The size of a painted crayfish must be decided by measuring, in a straight line--
(a) if its carapace is not damaged or missing--from the anterior mid-dorsal margin to the posterior mid-dorsal margin of the cephalothorax; or
(b) if its carapace is damaged or separated from its body--along the dorsal surface from the anterior margin of the first abdominal somite to the posterior margin of the sixth abdominal somite, when the tail is laid flat on a horizontal surface.