The hydatid of Morgagni is a cystic remnant of

Fallopian Tube Abnormalities:The fallopian tubes develop from the unpaired distal ends of the mullerian ducts. Congenital anomalies include accessory ostia, complete or segmental tubal agenesis, and several embryonic cystic remnants. The most common is a small, benign cyst attached by a pedicle to the distal end of the fallopian tube--the hydatid of Morgagni. Ref: William's Obstetrics; 24th edition; Chapter 3