26 



LECTUEES ON BIOLOGY 



elongation of one finger, and because the wing-membrane 

 extended between the hand and the body, exactly as in bats. 

 But as a matter of fact these fossils are the remains of a 

 long-extinct genus of reptiles, the Flying Saurians. Here, again, 

 like functions have produced likeness of organs in widely differing 

 classes of animals. 



Having reviewed 

 these facts, we can now 

 understand why Lam- 

 arck came to proclaim 

 his theory of evolution. 

 The most important 

 question which we shall 

 have to answer before 

 we can adopt his views 

 is, whether a trans- 

 mission of functional 

 increase or modification 



FIG. 7. SKELETON OF THE ANTEEIOE EX- 

 TREMITIES OF THE BAT AND THE FLYING SAURIAN 

 PTERODACTYLUS. 



of an organ to subse- 



quent generations is 



conceivable, or, in other words, whether we have a right to 

 assume the transmission by heredity of acquired characters. 

 With an answer to this question Lamarck's theory stands or 

 falls. We shall attempt to decide the important question in 

 the seventh lecture, where we shall also see how Darwin 

 explained the fitness of the organic world and the adaptation of 

 animals and plants to the ruling conditions of life. 



