82 NATURAL HISTORY OF BRITISH FRESH-WATER LEECHES. 
flat and of a brownish colour. They are deposited on leaves and 
stems of plants, sticks, stones, etc. The mode of fertilization 
and the manner in which the cocoon is fixed are described on 
p.p. 68-69. Breeding takes place from May to October. Rawlins 
Johnson (31) states that one individual deposited 12 cocoons 
during a period of 21 days. Each cocoon contains from 6-12 
ova, and the period of incubation extends 30 to 70 days according; 
to the state of the weather. 
Distribution .—As this species is so often confused with H. 
atomana, it is impossible to know to which species the records- 
belong. It is very widely distributed, however. The writer 
has taken specimens from the following localities :—Epping 
Forest, near Abridge in stagnant pond, Richmond Park, Chalfont 
St. Peters, Staines. 
Herpobdella atomaria Carena ( Nephelis vulgaris). Plate 
VII., Figs. 7 and 8. 
Description. —Very much like H. octoculata , but lighter in colour and 
with yellowish spots on the dorsal surface. The first ring of each somite- 
is much lighter in colour than the others. In this species the genital 
pores are separated by three rings (Plate VII., Fig. 8). Somite V is usually 
biannulate. 
Habits. —Similar to those of H. octoculata. 
Distribution .—Common. The writer has taken examples 
at Chigwell Row ; Epping Forest ; R. Roding, near Abridge ; 
Richmond Park ; Staines ; Totteridge ; R. Chess ; R. Wharf, 
Grassington, Yorks. 
Trocheta subviridis Dutrochet. Dutrochet’s Leech. Plate 
VII., Fig. 14. 
Description. —Body elongated, vermiform with well marked sucker at 
the posterior end. Dorsal surface dark brownish green, with two dark 
brown longitudinal bands. Ventral surface of a lighter hue. A distinct 
clitellum is often present. There are normally eight eyes, 4 in the second 
ring and two lateral pairs in the fifth ring. The anus opens between the 
third and fourth ring, reckoning from the posterior disc (cf. Haemopis 
sanguisuga). Length at rest 80—100 mm. ; 200—215 mm., when extended. 
Width 7-15 mm. 
Habits. —Lives in streams contaminated with sewage, and on 
land in gardens, on lawns, paths or under boxes. It feeds upon 
earthworms, which are swallowed whole. The cocoons are 
elliptical, dark brown and are attached to foreign bodies. They 
measure from 9-14 mm. in length and 6-8 mm. in width. 
