The two least significant bits in the first byte of a MAC address are the special flag bits that identify whether an address is:
Individual (0) or group (1)
Universal (0) or local (1)
Figure 2.2 shows the position of these important bits as they appear when each byte of a MAC address is written in binary with its most significant bit on the left.
This is the normal mathematical order in which the bits in a byte are expressed. See Appendix B.