General:
In most, water for breathing taken in chiefly through the spiracle rather than the mouth (except for those living off the bottom);
Most give birth to live young (some have eggs encased in a horny capsule); the snout may function as an electroreceptive organ (as may be true for all elasmobranchs).
Gill openings ventral; anterior edge of the greatly enlarged pectoral fin attached to side of head, anterior to the gill openings; anal fin absent; eyes and spiracles on dorsal surface; anterior vertebrae fused to form a synarcual; suprascapulae of pectoral girdles joined dorsally over vertebral column and articulating with column of synarcual or fused with synarcual; nictitating membrane absent, cornea attached directly to skin around the eyes; body generally strongly depressed; jaws protrusible in most; teeth pavementlike;
In most, water for breathing taken in chiefly through the spiracle rather than the mouth (except for those living off the bottom);
Most give birth to live young (some have eggs encased in a horny capsule); the snout may function as an electroreceptive organ (as may be true for all elasmobranchs).
Gill openings ventral; anterior edge of the greatly enlarged pectoral fin attached to side of head, anterior to the gill openings; anal fin absent; eyes and spiracles on dorsal surface; anterior vertebrae fused to form a synarcual; suprascapulae of pectoral girdles joined dorsally over vertebral column and articulating with column of synarcual or fused with synarcual; nictitating membrane absent, cornea attached directly to skin around the eyes; body generally strongly depressed; jaws protrusible in most; teeth pavementlike;
