Alors en fait il s'agirait que non.
Alchemist, Tentacle/Vestigial Arm: What does "extra attacks" mean for these discoveries?
It means "extra," as in "more than you would be able to make if you didn't have that discovery."
For example, if you're low-level alchemist who uses two-weapon fighting, you can normally make two attacks per round (one with each weapon). If you take the tentacle discovery, on your turn you can make
* two weapon attacks but no tentacle attack,
* a weapon attack with your left hand plus a secondary tentacle attack, or
* a weapon attack with your right hand plus a secondary tentacle attack.
At no time can you make a left hand weapon attack, a right hand weapon attack, and a tentacle attack on the same turn because the tentacle discovery says it "does not give the alchemist any extra attacks or actions per round." This language is calling out that the tentacle is not a standard natural weapon and doesn't follow the standard rules for using natural weapons (which would normally allow you to make the natural weapon attack in addition to your other attacks).
Likewise, if you instead took the vestigial arm discovery and put a weapon in that arm's hand, on your turn you can make
* a weapon attack with your left hand and one with your right hand,
* a weapon attack with your right hand and one with your vestigial arm, or
* a weapon attack with your left hand and one with your vestigial arm,
At no time can you make a left hand weapon attack, a right hand weapon attack, and a vestigial hand weapon attack on the same turn because the vestigial arm discovery says it "does not give the alchemist any extra attacks or actions per round."
The exact same restrictions would apply if your race had claws or you had some other ability to add claws to your limbs: the text of both discoveries says they do not give you any extra attacks per round, whether used as natural weapons, wielding manufactured weapons, or adding natural weapons to a limb that didn't originally have natural weapons.
Remember that these two discoveries do not have any level requirements, and therefore are not especially powerful; permanently adding additional attacks per round is beyond the scope of a discovery available to 2nd-level alchemists.