User blog comment:John Alfred Hammond, CEO/Do we really know which Compies are which?/@comment-1791057-20130708042736/@comment-1791057-20130710214221

It has three digits, but the third is vestigial. Refer to Ostrom 1978 and Peyer 2006.

"Since there are no unmatched extra phalanges or claws, and it seems highly improbable that only corresponding elements would be missing from both hands, I conclude that there could only have been two functional digits in the hand of Compsognathus, plus a remnant (metacarpal) of a third, non-functioning digit. (Ostrom 1978).