Complex sentence: The upper register displays a row of three seated or squatting winged creature, rather monkey-like with human faces, long forearms, and long tails, These however are surely, if run-downs, descendants of the sphinxes on a goal beaker from Amlash.
Split into simpler sentences: The upper register displays a row of three seated or squatting winged creatures, rather monkey-like with human faces, long forearms, and long tails. These are perhaps descendants of the sphinxes on a goal beaker from Amlash.