322 PROCEEDINGS OF SECTION D. 
We have seen that the sea is impassabler Not so rivers, 
for fresh water does not kill earthworms—which will with- 
stand immersion in fresh water for weeks, or at any rate for 
several days; whilst several species live habitually in the 
bottom of rivers or ponds; while a few are “ amphibious ’’— 
and, moreover, rivers imply continuity of dry land. High 
mountains do not deter earthworms, for I have examined 
worms collected at considerable heights by Mr. Ed. 
Whymper, the well-known Alpinist, from 8000 feet in the 
Swiss Alps, and from the great height of 15,871 feet at the 
very summit of Corazon, in the Andes. It appears that so 
long as soil, with some vegetation, exists, worms may tra- 
verse even high mountain ranges. But a desert, by its dry- 
ness, and by the absence of food in the form of vegetable 
matter, forms an insuperable barrier to earthworms. 
We are thus led to the conclusion that, like mammals, 
earthworms can only be dispersed over the surface of this 
planet by their own active locomotion over a continuous 
tract of land-surface in which vegetation of some sort grows. 
But it is important to bear in mind that, at the present 
time, there is a constant chance of alien earthworms being 
introduced into all lands and countries occupied by civilised 
races, or in trade connection with other countries. This 
introduction is effected by the agency of man. 
Plants, with a small quantity of soil around the roots, 
are sent to and from various parts of the world, and in the 
soil small earthworms or their cocoons are frequently em- 
bedded. At any rate, at such centres of horticulture as 
Kew Gardens, in London, it is a frequent occurrence for 
foreign earthworms to be found in the wardian cases con- 
taining plants received from distant foreign countries. 
We must also remember that the Polynesians, like the 
Maoris, were great travellers by sea, and carried with them 
vegetables, such as the taro, kumara, and so on; and this is 
a possible means of introductions of cocoons into distant 
lands. 
But, whatever may be the actual means by which alien 
worms are introduced by man’s agency, it is a fact, well 
known to all lumbricologists, that, as soon as settlement has 
been long enough to enable settlers to cultivate gardens, 
European earthworms, of the genera Lumbricus and Allolo- 
bophora, make their appearance in the soil. In and around 
towns, both in New Zealand and Australia, we know how 
difficult it is to find native earthworms; they are driven out 
of the cultivated land, and have to be sought for further 
and further away from closely-inhabited areas. The fact 
