I completely agree with aggman as well. As a rule, we aquarists should not purchase livestock with which we are unacquainted and ill-equipped to manage. It is a terrible practice. And when it occurs, the reputation of our hobby suffers.
With that said, I stand by my decision. Here is my logic. Darby's received the creature by mistake. As such they were selling it for only 15 dollars. When I inquired as to what they were going to feed it, the reply was, "I don't know. They're really hard to keep. We'll probably just try some brine shrimp." Darby's is a business. They don't have time to perform an exhaustive search of the difficult to find research out there. So if it stayed at Darby's, it would probably starve to death. Further, it was cheap. So any novice, was just as likely to come in and take the poor thing home. They might think, "If it dies, so what. It was only 15 dollars." And if a someone with that mentality took it home, you can be pretty sure it would starve to death.
So I decided to attempt to keep it alive, not because I had to have it, but because if I'm successful the data I collect will further the hobby. I've started collecting data on water parameters, feeding regimen, and I'm taking notes on his behavior. I'm under no illusion that it will live. But it was doomed from the moment it was collected from the ocean. Maybe some good can still come of it.
Some of you might think that due to the law of supply and demand, my purchase will encourage Darby's to order more cromatulid crinoids (feather stars). I disagree. The employee that I spoke with told me that not much is known about them and, for that reason, they should probably stay in the ocean. I don't think they'll be ordering more until the probability of long-term survival is a little greater.
To those of you who provided me with information and links, many thanks. It was all very helpful. I've done a lot of research in the past couple of days and I've now got a plan. I'll keep recording data. I'll compile valuable resources I've found. And I'll keep everyone updated on my progress.