What species do these 2 cacti belong to?

[arturo conan]

maybe it is difficult because they are very small

[Dave Adams]

I think the first is a mammillaria I don't know the species though and the second looks like echinopsis chamacereus. Hope that helps.

[petalka]

wouldn't be the first one a Thelocactus ?

[7george]

I also think this is Mammillaria: Thelocacti don't have felt and bristles between tubercles (axils).

[WayneByerly]

... and the second looks like echinopsis chamacereus.

I've an Echinopsis chamacereus (that is blooming like MAD) and while it does look SOMEWHAT the same to me (and this is just ME ... I'm not an expert) mine does not have any of the spiraling that this one does ... just a comment.

[Dave Adams]

I have E. (Chamacereus) Sylvestrii the red form but there are loads of cultivars, mine is kind of spirally too, seems quite long stems compared to some others I have but they vary from clone to clone.
Some Coryphantha look like Mammillaria whilst juvenile but I still think its a Mammillaria

[Dave Adams]

Could be a form of M. Compressa (f.Bernalensis)?

[Dave Adams]

More like f.Centralifera looking at Daiv's pics on here

[mikethecactusguy]

Second one sure looks like a Echinopsis chamaecereus. Peanut cactus.
IMO