Found something weird at the bottom of my tank

[leafyseadragon]

I was topping off the tank this morning, and noticed something at the bottom of the tank near some base rock. There are two things which look like open but empty pods down there.

I guess they look like pistachio shells after the nut inside has been removed, just much smaller. Maybe about 1/4-1/2".

Anyone have any idea what these things are? My tank is cycling, so there is nothing in there but LR, base rock, and sand.

 

[reefrunner69]

Pods are crusteceans, just like other crusteceans, they molt as they grow, you are probably seing the molt

 

[leafyseadragon]

Can you point me to a web site with a picture of a live pod so that I know what to look for in the tank?