lating action of the pectorals. The great size, however, of these fins indicates that, on occasion, they can shoot along with great swiftness. They are very voracious, devouring any fishes that they can master, as well as crustacea, and shelled mollusca; the strong flat teeth, with which their jaws are paved, are able to crush to powder the stoutest shells of lobsters and crabs. Some of the species, especially those of tropical seas, grow to an immense size, and are ferocious in proportion to their dimensions. Specimens of the Cephaloptera have been seen twenty five feet in length, and thirty in breadth; and one was captured a few years ago at Barbadoes, which weighed three thousand five hundred pounds. Col. Hamilton Smith saw one of these monsters seize and carry down a man who was swimming in the sea near Trinidad.
About a hundred and thirty species are known to belong to this Family, all of which are marine. They are found in all seas, and the British coasts possess no fewer than sixteen. The following groups constitute the Sub-families of the Rays.
1. Rhinobatina. The Shark-rays. This form may be considered as almost equally partaking of the characters of the two Families whose names it conjointly bears. The body is much longer than broad, the tail is thick, and tapers gradually from the trunk; the snout is short and elongated. They mostly inhabit the Indian Ocean and the Red Sea.
2. Torpedinina. The Electric Rays. Here the tail is short and fleshy, but distinctly separated from the disk of the body, which is nearly
