weapon. It may serve to protect the eyes when the animal rushes through brushwood. In the female the tusks are small.
ANSWERS TO CORRESPONDENTS, &c.
Conchologist.—Your shells are Helix nemoralis (immature), Hyalinia (Vitrea) pura, and Buliminus obscurus. Vitrea pura is a much smaller shell than V. nitidula, the latter may be distinguished from V. radiatula by the striæ not being continued from whorl to whorl. B. obscurus is much smaller than any member of the genus Clausilia. If you examine in May the trunks of beech trees growing on calcareous soils you will find B. obscurus and Clausilia laminata ascending them in large numbers to spend the summer aloft, coming down again in October to go into hybernation at the base of the trees during the winter months. You will find C. rugosa (in modern terminology, C. bidentata) equally common on the trees, it is smaller and thinner than C. laminata. B. obscurus is a short, stout little shell, seldom exceeding 9 millimetres in height.
Gardener. Diseases of the Cultivated Chrysanthemum.—At the present time three diseases are recorded for this country, viz., sclerotium disease (Sclerotinia sclerotiorum, Massee); corticium disease (Peniophora chrysanthemi, C. B. Plowright), and the only too familiar Rust (Puccinia hieracii, Mart). The sclerotium, which first appears as a white mould on the stem just above the ground, forms black lumps within the stem. The stem becomes very brittle and falls. From the black nodules in the following spring, small funnel-shaped brownish fungi with long, weak, dark stems appear. The spores from these settle upon dead organic matter, forming an abundant mycelium which ultimately attacks the base of the stems of chrysanthemums. It is said that fresh stable manure favours the spread of the disease. Diseased stems should be carefully collected and burnt.
The corticium disease also appears on the lower part of the stem, forming a white growth in autumn; Dr. Plowright, who first discovered it, says it resembles a splash of whitewash. It is not confined to the stems but extends into the adjacent soil. Diseased plants are shorter in height and thinner in the stem than healthy; they always die within the year. This disease has hitherto been observed only at King’s Lynn in Norfolk, but it is very possible it occurs in other parts of the country. Dr. Plowright remarks that the only treatment is burning the diseased plant. It is useless to separate the apparently healthy shoots.
The well-known chrysanthemum rust first appeared in 1897, and spread with great rapidity in the very dry summer of 1898. The snuff-coloured uredo spores (summer form) are familiar to all cultivators of chrysanthemums. This fungus occurs on many wild plants of the order Compositæ, notably the hawk-weeds (Hieracium). All diseased plants should be burnt. The disease may be prevented by spraying the new leaves with potassium sulphide solution.
It is to be hoped that the chrysanthemum leaf blight (Cylindrosporium chrysanthemi), which has caused so much damage to cultivated plants in Ontario, Canada, will not find its way into this country. It forms large dark patches on the leaves, which turn yellow and hang down; the flower buds do not expand. It is stated that fungicides are useless.