Question for the Hive Mind: Cactus IDs

I'm either sick or underslept to the point of feeling sick on Sunday evening as I write this, so I don't have it in me to write very much. I've had these photos for a long time, and have been meaning to go to CactiGuide.com or somewhere and try to come up with IDs so I could use them for List posts, but I never did. If you have a guess on any of them, leave it in the comments. Or keep it to yourself. Whatever.

I, meanwhile, am going to go to bed early and hope that I'm just tired. It doesn't feel like tired -- every joint and muscle is achy, I have a headache, my face feels hot, my eyes and mouth are dry -- but this has happened before, once or twice a year for several years, and if I'm sick, it's the kind of sick that twelve straight hours of sleep usually cures.

There will be a mashup this afternoon; I wrote that post already.

Cactus NOID no. 5.


Cactus NOID no. 6. (Cephalocereus sp.?) Espostoa lanata?


Cactus NOID no. 7; Ferocactus sp.


Cactus NOID no. 8.


Cactus NOID no. 9. (Gymnocalycium?) Echinopsis sp.


Cactus NOID no. 10.


Cactus NOID no. 11. (Mammillaria sp.?) Echinocereus sp.


Cactus NOID no. 12 (tagged Ferocactus sp.).


Cactus NOID no. 13. (Melocactus sp.?)


Cactus NOID no. 14; Mammillaria sp.


Cactus NOID no. 15, with fruit; Mammillaria sp.


Cactus NOID no. 16; Mammillaria sp.