Placements within the metazoan crown-group have been rebutted, and it is most likely that these peculiar organisms lie in the stem group to the animals.
With the advent of traps that incorporate a special pressure-maintaining chamber, undamaged larger metazoan animals have been retrieved from the deep sea in good condition.
This non-sentient material included higher plants, microorganisms, and the more degenerate metazoan endoparasites which, they argued, had nervous and sensory systems that were almost atrophied.
