Sorry for opening this topic again, but I've come to a theory why there is this empty space in the shell of the silt striders. I've seen one speculation saying that the empty space might have been an 'air sac' with the means of being some sort of trait for sixual attraction, like the comb with roosters or something like that. Well, what if it was actually used to breed the eggs, like with seahorses. Female silt striders could lay the firtilised eggs in the shell of the male, where the heat of his body would breed out the eggs. This evolution could have appeared because it was safer to carry the eggs instead of laying them on the ground (as silt striders are quite big and tall it would have been hard to protect them), and considering they are 'nomadic' (or migratory?) species it would also benifit them to carry the eggs and hatched larvae with them. When the larvae become too big the silt strider would sit down on the ground and the shell would open... thus revealing the soft inside. When a silt strider dies, the dunmer could have discovered this empty space in the shell and use it as a refuge.

I could think of a story on how the discovery of its use for transportation was made...: a velothi scholar was observing the hatching of silt strider nymphs (?) while hovering over the silt strider in labor by the means of a levitation spell. He was so focused on the observation that he forgot to recast his levitation spell and fell into the parental pod once all the nymphs had descended. The advlt strider was startled and in panique rose to his feet and started running. The scholar was unable to get out of the pod from this height so he was stuck. In an attempt to get the silt strider to his knees the scholar kicked the soft tissue of the fleshy bulk of the silt strider. It didn't do much harm to the creature, but it suddenly made a sharp turn to the left, almost throwing the scholar overboard. The smart scholar tried another part of the bulk and it turned right. For more precise control he tried some of his hairpins to press smaller areas. By nightfall he had gained complete control over the silt strider.

Well, so far my theory. What do you think? (please don't tell me someone came up with that same idea as well And also, I don't know if I was correct to use a velothi scholar, ah well, fantasy)

oh yes... if he had a levitation spell he just could have levitated out of the pod... so let's make it a levitation potion and he only had one!

Or perhaps building further on someone's theory that a silt strider might have been evolved from netches ... the silt strider nymphs might have kept the sac of gass (which I assume the netches use) to fly out of the parental pod and stay in the air untill their legs have become firm enough to walk. The sac of gass would then be depleted and turn into a hard exoskeletal abdomen? This way the silt strider doesn't even need to sit down on the ground, which would make the scholars desire to levitate above the silt strider in labor even more logical... it still would have been quite foolish of him to take just one rise potion with him, but yeah... scholar minds can be clouded from time to time...

Which could actually turn the evolutional theory around by stating that netch evolved from silt striders: some nymphs would lose their sacs much slower and remained safe in the air for a longer period so had more chance to survive and that way some silt striders would get selected with genes that cause abnormal long duration of maintaining the sac until the sac no longer disappeared and the legs would evolve into tentacles (for those 'flying silt striders' that could use them to catch things like we catch stuff with our feet and it would prove usefull to collect food from the ground without touching the ground and thus having again much more benefit to reproduce...)

Which leads to a next question: could the same (like done with silt striders) be done to bull netches (asuming they still reproduce the same way as silt striders with their pods) and used as flying transport?

It is actually stated in Morrowind that their shells are hollowed out by the Dunmer to make space for riders/cargo. The process also gives 'drivers' access to Strider brain matter and allows them to manipulate the creature's internal organs.

Ooh... I didn't read it that way. On TES Wiki it says 'cut away' instead of hallowed out, so I assumed that the empty space was already there. Also, that would make for a very thick shell Although my explanation is more spactacular, yours is probably the most logical one... although it still doesn't explain how they got the idea of doing it

Your theory about the origin of the hole in the shell may be wrong, but I like your idea of small, flying silt-larvae.