Human Magus with the Favoured class of Magus can select a Favoured Class Bonus, Bonus Magus Arcane Pool, granting an Arcane Pool of 1/4 Arcane point (ARG P73).
Teifling and Suli Magus should also have access to the same favoured class bonus (ARG p170, p203), but currently PCGen won't allow Bonus Magus Arcane Pool on those races.
Pathfinder currently Released Supplements, Inner Sea World Guide, Carrion Crown Players Guide
As of 6.01.08 I can see two instances of this Favoured Class Ability. One for humans only, one for humans, suli and tieflings. Tested on Human lvl 1 Magus.
Also, Half-Elf is not listed on the other instance of that ability.
Line 573 is the catch-all ability.
Lines 650, 713, 876, 947 are the single-species versions of the same ability.