Assertion: pit viper's pit | /r/CapableOf | line the upper
Facets:
Source sentences:
text: Most superficially, pitvipers possess one large pit organ on either side of the head, between the eye and the nostril (loreal pits), while boas and pythons have three or more comparatively smaller pits lining the upper and sometimes the lower lip, in or between the scales (labial pits).