These fins have a concave front edge with rounded posterior corners. Like sharks, it has a boneless skeleton made of cartilage, a tough, elastic substance composed of collagenous and/or elastic fibers, cells, and a firm, gel-like substance called the matrix.
These fins have a concave front edge with rounded posterior corners. Like sharks, it has an unossified skeleton composed of cartilage, a resilient material made up of collagenous and/or elastic fibers, cells, and a firm, gel-like substance called the matrix.