Ray fish. Coloured X-ray of a male ray, Raja sp., seen from below. The front is at lower left with the two oval nasal openings (green) just in front of the B-shaped mouth. Further back on the head are the feathery gills (yellow/green). The intestines (red & yellow) are at the back of the body on either side of the vertebrae. The vertebrae also form the ray's tail. Behind the intestines on either side of the body are claspers (yellow) which the male uses to transfer sperm to the female during mating. The large pectoral fins at upper left and lower centre move the ray by wave-like flaps. Rays are cartilaginous fish which live on the bottom of shallow to deep water.