Crypta Magna is the remnant of
Medial surface of each tonsil has 15-20 crypts, the largest of which is called Intratonsillar cleft or crypta Magna (which represents the persistence of the ventral poion of the second pharyngeal pouch)'.Ref: PL Dhingra, Diseases of Ear, Nose & Throat, 7th edition, pg no. 291
First Pharyngeal pouch
Second Pharyngeal pouch
Third pharyngeal pouch
Fouh pharyngeal pouch
Oral cavity & Oesophagus