74 THE TRANSFORMATIONS OF THE ANIMAL WORLD 



Outside the consideration of series of forms, 

 great importance must be accorded to certain 

 extinct types which take their place between two 

 zoological groups now entirely distinct, and establish 

 a link between them. There is no more decisive 

 example than that of the Archceopteryx, the bird 

 of the lithographic limestone of Solenhofen ; its 

 beak furnished with teeth planted in gums, 

 its tail formed of elongated vertebrae, its wings 

 bearing at their extremities distinct fingers with 

 claws, the presence of ventral ribs, and the arrange- 

 ment of the bones in the phalanges, all constitute 

 an aggregate of reptilian characteristics which 

 permit us, without any hesitation, to consider the 

 class of Birds as derived from the stock of Reptiles. 

 We are acquainted, at the present moment, with 

 a certain number of these links between orders and 

 even classes now quite distinct ; for example, between 

 the Amphibians and the Reptiles, and between the 

 Cystidea, on the one hand, and the Blastoids, the 

 Crinoids, and the Echinida, on the other. These 

 transitional types point out to us the road taken in 

 the development of life ; but we must not forget 

 that their number is exceedingly restricted, and 

 that the majority of the fundamental types of 

 the animal kingdom come before us without any 

 links between them from a palceontological point of 

 view. 



Should this absence of transitional forms be taken 

 as a decisive objection to the Darwinian theory ? 

 Neumayr does not think so, and strives to give in 

 various cases plausible explanations of these lacunae. 

 Thus we have not discovered the primitive type of 



