174 Transactions of the Society. 



there was to be caught ; for it lay in a flat plot of ground, where there 

 was an entire absence of trees and shade, so that its surface was fully 

 exposed to every wind that blew. 



The eggs, of course, must often fall on unsuitable places, and be 

 carried past suitable ones ; and this accounts for the capricious appear- 

 ances of Eotifera in some well-watched pond, and for the frequent 

 disappointments of the naturalists who visit it. To this aerial carriage 

 of the eggs is also due the otherwise perplexing fact, that when any rare 

 Eotiferon is found in one spot, it is frequently found at the same time 

 in closely neighbouring ponds and ditches, even in such^ an unlikely 

 hole as the print of a cow's foot filled with rain, but not at all in 

 more promising places at some distance off. 



Admitting then this fitful shower of eggs as proven, we at once 

 see another way in which they may readily travel to distant lands. 

 For it is quite possible that now and then they may fall on the cargo 

 of an outgoing ship. Here they would lie safely in cracks and creases 

 till, the journey being over, the knocking apart of packing-cases and 

 the shaking of wrappers would set them afloat again, to drop down, 

 it may be, into the Botanical Gardens of Sydney, the shore-pools of 

 Ceylon, or the ponds of Jamaica. In fact these Kotifera would have 

 really done what I have already pointed out that they seemed to do, 

 they would have followed the flag. 



The eggs of the tube-makers, however, and of such Eotifera as 

 live only in the clear waters of lakes and deep ponds, present a greater 

 difficulty ; for their eggs either lie within their tubes, or are attached 

 to growing weeds, or fall down to a bottom which lies covered all the 

 year round with several feet of water. The wind and sun here cannot 

 be the only means of dispersion. Aquatic birds and insects are pro- 

 bably assisting agents. These, as they swim among the water-plants, 

 must frequently set free the eggs from the tubes of the Ehizota, as 

 well as those which adhere to confervse, potomogetons, and water- 

 lilies, and so get them attached to their bodies. Then away they 

 fly, carrying the eggs to some far distant lake, or shaking them off 

 into the air with the beating of their wings. 



In confirmation of this idea I may mention that the well-known 

 naturalist Mr. John Hood of Dundee, who has added so many re- 

 markable species of Ehizota to our rotiferous fauna, informs me that 

 the Scotch lakes most prolific in new and rare species are those which 

 are visited annually by wild-fowl from the north. Prof. Leidy also 

 informs me that his collector, Mr. Seal, noticed sandpipers haunting 

 the duck-pond where he found an Asplanchna very similar to Ebhes- 

 hornii, and that he thought that " these birds were especially instru- 

 mental in distributing the lower forms of aquatic life." I may add 

 also that, on one occasion, I found in a temporary rain-puddle, barely 

 a yard across, a living ciliated ovum of Plumatella rejpens. Of course 

 the puddle itself contained no adult forms, and the ovum must have 

 been brought by some bird the distance of at least half a mile. The 

 twin polypes were already partially developed inside the ovum, and it 



