Excretory structure in Saccoglossus is
coxal gland
proboscis gland
renette gland
green gland
Hemichordates have proboscis gland in the proboscis for excretion.
Renette gland - Aschelminthes
Coxal gland - Arthropoda (Arachnida)
Green gland - Arthropoda (Crustaceans)