BRITISH ANNELIDS. 187
The colour is reddish brown, with lighter girdle and under-surface.
Hitherto I have found it only in the north, and I believe it would
occur plentifully in the pine forests of Scotland. It is without
known varieties, and forms an admirable type.
2. Eisen's Worm (Lumbricus eiseni, Levinsen), is the
first Essex representative of this group which I had the pleasure to
examine. It is not a true Lumbricus, although it has some affinities
with that genus, especially if we examine the terrestrial form. The
dendrobaenic type closely resembles Boeck's worm in colour. The
setae, however, are arranged in four couples which are wider apart
than in the true earthworms. The lip and peristomium form a
perfect mortise and tenon, as in Lumbricus. There are seven to ten
girdle segments, but usually the clitellum covers the 24th to the 31st.
It specially delights in old decaying tree stumps. I have received
from Essex, however, not only the typical dendrobaene, but also a
terrestrial variety, which differs so widely from the type that I have
named it var. gracilis, on account of its very slender appearance. It
is usually about an inch in length, or at most one and a half inches,
and is composed of some ninety to 100 segments. The tail is some-
what flattened and spatulate, as in the true Lumbrici, when the
worm lives in the soil ; but angular when found in trees. The variety
also has a beautiful iridescent play upon the back which the type has
not. There are no papillae on the girdle (i.e., tubercula pubertatis),
and those which carry the male pores on segment 15 are but
slightly developed. The variety differs from the type in colour,
shape, and habitat, but not in the position of the different organs.
My Essex specimens of var. gracilis are from the side of a ditch,
Becton Road, Plaistow Marsh, collected by Mr. W. Allen. The
type came from an old tree stump in Epping Forest.
3. The Celtic Worm (Allolobophora celtica, Rosa), like the
preceding, has both a terrestrial and a dendrobaenic form. They
differ so widely in appearance that I was for a good while unable to
decide whether or not to regard them as distinct species. The form
described by Rosa under this name is found in the soil. The tree-
dweller (var. rosea, Friend) ought to be the type as representing the
genus Dendrobaena. The prostomium or lip does not cut backwards
into the first ring, as is the case with the foregoing. The setae are in
eight rows. The ground form is of a violaceous colour on the back,
whereas var. rosea is a warm rosy brown. The male pores in Rosa's
species are on papillae which affect the two adjoining segments by
O 2