Assertion: vertebrate's organ | /r/HasProperty | unique
Facets:
value: to chondrichthyes
type: OTHER
Source sentences:
text: They have three specialized organs that are unique to Chondrichthyes; the epigonal organs (lymphoid tissue similar to mammalian bone) that surround the gonads, the Leydig's organ within the walls of their esophagus, and a spiral valve in their intestine.