Their Sarcophagi are their phylacteries, they're resting there until the new body arrives, and they can reattach their spirits into a new corporeal form.
In other news, my fort has lost about 2/3 of it's population (Previously 150) to mass murder-age brought about by my Emerald Caterpillar of doom that slaughtered 2/3 of the military (yes, that number keeps repeating, it's freaking me out) almost all my useful legendaries are dead, my Mayor is a legendary bone carver, and my manager/bookkeeper is a s legendary stonecrafter. (Admittedly, with 60 jillion elephants to processes, bonecarving is a handy skill)
So now we're rebuilding, mostly it's just tables and so forth that need to be repaired, beds to be expanded, since it seems the tantrum spiral was exacerbated by the fact that they were set up in a dormitory. Almost all my miners are dead, since they got pimpslapped by my Captain of the guard before she was slaughtered herself and they went on a pickaxe murder spree. My Planter went around beating people to death, causing much of the initiating factors of the sorrow, which sucks since I had cages and forgot to set up a jail. I'm ignoring justice for now, since most of the useful still alive dwarves are murderers, if out of most likely self defense.
I managed to survive, I think, by Conscripting the still sane, not-pissed-off dwarves into impromptu doctors who ran through the melee dragging their comrades to safely while dodging bolts, pickaxes, and fists. Naturally, casualties were high, but most of them were migrants from earlier in that season so it's not a terrible loss, I managed to patch up enough to stabilize the population, and the death of most of the instigators led to the mood starting to calm down. Enough to start burying the dead anyways, so I rapidly started to throw bodies from the graveyard into proper coffins, not fast enough to prevent a lot of dwarves from going insane with grief, but enough to keep ghosts down to only a small child. I slab'd him into the afterlife and now aside from the mayor and manager screaming at each other everything seems to be getting ok.
Unfortunately, what I thought was an aquifer turned out to just be a pond, so the elaborate sewer I built to allow renewable, cleanable water to my hospital is completely useless.
I'm thinking of creating a new fort with an aquifer, I forgot how much of a hassle starting without one is. I like intricate and complicated water systems, so running a fully dwarf power fort is difficult. I like being able to recover functionality and run a fort with 20 dwarves where it would otherwise take 200. It makes life simpler when it all goes to hell. It also allows really awesome defense mechanisms, like toggleable defense systems, which can be taken down to run tests, or run repairs/modifications.