One night in early May in northern Taiwan a strange looking spider carrying a large white "package" underneath itself ran in front of me and stopped, so I photographed it. The package is roughly the size and shape and color of a round dental floss dispenser that one would carry in one's pocket, perhaps a little smaller, about 2.5 cm in diameter.
I took some photos with a flash and without. The total span of the spider's legs was about 10 cm.
I'm guessing this would be an egg case, but it's surprisingly large, could it be prey? I suppose if a spider didn't have a home of any kind it would have to carry its meals with itself. It seems to be well adapted to this and moved quickly even with the large load.
Question: What kind of spider is this and what is it carrying underneath itself?