Pink Cactus!

[MadCactus42]

Hi everyone! I am very VERY new at all this forum posting, but I'd like to know if anyone recognises this cactus.
I recently acquired it from a lady who said she didn't want it, along with 4 others- too dangerous for small children, she said. Got them for free!
Anyway, I got them home and realised that most of them were horribly overwatered (At least, that was my diagnosis from the Internet). With this one, the top had even gone rotten and hollow, so I cut all the rot off, and left it to dry/callous.
I've included pics of the cactus before and after beheading, so does anybody know what it actually IS?
I'm a very inexperienced cactus collector, so any tips on how to proceed from here would also be very greatly appreciated. I've never beheaded a cactus before!!!
Thanks,
MadCactus42

[greenknight]

It's a Mammillaria, maybe Mammillaria crinita subsp. zeilmanniana, but hard to be sure. The pink color is due to the rot, perhaps something the plant produces in defense. All you can do is let it dry out and hope.

[DaveW]

I think some of the Mamm's are naturally pink fleshed, so I don't think that is caused by rot. Rot would be brownish and also the vascular bundles look quite healthy. From the fact the pink is also showing between the tubercles it looks as if the plant is excessively turgid from overwatering as you say.

"Rapid Growth: Growing plants super fast via overwatering/fertilizing and/or grafting generally results in bloated plants. Because these plants generally are so water filled and the skin not as thick as normal, they are more easily affected by pathogens. Once a really bloated plant gets rot, it spreads a bit more quickly. You also run risks of splitting the plants, which leave a nice open target sign for nasties."

http://www.kadasgarden.com/Crot.html" onclick="window.open(this.href);return false;

viewtopic.php?t=12284" onclick="window.open(this.href);return false;

[MadCactus42]

Thanks for the fast replies!

Epic info- finally can put a name to this little chap!
I had no idea the pink outside was due to bloating either.
Thank you all again for the help- greatly appreciated!