Why aren't B.Th., B.Ed., Mus.B., B.Chir. or M.B. degree holders members of Cambridge's Senate? I don't understand the goal or reason behind B II 2 Degrees | Student Registry, but I'm even more addled by the boldened sentence below. Why aren't these undergraduate degree-holders members of the Senate? I know medicine (MB,BChir) is an undergraduate degree in the British Isles.

Holders of Postgraduate Certificates or the B.Th., B.Ed., Mus.B., B.Chir. or M.B. degrees are not thereby members of the Senate, so may still be able to receive a degree under Statute B II 2 if they are otherwise eligible and do not hold any Cambridge Masters degree or Doctorate. Holders of the LL.B. degree may become members of the Senate by having it formally re-designated as an LL.M., however, and all holders of the B.A. are entitled to the M.A. once they have held the B.A. for the required period.
To some extent, the answer is &quot;because the statutes and ordinances say so&quot;. However: these are not 'standard' Cambridge undergraduate degrees. If you go to Cambridge and study a 3-year undergraduate programme in theology, education, music or medicine, you will graduate with a BA degree. The listed degrees are/were awarded for specific, somewhat vocational, courses - for example, the BTh is a special two-year programme for people training for ordination.