Page:The Zoologist, 4th series, vol 1 (1897).djvu/482

454 or well-marked varieties. When I first took up the study some years ago it was assumed that the total number of species did not exceed ten. I believe that two or three other species might be certainly added to the list if the localities as yet unsearched were to be examined. Special attention should be given to the Earthworms of Shetland, the Scottish Highlands, the extreme south-west of England, the Scilly and other isles, of all of which we at present know practically nothing.

Some years ago I adopted the plan of denoting the girdle-segments, and those carrying the glands known as tubercula pubertatis by means of a fraction. Thus $30–36⁄31–35$ would denote that the species had a girdle in the adult which extended from the 30th to the 36th segment, while the 31st to the 35th segments were marked by tubercula. Sometimes, however, the tubercula are on alternate segments, when they are denoted by the symbol $30–36⁄31:33:35$. I have not seen any better method of denoting these important organs, so shall adopt it in the present list. The genus which is still the least satisfactory is Allurus. I formerly reported five species, but to-day I reckon three, with one well-marked variety. No new light having been thrown on Dugès' Amphisbena, I have dropped it from the list. I omit all aliens known to be imported from abroad, such as the ubiquitous Perichæta.

Lip or prostomium cutting right through the peristomium, or forming a complete mortise and tenon. Girdle of five or six segments. On the four innermost a band formed by the tubercula pubertatis on the ventral surface. Eight setæ in each segment but the first, arranged in four couples, not in equidistant rows. Male pores on the 15th segment with or without papillæ. Colour dark brown, red, or violaceous, with iridescence. Body cylindrical in front, flattened behind to enable the creature to retain its hold in the burrow when the head is exposed. Slime exuded especially when irritated, but no coloured fluid thrown out from dorsal pores as is the case with many species of Allolobophora. The species at present known in the British Isles, with some of the localities, are as follows:—