186 
The British Leeches 
as T. subviridis have been reported from the Zoological Society’s 
Gardens have led to the supposition that this species has been intro¬ 
duced together with some foreign animal, and that the latter locality 
has been its centre of distribution. 
There is little, however, to substantiate this view. The geographical 
range of T. subviridis is, as we have seen, somewhat limited, on the other 
hand a number of closely allied forms occur in the Oriental Region for 
which it might be mistaken. To an Oriental species indeed ( Whitmania 
ferox) Blanchard (1896, p. 322) has referred the leech described as T. sub¬ 
viridis by Murie (1865, p. 659), taken post mortem from the viscera of a 
Moluccan deer in the Zoological Society’s possession. The identity 
again of the land leeches found in 1877 by Professor Garrod in the 
above Society’s Gardens and referred to by Hal ting ( loc. cit.) as probable 
examples of Dutrochet’s leech is by no means beyond dispute. 
The species in question is in fact rare but indigenous in this country, 
although the factors which determine its somewhat sporadic occurrences 
are obscure. It is probably not so uncommon as is generally supposed. 
Its superficial resemblance to an earthworm may not infrequently have 
caused it to be overlooked and our ignorance of this species, as in 
the case of several other English leeches, is undoubtedly largely due 
to the small amount of attention which British Hirudinea have hitherto 
received. 
Trocheta subviridis is carnivorous, devouring piecemeal various 
species of earthworms and also (Blanchard, 1894 b, p. 64) the larvae of 
insects. It is amphibious, frequently leaving the water in order to 
pursue its prey in moist situations upon land. According to Moquin- 
Tandon (1845, p. 312) the egg-capsules, which are elliptical, flattened, 
dark brown and nearly opaque, are attached by their extremities, as in 
the case of Herpobdella , to some foreign body and attain a length of 
9—14 mm. and a width of 6—8 mm. 
LIST OF BRITISH HIRUDINEA. 
Sub-order I. RYNCHOBDELLAE. 
Family I. ICHTHYOBDELLIDAE. 
Genus. Branchellion. 
Species. B. torpedinis. 
Genus. Trachelobdella. 
Species. T. lubrica. 
