FOOD, HABITS, ETC. 85 



dispersal. Not infrequently large Water Beetles 

 have been captured in flight from one piece of water 

 to another that have proved to be carrying molluscs 

 attached to them. It may be one or more Bivalve 

 Shells holding tight on to the legs, or a freshwater 

 Limpet (Ancylus) or two, adhering to the wing-cases. 

 The fry of other kinds of Snails may be readily 

 transported in similar fashion. Water-fowl and 

 Wading Birds have likewise been taken with 

 Bivalves adhering to their feet, and have been 

 observed to fly off with water-weeds clinging to 

 them that might well bear both small kinds of shells 

 and ova. Young Snails may also be transported 

 sticking to the bird's plumage. On the arrival of 

 the insect or bird at a fresh piece of water these in- 

 voluntary passengers drop off, and in this way fresh 

 colonies are started. 



Land molluscs and their eggs adhering to vegeta- 

 tion are carried down by flood waters and stranded 

 on subsidence in fresh pastures. Small forms 

 dwelling in swampy ground and ova may further- 

 more be conveyed to distances in the mud sticking 

 to birds' feet, or clinging to their feathers, especially 

 if the birds be such as roost on the ground. 



Transport by man, both intentional and acci- 

 dental, hardly enters into consideration here ; but it 

 is interesting to remark how the commoner and 

 hardier European Slugs and Snails have been intro- 

 duced near ports of call in many widely separated 



