I was observing this spider (caught in a Petri dish) under my microscope, when I noticed that a small, round object emerged from its rear end. It appeared to be black and white in appearance. I am guessing that it is an egg, but I am not sure whether it is one or not. The diameter of the object is approximately 300µm.
The spider seems to resemble Hasarius adansoni from photos:
The scale bars in the image are 5mm in length. The spider and the object are imaged together in the frame for scale.
Can anyone conclusively identify the spider and the object? The photo was taken in Singapore in November (although the seasons don't really matter in Singapore).