340 LAMARCK, HIS LIFE AND WORK 



flanks, and with those which connect the tail with 

 the two hind feet, forming in these animals great 

 membranous wings with which they fly perfectly, as 

 everybody knows. 



" Such is then the power of habits, which have a 

 singular influence on the conformation of parts, and 

 which give to the animals which have for a long time 

 contracted certain of them, faculties not found in 

 other animals. 



" As regards the amphibious animals of which I 

 have often spoken, it gives me pleasure to communi- 

 cate to my readers the following reflections which 

 have arisen from an examination of all the objects 

 which I have taken into consideration in my studies, 

 and seen more and more to be confirmed. 



" I do not doubt but that the mammals have in 

 reality originated from them, and that they are the 

 veritable cradle {berceau) of the entire animal king- 

 dom. 



" Indeed, we see that the least perfect animals (and 

 they are the most numerous) live only in the water ; 

 hence it is probable, as I have said (vol. ii., p. 85), that 

 it is only in the water or in very humid places that 

 nature causes and still forms, under favorable con- 

 ditions, direct or spontaneous generations which have 

 produced the simplest animalcules and those from 

 which have successively been derived all the other 

 animals. 



" We know that the Infusoria, the polyps, and the 

 Radiata only live in the water ; that the worms even 

 only live some in the water and others in very damp 

 places. 



" Moreover, regarding the worms, which seem to 

 form an initial branch of the animal scale, since it is evi- 

 dent that the Infusoria form another branch, we may 

 suppose that among those of them which are wholly 

 aquatic — namely, which do not live in the bodies of 

 other animals, such as the Gordius and many others 



