Upon swallowing the earthworm, the worm instantly regains sight due to the exposure to blood. It the burrows into your stomach tissue and lays eggs which will continue to come out in your faeces till you die.
Well, it's the stomach because the food we eat is temporarly stored. And that's what happens when an earthworm eats food, it's temporarly stored in the crop. So in other words the "stomach" is similair to the crop.
An earthworm - (arethari Wormitus) has a different number of stomachs depending on its age, gender and size. For instance a long, male worm aged 20 years or more will have on average, 28 stomachs. However a young, female worm sized 3 inch or less will most defiantly have only 1 stomach.
An earthworm and all insects are invertebrates because they lack an internal skeleton, especially because they don't have a backbone. Well to tell you an earthworm is an invertebrate. An earthworm is an invertebrate.