The Pamphlet Collection of Sir Robert Stout: Volume 6
Sub-Order II.—Batoidei
Sub-Order II.—Batoidei.
Gill-openings ventral. In a few of the genera, which we place first, the habit is still that of the Sharks; but the body is depressed; and in the typical genera the trunk, which is surrounded by the immensely developed pectoral fins, forms a broad flat disk, with a thin and slender tail. Spiracles always present. Five pairs of gill-openings. No anal fin; dorsal fins, if present, on the tail. Temperate and tropical seas; some species pelagic; some entering fresh waters, or entirely limited to rivers within the tropics. Rays.