Complex sentence: Herla warns his remaining companions not to dismount until the dog alights, but the dog, Map says wryly, has not yet alighted, and Herla and his host have become eternal wanderers.
Split into simpler sentences: Herla warns his remaining companions not to dismount until the dog alights. But the dog, Map says wryly, has not yet alighted, and Herla and his host have become eternal wanderers.