I just wanted to say that I believe you're seeing it from a quite anthropocentrical standpoint. It doesn't make much sense to search for patterns like even or odd numbers of fingers or limbs.

In evolutionary terms, there is no reason at all why symmetry should be inconsistent - like 4 fingers on one hand and 5 on the other.

So, no matter where you search for inconsistencies, you will always find even numbers:

• 4 fingers x2 = 10
• 7 ribs x2 = 14
• 5 toes x2 = 10

The Eleven Armed Sea Star in @Oreotrephes' answer isn't much of an exception, it's just centrically symmetric.

I just wanted to say that I believe you're seeing it from a quite anthropocentric standpoint. It doesn't make much sense to search for patterns like even or odd numbers of fingers or limbs.

If evolutionary tends to result in bilateral symmetry, there is no reason at all why the symmetry should be inconsistent - like 4 fingers on one hand and 5 on the other.

Consistent bilateral symmetry will always result in even numbers:

• 4 fingers x2 = 8
• 7 ribs x2 = 14
• 5 toes x2 = 10

The Eleven Armed Sea Star in @Oreotrephes' answer isn't much of an exception to the rule of symmetry, it's just radially symmetric.