Chap. XIII.] 
LEECHES. 
483 
the march of troops in the mountains, when the Kan- 
dyans were in rebellion, in 1818, the soldiers, and 
especially the Madras sepoys, with the pioneers and 
coolies, suffered so severely from this cause that numbers 
perishedi 1 
One circumstance regarding these land leeches is re- 
markable and unexplained ; they are helpless without 
moisture, and in the hills where they abound at all other 
times, they entirely disappear during long droughts ; — 
yet re-appear instantaneously on the very first fall of 
rain ; and in spots previously parched, where not one 
was visible an hour before, a single shower is sufficient 
to reproduce them in thousands, lurking beneath the 
decaying leaves, or striding with rapid movements 
across the gravel. Whence do they re-appear ? Do 
they, too, take a " summer sleep," like the reptiles, 
molluscs, and tank fishes ? or may they, like the Roti- 
fera, be dried up and preserved for an indefinite period, 
resuming their vital activity on- the mere recurrence of 
moisture ? 2 
Besides a species of the medicinal leech, which 3 is 
1 Davy's Ceylon, p. 104 ; Mae- 
shall' s Ceylon, p. 15. 
2 See an account of the Botifera 
and their faculty of repeated vivi- 
faction, in the note appended to 
this chapter. 
3 Hirudo sanguisorba. The 
paddi-field leech of Ceylon, used 
for surgical purposes, has the 
dorsal surface of blackish olive, 
with several longitudinalstrise,more 
or less defined ; the crenated 
margin yellow. The ventral sur- 
face is fulvous, bordered laterally 
with olive ; the extreme margin 
yellow. The eyes are ranged as 
in the common medicinal leech of 
I I 
Europe ; the four anterior ones 
rather larger than the others. The 
teeth are 140 in each series, ap- 
pearing as a single row ; in size 
DOHSAL. VENTRAI. 
diminishing gradually from one 
end, very close set, and about half 
Ihe width of a tooth apart. When 
lull grown, these leeches are about 
2 
