expansion in the full grown whale, the tail will considerably exceed twenty feet across.

The entire member seems a dense webbed bed of welded sinews; but cut into it, and you find that three distinct strata compose it: — upper, middle, and lower. The fibres in the upper and lower layers, are long and horizontal; those of the middle one, very short, and running crosswise between the outside layers. This triune structure, as much as anything else, imparts power to the tail. To the student of old Roman walls, the middle layer will furnish a curious parallel to the thin course of tiles always alternating with the stone in those wonderful relics of the antique, and which undoubtedly contribute so much to the great strength of the masonry.

But as if this vast local power in the tendinous