**Cyril Walker **was a paleontologist and curator of fossil reptiles, amphibians, and birds at London's Natural History Museum.David Ward has contributed to many journals and books, and has amassed one of the world's most comprehensive collections of fossil shark and ray remains.

**Cyril Walker **was a paleontologist and curator of fossil reptiles, amphibians, and birds at London's Natural History Museum.David Ward has contributed to many journals and books, and has amassed one of the world's most comprehensive collections of fossil shark and ray remains.