This paper classifies the abnormalities of the anterior chamber cleavage syndrome (mesodermal dysgenesis of the iris and cornea). The anatomic findings are arranged in a tabular stepladder fashion which builds from simple to more complex combinations, most of which have been previously known by eponyms. There are three groups of anomalies: 1) peripheral, 2) central, and 3) combinations of the two. 1) The peripheral anomalies consist of a prominent Schwalbe's ring, iris strands to Schwalbe's ring, and hypoplasia of the anterior iris stroma. Developmental glaucoma is commonly present. 2) The essential feature of the central anomalies is a defect in the corneal endothelium and Descemet's membrane with an overlying corneal opacity. Additional components include central iridocorneal adhesions, keratolenticular approximation with cataract, and scleralizaiton of the cornea. Chorioretinal anomalies, developmental glaucoma, and systemic malformations may be present. 3) Central and peripheral combinations may exist in the same eye, in both eyes of the same patient, or within the same family.