In Greek mythology, Orthrus (Greek: Ὄρθρος , "Orthros") or Orthus (Greek: Ὄρθος , "Orthos") was, according to the mythographer Apollodorus, a two-headed dog who guarded Geryon's cattle and was killed by Heracles. He was the offspring of the monsters Echidna and Typhon, and the brother of Cerberus, who was also a multi-headed guard dog.
Orthrus and Cerberus both had more than one head each.
( z1 have :ARG0 ( z2 and :op ( z3 animal :name ( z4 name :op "Orthrus" ) ) :op ( z5 animal :name ( z6 name :op "Cerberus" ) ) :mod ( z7 both ) ) :ARG1 ( z8 head :quant ( z9 more-than :op 1 ) ) )