Lying in one corner of my room was a female spider who had mated and laid eggs into a sac. I took those eggs and kept few in a cavity slide and sealed it, the remaining eggs still being inside the egg sac kept on a watch glass.
You can see how one egg appears to be under foldscope. This egg is about 3 days old. One can make out some movements of the developing embryo on the 4th day.

After about few days this is how the egg looked. Or rather the thing inside it looked. You can make out some structures which are going to become the legs of the spider in future.

A bit more clear in 1-2 days later… the movements (clearly it seems to be the beating heart of embryo.

Two eggs adjacent to each other

Embryo development and organ formation ended after a total of 10-12 days from the day of egg laying. The image below seems to show a fully formed spiderling still inside the egg. Amazing how the egg changed its shape to accomodate the spiderling.

The thing I missed to capture, was what was on the 14th day. On looking at the watch glass, I saw barely 2-3 spiderlings remaining. All of them soon after getting out of their eggs, ran off in random directions. I went straight to my foldscope to inspect the slide. This is what I observed.

The legs of the spiderlings, the abdomen were all covered in fine hair or setae. Eyes were eight in number (was left amazed when I saw this!)
A view of the head (and four of its legs). There is a line present on its head (or rather the head and the thorax together called as the cephalothorax). This line is significant as it helps the spiderling undergo ecdysis and escape from its old exoskeleton. It is the line of ecdysial cleavage, called dorsal ecdysial line.
The image appears blue because of a filter I used in my phone.

A bit curious about the how many eyes would be present, I observed the slide under a phase contrast microscope. At 200x, this is what I saw that left me amazed : ) Eight eyes; clusters of three were present on either side and two eyes present median in position.

The spiderlings still inside the slide.

Ronak Hati,

UG student,

Ramnarain Ruia Autonomous College.