Judging by the short stalks, my theory is they are immature polyps. As you can see by my "babies", the stalks are just forming, the tentacles are short, and the polyps are still tan colored... unlike the adult polyps which have bright green centers. When the adult polyps are expanded, they should be about 1" across, with tentacles about 1/2" or more in length. There are times during the day when the polyps on mine will retract, usually for a short period late in the evening. If your polyps aren't extending at all, then something isn't just right. What kind of lighting do you have? How are your nitrate and phosphate levels? Have you tried feeding them frozen (thawed, of course) mysis shrimp?