Reverse germination?

Hey all, I successfully germinated 6 out of 10 seeds from a reggie bag my friend gave me. This is really a trial run to get the feel of growing, but I'm doing a lot of reading as I go along and more questions arise. I left the 6 germinated seeds in soil for more than a week with only two of the plants sprouting up seedlings. Because I was curious, and only wanted to deal with 2 plants maximum anyways, I slowly moved layers of soil to find the seeds to see what had happened. All 4 of the ones that hadn't sprouted had withdrawn their germinated roots and were black seeds again with little white dots on the end of the seed. Anyone have any idea what this means? I think that the temp might not have been high enough, or consistent enough. Just curious, thanks for the help.

~~Be easy

I can't say for certain but it sounds like the taproot was ripped off when digging them out (or they just withered and you couldn't see them). I know nothing about your grow so wouldn't hazard a guess as to why.

Thanks, I'm pretty sure the taproots didn't come off when I was digging them out because when I plant the the seeds they had already cracked pretty far with the taproots coming. All these seeds were basically closed tight.