58 
MADAGASCAR 
The earthworms of the island are specially remarkable. 
Of the smaller species Pontoscolex corethattriis and Peri- 
chceta biseriahs occur the most frequently. A truly gi¬ 
gantic species was discovered by me in 1886 (Kynotus 
Darwinii). I possess several specimens of the thickness 
of the finger and a yard and a half in length. In the 
formation of mould and preparation of the soil they take 
a pre-eminent share, for they make deep passages in the 
ground and thus contribute to the airing and breaking 
Excrement of tlie earthworm (Kynotus Darwinii) 
(greatly reduced). 
Up of the surface mould. These gigantic annelida, after 
the fashion of our earthworms at home, pass a mass of 
earth through their intestines to cast it up afterwards 
on the surface; masses of these lumps of excrement lie 
about in many places. When dry they weigh on an 
average from 4^ to 5 ounces, and some specimens attain 
the weight of from 6 to 6| ounces. The disturbance 
of soil must thus be very considerable, and it is calculat¬ 
ed that these animals are able in the course of 50 years 
to supply to the surface a stratum three feet in thickness. 
