as though just caught in the Severn below, astonished him as much as though he had found Darwin himself. In the scale of evolution, one vertebrate was as good as another. For anything he, or anyone else, knew, nine-hundred-and-ninety-nine parts of evolution out of a thousand lay behind or below the Pteraspis. To an American in search of a father, it mattered nothing whether the father breathed through lungs, or walked on fins, or on feet. Evolution of mind was altogether another matter and belonged to another science, but whether one traced descent from the shark or the wolf was immaterial even in morals. This matter had been discussed for ages without scientific result. La Fontaine and other fabu lists maintained that the wolf, even in morals, stood higher than man; and in view of the late civil war, Adams had doubts of his own on the facts of moral evolution:
'Tout bien considéré, je te soutiens en somme,
Que scélérat pour scélérat,
II vaut mieux être un loup qu'un homme.'
It might well be! at all events it did not enter into the problem of Pteraspis, for it was quite certain that no evolution worth treating as proof of the principle, had occurred back to the time of Pteraspis, and that before Pteraspis was eternal void. No trace of any vertebrate had been found there; only starfish, shell-fish, polyps, or trilobites whose kindly descendents he had often bathed with, as a child, on the shores of Quincy Bay.
That Pteraspis and shark were his cousins, great-uncles or grand fathers, in no way troubled him, but that either or both of them should be older than evolution itself seemed to him perplexing; nor could he at all simplify the problem by taking the sudden back-somersault into Quincy Bay in search of the fascinating creature he had called a horse shoe, whose huge dome of shell and sharp spur of tail had so alarmed him as a child. In Siluria, he understood, Sir Roderick Murchison called the horse-shoe a Limulus, which helped nothing. Neither in the Limulus nor in the Terebratula, nor in the Cestracion Philippi, any more than in the Pteraspis could one conceive an ancestor, but, if one must, the choice mattered little. Cousinship had limits but no one knew enough to fix them. When the vertebrate vanished in Siluria,
