4 ORGANIC EVOLUTION 



barnacles, which nature produces in a wonderful manner, 

 out of her ordinary course. They resemble the marsh 

 geese, but are smaller. Being at first gummy excrescences 

 from pine-beams floating on the water, and then enclosed 

 in shells to secure their free growth, they hang by their 



FlG. i. Goose -barnacles (Le/itis ai/af/fcra) attached to a floating piece of wood. Natural 



size. From Brehm's Thlerleben. 



beaks, like seaweeds attached to the timber. Being in pro- 

 cess of time well covered with feathers, they either fall into 

 the water or take their flight into the free air, their nour- 

 ishment and growth being supplied, while they are bred 

 in this very unaccountable and curious manner, from the 

 juices of the wood in the water. I have often seen with 

 my own eyes more than a thousand minute embryos of 



