Characteristics of Chondrichthyes
Chondrichthyes share many common characteristics among each other; their main defining feature is having a cartilaginous skeleton. Other features found in Chondricthyes include similar coloration patterns, placoid scales, pectoral fins, and ampullae of lorenzini. Coloration in Chondricthyes usually follows a lateral line where the ventral side of the body is lighter and the dorsal side is a darker. The pectoral fins in chondricthyes are found on the sides of the body. Placoid scales are small, sharp, and overlapping. Gill arches in sharks are located on the side of the body, whereas, rays and skates have gill arches on the ventral side of their body. The ampullae of lorenzi are distributed on the dorsal side and pectoral fins on rays and skates and on the head of sharks. The eyes are located on the sides of their head. Some Elasmobranchs are characterized by inward-facing teeth, arranged in rows, unattached to the jaws. Lastly, male sharks contain pelvic fins called claspers used for mating.
http://vertebrates.voices.wooster.edu/chondrichthyes/
Chondrichthyes share many common characteristics among each other; their main defining feature is having a cartilaginous skeleton. Other features found in Chondricthyes include similar coloration patterns, placoid scales, pectoral fins, and ampullae of lorenzini. Coloration in Chondricthyes usually follows a lateral line where the ventral side of the body is lighter and the dorsal side is a darker. The pectoral fins in chondricthyes are found on the sides of the body. Placoid scales are small, sharp, and overlapping. Gill arches in sharks are located on the side of the body, whereas, rays and skates have gill arches on the ventral side of their body. The ampullae of lorenzi are distributed on the dorsal side and pectoral fins on rays and skates and on the head of sharks. The eyes are located on the sides of their head. Some Elasmobranchs are characterized by inward-facing teeth, arranged in rows, unattached to the jaws. Lastly, male sharks contain pelvic fins called claspers used for mating.
http://vertebrates.voices.wooster.edu/chondrichthyes/