THE CREATION OF SPECIES 



species of ostracoderms and several kinds of true 

 fishes. 



"The soft mud on the bottom of the pool was now 

 turned into a fine-grained, sandy limestone, and in 

 it the fossilized animals were preserved in the very 

 attitudes they had assumed when they ceased to 

 struggle out of the enclosure. One in its death 

 agony, had plunged into the mud with sufficient 

 force to remain there, head down, in a vertical posi- 

 tion. Others were arranged in horizontal series, 

 uniformly headed in a northeast direction. Their 

 heads were turned against a gentle current of water, 

 as was shown by the fact that the tops of all the ferns 

 were pointed in nearly the opposite direction." 



Some of these specimens were so well preserved 

 that the shape of the body and many details of its 

 external surface could readily be observed. More- 

 over, when the specimens -had been transported to 

 the laboratory and there laboriously cut into sec- 

 tions with the diamond saw, and the sections pol- 

 ished and varnished, the arrangement of the internal 

 organs was also revealed. And it is the study of 

 these specimens which leads Professor Patten now 

 to declare with much confidence that the ostraco- 

 derms were neither vertebrates nor invertebrates, 

 but a class intermediate between the two: "In fact, 

 the real missing links in the animal kingdom. The 

 posterior part of the body was membraneous and 

 decidedly fish-like in shape; but the contour of the 

 whole animal, especially the head, the natural ap- 

 pendages, the eyes, and the mode of locomotion, 

 were more like those of the marine scorpions. The 



175 



