Figure B Back view of 40 million-year-old Mesohippus' Metacarpal (image) New York Institute of Technology Share Print E-Mail Caption Back view of 40 million-year-old Mesohippus' metacarpal. While three fully formed toes are visible, the researchers contend that ridges on the side of the toes represent the two missing digits, and that therefore, all 5 digits are expressed. Credit NYITCOM Usage Restrictions None Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.