NATURAL HISTORY OF BRITISH FRESH-WATER LEECHES. 8l 
Distribution. — Britain :—Generally distributed. Near Clacton 
(per Mr. Picton) ; Epping Forest ; Chigwell Row ; R. Stort 
(H. W.) ; Finchley, Hampstead, Muswell Hill, Walthamstow, 
Tottenham, Totteridge (W. Blair) ; near Norwich (Brightwell, 
9) ; Eckington Canal (Evans, 15). 
Ireland :—Common (Scharff, 39). 
Foreign :—Occurs throughout the greater part of Europe, 
and is found in Transcaucasia and Syria (Blanchard, 6). 
Hirudo medicinalis, L. ( =Sanguisuga officinalis, Sav.). The 
Medicinal Leech. Plate VII., Figs. 11-13. 
Description. —Body elongate and slightly flattened. The dorsal surface 
has a well marked pattern with three pairs of longitudinal yellowish 
bands. The lateral pair has an uninterrupted inner band of dark brown, 
while each of the median and intermediate pairs has an interrupted band 
of dark brown running down the middle. The ground colour of the dorsal 
surface is usually a dark olive green, but may be slatey grey or reddish 
brown. The ventral surface is dark brown with irregular grayish green 
patches. Length 100-150 mm., and width 10-15 mm. Another 
specimen when extended measured 250 mm. long and 30 mm. wide. (I 
am indebted to Mr. Wm. N. Blair, jun., for two specimens taken in the 
New Forest in 1911, from which the above description has been written- 
Habits. (See pp. 70-74.) 
Distribution. — Britain : — Near Norwich (Brightwell, 9) ; 
Christchurch, Hants ; Weymouth (Johnston, 32) ; Loch Leven ; 
L. Fleury near Blairnlone, near Comrie; L. of Monteith ; 
Gartincebar (Dalyell, 12) ; New Forest (W. N. Blair, 1911). 
Ireland :—Lough Mask (Scharff, 39). 
Foreign :—Germany (I. of Borkum and Thuringia, Johannson, 
30) ; Italy (Blanchard, 7). 
Herpobdella octoCulata (=Nephelis octoculata, L.). Plate 
VII., Fig. 9. 
Description .—Body elongate, slightly flattened. Colour brown or 
reddish brown on dorsal surface, lighter beneath. Colour generally 
uniform. Length 20-50 mm., and width 2-5 mm. The clitellum is often 
well marked. Genital openings separated by 4 rings (see Plate VII., 
Fig. 9). Somite V is triannulate. Eight eyes, 4 in the first ring and two 
pairs in the 5th, as in H. atomaria. 
Habits. —Lives in mud in stagnant ponds, on weeds and under 
stones in running streams. This is a very common species 
and has often been confounded with H. atomaria. It preys 
upon the smaller aquatic worms and insect larvae. The cocoons 
are elliptical in outline (4-6 mm. long and 2-4 mm. wide), are 
